江苏省麦(油)后棉的栽培与育种

Study on Growing Practices and Breeding of Double-Cropping Cotton Following Wheat, Barley or Rapeseed

麦(油)后棉,巳成为江苏省重要的种植制度之一。即大元麦后移栽棉,油菜后移栽棉,小麦后移栽棉,大元麦后直播棉,油菜后直播棉。该种植制度具有较好的经济效益、生态效益和社会效益,以麦后移栽棉为例,比麦套棉每亩增产粮食50—75千克,综合经济效益提高4.9—18.5％,并能减轻某些病虫危害。 麦(油)后棉苗期生长速度快,移栽时个体大;株高增长高峰期后移,果枝增长高峰期与株高增长高峰期重叠,蕾数前少后多,果枝增长高峰值低而长;叶面积增长与干物质积累前慢后快,只有一个成铃高峰。技术要求培育大壮苗,合理密植,准确化控和适当延期打顶。 中熟棉品种改作麦(油)后短季栽培,棉花要减产5—10％。以北方早熟品种在本省作麦(油)后栽培,成铃率低(4.24个百分点)、衣分低(1.56个百分点)、单铃籽棉重轻(0.22克),衣指轻(0.33克)、后期易早哀。适合我省麦(油)后短季栽培的棉花品种模式:苗期快发,耐迟播,植株偏矮,避台风;吐絮集中,秋季避连阴雨。

Double-cropping cotton following wheat, barley or rapeseed has become one of the important cropping systems in Jiangsu province. In this system, cotton is either transplanted or directly sown. This cropping system gives remarkable economic,ecological and social benefits. For example,transpanting cotton following wheat or barley produced 50-75 kg/mu grain more than cotton-wheat (barley )relay intercroping; the comprehensive economic benefit of the former was 4. 9-18. 5 percent higher than that of the latter . Transplanted double-cropping cotton plants are characterized by rapid growth at the seedling stage, large seedling size at transplanting ,later appearance of the peak growth period of plant height , a large amount of squares and fast increases in leaf area and dry matter accumulation in the late growing season,etc. The key techniques for growing cotton under this cropping pattern include transplanting larger and healthy seedlings,a proper planting density,chemical control of plant growth, and later topping. The current cotton cultivars, either medium or early maturing, usually reduce their yields when used as a short season crop after summer-harvested crops. So it is an urgent need to breed new cultivars suitable for this cropping system,i. e. ,tolerant to late sowing,rapid developing at the seedling stage , shorter plants,concentrated opening of bolls,and less affected by typhoon and autumn rain.