This document provides an overview of plant breeding methods for cross-pollinated crops. It discusses mass selection, progeny selection, and recurrent selection as methods of population improvement. It also describes hybridization techniques like single cross hybrids, double cross hybrids, and three-way cross hybrids. The objectives of plant breeding are to improve traits like yield, quality, disease resistance, and abiotic stress tolerance. Plant breeding has significantly increased global food production through the development of superior crop varieties.

1. SUBMITTED BY
ANANDA LEKSHMI .L
2018600801
GENETICS AND PLANT BREEDING
GPB 606 APPLIED CONCEPTS OF CROP
BREEDING (3+1)

2. INTRODUCTION
 Plant breeding is an applied branch of Botany, which deals
with improvement of agricultural crops.
 This branch of agricultural science has contributed
maximum to the increase in food production all over the
world.
 Riley, 1978 defined plant breeding as a technology of
developing superior crop plants/ varieties for various
purpose.
 Frankel, 1958 defined plant breeding as the genetic
adjustment of plants to the service man.
 Plant breeding is a branch of biology concerned with
changing the genotype of plant so that they become more
useful.

3.  The choice of breeding methods mainly
depends on
1. the mode of pollination
2. Mode of reproduction
3. Gene action
4. Breeding objectives of crop species

4. OBJECTIVES OF PLANT BREEDING
The prime aim of plant breeding is to improve the
characteristics of plants that they become more useful
automatically and economically. Some of the objectives
may be summarized as follows.
 1. Higher Yield:
 2. Improved Quality
 3. Disease and Pest Resistance:
 4. Maturity Duration:
 5. Agronomic Characters:

5.  6. photo and Thermo Insensitivity:
 7. Synchronous Maturity:
 8. Non-Shattering Characteristics:
 9. Determinate Growth Habit:
 10. Dormancy:
 11. Varieties for a New Season:
 12. Moisture Stress and Salt Tolerance:
 13. Elimination of Toxic Substance:
 14. Wider Adaptability:
 15. Useful for Mechanical Cultivation:

6. CROSS POLLINATED CROPS
 Each genotype has equal chance of mating
with all other genotypes
 Individuals are heterozygous in nature
 Higher degrees of inbreeding depression
 Wide adaptability and more flexibility to
environmental changes due to
heterozygosity and heterogenity
 Cross pollination permits new gene
combination from different crosses
 Individuals have deleterious recessive gene
which are concealed by masking effects of
dominant gene

7. BREEDING METHODS IN CROSS
POLLINATED CROPS
I) Selection (Population
Improvement)
A) Without progeny testing. i)
Mass selection
B) With progeny testing i.e
a) Progeny testing – i) Plant
to row ii) Ear to row
b) Recurrent selection –
i) Simple recurrent
selection
ii) Recurrent selection
for GCA.
iii) Recurrent selection
for SCA.
II) Heterosis breeding
III) Synthetic breeding
IV) Composite Breeding

8. MASS SELECTION:
 Mass selection is the oldest method of breeding commonly
used for cross pollinated crops.
 In this method number of plants are selected on the basis of
their phenotype, and the open pollinated seed from them is
bulked together to raise the next generation.
 The selected plants are allowed to open pollinate i.e to mate
at random.
 mass selection is based on maternal parent only,
 there is no control on the pollen parent.
 Selection of plant is based on the phenotype and no progeny
test is conducted.

9.  This method of breeding is an extremely simple and selection
cycle is very short i.e of only one generation but it may be
repeated one or more times to increase the frequency of
favourable alleles.
 The efficiency of mass selection primarily depends upon the
number of gene controlling the character, gene frequency and
heritability of concerned traits.

