Memoir

COLLEGE OF AGRICULTURE ANIMAL SCIENCE
AND VETERINARY MEDICINE (CAVM)
SCHOOL OF AGRICULTURE RURAL
DEVELOPMENT AND AGRICULTURE
ECONOMICS
DEPARTMENT OF CROP SCIENCE
Presented by:
Jean Baptiste NDAHIMANA
Ladislas NIYIRAGIRA
A dissertation submitted for the partial fulfillment of the requirement for the Bachelor’s
degree (A0) with Honor in Crop Production.
Supervisor:
Dr.Nyamangyoku Ishibwela Obedi, PhD
Academic year: 2015-2016
Busogo, May 2016
TOPIC: Evaluation of Genetic Compatibility between Different
Cultivars of Irish Potato in Rwanda

DECLARATION
We, Jean Baptiste NDAHIMANA and Ladislas NIYIRAGIRA declare that our
research project entitled, “Evaluation of Genetic Compatibility Between
Different Cultivars Of Irish Potato In Rwanda” under supervision of Dr.
Nyamangyoku Ishibwela Obedi, PhD is original and has not been submitted or
published for any other degree award to any other Institution or University .
Jean Baptiste NDAHIMANA
Date......................................... Signature...........................................
Ladislas NIYIRAGIRA
Date.......................................... Signature.........................................
Supervisor:
Dr. Nyamangyoku Ishibwela Obedi, PhD
Date.......................................... Signature..........................................

DEDICATION
This work is dedicated to:
Almighty God,
Our Parents,
Our Brothers and Sisters,
Our friends and Classmates,
All who in one-way or another have helped in
our studies!

ACKNOWLEDGEMENT
Unlimited thanks for God, the greatest and almighty, on his uncountable and infinite graces,
guided us to complete this work. We would like to express our deepest thanks, gratitude and
deep appreciation to Dr. Nyamangyoku Ishibwela Obedi, PhD for suggesting the problems,
supervision, continued assistance,Guidance, encouragement, following the progress of the work
with great interest and continuous criticism during the preparation and finalization of the present
work. This helped us to complete the work and present it in this form. We wish to express our
sincere appreciation and deep gratitude to Dr.Athanase NDUWUREMYI and Mr.Theophile
from RAB Musanze, for his directing, materials, continuous encouragement, and valuable
advices for this work.Deep thanks for Mr.Donatien MUNYAMAHORO, Laboratory technician
in UR-CAVM Busogo campus, for his assistance, continuous support for practical parts of this
research work and constant helping during data collection in green house.

TABLE OF CONTENTS
DECLARATION .....................................................................................................................................i
DEDICATION.......................................................................................................................................iii
ACKNOWLEDGEMENT ......................................................................................................................iv
TABLE OF CONTENTS.........................................................................................................................v
LIST OF TABLES ................................................................................................................................vii
LIST OF FIGURES.................................................................................................................................8
LISTE OF APPENDICES .......................................................................................................................9
ACRONYMS AND ABREVIATIONS ...................................................................................................x
ABSTRACT...........................................................................................................................................xi
CHAPTER ONE: INTRODUCTION ....................................................................................................xii
1.1. Background ................................................................................................................... xii
1.2. Problem statement .........................................................................................................xiv
1.3. OBJECTIVES OF THE STUDY ....................................................................................xv
1.3.1. General Objective ................................................................................................................ xv
1.3.2. Specific objectives ............................................................................................................... xv
1.3.3. Hypothesis ........................................................................................................................... xv
1.3.4. Justification of study ............................................................................................................ xv
CHAPTER TWO: LITTERATURE REVIEW......................................................................................xvi
2.1. Historical of Irish potato in Rwanda...............................................................................xvi
2.2. Classification and General Description ..........................................................................xvi
2.2.1. Classification .......................................................................................................................xvi
2.2.2. Botanical description............................................................................................................xvi
2.3. Crop ecology ............................................................................................................... xvii
2. 4. General Description ................................................................................................... xviii
2.5. Geographical Distribution...............................................................................................xx
2.5.1. Origin and history of introduction..........................................................................................xx
2.5.2. Native range..........................................................................................................................xx
2.5.3. Introduced range ...................................................................................................................xx
2.5.4. Habitat.................................................................................................................................xxi
2.6. Biology..........................................................................................................................xxi
2.6.1. Reproductive biology ...........................................................................................................xxi

2.6.2. Breeding and seed production..............................................................................................xxii
2.6.3. Breeding potatoes...............................................................................................................xxiii
2.7. Cultivation and use as a crop........................................................................................xxiv
2.8. Means of movement and dispersal ................................................................................xxv
CHAPTER THREE: MATERIALS AND MEHODS.......................................................................... xxvi
3.1. Site Description ...........................................................................................................xxvi
3.2. MATERIALS ..............................................................................................................xxvi
3.2.1. Cultivars used ....................................................................................................................xxvi
3.2.1.1. Agronomic Characters of Cultivars Used .....................................................................xxvi
3.3. Fertilizers used.............................................................................................................xxix
3.3.1.Weeding and earthing-up ....................................................................................................xxix
3.3.2.Diseases and pest control....................................................................................................xxix
3.4. Equipments:.................................................................................................................xxix
3.5. METHODS...................................................................................................................xxx
3.5.1. Experimental design layout .................................................................................................xxx
3.5.2. Procedure used during crossing ..........................................................................................xxxi
3.5.3. Observed parameters......................................................................................................... xxxii
3.5.4. Statistical analysis............................................................................................................. xxxii
CHAPTER FOUR: RESULTS AND DISCUSSION.........................................................................xxxiii
4.1. Growth parameter ..................................................................................................... xxxiii
4.1.1. Germination Rate............................................................................................................. xxxiii
4.1.2. Height.............................................................................................................................. xxxiv
4.1.3. Number of tillers.............................................................................................................. xxxvi
4.2. Reproductive parameters...........................................................................................xxxvii
4.2.1. Flowers........................................................................................................................... xxxvii
4.3. Yield parameters............................................................................................................. xl
4.3.1. Number of Tubers ................................................................................................................. xl
4.3.2. Yield per plot ....................................................................................................................... xli
CONCLUSION AND RECOMMENDATIONS..................................................................................xliii
REFERENCES....................................................................................................................................xliv
APPENDIX..........................................................................................................................................xlv

LIST OF TABLES
Table 1.Results of experimental crosses between four varieties in Experiment I....................xxxix

LIST OF FIGURES
Figure 1.Germination Percentage for experiment I ................................................................xxxiii
Figure 2.Germination Percentage for experiment II ...............................................................xxxiv
Figure 3.Plant height varies in different days after sowing for Experiment I ...........................xxxv
Figure 4.Plant height varies in different days after sowing for Experiment II..........................xxxv
Figure 5. Number of tillers due to Four Varieties for Experiment I........................................xxxvi
Figure 6.Number of tillers due to Four Varieties for Experiment II.......................................xxxvii
Figure 7.Number of Flowers due to Variety for Experiment I..............................................xxxviii
Figure 8.Number of Flowers due to Variety for Experiment II.............................................xxxviii
Figure 9.Number of tubers due to Variety for Experiment I........................................................xl
Figure 10.Number of tubers due to Variety for Experiment II....................................................xli
Figure 11.Yield due to four Varieties for experiment I ..............................................................xli
Figure 12. Yield due to four Varieties for experiment II ........................................................... xlii

