Abstract High temperatures are among the major stresses that affect potato production in the tropics. Climate change is already affecting weather patterns in traditional potato growing areas, where unpredictable rainfall and higher temperatures contribute to increased pressure from pests and diseases and put yield and quality at risk. High temperatures can lead to increased concentrations of glycoalkaloid, which is known to cause the bitter taste in potatoes and can have a negative effect on human health. Since 2004, the International Potato Center has sought to improve the heat tolerance of its late blight-resistant population B3 by developing the new “LBHT” sub-population. We determined the narrow-sense heritability of yield components, broad-sense heritability of glycoalkaloid concentrations, and correlations between these traits in LBHT in order to ensure the quality of heat-tolerant potato clones. Thirty-two LBHT clones were crossed in sets under North Carolina Design II to obtain 64 progenies. Progeny tests were conducted in three locations in Peru: San Ramon, La Molina, and Majes, where average night:day temperatures ranged 15.1°–22.6°C and 22.9°–27.5°C, respectively, using randomised complete block designs (RCBD) with four sets and three replications of 50 genotypes per progeny. Twenty LBHT clones were grown in the same locations using RCBD with three replications. At harvest, the number and weight of marketable and non-marketable tubers were recorded, samples of tubers of each clone were taken, and glycoalkaloid concentrations were determined by spectrophotometry. Narrow-sense heritability for tuber yield, tuber number, and average tuber weight were 0.41, 0.50, and 0.83, respectively. Correlation of tuber number and average tuber weight was highly significant with tuber yield: r=0.77 and 0.74, R²=0.59 and 0.54, respectively. The heritability and correlation values indicate that additive genetic variance was higher than non-additive genetic variance, and that yield components can be used as indirect selection criterion for tuber yield. Broad-sense heritability for glycoalkaloid concentrations on fresh weight was 0.63, and correlation between glycoalkaloid concentrations and tuber yield under high temperatures was low (r=0.33 and R²=0.11). High heritability and low correlation between yield and glycoalkaloid concentrations will allow the selection of clones with high tuber yield and low glycoalkaloid content under heat and virus pressure in humid tropical San Ramon. Eight clones that showed good tuber yield and low glycoalkaloid concentrations can serve as candidate varieties, and may be valuable parents in breeding programmes aimed at improving heat tolerance with minimum risk of glycoalkaloid accumulation under stress Manuel Gastelo

1. Heritability for Yield and Glycoalkaloid content in
Potato Breeding for Heat tolerance and Disease
resistance
Manuel Gastelo, Luis Diaz, Gabriela Burgos, Thomas zum Felde, Merideth Bonierbale
A P A 1 0 t h T R I E N N I A L C O N F E R E N C E 2 0 1 6 October 9 – 13, 2016 Addis Ababa, Ethiopia

2. Climate Change – Effects on Potato
 Reduction of tuber yield
 Increase glycoalkaloids
content

3.  Determine the narrow-sense heritability of yield
components and Broad-sense heritability for
Glycoalkaloid concentration in LBHT clones under
warm conditions.
 Determine correlations between tuber yield with
yield components and glycoalkaloid concentration.
 Select clones with high tuber yield and low
glycoalkaloid concentration under war conditions.
Objectives

4. Materials and Methods
Experimental Sites in Perú. 2014 – 2015
Locality Altitude
masl
Latitude Longitude Agroecological
Zone
Temperature Average
Day Night Average
San
Ramon
828 11º08’ S 75º20’ W Intermediate
tropics
27.52 22.57 25.14
La Molina 244 12º05’ S 76º56’ W Lowlands tropics 22.99 193.9 21.42
Majes 1294 16º28’ S 72º06’ W Intermediate
tropics
22.89 15.08 18.98
 Two experiments.
 Exp 1.- 64 full-sib families from crosses of LBHT clones using mating
design II North Carolina.
 Exp 2.- 20 LBHT clones.
 Randomized complete block with 3 replications.

5. Characteres evaluated:
At Harvest
 Number and weight of marketable and non-marketable tubers.
 Samples of tubers of each clone were taken and glycoalkaloid concentrations
determined by spectrophotometry in peeled tubers.
Estimation under warm conditions
 Narrow-sense heritability from male variance components for yield
components and tuber yield in LBHT population.
 Broad-sense heritability for glycoalkaloid concentration in LBHT clones.
 Peason correlations to measure the association between tuber yield with
yield components and glycoalkaloid concentration in LBHT clones.
 Selection of clones with glycoalkaloid concentrations less than 20 mg/100g of
fresh weight and high tuber yield.

