孕穗期低温胁迫对寒地水稻产量和品质的影响

以黑龙江省25份主栽水稻品种及苗头品系为试材,在孕穗期平均16.1℃,处理5 d的试材为低温处理,以正常栽培管理的试材为对照,分析低温胁迫对不同水稻品种(系)品质性状及产量的影响。结果表明,低温处理导致所有试材每穴实粒数、结实率、千粒重和产量下降,根据相对结实率分为1、3和5级,其中以3级最多、5级最少,分别占总材料的56%和8%。低温处理导致材料糙米粒长、宽和厚下降,但是1和3级材料下降幅度更大;低温处理稻米整精米率、直链淀粉含量、蛋白质含量、起浆温度和消减值增加,稻米糙米率、精米率、最高黏度和崩解值下降,但是耐冷性中等的材料直链淀粉和蛋白质含量增加幅度更大。相关分析表明,相对结实率与每穴实粒数、每穴产量和冷胶黏度的冷水反映指数(CRI)呈极显著正相关,与崩解值和回复值的CRI值呈显著正相关。综上所述,孕穗期低温胁迫对水稻产量和品质的影响在品种间存在很大差异,在低温胁迫下耐冷性极强品种(系)每穴实粒数、结实率、千粒重、直链淀粉和蛋白质含量及最高黏度对低温反应迟钝,这是耐冷性极强品种(系)保持较高产量和优良品质的重要形态特征和生理原因。

Effect of cold stress at booting stage on rice yield and quality in the cold region

In the present study, we selected 25 main rice cultivars (lines) in Heilongjiang Province and simulated low temperature stress at 16.1 °C for 5 days to investigate the effect of rice cold tolerance at the booting stage on the rice yield and quality. Our results showed that the full seed number, setting percentage, 1000 grain weight, and yield of all treatments decreased. The rice cultivars were classified as 1, 3, and 5 by relative setting percentage. Most of the rice cultivars belonged to Class 3, and few were in Class 5, while Classes 3 and 5 accounted for 56% and 8% of the rice cultivars, respectively. The low temperature stress decreased the length, width, and thickness of brown rice, and additionally, the decline in Classes 1 and 3 (lines) was greater than in Class 5. The head-milled rice rate, amylose and protein content, pasting temperature, and setback value increased under low temperature stress, whereas the brown rice rate, milled rice rate, peak viscosity, and breakdown value decreased. Moreover, the increase in amylose and protein content was higher in the medium cold-tolerant cultivars. The correlation analysis results showed that the relative seed setting rate was significantly, positively correlated with the CRI of the number of grains per cave, yield per cave, and cool paste viscosity. Such rate was also significantly, positively correlated with the CRI of the breakdown and consistence values. In conclusion, the reduction of grain yield and quality under low temperature treatments during heading and early grain filling largely varied depending on the rice cultivar. The cold tolerance of the germplasm was closely correlated with the low temperature reaction of the full seed number, setting percentage, 1000 grain weight, amylose and protein contents, and peak viscosity. At low temperatures, the higher cold tolerance corresponded well to the lower starch viscosity. Such findings are important morphological specificity and physiological mechanism in maintaining the grain yield and fine quality of rice varieties under cold stress at the booting stage.