LISTE OF APPENDICES
Appendix 1. Photos of Gikungu.............................................................................................................45
Appendix 2. Photos of Victoria..............................................................................................................45
Appendix 3. Photos of Mabondo...........................................................................................................45
Appendix 4. Photos of Kirundo .............................................................................................................45
Appendix 5.Period of activities plan ......................................................................................................45
Appendix 6.Germination Percentage......................................................................................................46
Appendix 7. Germination Percentage for experiment II..........................................................................46
Appendix 8.Height due to varieties for 45DAS By Experiment No
1 .......................................................46
2 .......................................................46
Appendix 10.Number of Tillers by Experiment No
1...............................................................................46
Appendix 11.Number of Tillers By Experiment No
2 ..............................................................................46
Appendix 12.Number of flowers By Experiment No
1.............................................................................47
Appendix 13.Number of flowers By Experiment No
2.............................................................................47
Appendix 14.Number of tubers By Experiment No
1...............................................................................47
Appendix 15.Number of tubers By Experiment No
2...............................................................................47
Appendix 16.Yield due to Varieties for experiment I .............................................................................47
Appendix 17.Yield due to Varieties for experiment II ............................................................................47

ACRONYMS AND ABREVIATIONS
PNAP: Programme National d’Amélioration de la Pomme de terre,
FAO: Food and Agriculture Organization
NGOs: Non Governmental Organizations
OECD: Organisation for Economic Co-operation and Development.
DNA: Deo xyribo Nucleic Acid
SNS: Service National des Semences,
ISAR: Institut des Sciences Agronomiques du Rwanda
UR-CAVM: University of Rwanda,College of Agriculture Animal Sciences and Veterinary
Medicine
MINAGRI: Ministry of Agriculture
TPS: True Potato Seed
PH: Hydrogen Potential
DRC: Democratic Republic of Congo
0
C: Degree Celsius
DAS: Days after Sowing
RAB: Rwanda Agriculture Board
CIP: Crop Intensification Program
Kg: Kilogram
G%: Germination Percentage
CRD: Completely Randomized Design
Gy: Gamma Rays
Ha: Hectare

ABSTRACT
This study was carried out in Green house of UR-CAVM, Busogo campus where used four
varieties brought from RAB Musanze. The objective was to evaluate genetic compatibility
between different cultivars of Irish potato in Rwanda, two experiments in different seasons with
target to get berries after crossing were performed, but due to heavy rains they doesn’t achieve
by the first experiment all the crosses made failed and fall down. the process was repeated at the
end of February up to may 2016, there is special findings Noted and discussed during these two
experiments in this study; it was observed that there were some good features of Irish potato used
like to bear high number of flowers even if all crosses made didn’t succeed for bearing berries
because of incidence of heavy rains caused them fall down all of two experiments. In comparison
of both experiment I and II; Based on considered parameters of emergence rate, number of
tillers, plant height at 15 DAS; at 30 DAS and 45 days after sowing; number of flowers/plant
and variety number of tubers, yield/ha per plot or variety. It was noticed that varieties used in
experiment I was highly effective and significantly differently from experiment II. During the
first work, synthetic fertilizer were not applied for management of Nitrogen quantity in soil
which may prevent plant from flowering. For the second experiment, fertilizes (animal manures,
NPK and Urea) were used and stolons were removed, but flowers were not significant
compared to the first experiment. Further researchers may work also on the following vegetative
parameters: Growth Vigor, Diseases and pests’ resistance, Success rate of crossing, number of
berries (seeds), number of seeds and yield parameters like size of tubers.

CHAPTER ONE: INTRODUCTION
1.1. Background
Irish Potato (Solanum tuberosum L.) ranks as the most important food crop in the world after
rice, wheat and maize (Akkale et al., 2010). Improvement in Irish potato crop is essential as it is
one of the most important cash crops of different countries. It is widely cultivated over an area of
2024.9 thousand hectares, with an average yield of 18.1 tons per hectare (Anonymous, 2009).
Because of nutritional value and broad adaptability, its consumption is increasing day by day.
Unfortunately, potato production developing countries is much lower than the other potato
growing countries because of the low yield of the adapted varieties. A narrow genetic base of the
germplasm used for development of cultivars is another reason for the low yield of potato
varieties grown in this region. Kenya is the fifth biggest potato producer in sub-Saharan Africa,
with 790.000 tones .Furthermore, the crop is an important food and cash crop in the medium and
high rain fall areas where 500.000 farmers are cultivating 108.000 ha with an annual production
of over 1 million tonnes in two growing seasons. In this region especially in Rwanda, the Irish
potato production is deal with different constraints like: soil acidity, low application of
fertilizers, limited use of certified seeds, inadequate use of fungicides and other synthetic
products (J.Muthoni and D.O. Nyamongo, 2009)
Knowledge about germplasm diversity and genetic compatibility among potato germplasm could
be a valuable aid in crop improvement strategies. A number of methods are currently available
for analysis of genetic diversity in germplasm accessions, breeding lines and segregating
populations. These methods have mostly relied on pedigree data, morphological data, agronomic
performance data, biochemical data, and molecular (DNA-based) data (Mohammadi and
Prasanna, 2003).
Irish potato crops were first introduced in Rwanda at the beginning of the 19th
century and are
now being cultivated throughout Rwanda, particularly in the northern provinces of Ruhengeri
and Gisenyi where rainfall and soil conditions are favorable. Since the mid-1970s, when
transport and infrastructure developed, marketing potatoes for urban consumption has taken on a
new importance. In 1979 the Government of Rwanda initiated a national programme to improve

potato production (Programme National d’Amélioration de la Pomme de terre, PNAP) that
concentrated on the development and dissemination of improved varieties.
Unfortunately, the civil war in 1994 damaged the country’s infrastructure and potato production
was seriously affected. But since 1999, both FOs and NGOs have initiated activities to rebuild
both the physical and knowledge infrastructure. However, the potato production and marketing
chain is still facing serious problems, such as insufficient production and poor quality of seed
material, the lack of storage facilities, and other management inefficiencies.
The Ruhengeri and Gisenyi provinces are situated in the northwest of Rwanda at the frontiers
with Uganda and the Democratic Republic of Congo. Population density is high, at more than
500 habitants/km2
, and agricultural activities provide 90% of the population with income. Agro-
ecological situations are very diverse and include rich soils derived from the volcanic chain.
Policies for promoting potato production initially targeted the volcanic soils where yields (at
approximately 110 kg/are) are twice that of other soils. Potato production also spread to other
zones because local urban markets developed over time and smallholders easily adopted crop-
production techniques. A survey of potato producing farmer households indicated that up to 85%
of the farmers rent and own land (<3 ha). They rely heavily on family labor forces, get income
from selling surplus production and renting out labor, invest in renting and buying land, and all
have small cattle, while some also have large cattle.29 Most of the potato crop is marketed
(around half of the smallholders’ production), some is consumed (around one quarter) and the
remainder is kept for seed (another quarter).
The national agricultural research institute (Institut des Sciences Agronomiques du Rwanda,
ISAR) has long experience in breeding high-yield potato varieties that are resistant to pests, and
in producing quality ‘breeder’ seeds. With donor support, the Ruhyengeri research station built
new greenhouses for improved potato seed production and relaunched on-station and on-farm
trials. The national seed service (Service National des Semences, SNS) is the next operator in the
seed chain; using improved seed material from ISAR it produces foundation seed for further
multiplication by producers. SNS provides technical support to these producers and supervises
certification of registered potato seeds.