10. DIAGRAM

11. MERITS: DEMERITS:
 Rapid and simple
 Selection cycle is short
 Have high heritability
 Effective in improving yeild
of cross pollinated crops
 Phenotypic performance is
greatly influenced by
environment factors.
 Selection is based on the
phenotype. Progeny test not
carried out
 No control over pollination
MASS SELECTION

12. ACHIEVEMENTS OF MASS SELETION:
 Early varieties of pearl millets were developed through mass
selection, like Babapuri,Jamna nagar Gaint,AF3 ,Pusa Moti
 Improved the yeilding ability of toria(B.compestris var. toria)
16% oil yeild.
 Maize varieties :T41. T19, jaunpuri (popular in U.P)
 Cotton : C402, C520, from desi cotton and 100F, A19 from
american cotton.
 Castor: S20, B1 ,B4

13. SELECTION (with Progeny Testing)
 In this method initial plants are selected on the basis of their
phenotype, but the final selection of plant based on progeny test.
This method includes progeny selection on ear to row method
and recurrent selection.
Progeny Selection (Ear to Row Method):
 Hopkins in 1908 developed this method, extensively used in
maize. In its simplest form it consists of
 i) 50- 100 number of plants are selected on the basis of their
phenotype and are allowed to open pollinate. The seeds from
individual plants are harvested separately.
 ii) A single row of 10-50 plants i.e a progeny row, is grown from
each selected plant. The progeny rows are evaluated for desirable
character and superior are identified.

14.  iii) Several phenotypically superior plants are selected from the
superior progenies and selected plants are permitted to open
pollinate.
 iv) Small progeny rows are again grown from the selected plants,
and the process of selection is repeated.
 This method is relatively simple and the selection cycle is of one
year only.
 However, it suffers from the defect that the weak and inferior
progenies pollinate plants in the superior progenies. This reduces
the effectiveness of selection.

16. MERITS; DEMERITS:
1) In this method the selection is
based on the progeny test and not
phenotype of individual plants,
hence it is more efficient than mass
selection in the identification of
superior genotypes.
2) Inbreeding may be avoided to
certain extent by selecting
sufficiently large number of
progenies.
3) It is simple and easy.
1) There is no control on
pollination and plants are allowed
to open pollinate, thus selection is
based on maternal parent only. This
reduces the efficiency of selection.
2) Many progeny selection schemes
are complicated and involve
considerable work.
3) The selection cycle is usually of
the two years. Thus , time
requirement for selection is twice
as that of mass selection.
PROGENY SELECTION

17. RECURRENT SELECTION
 The initial idea of recurrent selection was independently given by Hayes and
Garber in 1919 and East and Jones in 1920.
 But the term recurrent selection was first coined by Hull in 1945.
 Definition:
 Recurrent selection is defined as reselection generation after generation, with
intermating of selected plant to produce the population for the next cycle of
selection.
 The idea of this method was to ensure the isolation of superior inbreds from
the population subjected to recurrent selection.
 The isolation of an outstanding inbred line depends on two factors:
 1) The proportion of superior genotypes present in the base population from
which lines are isolated and
2) The effectiveness of selection during the inbreeding of desirable genes.

18.  Types of Recurrent Selection:
 These are four types of recurrent selection.
i) Simple recurrent selection (SRS)
ii) Recurrent selection for general combining ability
(RSGCA)
iii) Recurrent selection for specific combining ability
(RSSCA)
iv) Reciprocal recurrent selection (RRS)

19. Simple Recurrent Selection (SRS) :
 A type of recurrent selection that does not include
tester is referred as simple recurrent selection.
 It is also known as phenotypic recurrent selection as
it is based on the phenotype of the parent
 It does not measure the combining ability
 Used for characters having high heritability

21. Recurrent Selection for General Combining
Ability (GCA):
 A form of recurrent selection used to improve the
general combining ability of a population for a
character.
 selection is based on the heterozygous tester cross
performance
 It is also known as half sib recurrent selection
 Used for genetic improvement of quantitative
character.
 Improves those character with addictive gene action.

23. Recurrent Selection for SCA:
 It was originally proposed by Hull in 1945
 recurrent selection that is used to improve the SCA
of a population for a character
 by using homozygous tester is referred as (RSSCA)
recurrent selection for specific combining ability.
 It is also known as half sib recurrent selection with
homozygous tester.
 Used to improve polygenic characters

25. Reciprocal Recurrent Selection (RRS):
 used to improve both GCA and SCA of a population for a
character
 using two heterozygous testers.
 Comstock et al in 1949, proposed this method.
Main Features of these Methods:
1) It is used for improvement of polygenic characters.
2) Selection is made on the basis of test cross
performance.
3) Two heterozygous tester are used as a source of
population.

