DefinePK

Abstract

In wheat improvement programs development of new high yielding varieties requires information about, inheritance mechanism, identification of superior germplasm and combining ability of parents to transmit desirable attributes to offspring. In the current study, three genetically diverse elite advanced lines i.e. PR-105, PR-108 and PR-109 and three commercial wheat cultivars Faisalabad -2008, Lasani-2008 and Pirsabak-2013 were sown in crossing block during 2013-14. They were crossed in line × tester mating design to develop F1 hybrids. F1 hybrids along with their parents were evaluated in randomized complete block design with three replications at Cereal Crops Research Institute Pirsabak, Nowshera Khyber Pakhtunkhwa-Pakistan during 2014-15 for seven important traits. Analysis of variance revealed highly significant (P≤0.01) differences among the genotypes for the studied traits. Based on desirable General Combining Ability (GCA) effects, among the lines and testers, line (PR-105) and tester (Faisalabad-2008) were found best for earlier heading, maturity and high grain yield. Based on desirable Specific Combining Ability (SCA) effects,  crosses, PR-109 × Lasani-2008 (for days to heading and maturity), PR-108 × Pirsabak-2013 (for flag leaf area), (PR-108 × Faisalabad-2008 (for biological yield) and PR-105 × Lasani-2008 (for grain yield) were best specific hybrids involving high × low and high × high GCA effects of parents and could be advanced to later segregating generation to extract potential transgressive segregants lines. Contribution of lines × tester interaction to the total variation was greater than lines and testers individually, indicating greater potential/variation of hybrids appearing for most of the traits. Ratio of GCA variance to SCA variance showed predominance of non additive gene action for all the studied traits. The identified superior crosses could be advanced through mass selection and therefore, single plant selection should be delayed to late segregating generations (F6) to derived potential lines for economically important traits.
Keywords:  Combining Ability; Gene Action; Line × Tester; Mating Design; Variance Components; Yield
http://dx.doi.org/10.19045/bspab.2018.70019