According to an extensive survey34, potato producers face numerous problems relating to
production and storage that affect both the yield and quality of potatoes.
They feel that the technologies offered by research and extension services are dated in terms of
soil and water conservation measures, potato varieties, organic fertilizer production techniques,
and chemical fertilizers. This research will be focused to the evaluation of genetic compatibility
between different Irish potato cultivars in Rwanda; we shall recommend others researcher to
continue the process in the way of overcoming the problem of high yield potato seeds and
disease resistance varieties in Rwanda (Mabondo, Kirundo, Gikungu and Victoria).
1.2. Problem statement
The availability of high quality and of high yielding Irish potato seeds which are free and
resistant from diseases still major constraint in the production of this crop in Rwanda generally
and in Busogo sector Particular, where farmer’s level to understand the use of selected and
improved seed still problem. There is a speculations and the scarcity of the high quality seeds at
planting time where available seeds are genetically weak and very sensitive to drought, pests and
disease problems for farmers in different cultivated regions .The current used seed is reported to
be susceptible two diseases: late blight (Phytophtora infestans) and bacterial wilt(Pseudomonas
solanacearum). Based on these problems, the research was conducted at UR-CAVM, Busogo
sector, Musanze District, Northern Province Rwanda in order to start long term process of
improving Irish potato seeds into availability of high quality seeds, increase the awareness of
farmers in this region about the agricultural practices and improve Irish potato production though
breeding. This research was focused to the evaluation of genetic compatibility between four
cultivars of Irish potato in Rwanda; because of the time limit others will continue the process in
long term that will contribute to overcome the problem of potato production and disease
resistance varieties in Rwanda.

1.3. OBJECTIVES OF THE STUDY
1.3.1. General Objective
The main objective of the study was to evaluate the genetic compatibility between four cultivars
of Irish potato in Rwanda.
1.3.2. Specific objectives
 To study Irish potatoes life cycle stages especially flowering stage
 To evaluate compatibility of cultivated varieties though different crosses
 To develop and evaluate berries sustainability and health of Irish potatoes for further
steps in the near future activities.
1.3.3. Hypothesis
For achieving our objective, the following hypothesis were identified and considered:
 There is a significant genetic compatibility between all potato cultivars
 There is genetic compatibility between some potato cultivars
 There is no genetic compatibility in all potato cultivars
1.3.4. Justification of study
In this research, we are crossing flowers (genetic materials) of four potato varieties, by these
crosses, we expected to get berries with new traits from different parents who will be providing
new improved seeds for high yield and disease resistance at the end of this breeding project will
be done in long term. And finally we will have the wonderful potato varieties which are reputed
to be one of the best flavored potatoes around. Those will be productive, delicious and resistance.
We were supposed to analyze, how quickly resistance to beetle and blight accumulate a multi-
gene durable resistance. It will not break down to new races of blight fungus in the way single-
gene resistances do. True potato seed-will be harvested from the berries that grown among the
foliage of potato plants.
Each plant can produces dozens of berries, each of which contains hundreds of tiny seeds,
similar in appearance to tomato seed, which can be used by other researchers in the following
stages. This research shall help in food security improvement in actual subsistence farming.

CHAPTER TWO: LITTERATURE REVIEW
2.1. Historical of Irish potato in Rwanda
The potato introduced in Rwanda by German soldiers and Belgian missionaries in the early 20th
century. Today, Ibirayi Byavuye Iburayi (That’s mean: “Potatoes are from Europe”).potatoes are
second most important crop after plantains and, in the sub-Sahara region, Rwanda is the third
largest producer ( ISAR, 2004).
Since 1961, Rwanda’s potato output has risen from less than 100 000 tones to 1.3 million tonnes
in 2005. The harvest in 2007 was only smaller. Potatoes grow well in several parts of country
mainly with elevation above 1 800m and some areas do intercropping .Most of small farmers
consist that intercrop of potato with beans and maize, and yield average almost 10 tonnes per
hectare (ISAR,2004). The potato underpins food security in Rwanda; annual consumption is very
high with 124kg per person.
2.2. Classification and General Description
2.2.1. Classification
Irish potato (solanum Tuberosum.L) is spermatophytes belong to the class of dicots, order of
solanales, solanaceae family. Irish potato is tetraploid (2n=48) and is the best known species of
the genus (Theorez, 2000).
2.2.2. Botanical description
The potato, (Solanum Tuberosum), is a member of the nightshade family. It is closely related to
tobacco, the tomato and the eggplant. In the same family are found certain poisonous plants.The
potato is treated as annual crop. The tuber is an enlarged underground stem produced at the end
of stolon and not on the proper roots. Some varieties of potato produce true seeds frequently,
whereas other seldom produce them, but the chief mode of propagation is by means of tubers.
The tubers bear buds or eyes that are arranged in a more or less spiral form. They vary greatly in
number and depth, according to the variety. They are more numerous on the bud end.

Roots
The roots of potato Plants are rather extensive. It has been found that at blossoming time roots
meet from plants spaced 3 feet apart each way. Some roots penetrated the soil to a depth of 18
inches, although the main growth was within 8 inches of the surface. More over the root growth
was with 2or 3 inches of surface between rows. Roots of some varieties have been observed to a
depth of 3 feet.
Flowers
The flowers of the potato plant are in terminal clusters, each flower normally has five stamens
and a two celled pistil and sometimes seeds are formed. The fruit or seed ball is around, has a
diameter of about 3/8 inch, and possesses a structure similar to that of the tomato.
The flowers are cross fertilized, and that reason when the true seeds are planted, the resulting
progeny may be different from the immediate.
2.3. Crop ecology
Temperature
Potato is hardly crop that well resist to relative coldness (20
C) and warmth. Excess temperature
destroys it, when it is accompanied with dryness. Optimum temperature is 15 to 250
C
(MINAGRI, 2002) .It greatly influences the type of growth. High temperatures stimulate the
growth of stems, whereas the low temperatures favor the growth of tubers.
Potato is very sensitive to frost. The zero vegetation is between 6 and 80
C .A soil temperature
above 250
C is unfavorable to the tuber formation. (Ahmed, 1996). A high temperature above
290
C disrupts the tubers formation and cause regrowth. Tubers may freeze from the moment the
temperature gets below about -20
C (Rousselle et al, 1996).
Rainfall
The soil moisture content must be maintained at a relatively high level. For best yield, a 120 to
150 days crop requires from 500to 700 mm of water (FAO, 2008). In general, water deficits in
the middle to late part of the growing period tend to reduce yield more than those in the early
part. In Rwanda, rainfall ranges from 500-600 mm (MINAGRI, 2002)

Sunlight
Generally for all green plants, potato requires sunlight for growth and photosynthesis to take
place. Vegetative growth of potato is favored by high day length between 14to 18h. A
photoperiod of less than 12 hours promotes tuberization. The effect of long day can be mitigated
by low temperatures. (Ahmed, 1999).
Soil
The potato can be grown almost on any type of soil, except saline and alkaline soils. Naturally
loose soils, which offer the least resistance to enlargement of tubers, are preferred, and loamy
and sandy loam soils that are rich in organic matter, with good drainage and aeration, are the
most suitable. Soil with a pH range of 5.2 to 6.4 is considered ideal (FAO, 2008) In Rwanda,
potatoes are grown on soil which is rich and fresh with good aeration (MINAGRI, 2010).
The excessive alkalinity of soil can cause the development of common scab on tubers. The
potato is relatively tolerant to salinity compared to other vegetable crop. However, a high salt
concentration can block the absorption of water by the root system. When the salt content is
high, wilting point is reached early. It can reduce the salinity of the soil by leaching with fresh
water irrigation (Ahmed, 1999).
2. 4. General Description
Solanum tuberosum is a herbaceous plant that grows to 0.4-1.4 m tall and may range from erect
to fully prostrate (Spooner and Knapp 2013). Stems range from nearly hairless to densely hairy
and may be green, purple, or mottled green and purple. Leaves are pinnate with a single terminal
leaflet and three or four pairs of large, ovoid leaflets with smaller ones in between (Spooner and
Knapp 2013; Struik 2007). The blades range in size from 8-22 x 5-13 cm with the petioles
ranging from 2-6 cm. Tubers, spherical to ovoid in shape, is swellings of the rhizome. The flesh
of the tubers varies in colour from white to yellow to blue and the skin varies from white through
yellow to tan and from red through blue.
The colour of the flesh may or may not correspond to the colour of the skin. The texture of the
surface may vary from smooth to netted or russetted (Spooner and Salas, 2006). On the surface

