Direct selection for grain yield and correlated response in bread wheat under normal and late sowing dates [electronic resource].

Includes reference.

The present investigation was carried out at Kom-ombo Agric. Res. Stat., ARC, during the three growing seasons of 1999/2000, 2000/2001 and 2001/2002, to study the response to direct selection for grain yield under normal and late planting and estimate the correlated response of the other studied traits. The basic material used in this study consisted of 120 F₃ families stemmed from bread wheat cross [(C.27Ix INIA SIB/PAK) x (KI34(60)4/TOB/BMAN//BB/3/CAL)]. The results indicate significant differences among F₃ families for grain yield/plant, its components and biological yield/plant. Phenotypic coefficients of variability for traits under study ranged from 9.38% to 18.53% while gcv ranged from 9.20% to 17.32% under normal planting. On the other hand, pcv ranged from 9.49% to 19.89% while gcv ranged from 9.18% to 18.53% under late planting. Broad sense heritability estimates for the studied traits ranged from 85.20% for grain yield to 96% for 10OO-kw under normal planting while it ranged from 72.20% for grain yield to 93.500/0 for No. of kernels/spike under late planting. Heritability values for grain yield were (85.2 and 72.2%), (59.4 and 51.5%) and (54.5 and 41.2 %) for C₀, C₁ and C₂, under normal and late planting, respectively. After two cycles of pedigree selection for grain yield/plant the observed response was 20.21 and 18.47% under normal and late planting, respectively, measured as deviation from F₃ bulk and 7.62 and 7.54% under normal and late planting, respectively, measured as deviation from the better parent. While, direct selection for grain yield/plant under normal planting was accompanied with an increase ranged from 12.04% for 1000-kw to 19.79% for No. of spikes/plant compared with population bulk. While, direct selection for grain yield/plant under late planting was accompanied with an increase ranged from 4.56% for No. of kernels/spike to 16.82 % for biological yield/plant. Direct selection for grain yield at normal and late (heat stress) planting using pedigree selection method was effective in isolating lines have high yielding ability and some of yield components.

Summary in Arabic.

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