川棉243对棉铃虫的抗性及其机理

RESISTANCE AND ITS MECHANISMS OF COTTON VARIETY CHUANMIAN 243 TO COTTON BOLLWORM

抗性鉴定结果表明 ,川棉 2 43对棉铃虫属Ⅱ级抗性水平 (抗 )。叶片少毛是川棉 2 43的一个形态学方面的抗性特征 ,由于叶片正面叶脉茸毛密度低、叶肉不着生茸毛 ,因此川棉 2 43棉株上棉铃虫落卵量分别较常规品种川棉 5 6和中12的低 39.0 %和 2 7.7%。由于体内富含有毒次生代谢物质棉酚和单宁 ,使川棉 2 43具有生化抗性 ,棉铃虫幼虫对其取食的趋性弱、取食量小 ,取食后生长发育受阻、种群存活率与生殖力下降 ,种群增长指数分别较取食中 12和中无 15 1的低 39.4%和 5 2 .6 %。在棉铃虫中等程度发生年份 ,种植川棉 2 43至少可减少用药防治

Resistance identification showed that the cotton ( Gossypium hirsutum) variety Chuanmian 243 has steady resistance to cotton bollworm ( Heliothis armigera), in Degree Ⅱ.Morphologically,the leaf veins on the upper surface are hardly pubescent and its mesophyll has no hair at all,resulting in 39.0% and 27.7% less egg laying of the pest than that of the widely-cultivated varieties Chuanmian 56 and Zhong 12,respectively.Biochemically,Chuanmian 243 contains more toxic secondary substances,gossypol and tannin, thus decreasing the selection of the larvae to the cotton plants,preventing larval growth and development, and reducing the survival rate and fedundity of cottonworm.As compared with the varieties Zhong 12 and Zhongwu 151,population increase index of the pest on the plants of Chuanmian 243 decreases by 39.4% and 52.6%,respectively.As a result,Chuanmian 243 can save at least two pesticide applications in years of medium degree of bollworm incidence.