Detection of Gene Action for Morpho-physiological Traits With Reference to Heat Tolerance In Wheat (Triticum Aestivum L.)

Abstract

The present investigation entitled “Detection of Gene Action for Morpho-Physiological Traits with Reference to Heat Tolerance in Wheat (Triticum aestivum L.)” was carried out at CRC, Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut. The experimental materials for the present study involved 10 genetically diverse wheat varieties namely, HUW 510, PBW 373, RAJ 3765, K 9423, AAI 1536, RAJ 4128, HUW 251, C 306, DBW 17 and PBW 343. These parental lines were mating in diallel fashion excluding reciprocals during the rabi season of 2015-2016. The parents and their 45 F1s were also grown in the next year during rabi season of 2016-2017 under irrigated conditions in randomized block design with three replications with two date of sowing i.e. timely sown (E1) on 25 November, 2016 and late sown (E2) 30 December 2016.Analysis of variance involved sufficient variation was present among parents and hybrid for the traits viz., traits viz., 50 % flowering, plant height, number of productive tillers per plant, grain filling duration,1000 grain weight, biological yield per plant, proline content and grain yield per plant under both the environments. Whereas, spike length, grains per spike and leaf senescence showed significant difference under timely sown and chlorophyll content at anthesis, and chlorophyll content at 10 days after anthesis revealed significant difference under late sown condition. Heterosis was observed for all characters, for grain yield per plants maximum heterosis and per se performance was show RAJ 3765 x C 306, RAJ 4128 x HUW 251 and K 9423 x C 306 . Based on the present investigation, genotype PBW 343, DBW 17, AAI 1536, C 306, RAJ 3765 and K 9423 appeared to be the best combiner for grain yield and its contributing characters. An overall assessment of parents for all the studied characters indicated that RAJ 3765, C 306 and K 9423 were found to be desirable for most of the characters on the basis of Heat Susceptibility Index. It is well known that grain yield is prime concern of any breeding programme, therefore crosses HUW 251 x C 306, RAJ 3765 × C306, C 306 x DBW 17, RAJ 4128 x C 306 and RAJ 3765 x DBW 17 which exhibited comparatively more tolerance among 45 F1‟s for grain yield per plant were considered as desirable for heat stress tolerance in late sown. High heritability coupled with high genetic advance was observed for the traits viz., proline content in timely sown whereas proline content, biological yield per plant and grain yield per plant in late sown, indicating that these traits are governed by the additive gene action which would be effective for selection for a better genotypes of bread wheat at phenotypic basis. Grain yield per plant had positive and significant correlated withdays to 50% flowering, days to maturity, number of productive tillers per plant, grain filling duration, spike length, number of grains per spike, 1000-grain weight and biological yield per plant under both the environment. The significant association of these characters with grain yield per plant reflected that by improving these traits, grain yield per plant could be improved. Path coefficient analysis revealed that direct effects on grain yield with the characters biological yield per plant, harvest index, days to maturity, 1000-grain weight and flag leaf area.