Grain yield and other traits of tall and dwarf isolines of modern bread and durum wheats

Near-isogenic Rht lines of ten modern bread wheat (Triticum aestivum L.) an d six durum wheat (T. turgidum L.) cultivars were developed and evaluated i n replicated trials under three soil moisture treatments for two years in n orthwestern Mexico. The three soil moisture treatments were created by prov iding one, two or six irrigations during each crop season. Grain yield and other traits were measured for each line in each trial. Mean grain yields o f short and tall T. aestivum or T. turgidum isolines were similar in the lo west yielding environment when mean grain yields (0% grain moisture) of T. aestivum and T. turgidum were 2,232 and 1,870 kg ha(-1), respectively. Mean grain yield of dwarf T. aestivum was significantly higher than that of tal l genotypes in another five trials with moderate to high yields. The perfor mance of dwarf and tall T. turgidum isolines was unpredictable in moderate yielding trials, and the dwarf isolines yielded significantly more in trial s that received six irrigations. Given that the tall isolines produced sign ificantly more straw than their shorter counterparts, cultivation of tall w heats may be beneficial in semiarid environments where farmers' yields are close to 2.5 t ha(-1) or lower, and straw has value.