摘要：

为了探究影响茎秆强度的关键因素,筛选在小麦“强秆育种”中有价值的亲本资源,以72份小麦品种(系)为材料,首先综合小麦开花期、灌浆期、乳熟期3个生育时期的茎秆强度进行所有材料的聚类分组,在此基础上进一步分析这些小麦材料茎秆横切面的显微结构和木质素、纤维素含量的遗传变异及其与茎秆强度的相关性,明确与茎秆强度相关的关键性状;利用主成分分析提取茎秆横切面显微结构的主因子、计算综合因子得分,进一步结合木质素、纤维素含量进行聚类分析,从而综合评价不同小麦品种(系)茎秆强度相关性状的表现。结果显示,开花期—灌浆期,小麦茎秆强度变弱的同时,机械组织厚度也出现了显著减少;薄壁组织厚度、机械组织厚度、大维管束面积、木质素和纤维素含量在强茎秆强度小麦中远高于弱茎秆强度小麦;相关分析同样显示,机械组织厚度、大维管束面积、木质素和纤维素含量与茎秆强度呈显著或极显著相关性。最后将茎秆显微结构的主成分综合因子得分和木质素、纤维素含量作为3个变量进行聚类分析,共筛选出18份在茎秆显微结构和生化指标方面表现突出的小麦材料,其可作为小麦“强秆育种”的重要遗传资源。

关键词: 小麦, 强秆育种, 茎秆强度, 显微结构, 木质素含量, 纤维素含量

Abstract:

In order to explore the key factors affecting stem strength and screen the valuable parent resources for wheat "strong stem breeding" ,72 wheat varieties(lines)were used as materials.Firstly,the strength of stems in flowering stage,filling stage and milk stage of wheat was comprehensively analyzed and all the materials were grouped into clusters.On this basis,the genetic variation of lignin content,cellulose content and microstructure of wheat stem and their relation with stem strength were further analyzed,and the key characters related to stem strength were defined.In addition,principal component analysis(PCA)was used to extract the main factors of stem cross section microstructure,and calculate the score of comprehensive factors,and further cluster analysis was carried out combined with lignin and cellulose content,so as to comprehensively evaluate the performance of stem strength related traits of different wheat varieties(lines).The results showed that the mechanical tissue thickness decreased significantly or extremely significant at the same time as the strength of wheat stem weakened from flowering stage to filling stage.Moreover,parenchyma thickness,mechanical tissue thickness,large vascular bundle area,lignin and cellulose content in high stem strength wheat were much higher than those in low stem strength wheat.Correlation analysis also showed that mechanical tissue thickness,large vascular bundle area,lignin and cellulose content were significantly of extremely significantly correlated with stem strength.Finally,the lignin content,cellulose content and the main component comprehensive factor scores of the stem microstructure were used as three variables for cluster analysis,and a total of 18 wheat materials with outstanding performance in the stem microstructure and biochemical indicators were screened out.These wheat materials can be used as important genetic resources for wheat "strong stem breeding".

Key words: Wheat, Strong stem breeding, Stem strength, Microstructure, Lignin content, Cellulose content