Effects of sowing date, variety and nitrogen top-dressing at jointing stage on starch granule size distribution of waxy maize | 播期、品种和拔节期追氮量对糯玉米淀粉粒分布的影响

Chinese. 【目的】明确播期、品种和拔节期追氮量对糯玉米淀粉粒分布的影响及其与淀粉糊化和热力学特性间关系。【方法】以国家糯玉米区域试验对照品种(苏玉糯5号、垦粘1号和苏玉糯1号)为材料,设置春播和秋播处理,研究拔节期追氮量(0、150和300 kg?hm-2)对糯玉米淀粉粒分布的影响。【结果】播期、品种和拔节期追氮量单因子及其互作对淀粉粒体积分布存在显著影响,且播期处理间淀粉粒径和粒度分布的变异远高于拔节期追氮量和品种处理间的变异。总体上,秋播处理下淀粉平均粒径较小、粒径＞17 μm比例较低、9―17 μm比例较高。不同品种间,淀粉平均粒径以苏玉糯1号最低,苏玉糯5号最高,＞17 μm比例苏玉糯5号和垦粘1号间差异较小,以苏玉糯1号最低。随着拔节期追氮量的增加,糯玉米淀粉平均粒径和＞17 μm比例先升后降,13―17 μm比例先降后升。淀粉平均粒径和＞17 μm比例与峰值黏度、崩解值呈显著负相关,与糊化温度呈显著正相关;9―17 μm颗粒比例与峰值黏度、崩解值呈显著正相关,与糊化温度呈显著负相关;淀粉粒分布与回复值、热焓值及回生值无显著相关关系。【结论】播期、品种和拔节期追氮量单因素及其互作对淀粉粒分布有显著影响,且播期是影响淀粉粒分布的关键因子。秋播处理下,选择垦粘1号并拔节期追氮150 kg?hm-2,淀粉平均粒径和＞17 μm比例较小,9―17 μm比例较高,其糊化特性和热力学特性亦较优。

English. 【Objective】 The objective of the study is to understand the effects of sowing date, variety and nitrogen (N) top-dressing at jointing stage on waxy maize starch granule size distribution and clarify the relations between granule size distribution and pasting and thermal properties. 【Method】The effects of N top-dressing (0, 150 and 300 kg?ha-1) at jointing stage on waxy maize starch granule size distribution were studied under spring and autumn treatments using national regional test control varieties (Kennian 1, Suyunuo 1 and Suyunuo 5) as materials.【Result】Starch granule size distribution was significantly affected by the single factor and interactions of sowing dates, varieties and N top-dressing amount at jointing stage, and the variation coefficients from sowing dates were larger than varieties and N topdressing treatments. In general, the average diameter and the proportion of diameter higher than 17 μm were lower under autumn sowing treatment. Among the 3 varieties, the average diameter was the lowest for Suyunuo 1 and the highest for Suyunuo 5, the proportion of diameter higher than 17 μm was lowest for Suyunuo 1 and similar between Kennian 1 and Suyunuo 5. With the increment of N top-dressing at jointing stage, the average diameter and the proportion of diameter higher than 17 μm rose first and fell later, whereas the proportion of diameter between 13 and 17 μm fell first and rose later. The average diameter and the proportion of diameter higher than 17 μm were negatively correlated to peak viscosity and breakdown, whereas it was positively correlated to pasting temperature, onset temperature, and peak temperature. The proportion of diameter between 9 μm and 17 μm was positively correlated to peak viscosity and breakdown, whereas it was negatively correlated to pasting temperature, onset temperature, and peak temperature. No significant correlations were observed between starch granule size distribution and setback, enthalpy of gelatinization and the percentage of retrogradation. 【Conclusion】 It was concluded that the sowing date was the key factor that change the granule size distribution. In the autumn sowing treatment, using Kennian 1 as material and topdressing 150 kg?ha-1 N at jointing stage, the starch presented higher proportion of diameter between 9 and 17 μm, lower average diameter and the proportion of diameter higher than 17 μm, which results in better pasting and thermal properties.