Genotypic variability in core collection of bread wheat genotypes for drought and heat tolerance
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Date
2021-06
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CCSHAU, Hisar
Abstract
The demand of wheat is expected to increase due to population explosion but climatic factors such as drought and heat stress are causing serious threat to wheat production. Availability of genetic variability along with knowledge of yield attributing traits is helpful in breeding wheat genotypes for these stressed conditions. The present investigation was therefore, carried out to study the genetic variability for yield and attributing morphological traits, identification of traits which can be used for indirect selection and validation of SSR markers associated with combined stress of heat and drought. With this regard forty wheat genotypes were evaluated under four sowing conditions at Research Area, Wheat and Barley Section, Department of Genetics and Plant Breeding, CCS HAU, Hisar during rabi 2018-19 and 2019-20. Significant genetic variability was observed for all the morphological and physiological traits. Correlation and path analysis revealed that biological yield, harvest index, thousand grain weight, SPAD, NDVI and chlorophyll fluorescence reading were associated with grain yield and had direct or indirect effect on grain yield. Stress indices revealed that genotypes NIAW 3170, PBW 676, HD 3298, HD 3217, WH 1202, WH 1164, PBW 773, HD 1621 and WH 1142 were found tolerant to restricted water stress condition. Similarly genotypes HD 3237, WH 1124, DBW 252, WR 544, HD 3043, HD 3226, HD 3298, HI 1623, DBW 278 and WH 1202 were found tolerant to high temperature. Genotypes HD 3237, HI1623, NIAW 3170, WH 1202, HD 1621, HD 3226 and DBW 278 were found stable for dual stress conditions. Cluster analysis grouped the forty genotypes into 5 clusters and revealed that these genotypes were highly divergent. Similarly significant genetic diversity was noted based on 12 polymorphic SSR markers. Out of 12 polymorphic SSR primers, WMC 24, GWM 374, WMC 661, GWM 247, GWM 6, GWM 186, GWM 335 and GWM 508 were found associated with both drought and heat tolerance.