DEVELOPMENT AND VALIDATION OF CORE SETS IN SOYBEAN (Glycine max L. Merrill) GERMPLASM
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Date
2023-05-25
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University of Agricultural Sciences, Bangalore
Abstract
The development of a reduced representative set from a large base collection enhances its role in crop improvement. Considering the size of current soybean germplasm (2000 accessions) obtained from IISR (Indian Institute of Soybean Research), Indore, Madhya Pradesh, felt the difficulty in conserving, characterizing, and evaluating it, an attempt was made to develop a core set in order to increase its usage in breeding. A set of 2000 germplasm accessions along with 3 check varieties were characterized for 13 qualitative traits and 7 quantitative traits following augmented design at GKVK, UAS, Bengaluru. Substantial polymorphism for qualitative traits and genetic variability for quantitative traits in the germplasm were observed. A total of eight core sets were developed using seven quantitative traits data following standard stratified clustering approach. Qualitative trait-based statistics such as chi-square test, class coverage and
Shannon-Weaver diversity index were used as validation criteria to examine homogeneity, retention of qualitative traits-based classes, and polymorphism diversity respectively. Quantitative trait-based univariate statistics (mean and variance) and standardized multivariate statistics (SMD%, CR%, VD% and VR%) were used to assess the representativeness of core sets. A Core set of 15 per cent size developed using logarithmic sampling with preferred allocation strategy was identified as the best representative of the base collection. This core set is suggested as a priority resource for use in breeding programme. To identify trait specific accessions from the core set, 300 (15% core size) soybean germplasm accessions were characterized for 13 qualitative traits and 7 quantitative traits using augmented design at two locations, viz., GKVK Bengaluru and KVK Dodballapura, during Kharif 2022. Based on early flowering, less plant height, early maturity and higher expression of accessions for other four traits, single trait-specific and multiple trait-specific accessions were identified. Twenty five
accessions were found promising for combination of desirable traits.