Combining Ability and Heterosis for Earliness, Growth and Biological Yield of Some Flax Genotypes at Normal-irrigation and Water-Shortage Environments

Abstract

Six parents and their 15 F1 crosses were evaluated in 2019/2020 season under normal and drought-stress for earliness and its related traits of flax. A filed experiment was devoted for each normal and drought-stress), using RCBD with three replicates. Mean squares of general and specific combining abilities were highly significant for most traits, indicating the relative importance of both additive and non-additive influences of genes in the inheritance of these traits. δ 2 GCA δ 2 /SCA variances under normal-irrigation and drought-stress were greater than unity for days to maturity, plant height at harvest and stem diameter. P1 was found to be the best combiner for earliness under both conditions. While, P4 and P5 were good combiner for plant height at flowering and at harvest and biological yield under drought conditions. The best heterosis (mid and better parent) for the earliest hybrids was recorded by hybrid No. 11 under normal and hybrid No. 7 under drought. Hybrids No. 6 over mid-parents and No. 11 over better-parents under drought for days to maturity shown the best heterosis. While, hybrids No. 8 and 10 recorded the best heterosis for plant height at flowering under both situations. But, the best heterosis were recorded by hybrids No. 2 and 8 for plant height at harvest and hybrids No.7 and 13 for technical stem length shown under normal irrigation conditions. The hybrids No. 4 and 9 for biological yield per plant showed the best heterosis over mid and better parents under normal and drought conditions, respectively.

Seed Priming and Foliar Supplementation with β-aminobutyric Acid Alleviates Drought Stress through Mitigation of Oxidative Stress and Enhancement of Antioxidant Defense in Linseed (Linum usitatissimum L.)

“…Yield and yield-related parameters of different linseed genotypes were influenced differently by varying levels of DS as adverse effects of DS depend on plant species, time of incidence, severity and duration of DS, etc. [48]. With water deficit conditions, the number of capsules per plant, number of seeds, 1000-seeds weight, plant height, the number of branches per plant and seed yield declined as compared to normal irrigation [46].…”

“…The incidence of DS at critical growth stages (seedling, flowering, grain development, etc.) significantly reduces the seed yield of linseed [47,48]. The negative impacts of DS on the vegetative growth characteristics of linseed also hinder the progression of its reproductive growth life cycle [49].…”