不同穗型小麦品种小花发育成粒对氮肥的响应

为探索不同穗型小麦品种小花发育成粒对氮肥的响应,本试验以大穗型品种‘周麦16’和多穗型品种‘豫麦49’为供试材料,设置不同施氮水平0 kg(N)·hm~(-2)、180 kg(N)·hm~(-2)和360 kg(N)·hm~(-2),观察分析了两个穗型小麦品种小花发育动态模式和结实特性。结果显示,随着生长度日(GDD)的增加,不同氮水平下2品种小花发育动态变化趋势相似,小花分化均符合二次曲线方程模式,退化和败育符合一次线性方程,R2均达显著水平。大穗型品种‘周麦16’小花分化总数显著高于多穗型品种‘豫麦49’,在360 kg(N)·hm~(-2)处理差异极显著;大穗型品种‘周麦16’表现出随施氮量增加,小花分化和退化速率提高,有利于可孕小花的形成、增加结实粒数,最终180 kg(N)·hm~(-2)处理结实粒数显著高于其他处理,较360 kg(N)·hm~(-2)处理平均每穗粒数增加2.04粒;多穗型品种‘豫麦49’尽管分化小花总量不高,但小花退化和可孕小花败育速率较低,在180 kg(N)·hm~(-2)施氮水平表现出高的可孕小花数量和结实粒数,但与高施氮处理相比差异不显著。表明就增加穗粒数而言,两品种均以180 kg(N)·hm~(-2)较为适宜,从最终产量及产量构成分析结果来看,‘豫麦49’表现出与穗粒数相同的结果,而‘周麦16’在高施氮条件下可通过增加成穗数和穗粒数提高产量。

Response of florets development and grain formation in different spike wheat cultivars to nitrogen application

Wheat provides 20% of the calorie and protein consumed by humans. Further improvement in wheat yield potential is needed to meet future food demand. As yield is related to the number of grains, an understanding of the generation of grain is critical for increasing yield. Nitrogen is an important nutrient affecting the growth and development of wheat. Wheat yield is calculated as the number of grains per square meter, which in turn is related to the number of fertile florets at anthesis. In this study, the dynamics of floret generation and degeneration were studied in contrasting conditions of 0 kg·hm-2, 180 kg·hm-2 and 360 kg·hm-2 of nitrogen (N). The modern, well-adapted large-spike wheat cultivar 'Zhoumai 16' and multi-spike wheat cultivar 'Yumai 49' were used at the materials. The results indicated that the dynamic characteristics of floret development of two cultivars were similar un-der different nitrogen applications with increasing degree-days (GDD). The dynamics of floret differentiation conformed to quadratic curve model. Besides, both floret degeneration and infertility conformed to linear equation. Moreover, the correlations were all signifi-cant. The large spike-cultivar 'Zhoumai 16' developed more florets than multi-spike cultivar 'Yumai 49', especially under nitrogen level of 180 kg(N)·hm-2. For increased nitrogen application, large spike cultivar wheat 'Zhoumai 16' had more floret differentiation and faster floret differentiation and degeneration rates, which helped increase kernel number. This clearly indicated that the number of florets was not the only factor that determined grain number, hence there was need to place more focus on cultivation regulation at later stages of floret development. However, multi-spike cultivar 'Yumai 49' had more floret differentiation and fertile spikelet under medium nitrogen level [180 kg(N)·hm-2] than under low and high nitrogen levels. Although the total number of floret differentiation of multi-spike cultivar 'Yumai 49' was less than that of large-spike cultivar 'Zhoumai 16', the degeneration and infertility rates were rather low. Compared with multi-spike cultivar wheat, the 1000-kernel weight of large-spike cultivar was highest for three different nitrogen levels. Under the experimental condition, yield of two cultivars of wheat peaked under 180 kg(N)·hm-2. It was concluded that 180 kg(N)·hm-2 in-creased kernel number of different spike cultivars. However, yield of large-spike cultivar 'Zhoumai 16' improved by increased spike and grain number under high nitrogen rate.