of the tuber are auxiliary buds with scars of scale leaves that are called eyes (Struik, 2007).
When tubers are planted, the eyes develop into stems to form the next vegetative generation.
The terminal inflorescences are cymes that are 5-11 cm long and generally found in the distal
half of the plant (Spooner and Knapp 2013; Struik 2007). The inflorescences are usually
branched and may contain up to 25 flowers. The peduncle is 0-22 cm long and the pedicels are
10-35 mm long in flower and fruit, spaced 1-10 mm apart.
The pentamerous flowers, 3-4 cm in diameter, are all apparently perfect with styles of the same
length (Sleper and Poehlman 2006; Spooner and Knapp 2013). The corolla may be a range of
colours, including white, pink, lilac, blue, purple, and red-purple. The colour may be uniform or
the pointed tips of the petal lobes may be white or there may be a second colour either stippled,
in bands or in a star, and this may occur on either side of the corolla (Spooner and Knapp 2013).
The petals are fused to create a tubular flower (Sleper and Poehlman 2006). The stamens have
filaments that are 1-2 mm long and anthers that are 3-8 mm long (Spooner and Knapp 2013). The
anthers form a cone-shaped structure through lateral joinings, serving to conceal the ovary
(Struik 2007). They are typically bright yellow or orange with the exception of male-sterile
plants in which the anthers are light yellow or yellow-green (Sleper and Poehlman 2006). The
style is 9-13 mm by approximately 1 mm (Spooner and Knapp 2013).
The fruits are spherical to ovoid berries, about 1-4 cm in diameter. They are green or green
tinged with white or purple spots or bands when ripe (Spooner and Knapp 2013; Spooner and
Salas 2006). The berries may lack seeds or contain up to several hundred (Bailey and Bailey
1976). The seeds are ovoid and approximately 2 mm long. They are whitish to greenish when
fresh and brownish when dry. The lateral walls of the testa are thick and "hair-like" and cause the
seeds to be mucilaginous when wet (Spooner and Knapp 2013). Some cultivars may exhibit
premature dropping of floral buds, male sterility, and/or inability to set fruit (Gopal 1994). The
berries are toxic due to the presence of glycoalkaloids (Bailey and Bailey 1976).

2.5. Geographical Distribution
2.5.1. Origin and history of introduction
Solanum tuberosum ultimately traces its origin to Andean and Chilean landraces developed by
pre-Colombian cultivators. These landraces exhibit tremendous morphological and genetic
diversity and are distributed throughout the Andes, from western Venezuela to northern
Argentina, and in southern Chile. The wild species progenitors of these landraces have long been
in dispute, but all hypotheses centre on a group of approximately 20 morphologically similar
wild species referred to as the Solanum brevicaule complex (Correll 196; Grun 1990; Miller and
Spooner 1999; Ugent 1968; van den Berg et al. 1998).
The first record of S. tuberosum subsp. andigena outside South America was in the Canary
Islands in 1567 (Hawkes and Francisco-Ortega 1993; Ríos et al. 2007), and shortly thereafter in
continental Spain in 1573 (Hawkes 1990; Hawkes and Francisco-Ortega 1992; Romans 2005).
Forms of the introduced S. tuberosum subsp. andigena were adapted to the longer day lengths
and climate of European latitudes through selection (OECD 1997). These converted forms are
known today as S. tuberosum subsp. tuberosum (or S. tuberosum).
From Europe, S. tuberosum was transported to North America. S. tuberosum may first have been
transported from England to Bermuda in 1613 and then from Bermuda to the North American
mainland in 1621, a hypothesis favoured by Laufer (1938) and Hawkes (1990). S. tuberosum
was present in India by 1610 and mainland China by 1700 (Sauer 1993). S. tuberosum was taken
to New Zealand in 1769 by Captain Cook and gained agronomic significance for the native
Maori by 1840 (Sauer 1993). Missionaries may have played a crucial role in the distribution of S.
tuberosum from Europe throughout the world (Laufer 1938; Sauer 1993).
2.5.2. Native range
South America Argentina, Chile, Venezuela
2.5.3. Introduced range
Solanum tuberosum ranks as the world's fourth most important food crop, behind maize, rice,
and wheat (FAO 2014). It is cultivated worldwide in over one hundred countries throughout
Africa, Asia, Australia, Europe, and North and South America (USDA-ARS 2014).

Landrace populations introduced in post-Colombian times are still maintained out of their natural
range in Mexico and Central America, the Shimla Hills of India, and in the Canary Islands
(Spooner and Knapp 2013). S. tuberosum is very rarely known to escape cultivation (Simon et al.
2010).Canada is one of the largest potato producers in the world, with production calculated at
over 4.5 million metric tonnes in 2012 (Statistics Canada 2012).
2.5.4. Habitat
Solanum tuberosum rarely exists as a wild plant other than as a volunteer (Burton 1989; Simon et
al. 2010). S. tuberosum is cultivated around the world, although in the tropics it is grown in the
cool highlands, typically at elevations over 1000 m, and in the subtropics it is grown during the
cooler winter, autumn, and spring seasons or at mid-elevations (Hijmans 2001). S. tuberosum
grows best in cool climates, with higher temperatures favoring foliar development over
tuberization (Haverkort 1990). S. tuberosum is not frost tolerant and will be killed at
temperatures of -3°C or lower (Li 1977). It can grow in a range of soil types, but is sensitive to
drought stress and therefore can only be cultivated where there is adequate rainfall or the ability
to irrigate (Bohl and Johnson 2010; Haverkort 1990). Differences in tolerance to frost and
drought occur within the species. Thus, cultivars have been selected with greater adaptation to
these stresses.
2.6. Biology
2.6.1. Reproductive biology
Solanum tuberosum is a perennial . The commercial crop is propagated vegetative using tuber
pieces or small whole tubers that are commonly referred to as seed or seed potatoes or through
plant cuttings or plantlets. S. tuberosum may also be reproduced by botanical seeds, which are
commonly referred to as true potato seeds or TPS. True potato seed production is practiced in
breeding programs under greenhouse or growth chamber conditions. Some programs have also
used open pollination conducted outdoors. True potato seed production in the natural
environment varies with cultivar and weather conditions. The degree to which flowering occurs,
the duration of flowering, and the response of flowering behavior to environmental conditions is
greatly influenced by cultivar (Burton 1989).

The environmental conditions that influence flower initiation and development include light
intensity, quality and duration (day length), temperature, water supply, and available soil
nutrients. Flowers of some varieties may abscise prematurely. Tetraploid S. tuberosum is self-
compatible, although most of the related diploid species are self-incompatible. Pollen sterility
occurs frequently in S. tuberosum, and ovule sterility occasionally; many varieties do not
produce any botanical seed. Flowering starts on branches located near to the base of the plant
and proceeds upwards. Each flower will typically remain open for 2 to 4 days, with the stigma
being receptive and pollen being produced for approximately 2 days (Plaisted 1980).
Fertilization occurs approximately 36 hours after pollination (Clarke 1940). Viable seeds require
a minimum of 6 weeks to develop.
2.6.2. Breeding and seed production
The majority of breeding with Solanum tuberosum involves crosses between tetraploid
genotypes followed by phenotypic recurrent selection (Carputo and Frusciante 2011; Dean
1994). Parents are selected to be diverse in order to minimize homozygosis and inbreeding
depression, and test crosses may be performed in order to determine which parent combinations
are desirable. Selection is typically applied at the phenotypic level, although molecular markers
are increasingly used (Bradshaw 2007; Carputo and Frusciante 2011).Due to the heterozygosity
and tetraploidy of S. tuberosum, traits are expected to segregate in the F1 generation, and large
populations are typically generated, on the order of tens of thousands (Carputo and Frusciante
2011; Howard 1978). From the F1 generation, tubers will be removed and planted, representing
the first clonal generation. The clones will then be put through a series of field trials in an
increasingly diverse range of environments over a number of years, and selection will be applied
to reduce the number of clonal lines until only one or a few remain (Carputo and Frusciante
2011; Dean 1994).The main objectives of breeding include increased yield, improving quality
characteristics of tubers such as skin and flesh colour, tuber size and shape, eye depth, nutritional
properties, cooking/after cooking properties, processing quality, and introducing resistance to
biotic and abiotic environmental stresses (Carputo and Frusciante 2011; Howard 1978). Seed
potato production often occurs in regions that are separate from those used to produce the crop
for consumption.