6. Heat Tolerance in San Ramon a warm rain forest environment at 800 m.
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Average July Average August
Average September Average October
Temperature ºC
Hours
Night Night
Day
Average temperatures
during tuberization, were
22.6ºC in the night and
27.5ºC in the day

7. Harvest of LBHT
clones for broad-
sense heritability for
Glycoalkaloid
concentration
Harvest of progenies,
narrow- sense
heritability for yield
components
Harvest experiments in San Ramon – warm rain forest environment

8. Experiments in Majes – warm and dried environment
Harvest of LBHT
clones for broad-
sense heritability
for Glycoalkaloids
concentration
Harvest of
progenies,
narrow- sense
heritability for
yield
components

9. Source of variation df Tuber number per
plant
Tuber yield
per plant (g)
Average tuber
weight (g)
Environments (E) 2 1535.62 ** 22.32 ** 80411.32 **
Sets (S) 3 11.71 ns 0.20 ** 4676.97**
E x S 6 56.11 ** 0.45 ** 1732.40**
Replications/E/S 24 3.94 ns 0.02 ns 210.34 ns
Male/S 12 31.55 ** 0.14 ** 4463.27**
Female/S 12 27.99 ** 0.11 ** 839.12 **
Male x Female/S 36 8.99 ** 0.07 ** 485.04 **
Male/S x E 24 16.36 ** 0.07 ** 553.80 **
Female/S x E 24 7.36 ns 0.10 ** 467.86 **
Male x Female/S x E 72 7.36 ** 0.07 ** 333.67 **
Pooled error 360 3.64 0.01 159.78
C.V. % 20.77 17.63 18.83
Analysis of variance from North Carolina mating design II over environments for yield
components
**, Significant statistical differences at P<0.01
RESULTS

10. Estimates of narrow-sense heritability for
yield components in potato progenies
planted under warm conditions
Correlations between
tuber yield and its components
Traits h²
Tuber number per plant 0.50
Average tuber weight (g) 0.83
Tuber yield per plant (g) 0.41
Components Tuber
yield/plant
R²
Tuber number per
plant
0.77** 0.59
Average tuber weight
(g)
0.74** 0.55
Pearson’s correlation
values among tuber
yield per plant with
tuber number per plant
and average tuber
weight, were highly
significant (p<0.01)

11. ds concentration in fresh weight mg/100g fwGlycoalkaloids concentration in fresh weight
mg/100g fwGlycoalkaloids concentration in fresh weight mg/100g fw
Source of Variation df Marketable tuber yield per
hectarea t/ha-1
Glycoalkaloid
concentration in fresh
weight mg/100g fw
Environment (E) 2 5162.62 ** 3311.73 **
Replication/ E 6 97.59 ** 5.96 ns
Clones 21 370.20 ** 953.23 **
Clones x E 42 102.12 ** 351.39**
Pooled Error 126 13.742 6.79
C.V % 16.76 28.61
**, Significant statistical differences at P<0.01
Analysis of variance for marketable tuber yield and glycoalkaloid concentration
over environments under warm conditions

12. Estimates of variance components and broad-sense heritability for
glycoalkaloid concentrations.
Variance component Glycoalkaloid concentration
mg/100g fresh weight
Clonal Variance c 66.87
Clone x environment Variance ce 114.87
Broad-sense heritability h² 0.63
Pearson’s correlation between glycoalkaloid
concentrations and tuber yield under warm
conditions was low (r=0.33 and R²=0.11).
Under strong heat stress of warm rain forest San
Ramon, the range of glycoalkaloid concentrations
was from 1.2 to 90.99 mg/100g of fresh weight

13. 0
5
10
15
20
25
30
35
40
Marketable Tuber
Yield tha-1
CLONES
Glycoalkaloids mg/100g fresh weight in peeled tubers Marketable tuber yield tha-1

14. Conclusions and Recommendations
 The estimates of narrow-sense heritability
for yield components, were 0.50, 0.83 and
0.41.
 Correlation among yield components and
tuber yield were highly significant.
 High heritability for yield components in
LBHT population indicate enough genetic
variability for further gains in breeding for
heat tolerance.
 High heritability and low correlation
between yield and glycoalkaloid
concentrations will allow us to select
clones with high yield and low
glycoalkaloid concentrations

15.  Eight LBHT clones, showed low
glycoalcakaloid concentrations (2 to
7 mg/100g of fresh weight) and they
can be used as parents in breeding
programs or varieties suitable for
climate change under heat stress.
 Given the finding of high
concentrations of glycoalkaloid in
this population, assessment of
parental value for this feature is
recommended when selecting clones
to be used as parents in further
breeding.

16. THANK
YOU

17. The International Potato Center (known by its Spanish acronym CIP) is
a research-for-development organization with a focus on potato, sweetpotato,
and Andean roots and tubers. CIP is dedicated to delivering sustainable
science-based solutions to the pressing world issues of hunger, poverty,
gender equity, climate change and the preservation of our Earth’s fragile
biodiversity and natural resources.
www.cipotato.org
CIP is a member of CGIAR
CGIAR is a global agriculture research partnership for a food secure future. Its
science is carried out by the 15 research centers who are members of the
CGIAR Consortium in collaboration with hundreds of partner organizations.
www.cgiar.org