两淮麦区小麦品种穗发芽敏感性研究

Study on Preharvest Sprouting SuscEptibility in Wheat in Jianghual and Northern Huaihe Region

对两淮麦区40年来代表性小麦品种穗发芽敏感性进行了全面研究，主要结果是：（1）黄熟期的培养皿种子发芽、水层纸巾穗发芽、延期收获田间穗发芽调查和α－淀汾酶活性测定等方法对鉴别小麦品种穗发芽敏感性都有显著的效果；（2）经改进的水层纸巾7天穗发芽度试验是简便、有效、功能全面和适用性好的鉴定方法；（3）小麦品种穗发芽敏感性有4种类型：种子深休眠的低敏型、种子浅休眠与其它机制联合作用的低敏型、种子浅休眠的中敏型和无任何保护机制的高敏型；（4）低敏型和中敏型都有红、白皮两类品种，高敏型全是白皮品种；（5）红色种皮除有助于种子休眠外，还有延缓和减轻田间穗发芽的效应；（6）、1980年代以来的小麦品种抗穗发芽性有严重退化趋势，抗性品种只占12．5％，而50－70年代的供试品种有81．8％是抗穗发芽的；（7）就其重要性，抗穗发芽育种的地位不应低于抗病育种，应改善沿淮、淮北小麦品种布局，重视选择推广红皮品种；（8）小麦抗穗发芽育种选择指标─黄熟期7天穗发芽度；高抗＜1．15、中抗＜1．70；（9）推荐红皮品种博爱7023和马场2号、白皮品种丰产3号和百农3217为小麦抗穗发芽鉴定试验的标准品种。

Representative wheat cultivars released in the Jianghuai and northern Huaihe region of China from 1949 to 1989 were grown in a 3-replicated, randomized block layout in 1988 to 1990 and evaluated for preharvest sprouting susceptibility.The results indicated:Germination test by using intact spikes rolled in paper towels soaked in water layer (7 and 14 days ) and threshed seeds in petri dishes (7 and 10 days ) and by determining α- amylase activity will measure sprouting resistance of wheat cultivars;germination index and degree of sprouting can be used as reliable criteria for measuring the degree of sprouting resistance. Highly significant differences in the susceptibility to preharvest sprouting at yellow ripening was found based on germination percent (7 days)and degree of sprouting(7 days), susceptibility to sprouting of wheat cultivars can be devided into 4 types.Dormancy is the primary determinative factor to preharvest sprouting and factors of inhibition to sprounting in the spike are also involved. The effect of red seed coat of wheat on sprouting is rather complicated,besides deepening dormancy,it can inhibit or put off sprouting in the field.About 80 percent of cultivars released in 1950 to 1979 was resistant to sprouting,and more than 80 percent of cultivars released in the 1980 s was susceptible to sprouting.The importance and the relevant methods of preharvest sprouting resistance breeding of wheat in the Jianghuai and northern Huaihe region determination and selection criteria for this character were also discussed.