Genetic diversity in bacterial wilt tolerant genotypes of bell pepper (Capsicum annuum L. var. grossum Sendt.) using agro morphological and molecular markers
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Date
2022-12-18
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CSK HPKV, Palampur
Abstract
The present investigation was undertaken to estimate the genetic parameters of
variability, associations among traits and characterize the bell pepper genotypes using
agro-morphological and molecular markers to identify superior genotypes for future breeding
programmes. The experimental material comprised 24 genotypes, including one susceptible
(California Wonder) and two resistant (EC-464107 and EC-464115) checks, evaluated in
Randomized Complete Block Design (RCBD) with three replications during the summer rainy season, 2021. Sufficient genetic variability was observed among the genotypes for all
the traits under study. Based on mean performance, BWT-39-DR exhibited the highest
marketable fruit yield per plant followed by BWT-39, BWT-39-BR, Kandaghat Selection and
BWT-3Y-4L. These genotypes were also promising for other traits viz., days to 50 per cent
flowering, days to first picking, harvest duration, fruit width, average fruit weight, marketable
fruits per plant, capsanthin content, TSS and ascorbic acid content. High PCV and GCV along
with high heritability and genetic advance were observed for fruit shape index, marketable
fruits per plant and marketable fruit yield per plant suggesting that selection would be
effective for these traits. Marketable fruit yield per plant showed a significant and positive
correlation with marketable fruits per plant, harvest duration, capsanthin content, ascorbic
acid content, average fruit weight and primary branches per plant. Marketable fruits per plant
and average fruit weight were the best selection indices for increasing marketable fruit yield
per plant. Principal component analysis revealed that the first five significant principal
components explained 83.19 per cent of the variation. Genetic divergence analysis using the
D
2
statistic grouped the genotypes into 11 clusters, whereas the genotypes were divided into
two clusters using the UPGMA clustering method indicating that the population structure was
primarily based on genetic origin along with moderate to high gene flow. Twelve genotypes
viz., BWT-39, BWT-39-BR, BWT-39-DR, BWT-29, BWT-3Y, BWT-3Y-4L, Kandaghat
Selection, BWT-48-AC, BWT-49-AC, BWT-22-HY, EC-464107 and EC-464115 were found
common on comparing the agro-morphological and molecular clusters demonstrating the
congruence between the morphological and SSR data. Thus, based on combined approach of
agro-morphological and molecular characterization, it can be concluded that the genotypes
viz., BWT-39-DR, BWT-39, BWT-39-BR, Kandaghat Selection and BWT-3Y-4L can be
used either directly as varieties after multi-location testing as they are possessing high yields,
superior quality traits and resistance to bacterial wilt, or as parents in hybridization
programmes.