26.  4) It is used for improving population for GCA and
SCA for specific characters.
5) It is equally effective with incomplete, complete
and over dominance.
6) It is used for improvement of those characters,
which are governed by both additive and non-
additive gene action.
7) This method also requires three seasons for
completion of each cycle of selection

28. MERITS: DEMERITS;
1) Recurrent selection is an
efficient breeding method for
increasing the frequency of
superior genes for various
economic characters.
2) It helps in breaking
repulsion phase of linkage.
3) It helps due to in
maintaining high genetic
variability repeated intermating
of heterozygous population.
1) It is not directly used for the
development of new varieties.
2) This method involves lot of
selection crossing and selfing
work.
3) It permits selfing, which
leads to loss of genetic
variability.
RECURRENT SELECTION

29. HYBRIDIZATION
 Definition of Hybridization:
 The mating or crossing of two plants of dissimilar genotype is
known as hybridization.
 In plant crossing is done by placing pollen grain from one
genotype (male parent) on to the stigma of flower of another
genotype (female parents).
 The seed as well as the progeny resulting from the hybridization
are known as hybrid of F1.
 The progeny of F1 obtained by selfing or intermating of F1 and
the subsequent generation are termed as segregating generation.

30.  Hybrid and synthetic variety have been
highly successful in many cross –
pollinated species. E.g. Maize, Jowar, and
Bajara
 and even in some self – pollinated crops.
E.g. Rice, tomato, etc. In India almost all
the recommended varieties of maize are
either hybrid or composite varieties.

31. HYBRIDS
 Definition of Hybrid:
 The progeny of a cross between genetically different plants is
called hybrid.
 Most of the hybrid varieties are F1 from two or more purelines
(Tomato, L esculentum) or inbreds (Maize, Zeamays).
 An inbred is a nearly homozygous line obtained through
continuous inbreeding of cross – pollinated species.
 When F1 generation from a cross between two or more
purelines inbreds or other genetically dissimilar population is
used for commercial cultivation is called as hybrid variety.
 Hybrid varieties are the most potent means for the
exploitation of heterosis.

32.  Type of Hybrid:
 The commercially cultivated hybrids are of two types, i.e
A) Intraspecific hybrid and
B) Interspecific hybrid
 A) Intraspecific Hybrid:
 A hybrid between generally different genotypes of the same species. It
is also known as Intervarietal hybrid.
 Intraspecific hybrids are always fertile.
Based on type of cross , there are three types viz. ( a.
 a)Single cross hybrid,
 b) Double cross hybrid
 c) Three way cross hybrid.

33.  a) Single Cross Hybrid:
 A cross between two inbreds or varieties is referred as single
cross. E.g (A X B) and the hybrid progeny obtained from a cross
between two inbreds or varieties are referred as single cross
hybrid.
 In cross pollinated crops such hybrids are developed from a cross
between two inbreds, whereas in self pollinated crop, they
developed from a cross between two homozygous varieties.

34.  Merits Features of Single Cross Hybrid:
 1. They are developed in both self and cross- pollinated crop,
where heterosis is exploitable.
2. The total number of single crosses is n (n-1) /2 where ‘n’ is
number of inbred line.
3. It is more common in some self –pollinated species than cross
– pollinated species.
4. It is used for the development of double cross and three way
cross hybrid.
5. It is also used to predict the performance of double cross
hybrid.
6. It gives maximum degree of heterosis and produce uniform
plant.

35.  b) Double Cross Hybrid:
 A cross between two single crosses is referred as cross between
two single crosses is known as double cross hybrid.
 It is more commonly used in maize and Sugarbeet and it involves
for different inbred line viz. (A X B) X ( C X D).
 The rows of female and male parent are planted in the ratio 4:1 in
maize.
 The number of all possible double crosses among selected inbred
is calculated by n ( n-1) ( n-2) (n-3) /8 where ‘n’ is number of
inbreds involved.

36.  Double Top Cross Hybrid:
It refers to the hybrid progeny between a simple cross and an
open pollinated variety. i.e (A X B) X Open pollinated variety. It
is used in maize.
 Top Cross:
 A cross between an inbred line and an open pollinated variety is
known as top cross.
 It is also known as inbred variety cross, and
 is used as testing the combining ability of inbreds and not for
commercial hybrid seed production.

