白皮小麦收获前穗发芽及品种抗性机制探讨

对４８个白皮小麦种质及２个红皮小麦种质连续３年测定结果，品种间收获前穗发芽率，籽粒发芽率及收获后种子休眠特性差异显著。穗发芽敏感性因年份和种子发育时期而异，开花后３５－４０天较敏感，品种间差异大。休眠期长短与穗发芽率间呈极显著负相关。收获后的种子α－淀粉酶活性，降落值，与穗发芽率间分别呈极显著正相关和极显著负相关。

Pre-harvest Sprouting in White Wheats and Its Resistant Characteristics of Cultivars

Fourty-eight white and 2 red wheat genotypes were evaluated for pre-harvest sprouting on spikes and its resistance characteristics of cultivars in three crop seasons. Sprouting percentage on spikes (SPS) and germination percentage of threshed grains (GPG) were mea sured before harvesting, and seed dormancy period, alpha-amylase activity, falling number and water uptake rate, and inhibition percentage of glume-extracts on seed germination were deter mined after harvesting. There were significant varietal differences in SPS, GPG and dormancy period. The sprouting susceptibility varied with years and stages of seed development. The sprouting on spikes and its genotypic differences appeared to be more obvious at 35~40 days af ter anthesis. Seed dormancy was closely associated with sprouting resistance, and the average of correlation coefficients was -0.7855**. The correlation coefficients between sprouting percent age and seed alpha-amylase activity, falling number and water uptake rate at 4 and 8 hours were 0. 6789**,-0. 5490**, 0. 3574* and 0. 4413*, respectively. The inhibition effect of glume- extracts on seed germination was found, and its genotypic differences were especially clear at 24 hours after seed-soaking. Such effect in most resistant cultivars was greater than that in suscepti ble cultivars, but it was not important for sprouting resistance in some resistant cultivars. It is in dicated that sprouting resistance in white wheats is a complex character. Seed dormancy plays a major role, and alpha-amylase activity, falling number and glume substances also have consider able effects on the resistance expression. The resistance mechanism in different cultivars might be not the same.