Precautions are taken during seed potato production to minimize disease incidence (Dean 1994;
Hoopes and Plaisted 1987; Western Potato Council 2003). Insecticides and other insect control
measures will be used to reduce aphid populations, which are the main agents for spreading viral
diseases.
2.6.3. Breeding potatoes
Breeding new potato varieties is easy. You can hand-pollinate potato flowers in far less time than
it'll take you to read this article, but I'm going to attempt a reasonably thorough explanation, so I
hope you find it helpful.Potato breeding is done through sexual reproduction, i.e. pollinating
flowers to produce berries which contain true seeds (TPS).
Normally when you plant potatoes you propagate them from tubers, confusingly called seed
potatoes but which are not actually seeds, but root cuttings. You can't cross tubers. They can only
reproduce themselves as they are. Occasionally a plant may produce a spontaneous mutation but
it doesn't happen often enough to be useful as a breeding method. Flowers are the way to go,
because they give you the option to combine and reshuffle genes from the parent varieties of
your choice.There's a lot to be grateful for in the anatomy of a potato flower. Hand-pollinating
them is very easy. The flowers are large and easy to work with, and the individual parts are easy
to manipulate. What’s not so easy is making careful plans and predictions for what you might get
out of it, and that's because potatoes are tetraploid. To give a one-sentence summary: a tetraploid
has double the amount of genetic material that a normal (diploid) organism has, which is a bit
like inheriting traits from four parents rather than two. Tetraploids are a quirk of nature but in
potatoes they are a very successful one, and the vast majority of cultivated potatoes in Europe
and North America are tetraploid. You may still come across the occasional diploid. Kirundo and
its associated varieties are diploid. Diploid potatoes can be recognized by a tendency to have
smaller and less fleshy leaves, but the most distinctive feature is the berry. A diploid potato berry
has a distinctively pointed end, kind of strawberry shaped, while tetraploid berries are more
rounded and tomato-like. If you're feeling experimental you can try crossing a diploid with a
tetraploid. At best you will only get a few viable seeds out of it, but it's a brilliant way of
introducing new diversity into potatoes.

2.7. Cultivation and use as a crop
Cool summer temperatures are ideal for potato production. The optimum temperature for growth
is 21°C, and growth is restricted below 7°C and above 30°C (Western Potato Council 2003).
Tuber formation in S. tuberosum is favored by short days.
It is also essential to have ample soil moisture for optimum yields. Deep, well-drained sandy or
silt loam soils are ideal for growing S. tuberosum, with a soil pH between 5.5 to over 7.5
(Agriculture and Agri-Food Canada 2005).
There are many serious diseases that may be carried in seed potatoes, including late blight
(Phytophthora infestans (Mont.) de Bary), early blight (Alternaria solani Sorauer), and bacterial
ring rot (Clavibacter michiganensis subsp. sepedonicus (Spiekermann and Kotthoff) Davis et al.),
as well as several viral diseases. The best protection against such diseases is to use certified
disease-free seed potatoes. Crop rotations, the use of resistant cultivars, and proper sanitary
practices are also important for reducing the incidence of disease (Bohl and Johnson 2010;
Western Potato Council 2003). Fungicides may be applied to control fungal diseases, and the use
of insecticides to limit the presence of aphids can help to minimize the spread of insect-
transmitted diseases. Integrated pest management is strongly recommended, with a combination
of cultural and chemical approaches. Pesticides should only be applied when pest populations
exceed the economic threshold and then only the affected area should be treated. If multiple
pesticide applications are required, alternating between chemical groups will help to prevent
resistance to a given pesticide. To conserve tuber consumption or processing quality during
storage, it is important to prevent them from sprouting.
A sprout inhibitor can be applied either in the field 2 to 3 weeks before harvest, or after the
potatoes are placed in storage (Atlantic Potato Committee 2007; Western Potato Council 2003).
Tubers may be stored for up to 10 months, but adequate storage conditions are important in order
to maintain quality and prevent diseases.

2.8. Means of movement and dispersal
Information on seed dispersal is lacking. Birds are unlikely to distribute true potato seeds
because the berries are green and inconspicuous. Hawkes (1988) suggests that the distribution of
berries by small (or perhaps large) mammals is possible due to their sweet and aromatic nature.
However, there is no mention regarding the toxicity of the berries and whether this may impede
browsing by animals. Potato tubers are most likely to be spread during handling and
transportation.

CHAPTER THREE: MATERIALS AND MEHODS
3.1. Site Description
This experiment carried out in green house of UR-CAVM. The elevation of this region ranges
between 1900m and 2200m above sea level. The climate is predominantly highland tropical and
characterized by an annual average temperature ranges between 16 and 170
C.
3.2. MATERIALS
3.2.1. Cultivars used
Irish potato cultivars to be used in this experiment will be given by Rwanda Agriculture Board
(RAB Musanze).
They are: Gikungu, Kirundo, Victoria and Mabondo.
3.2.1.1. Agronomic Characters of Cultivars Used
1. GIKUNGU
 Accession Number: CIP 387233.24
 Selection Country: Rwanda
 Parentage: 382134.26 X 1-1039
 Time of introduction: 1988
 Diffusion year : 1992
Photos of Gikungu (Appendix 1)
Characteristics
 Skin color red
 Color of tubers: Yellow
 General Form of tubers Oblongue
 Depth eyes Shallow
 Cut Grande
 Dry Matter 23%
 Cycle 100 – 120 days
 Dormancy 10 week
 Yield T/ha 34.7
 Late blight Resistance Resistant
 Wilt Resistance Tolerant
 Storage capacity Middle

2. VICTORIA
At the moment, Victoria a successful Ugandan breed is the most requested variety. It is high
yielding, resistant to late blight and bacterial wilt, has a short production cycle, and a long
dormancy period. It has the potential to replace Sangema. The variety has potential in improved
marketing channels and even industrial processing. However, it is not yet widespread amongst
farmers.
 Accession Number: CIP 381381.20
 Country of Selection: Uganda
 Parentage: 378493.915 X BULK PRECOZ
 Year of introduction 1997
 Year of diffusion 2001
Photos of Victoria (Appendix2)
Characteristics
 Skin color of tubers Pink
 Color of flesh tubers Cream
 Introduction of tubers Round
 Depth Eye Shallow
 Cut Middle
 Dry matter 18%
 Cycle 100 – 110 Days
 Dormancy 6 Weeks
 Yield T/ha 30
 Resistance to Late blight Resistant
 Resistance to Wilt Tolerant
 Storage Capacity Middle
3. MABONDO
It has good yields, a seed dormancy of 7-8 weeks, is resistant to late blight and tolerates bacterial
wilt. These characteristics match perfectly with farmers’ requirements. Storability is good, but
not under traditional circumstances. ASSR abandoned the variety. It is, however, popular
amongst producers for own-consumption and therefore widespread in the volcanic region.
 Accession Number: RW 8212-6
 Country selection: Rwanda
 Year diffusion 1989

