晋麦21号原名运78—1。系山西省农科院棉花所于1973年冬在温室内用687—44[丰产2号×(碧4×南大2419)]作母本,山前麦作父本杂交,经连年分离选择于1978年育成。1985年3月经山西省品种审定委员会审定,定名为晋麦21号。特征特性半冬性,中熟,籽粒卵形,白粒,半硬质。千粒重40—42克,穗粒数32—35粒。穗圆锥形,小穗排列紧密,长芒、白壳,护颖卵形,颖嘴锐形。芽鞘绿色, Jinmai 21, formerly known as 78-1. Department of Agriculture, Shanxi Academy of Agricultural Sciences cotton in the winter of 1973 in the greenhouse with 687-44 [yield 2 (P 4 × Nanda 2419)] as the female parent Piedmont wheat father, after years of separation selected in 1978 Bred. March 1985 approved by the Shanxi Province Variety Approval Committee, named Jinmai 21. Semi-winter, medium maturity, grain oval, white grain, semi-hard. Thousand grain weight 40-42 grams, grains 32-35 grains. Spike conical, spikelets arranged in close, long-mans, white shell, retaining Ying oval, Ying mouth sharp shape. Sheath green,