拔节期追氮对春播和秋播糯玉米淀粉胶凝和回生特性的影响

以垦粘1号、苏玉糯1号和苏玉糯5号为材料,研究了拔节期追氮量(N 01、50和300 kg/hm2)对春播和秋播糯玉米淀粉胶凝和回生特性的影响,试验于扬州大学实验农牧场进行。结果看出,播期、品种和拔节期追氮量单因素及其互作对淀粉胶凝和回生主要特征值存在显著影响。糯玉米淀粉胶凝和回生特征值在拔节期追氮150 kg/hm2时和秋播条件下较优,即原淀粉具有较低的峰值温度、较高的热焓值,回生淀粉具有较低的回生值,且以垦粘1号表现较好。糯玉米淀粉胶凝和回生特征值之间存在一定的相关性。回生值分别与回生淀粉的热焓值、原淀粉的终值温度显著正相关,相关系数分别为0.82(P0.01)和0.47(P0.05);原淀粉的热焓值与峰值指数显著正相关,相关系数为0.53(P0.05),与原淀粉峰值温度、回生淀粉的终值温度显著负相关,相关系数分别为-0.53(P0.05)和-0.52(P0.05);回生淀粉的热焓值分别与回生淀粉起始温度、终值指数显著正相关,相关系数分别为0.46(P0.05)和0.66(P0.01)。综合考虑淀粉胶凝和回生特性在不同处理下的变化趋势,以秋播糯玉米淀粉在拔节期追N 150 kg/hm2处理下较优。

Effects of nitrogen top-dressing on starch gelatinization and retrogradation properties of spring and autumn waxy maize at the jointing stage

To understand the effects of nitrogen top-dressing amounts on starch gelatinization and retrogradation properties of spring and autumn sown waxy maize at the jointing stage, a study was carried out at the Experiment Farm of Yangzhou University in 2008. There were three cultivars (Suyunuo 5, Kennian 1 and Suyunuo 1) and three nitrogen top-dressing amounts (0, 150 and 300 kg/ha) in the study. The results show the main waxy maize starch gelatinization and retrogradation properties are significantly affected by the single factor and interactions between the nitrogen top-dressing amount at the jointing stage, sowing date and cultivar. In general, the gelatinization and retrogradation characteristics are better under the N 150 kg/ha nitrogen top-dressing amount and the autumn-sowing condition, especially for the cultivar Kennian 1, that is the raw starch has a lower peak temperature (T_p), higher enthalpy of gelatinization (ΔH_gel) and low percentage of retrogradation (%R). Results of the correlation analysis indicate that the percentage of retrogradation is positively correlated with enthalpy of retrogradation (ΔH_ret) (r= 0.82, P< 0.01) and T_c (r= 0.47, P< 0.05), and ΔH_gel is positively correlated with peak height index (PHI)(r= 0.53, P< 0.05) and is negatively correlated with T_p (r= -0.53, P< 0.05) and T_c of retrograded starch(r= -0.52, P< 0.05). ΔH_ret is positively correlated with though onset temperature (T_o) of retrograded starch (r= 0.46, P< 0.05) and PHI of retrograded starch (r= 0.66, P<0.01). Considering the starch gelatinization and retrogradation properties in different treatments, the autumn sowing waxy maize cultivars and the N 150 kg/ha nitrogen top-dressing amount at jointing stage are suitable to get better starch.