Photos of Mabondo (Appendix3)
Characteristics
 Color of flesh tubers white
 Color of flesh tubers Yellow
 General form tubers Round
 Depth Eye shallow
 Cut great
 Life cycle More than 120 day
 Dormancy period 7 Weeks
 Yield T/ha 35
 Storage Capacity Good
4. KIRUNDO
Kirundo has a good yield. Traders complain that quality decreases significantly even only one
week after harvest and they avoid this variety.
 Accession number: RW 8201-19
 Selection country: Rwanda
 Year of diffusion 1989
Photos of Kirundo (Appendix4)
Characteristics
 Color of tubers Blanche
 Skin Color of tubers white color
 General form of tubers round shape
 Profondeur des yeux Peu profonde
 Taille Middle
 Life cycle more than 100 days
 Dormancy period 6 Weeks
 Yield T/ha 32.5
 Storage capacity Good

3.3. Fertilizers used.
Organic manure mixed with sterilized soils was used to fertilize the soil for potatoes cultivation
in green house plots. Organic fertilizers were applied after the 2nd
soil tillage and plot
establishment,and immediately incorporated in 15 cm soil depth, using a hoe.
3.3.1.Weeding and earthing-up
Weeding was carried out 15 days after the potato seed have sprouted, while earthing up was
done two months after planting in order to keep the plants upright and the soil loose, prevent
insect pests such a tuber moth from reaching the tubers; and help prevent the growth of weeds.
3.3.2.Diseases and pest control
During this study, it was heavily raining . we faced a problem of potato late blight . the control
methods used was the application of Dethane at 2 times a week interval and Ridomil at 2 times a
growing seoson.
3.4. Equipments:
We wish we could give a simple list of materials used during our experiment, it’s important to
remember though that if they self-pollinate they may show some degree of inbreeding
depression:
 Used a blunt scalpel blade, tweezers or similar
 Used tweezers/scalpel/fingers for pulling off a single anther.
 Pollen collection from males gametes by Epondal tube
 Forceps for emasculation for females
 Labels were used to indicate date of crossing and cultivars crossed

3.5. METHODS
3.5.1. Experimental design layout
The experimental was Completely Randomized Design (CRD). The parents are four, replicate
four times and the total experimental units are 16 treatments.
The details of the experimental:
Number of Block=2
Number of Treatment=12
Number of Plots=4
Treatment Size= 60cmx50cm
Number of Holes per Treatment =12
Number of parents=4
Number of crosses=36
20Cm
20cm
m
40cm
30cm
R1
20Cm
20cm
m
40cm
30cm
R1
20Cm
20cm
m
40cm
30cm
R1
20Cm
20cm
m40cm
30cm
R1

3.5.2. Procedure used during crossing
Potato flowers are produced in cymes - bunches of flowers which open consecutively, 2 or 3 at a
time. The flowers last two to four days but tend to close up in late afternoon. Potato pollen is
white, powdery and very fine. The stigma is receptive for about 2 days and the period of pollen
shedding also lasts about 2 days. The best time for hand-pollination is in the morning when
pollen is most abundant, and when the temperature is fairly cool. But we wouldn't worry too
much about this; it works at other times too.
Below we have sequence of different steps followed during Irish potato crossing:
Step 1: Having chosen the variety we want to use as the female parent, to find a blossom at the
right stage. Potato pollen will be shed quite early, before the flower opens, so emasculation will
be done while it's still at the bud stage. We will be looking for a nearly-ready bud where the
calyx (outer green bit) has started to open but the petals are still shut. This is a variety with a
sticky-outy stigma, but with many varieties it will still be hidden inside the petals. Doesn't matter
either way, although a sticky-outy like this inevitably carries a small risk of picking up stray
pollen from elsewhere,
Step 2: we peeled back the petals and find the anthers inside.
Step 3: Using a blunt scalpel blade, tweezers or similar, we pulled/scraped the anthers off, being
very careful not to damage the style - the central stalk with the stigma at the end,
Step 4: After removing all the anthers we left with a denuded female part, ready to be pollinated
with the pollen of our choice.
Step 5: we found the flower we want to use as the male parent. Choose a blossom which is
newly opened, as those are the ones most likely to have a good pollen stash (the ends of the
anthers should be open at this stage). Pulled off a single anther using tweezers/scalpel/finger,
Step 6: we turned the anther over we’ll see it has a seam down the back, separating the two
pollen sacs. Additionally, each individual sac has a little slit down its centre. Carefully slip the
tip of a blunt scalpel blade through the slit and slide it along.

Step 7: Armed with our pollen-tipped scalpel, back to the bud we will be just emasculated and
dab the pollen powder onto the stigma - which is the babbly thing at the end. The stigma is
mildly sticky when it's receptive, so we should find the pollen grains sticking to it quite readily.
No need to make a song and dance with it - just a gentle dabbing so as not to risk damaging the
stigma,
Step 8: The next day, went back to the same flower and pollinate it again with pollen from
another fresh anther. The stigma remains receptive for two days in total but we don't know
exactly when that is, so for best results give it a pollen dab on three consecutive days. We shall
notice that the petals have opened on this flower now, although it looks a bit weird as it has no
anthers. Once the petals have closed and wilted a bit, we can assume it's no longer receptive.
Step 9: The berries were supposed to form.
3.5.3. Observed parameters
1. Germination rate: it was done in 10 DAS by counting all plants germinated and then
calculating their percentages.
2. Plant height: The heights of plants were measure by randomly chosing 12 plants in each
experimental unit with graduated rule. That parameter was taken three times with an interval of
15 days i.e. at 15days, 30 days and 45 after sowing.
3. Number of tillers: It was done in 45 DAS by counting all tillers in each plot and then
calculating their means with their comparison.
4. Number Flowers: The number of flowers were counted randomly by their availability in
each experimental unit
5.Number of Tubers:Those were determined after harvesting by counting he total number of
tubers from each plots
6.Fresh weight of tubers :those were determined after harvesting by weighing the total number
of tubers from each plot for fresh weight.
3.5.4. Statistical analysis
Data Analysis was done using M.s Excel by illustrating the means of observed parameters for
four varieties and comparing their variations after the experiment.

CHAPTER FOUR: RESULTS AND DISCUSSION
4.1. Growth parameter
4.1.1. Germination Rate
Figure 1.Germination Percentage for experiment I
During the First Experiment, Germination percentage was significantly different due to varieties
(Figure 1).at 10 DAS, Kirundo and Gikungu were germinated 100%while Mabondo was 91.6%
and Victoria was 75 %.at 15 DAS, All varieties were germinated 100%.there should be caused
by the varieties sown in each plots and compost used in fertilization. The results are in full
agreement with the findings of Bongkyoon (2004) who stated that the increase in compost affects
positively germination rate of potato.
91.6
100 100
75
100 100 100 100
0
20
40
60
80
100
120
Mabondo Kirundo Gikungu Victoria
G % at 10 DAS
G% at 15 DAS

Figure 2.Germination Percentage for experiment II
For the experiment II, Germination percentage due to varieties was not different (Figure 2).at 10
DAS, All varieties were germinated 100%.there should be affected by added quantity of mineral
and organic fertilizers in each plot.
4.1.2. Height
For the Experiment I, The change in height due to variety was significantly different (Figure
3)At 15 DAS,. The highest height 19.32 was Gikungu while Victoria gave the lowest value
(9.66). at 30 DAS , Gikungu gave the highest height of 38,8 and Victoria the minimum . At 45
DAS, Gikungu gave the maximum height and Victoria the minimum. The results are in
agreement with the findings of Mojtaba (2013), who stated that combined application of compost
and other organic fertilizers performed the highest plant height of potato.These results are
approximately similar to those noticed by Ahmed (1984) that height varies differently due to
crop genetic potential while characterizing local genotypes of Hippophae rhomboids and
screening of exotic germplasm for yield and growth in potato respectively.
100 100 100 100
0
20
40
60
80
100
120

