Differential Response of Some Bread Wheat (Triticum aestivum L.) Genotypes for Yield and Vegetative Traits under Optimum and Late Sowing Dates

: This research aimed at studying the effect of late sowing on the vegetative growth and yield of twelve genotypes of bread wheat ( Triticum aestivum L.). An experiment was carried out in 2012/2013 using two sowing dates: 28th of November (reference) and 27th of December (late) at two locations (Shambat Demonstration Farm, Faculty of Agriculture University of Khartoum and Hudeiba Research Station). The experimental design was a split-plot with three replications. The results showed that late sowing significantly affected most of the vegetative characters. The results showed significant differences ( p ≤ 0.05) among genotypes for vegetative growth and yield at both locations. The interaction of sowing date and wheat genotypes was significant ( p ≤ 0.05) for 50% booting, 50% anthesis, 95% maturity, leaf area index and grain yield. Under reference sowing date total yield was 2.21 tons/ha and under late sowing it was 1.43 tons/ha with a reduction of about 35%. The genotypes exhibited large variation in their response to heat stress imposed at late sowing indicating the possibility of improving this trait genetically. Genotype 56 was the earliest in maturity at both locations; therefore, it can be tested for cultivation south of Khartoum.