棉花抗枯、黄萎病性早期鉴定方法的研究

STUDY ON EARLY EVALUATION METHOD OF RESISTANCE TO FUSARIUM WILT ANDVERTICILLIUM WILT IN COTTON VARIETY

棉花品种（系）抗枯、黄萎病性鉴定表明，在苗床接种棉枯萎病菌粉９０ｇ／ｍ２，３月下旬至４月初播种，覆膜保温，待棉苗１～２片真叶时，采用沾根或伤根灌窝接菌，每苗接黄萎病菌液１０ｍｌ（２×１０７个孢子／ｍｌ），保持床温平均２２～２５℃，鉴定历期１７～２０天，积温４２３．５～４３８．４℃，发病达高峰，鉴定结果田间病床早期鉴定与大田病圃的抗性一致，苗期黄萎病鉴定与花铃期病情指数达极显著相关（ｒ＝０．７２５４～０．９２９５），是棉花抗病育种早期抗性筛选和鉴定的有效方法。

Evaluation of resistance of Fusarium wilt and Verticillium wilt in cotton cultivars showed that, after inoculating Fusarium oxysporum f. sp. vasinfectum at a dosage of 90 g/m2 which carried by cotton seed meal to the nursery before sowing, then each seedling was inoculated 10 ml of Verticillium dahliae spore suspension (2×107 spores/ml) by means of root soaking or watering the injured roots at 1-2 true leaf stage, and the nursery was covered with polythene film to keep the ayerage bed temperature at 22-25℃, thus the wilt symptoms began to appear in 10 days and showed top disease development when cumulative temperature reached to 423.5-438.4℃. In this case, the period of evaluation was 17-20 days. The results of three years' experiments indicated that the resistance of cotton to Verticillium wilt and Fusarium wilt at seedling stage were consistant with those at adult stage.Highly significant correlation for disease index (r=0.7254-0.9295) between seedling stage and flowering stage was observed.