不同生态区小麦品种的穗发芽抗性评价

本研究对来自不同生态区的137个小麦品种进行穗发芽抗性鉴定,计算相对发芽指数,并分析这些品种穗部籽粒性状、品质指标、吸胀萌发后0～72 h α-淀粉酶活性及其基因表达量与穗发芽抗性之间的关系。结果表明: 长江中下游麦区小麦的平均发芽指数最低,抗穗发芽品种最多,其次是长江上游麦区,黄淮麦区抗穗发芽品种相对较少。红粒品种小麦的相对发芽指数低于白粒品种,相对发芽指数与籽粒长度、宽度呈极显著正相关,与小穗数呈显著正相关,与穗型、穗色、穗长、小穗密度、穗粒数、千粒重无显著相关性。相对发芽指数与容重呈极显著负相关,与面团形成时间和出粉率呈显著负相关,与蛋白质含量、湿面筋含量、吸水率、稳定时间、沉降值、拉伸面积、延展性、最大阻力无显著相关性。不同品种的α-淀粉酶活性随吸胀萌发时间的延长呈上升趋势,萌发24～72 h的相对发芽指数与α-淀粉酶活性呈极显著正相关,穗发芽中抗以上品种萌发48 h后α-淀粉酶活性聚类分析结果与穗发芽鉴定结果一致。萌发后各时段α-淀粉酶基因表达量与相对发芽指数呈极显著正相关。

Evaluation of pre-harvest sprouting resistance of wheat varieties from different ecological regions.

The pre-harvest sprouting (PHS) resistance of 137 wheat varieties from different regions was evaluated and the relative germination index (RGI) was calculated. The relationships between PHS and grain quality traits, amylase activity and related gene expression level of these varieties were analyzed. The results showed that wheat varieties from the middle and lower reaches of Yangtze River Valley winter wheat region had the lowest RGI value and the highest ratio of resistant pre-harvest sprouting wheat varieties, followed by the varieties from the upper reach of Yangtze River Valley winter wheat region and from the Yellow and Huai River Valley. Red-grain wheat had lower RGI than white-grain wheat. RGI was positively correlated with seed length, seed width, and spikelet number, but not correlated with other grain traits (panicle type, ear color, ear length, and spikelet density, grain per spike and 1000-grain weight). RGI was negatively associated with the test weight, dough development time, and flour yield, but not with other quality indices (protein content, wet gluten content, water absorption, stability time, sedimentation, extension area, extensibility and max resistance). Amylase activity of different varieties increased with seed imbibition time. RGI was positively associated with α-amylase activity after germinating for 24-72 hours. The cluster analysis results of resistant varieties were consistent with the PHS resistance evaluation after 48 hours. RGI was positively associated with the related gene expression with seed imbibition time.