Figure 3.Plant height varies in different days after sowing for Experiment I
Figure 4.Plant height varies in different days after sowing for Experiment II
The change in height due to variety was significantly different in experiment II (Figure 4). At 15
DAS, the highest height 18.08 was Mabondo while Gikungu gave the lowest value 12.63. At 30
DAS, Gikungu gave the highest height of 40.53 and Victoria the minimum value 30.18. At 45
DAS, Gikungu Gave the maximum height with value 79 and Victoria the minimum height with
value 64.21 as shown by (Figure 6). This might be due to the presence of higher competition for
sunlight among plants grown at the closer intra row spacing. These results are in partial
agreement with the finding of Zaag et al. (1989) who indicated that plant height was initially
similar in all treatments but after 72 days the closely spaced plants became taller. Dennis et al.
(1994) also reported that as intra row spacing increased plant height decreased linearly.
13.85
17.425 19.32
9.66
28.43
37.25 38.8
18.82
60.85
68.21
74.11
29.91
0
10
20
30
40
50
60
70
80
Height in 15 DAS
Height in 30 DAS
Height in 45 DAS
18.08 17.7
12.63
15.9
39.53 38.4 40.53
30.18
77.36
70.08
79
64.21
0
10
20
30
40
50
60
70
80
90
Height in 15 DAS
Height in 30 DAS
Height in 45DAS

Similarly, Ifenkwe and Allen (1978), Law-Ogbomo and Egharevba (2009), Rajadurai
(1994) andZebarth et al. (2006) concluded that closer intra row spacing (higher plant density)
resulted in the highest plant height. This result is in conformity with the finding of Qadir et al.
(1999) and Qadir (1997) who confirmed that plant height was significantly higher in plants
earthed up at two weeks after the complete plant emergence.
4.1.3. Number of tillers
During experiment No
1, The number of tillers was significantly different in all four Varieties
(figure 5). The highest was Gikungu (T3) with (6.83) while the lowest was Victoria (T4) with
(2.33). First experiment showed that the number of tillers for Kirundo and Mabondo was
approximately the same as marked by their mean value of all varieties. These results are in
contrast with Khaliq (2002) who reported 5.55 numbers of tillers per plant.
Figure 5. Number of tillers due to Four Varieties for Experiment I.
4.5
4.75
6.83
2.33
0
1
2
3
4
5
6
7
8

Figure 6.Number of tillers due to Four Varieties for Experiment II
2, The number of tillers was significantly different in all four Varieties
(figure 6). The highest was Mabondo (T2) with (3.16) while the lowest were Victoria (T4) and
Gikungu with (2.0).In second experiment showed that the number of tillers for Gikungu and
Victoria were the same as marked by their mean value of all varieties. These results are in
contrast with Kushwah (1991) mentioned that the number of tillers per plant did not differ
markedly under different levels (120,150 and 180kg/ha) of nitrogen and these results are in are in
partial agreement with Khaliq (2002) who reported 5.55 numbers of tillers per plant.
4.2. Reproductive parameters
4.2.1. Flowers
1, The number of flowers was significantly different in all four Varieties
(figure 7). The highest in flowers was Gikungu (T3) with value 6.83 while the lowest in flowers
was Victoria (T4) with value 2.33.The experiment showed that the number of flowers for
Kirundo and Mabondo was approximately the same as marked by their mean value of all
varieties.
3.16
2.83
2 2
0
0.5
1
1.5
2
2.5
3
3.5

Figure 7.Number of Flowers due to Variety for Experiment I
Figure 8.Number of Flowers due to Variety for Experiment II
2, The number of flowers was significantly different in all four Varieties
(figure 8). The highest in flowers was Gikungu (T3) with value 22.5 while the lowest in flowers
was Victoria (T4) with value (1.6).In our second experiment showed that the number of Flowers
for Kirundo and Mabondo were significantly different as marked by their mean value of all
varieties .But all the flowers fall down prematurely before crossing period.
4.25
5.91
26.16
3.83
0
5
10
15
20
25
30
4.16 3.33
22.5
1.6
0
5
10
15
20
25

Table 1.Results of experimental crosses between four varieties in Experiment I
Date of crossing Cross – Female Cross - Male Description
04/01/2016 Kirundo Gikungu 0 seeds from 5 pollinations
04/01/2016 Gikungu Kirundo 0 seeds from 7 pollinations
09/01/2016 Mabondo Gilkungu 0 seeds from 1pollinations
09/01/2016 Mabondo Victoria 0 seeds from 1 pollinations
09/01/2016 Kirundo Gikungu 0 seeds from 1pollinations
09/01/2016 Victoria Gikungu 0 seeds from 2 pollinations
09/01/2016 Gikungu Victoria 0 seeds from 3 pollinations
09/01/2016 Gikungu Gikungu 0 seed from 3 pollinations
Days to flowering: The earliest days to flowering was observed from Gikungu in 40 days after
sowing .Whereas Mabondo was delayed seven days after Gikungu.

4.3. Yield parameters
4.3.1. Number of Tubers
Figure 9.Number of tubers due to Variety for Experiment I
Number of tuber was significantly different due to different potato varieties (Figure 9). The
highest number of tubers (14.16) was obtained from Gikungu and Victoria the lowest (1.75) the
increase in number of tubers to Gikungu might Mabondo and Kirundo are approximately the
same. These results are in contrast with Bintje, Jaerla and Spunta on number of tubers with doses
from 0.5 to 27 Gy. A dose of 3 Gy increased the number of tubers by 30% in Spunta and by 17%
in Jaerla, but it did not increase the number of tubers in Bintje. Doses of 9 and 10 Gy did not
Influence the number of neither tubers nor stems and decreased harvest index. A dose of 27 Gy
reduced yield and number of tubers.
9.16 9.5
14.16
1.75
0
2
4
6
8
10
12
14
16
mabondo kirundo gikungu victoria

Figure 10.Number of tubers due to Variety for Experiment II
Number of tuber was significantly different due to different potato varieties (Figure10). The
highest number of tubers (4.33) was obtained from Gikungu and Mabondo the lowest (2.83) the
increase in number of tubers to Gikungu might kirundo and Victoria is approximately the same.
4.3.2. Yield per plot
Figure 11.Yield due to four Varieties for experiment I
For experiment I, the yield from all plots was significantly different (Figure11), the highest
yields obtained from Mabondo with 4.471 kg/plot while the lowest yield was from Victoria with
2.822 kg/plot. Yield from Gikungu was 3.878 kg/plot comes the second while third yield was
Kirundo with 3.232 kg/plot. May be there was an influence of new sterilized soil used in each
plot and variety genetic potential. These results are in partial agreement with Alam(2005) who
2.83
3.16
4.33
3.5
0
1
2
3
4
5
4.471
3.232
3.878
2.822
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5

mentioned that different organic fertilizer had significant influences on the yield Contributing
parameters of Potato.
Figure 12. Yield due to four Varieties for experiment II
During the second experiment, the yield was significantly different due to variety potential
(Figure12), the highest yield obtained from Gikungu with value 2.368 kg/plot while the lowest
yield was from Victoria with value 1.710 kg. Yield from Kirundo was 2.188 kg/plot comes the
second while third yield was Mabondo with value 1.848kg/plot. These yields are mostly due to
some removed stolons and may be variety potential. these results are in full agreement with
Naher (2007) mentioned that fertilizer management practices had significant effects on the
yield and yield contributing characters of potato.
1.848
2.188
2.368
1.71
0
0.5
1
1.5
2
2.5

