氮肥用量对不同穗型小麦品种穗部结实特性的影响

目的]深入了解不同氮素水平下小麦穗部籽粒发育变化规律,为小麦高产施肥技术提供理论依据。方法]于2005~2006年,以大穗型小麦品种矮早8和多穗型品种周麦18为供试品种,设3个氮素水平,分别为180、2403、00 kg/hm2,研究了2种不同穗型的小麦品种籽粒结实粒数、小穗粒重、小穗单粒重在不同氮素水平下的空间分布特征。结果]供试品种在3个不同氮肥水平下小穗粒重、结实粒数随穗位的上升均呈先升后降的趋势,中下部小穗粒重、结实粒数的增加幅度明显大于中上部与上部小穗;平均单粒重随氮肥水平的增加先增加后减少,小穗单粒重最大的穗位低于小穗粒重最大的穗位。对于大穗型品种,小穗粒重和结实粒数表现出随氮肥施用量的增加而增加的趋势,而对于多穗型品种,小穗粒重表现出随氮肥施用量的增加呈现出先增后减的趋势,小穗结实粒数的影响呈现出不明显的趋势。增施氮肥对提高大穗型品种小穗粒重、结实粒数的效应更明显。结论]籽粒在穗部的位置决定了小麦穗部籽粒结实与物质积累的空间分布特征。这些研究结果对于量化小麦穗部籽粒产量的调控途径等具有重要的意义。

Effects of the Application of N Fertilizer on Seed-setting Characteristics in Spike Part of Different Spike Type Wheat Varieties

Objective] The study was conducted to know deeply the change law of grain development in spike part of wheat under different N fertilizer level so as to provide the theoretical basis for high yield fertilization technique in wheat.Method] In field test with the large-spike wheat variety Aizao 8 and multi-spike wheat variety Zhoumai 18 as tested materials in 2005～2006,the space distrbution characteristic of grain number of seed-setting,grain weight per spikelet and individual grain weight under different level of N fertilization was studied by applying 3 kinds of N concentration as 180,240,300 kg/hm2.Result] Under 3 levels of N-fertilizer,grain weight per spikelet and number of seed-setting of the tested varieties showed the trend of first increasing and then decreasing.The increasing extent of grain weight per spikelet and number of seed-setting in middle-lower spikelet was larger than that in the middle-top and top spikelet.The individual grain weight increased at the beginning and then decreased with the increase of nitrogen application rates.The maximal spike position for individual grain weight of spikelet was lower than the maximal spike position for grain weight of spikelet.As for large-spike variety,the grain weight per spikelet and number of seed-setting showed the trend of increasing with the increment of nitrogen application rates.As for multi-spike variety,the grain weight per spikelet showed the trend of first increasing and then decreasing with the increment of nitrogen application rates,the effect of number of seed-setting showed not remarkable trend.The effect of increasing N-fertilizer was more remarkable on increasing the grain weight per spikelet and number of seed-setting of large-spike variety.Conclusion] The grain position in spike part decided the the space distrbution chanracteristics of gain seed-setting and material accumulation in wheat spike part.The research results had important significance for the quantization of regulation approach of the gain yield in wheat spike part.