COMBINING ABILITY EFFECTS AND INHERITANCE OF MATURITY AND YIELD ASSOCIATED TRAITS IN F2 POPULATIONS OF WHEAT

In existing era of molecular breeding, conventional breeding has sustainable foundation, and molecular marker applications are certified through classical breeding. The present study was carried out with the objectives to determine the genetic variability, combining ability effects among populations, and gene action for maturity and yield traits in wheat. Six wheat lines i.e., IBWSN-177, IBWSN-52, IBWSN131, SRN-09111, PR-107 and NR-21, and three testers i.e., Pakhtunkhwa-15, Pirsabak-15 and Shahkar-13 were crossed during 2015-16 in a line by tester matting design. After advancing the generation during 2016-17, the parental lines and testers, and their eighteen F-2 populations were grown during 2017-18 in randomized complete block design with three replications. Significant (p <= 0.01) differences were observed among genotypes for all the traits. Line by tester F2populations revealed significant (p <= 0.01) variations for all the traits. However, testers were significant (p <= 0.01) for days to maturity, spikelets per spike and 1000-grain weight. Parental lines IBWSN-131 and IBWSN-52,testers Pakhtunkhwa-15 and Shahkar-13, and F-2 populations IBWSN-131 x Pakhtunkhwa-15, SRN-09111 x Pakhtunkhwa-15 and PR-107 x Shahkar-13revealed significant (p<0.01) GCA and SCA effects and acknowledged as best general and specific combiners for various traits. High x high, high x low and low x high general combiners were involved in F-2 populations with promising SCA and best mean performance. In proportional contribution,F-2 populations has maximum share to total variance for the majority of the traits. The ratios of GCA to SCA, and average degree of dominance were smaller and greater than unity, respectively, which revealed that non-additive gene effects governed all the traits. Due to non-additive gene action, the selection of promising populations in terms of maturity and yield traits should be delayed to later segregating generations. The said promising populations could be used in future breeding program to develop early maturing and high yielding wheat genotypes.