37.  Multiple Crosses:
A cross involving more than four inbred line is referred as
multiple crosses.
 Three Way Cross Hybrid:
The hybrid progeny by crossing of gene and inbred lines is
referred as three way cross hybrid. E.g (A X B) X C.
These hybrids sometimes used in maize, in which single cross
is used as female and inbred as male and are planted in the
ratio of 2:1.
These hybrids produced seed of normal shape and size but
the main drawback is the low pollen production efficiency of
the male inbred parent.

38.  B) Interspecific Hybrid:
 The F1 progeny between two different progeny of the same
genus is known as interspecific hybrid. It is also referred as
intrageneric hybrid.
 These hybrids are rarely used for commercial cultivation
because such hybrids are fertile only in few cases.
 In cotton interspecific hybrids between tetraploid cultivated
sp. (G. hirsutum X G. barbadense) and diploid cultivated
species (G. arboretum X G. herbaceum).
 E .g. A tetraploid level: Var.Laxmi, Surti, HB224, etc.
 At diploid level: DH-7, DH-9, and Pha46, etc.

39. ACHIEVEMENTS OF HYBRIDS:
 Hybrids are commercially exploited in maize,sorghum,pearl
millet, sugarbeet,watermelon,cucurbits,sunflower,onion etc.
 Indian has pioneered in developing hybrid in both desi and new
world cotton.
 First hybrid maize released in 1961, DCH: Ganga 1, Ganga 101,
Ranjit ,Deccan
 QPM opaque 2 gene, high starch Histarch hybrid Makka), baby
corn hybrid HM4.
 Recently released single cross hybrids are:
 HM10, Nithya Shree, Vivek Maize Hybrid 33, Vivek QPM 9

40.  In pearl millet:
 First hybrid developed by Panjab Agriculture university, in 1965
as HB1.
 Afterwords HB3, HB5 these were SCH fron CMS line Tift 23A.
And yeild upto 7tonnes per hector in National Demonstration
trials
 Downy mildew resistant hybrids PHB 10, PHB 11,BJ104 and
BK560
 Public sector hybrids:
 Pusa 23, HHB50, and HHB 67

41.  Sorghum was third crop in which hybrids was developed in India
 frist hybrid was in 1965 CSH1
 Over 50 hybrids are developed up to 2005
 Short duration hybrid SPH468 yeild potential of 35-45q/ha.
 Rabi season hybrids: CSH12R, CSH13R, CSH15R
 In pegion pea Hybrid ICPH8, developed by ICRISAT hyderabad.
 First CMS hybrid GTH-1 in 2004 57% yeild superiority.

42. SYNTHETIC VARIETY
 A variety which is developed by intermating in all possible
combinations a number of inbreed lines with good general
combining ability and mixing the seed of F1 crosses in equal
quantity
 First suggested by Hayes and Garber,1919
 Can be developed from inbreeds ,clones, open pollinated variety
 Can be grown for 4-5 yrs without reduction in yeild potential
 Gca based selection

43. MERITS DEMERITS
 Cheaper than hybrids
 more adaptable than
hybrids
 More resistant due to
genetic variability
 No need to purchase
new seeds every year as
that of hybrids
 Less uniform and
attractive than hybrids
 Yields less than hybrids
 Only applicable in
cross pollinated crops
SYNTHETIC VARIETIES

44. COMPOSITE VARITIES
 These are produced by mixing together the seeds of
several lines with outstanding performance, raising a
population from bulked seeds, and allowing the plant
to open pollinate.
 Genotypes with equal maturity height, seed size etcs
 Farmers can use the seeds for 3-4 years
 Cannot be reconsutituted because seggregating
population gene frequency changes with time..

45. ACHIEVEMENTS:
 In India first composite varieties released in 1967: Jawahar,
Kisan , Vikram ,sona and Vijay
 Based on local materials: Makki Safed 1 and Moti
 Based on exotic materials: Mansar ,Chandan 3
 Recently developed maized composites are Bajaura Makka,Pant
Sankul Makka 3
 Opaque 2 composites: Shakthi , Rattan ,Protina , VL Baby corn 1
 nutritional value of composites are superior.
 Sugarbeet-Pant synthetic 3
 Cauliflower - synthetic 3

46. REFERENCE:
 Agriinfo.in
 http://link.springer.com>chapter/1 Breeding of Field Crops
 Plant Breeding Principles and Methods ; B.D singh
 Molecular plant breeding :B.D Singh and N.S.Shekhawat