谷子核心种质表型遗传多样性分析及综合评价

Phenotypic Diversity Evaluations of Foxtail Millet Core Collections

通过遗传种质的多样性评估,可以指导深入研究资源和育种中优异互补亲本的选择,进而提高优异基因的交流累加和新品种培育的效率。本研究选用了来自世界各地的878份谷子核心种质通过15个表型性状的综合鉴定,评估遗传多样性和筛选优异种质资源,结果表明:(1)我国谷子资源的表型遗传多样性丰富,单穗粒重、穗长、穗粗、株高、茎节数和生育期均表现了丰富的变异;谷子育成品种遗传多样性相比农家品种下降明显,育种的遗传增益主要体现在株高和穗长的适度减低,以及茎粗、茎节数、穗粗、单穗粒重、单穗重及生育期的适度增加;(2)系统聚类分析将谷子资源分成3类,第Ⅰ类以来源为东北欧国家的品种为主,第Ⅱ类以北美和非洲的品种为主,第Ⅲ类以东亚、南亚的品种为主;我国种质可划分为春播型、春夏兼播型和南方型3类型;(3)采用主成分分析法和逐步回归分析法综合评判表明,叶鞘色、刚毛长度、粒色、米色、株高、穗长、茎粗和单穗粒重8个性状可作为谷子表型鉴定的主要指标。

Evaluation of genetic diversity could benefit the identification of optimal parental combinations for obtaining segregating offspring with maximum genetic variability, and facilitate the introgression of favorable genes from various germplasm into commercial cultivars. In this study, foxtail millet core collections including 878 world-wide accessions were evaluated through phenotypic analysis of 15 agronomic traits. Main conclusions are as follows：（1） Chinese accessions present higher level of phenotypic diversity, especially in grain weight per main stem, panicle length, panicle diameter, plant height, stem node number and growth period; phenotypic diversity is lower in elite cultivars than in traditional landraces; gains of breeding progress in foxtail millet are expressed in reduced plant height and panicle length, coupling with increased diameter of main stem, stem node number, panicle diameter, grain weight per main stem, panicle weight per main stem and growth period;（2） from the cluster analysis, foreign resources are divided into three categories according to the geographical origins, the first category mainly includes accessions from northeast European countries, the second cluster is mainly collected from North America and Africa, and the third group includes varieties mainly from East Asia, South Asia, African, and European countries; Chinese collections is able to be divided into three groups of spring-sowing, summer-sowing and southern ecotypes;（3） comprehensive assessment of phenotypic traits based on principal component analysis（PCA） and step regression analysis demonstrates that leaf sheath color, bristle length, hull color, grain color, plant height, spike length, stem diameter and grain weight per plant can be used as main identification indicators of foxtail millet phenotypic variations. This research will benefit the utilization of foxtail millet resources in variety breeding practices in the future.