CONCLUSION AND RECOMMENDATIONS
In comparison of both experiment I and II, Based on measured parameters of emergence rate,
number of tillers, plant height in 45 days after sowing, number of flowers/plant and variety
number of tubers, yield/ha per plot or variety. It was noticed that experiment I is significantly
differently from experiment II. During the first work, no synthetic fertilizers were applied for
management of Nitrogen quantity in soil which may prevent plant from flowering. For the
second experiment, fertilizes (animal manures, NPK and Urea) were applied, stolons were
removed, but flowers were not significant compared to the first experiment. The objective of this
study was Evaluation of Genetic Compatibility Between four Cultivars of Irish Potato in Rwanda
for disease resistance and yield improvement for future use and further research in UR-CAVM,
two experiments were performed in green house of UR-CAVM, Busogo campus where used four
varieties brought from RAB Musanze. In this research, it was marked that there was some good
features of Irish potato used like to bear high number of flowers even if all crosses made did not
succeed for bearing berries because of incidence of heavy rains caused them fall down all of
them in all two experiments done. It can be suggested to others researchers for the same study to
start early while conducting many experiments in green house and in open fields considering to
be successful and their comparison . In addition, future researchers have to make sure that
climatic conditions is better and well controlled to prevent the same incidence of intensive and
heavy rains which may cause crossed flowers falling down .it may be better also use of
hormones to prevent falling of immature flowers targeting Better and sustainable future results.
Further researchers may work also on the following vegetative parameters: Growth Vigor,
Diseases and pests resistance, Success rate of crossing, number of berries (seeds), number of
seeds and yield parameters like size of tubers.

REFERENCES
1. Arndt, G. C., Rueda, J. L., Kidane-Mariam, H. M. and Peloquin, S. J. 1990. Pollen
fertility in relation to open pollinated true seed production in potatoes. American Potato
Journal 67(8):499-505.
2. Askew, M. F. and Struik, P. C. 2007. The canon of potato science: 20. Volunteer
potatoes. Potato Research 50(3-4):283-287.
3. Austin, S., Baer, M. A. and Helgeson, J. P. 1985. Transfer of resistance to potato leaf
roll virus from Solanum brevidens into Solanum tuberosum by somatic fusion. Plant
Science 39(1):75-81.
4. Austin, S., Pohlman, J. D., Brown, C. R., Mojtahedi, H., Santo, G. S., Douches, D. S.
and Helgeson, J. P. 1993. Interspecific somatic hybridization between Solanum
tuberosum L. and S. bulbocastanum Dun. as a means of transferring nematode resistance.
American Potato Journal 70:485-495.
5. Bailey, L. H. and Bailey, E. Z. 1976. Hortus Third: A concise dictionary of plants
cultivated in the United States and Canada. Macmillan, New York. 1290 pp.
6. Barsby, T. L., Shepard, J. F., Kemble, R. J. and Wong, R. 1984. Somatic
hybridization in the genus Solanum: S. tuberosum and S. brevidens. Plant Cell Reports
3(4):165-167.
7. Report from (Theorez, 2000).
8. Report from (MINAGRI, 2006).
9. Report from MINAGRI(2007)
10. Report from (Spooner and Knapp 2013).
11. Report from (Spooner and Knapp 2013; Struik 2007)
12. Report from (Spooner and Salas, 2006).
13. Report from (Sleper and Poehlman 2006).
14. Report from (Struik 2007).
15. Report from (Spooner and Knapp 2013; Spooner and Salas 2006).
16. Report from (Bailey and Bailey 1976).
17. Report from (Gopal 1994).
18. Report from (Bailey and Bailey 1976).
19. Report from (Correll 196; Grun 1990; Miller and Spooner 1999; Urgent 1968; van den
Berg et al. 1998).
20. Report from (Hawkes and Francisco-Ortega 1993; Ríos et al. 2007).
21. Report from (Hawkes 1990; Hawkes and Francisco-Ortega 1992; Romans 2005).
22. Report from (OECD 1997).
23. hypothesis favoured by Laufer (1938) and Hawkes (1990)
24. Report from (Sauer 1993)
25. Report from (Laufer 1938; Sauer 1993).
26. Report from (FAO 2014).
27. Report from (USDA-ARS 2014).
28. Report from (Simon et al. 2010).
29. Report from (Statistics Canada 2012).
30. Report from (Burton 1989; Simon et al. 2010)
31. Report from (Hijmans 2001)
32. Report from (Haverkort 1990).

APPENDIX
Appendix 1. Photos of Gikungu
Appendix 2. Photos of Victoria
Appendix 3. Photos of Mabondo Appendix 4. Photos of Kirundo
Appendix 5.Period of activities plan
Activities Period (From December,2015 to May 2016)
O N D J F M A M J
Proposition and documentation on
research project
X X X
Preparation of project proposal,
submission and correction
X X X
field experimental, collection and
processing of data and document
arrangement
X X X X X X
Submission of document for
correction
X X
Submission of final document and
presentation
X X

Appendix 6.Germination Percentage
For experiment I
Variety G % at 10 DAS G% at 15 DAS
Mabondo 91.6 100
Kirundo 100 100
Gikungu 100 100
Victoria 75 100
Appendix 7. Germination Percentage for
experiment II
1
BLOCK Variety Height in 15 DAS Height in 30 DAS Height in 45 DAS
1 Mabondo 13.85 28.43 60.85
1 Kirundo 17.425 37.25 68.21
2 Gikungu 19.32 38.8 74.11
2 Victoria 9.66 18.82 29.91
2
BLOCKS Variety
Height in 15
DAS Height in 30 DAS
Height in
45DAS
1 Mabondo 18.08 39.53 77.36
1 Kirundo 17.7 38.4 70.08
2 Gikungu 12.63 40.53 79
2 Victoria 15.9 30.18 64.21
Appendix 10.Number of Tillers by
Experiment No
1
BLOCK Variety
Number of Tillers
in 45 DAS
1 Mabondo 4.5
1 Kirundo 4.75
2 Gikungu 6.83
2 Victoria 2.33
Appendix 11.Number of Tillers By
Experiment No
2
BLOCK Variety
Number of tillers for
Experiment II
1 Mabondo 3.16
1 Kirundo 2.83
2 Gikungu 2
2 Victoria 2
Variety
G % at 10 DAS For
Experiment II
Mabondo 100
Kirundo 100
Gikungu 100
Victoria 100

Appendix 12.Number of flowers By
Experiment No
1
BLOCK Variety Number of flowers
1 Mabondo 4.25
1 Kirundo 5.91
2 Gikungu 26.16
2 Victoria 3.83
Appendix 13.Number of flowers By
Experiment No
2
BLOCK Variety Number of Flowers
1 Mabondo 4.16
1 Kirundo 3.33
2 Gikungu 22.5
2 Victoria 1.6
Appendix 14.Number of tubers By
Experiment No
1
BLOCK Variety
Number of
tubers
1 Mabondo 9.16
1 Kirundo 9.5
2 Gikungu 14.16
2 Victoria 1.75
Appendix 15.Number of tubers By
Experiment No
2
BLOCK Variety
Number of
tubers
1 Mabondo 2.83
1 Kirundo 3.16
2 Gikungu 4.33
2 Victoria 3.5
Appendix 16.Yield due to Varieties for
experiment I
BLOCK Variety Yield in kg
1 Mabondo 4.471
1 Kirundo 3.232
2 Gikungu 3.878
2 Victoria 2.822
Appendix 17.Yield due to Varieties for
experiment II
BLOCK Variety Yield in kg
1 Mabondo 1.848
1 Kirundo 2.188
2 Gikungu 2.368
2 Victoria 1.710

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