长江中下游麦区小麦迟播的不利影响及育种对策

近年来长江中下游稻麦轮作区水稻成熟期不断推迟,致使小麦播期大幅度推迟,这已成为该麦区小麦高产稳产的主要障碍。迟播不仅导致小麦生育期缩短,积温、光照时数减少,营养生长不足,难以形成高产群体基础,还导致赤霉病和白粉病严重发生,增加了灌浆期遭遇高温危害的风险及收获前遇阴雨发生穗发芽的概率。为了减少小麦迟播的不利影响,除了栽培措施应对外,根本措施是培育适合迟播的小麦品种。在育种时应重点加强迟播条件下出苗快、生根快、分蘖早、越冬期仍能保持较大生长量和分蘖发生量等性状的选择;提高抗性,特别是赤霉病抗性、耐渍性和抗穗发芽性;注重选择灌浆速率高、耐高温逼熟的品种,利用灌浆速率的提高补偿灌浆时间缩短的不利效应,培育迟播高产品种。

Negative Effects of Late Sowing on Wheat Production in Middle and Lower Reaches of Yangtze River Valley and Breeding Strategies

The wheat sowing date is delayed largely because of planting late mature japonica rice varieties in large area and replacing artificial transplanting by machine transplanting and seed planting. Furthermore, the farmers harvest rice later until rice grain drier as it matures completely. That may bring the consequences of shortening the growth period, decreasing accumulated temperature and length of radiation for wheat production, thus leading deficiency on the nutrition growth of wheat. It also makes wheat more susceptible to scab and powdery mildew, increases the risk to encounter high temperature during grain filling stage and pre harvest sprouting before harvest. So late sowing has been the main hinder to get high yield for wheat. Although the adverse effects of late sowing could be compensated by cultivation measures, the basic and efficient measure is to breed cultivars suitable for late sowing. The strategies to breed wheat varieties with high yielding in late sowing condition are proposed as screening on the following characteristics: (1) varieties with early and fast growth in seedling, rooting, growing and tillering, with relatively high growth and tillers occurrence while in wintering period; (2) varieties with strong resistance to diseases, especially to scab, waterlogging and resistance to pre harvest sprouting; (3) varieties with high grain filling speed and heat tolerance, therefore compensation the adverse effect of shortening grain filling time by grain filling speed.