中国花生小核心种质的建立及高油酸基因源的发掘

Establishment of peanut mini core collection in China and exploration of new resource with high oleat

以中国花生种质资源数据库中记录的6 390份花生资源为材料,以其基本数据、特征数据和评价数据为信息,采用分层分组聚类以及随机取样与必选资源相结合的方法,构建了由298份资源组成的花生小核心种质,占基础收集品的4.66%。通过对小核心种质的植物学类型组成中各类型资源的遗传多样性指数的分析以及小核心种质与核心种质间各性状的比较,结果表明,本研究建立的小核心种质是有效的,基础收集品中各类型资源的多样性在小核心种质中均存在,核心种质中各种性状的变异在小核心种质中也均存在,所用25个性状的平均值差异均不显著。通过对花生小核心种质的种子脂肪酸组成的分析测试,发掘出高油酸新基因源7份,也证明了本研究建立的小核心种质有效性和实用性,其中某些资源还具有棕榈酸含量低、农艺性状好的特点,可以应用于相关研究中。

The characterization of diversity in germplasm collection is important for plant breeders and the genebank curators to manage the collection efficiently. The available large variability contained in germplasm accessions has not been adequately utilized in peanut improvement programs. The lack of information on agronomic and other economic traits of these germplasm is the primary reason, and extensive evaluation on them is required. The development of core collection could facilitate easier access to peanut genetic resources, enhance their use in crop improvement programs, and simplify the genebank management. This paper describes the development of a mini core collection from 6 390 accessions of peanut descriptor traits available from China genebank. The germplasm accessions were first stratified by botanical types and then grouped by ecological origin within each of botanical varieties. Data on 15 morphological and seed chemical traits were used for clustering by SAS method. From each cluster, 1 to 2 percent accessions were randomly or compulsorily selected to constitute a mini core collection consisting of 298 accessions. The accessions widely grown in production or extensively used in breeding programs must be included in the core collection. The rest of included accessions were randomly selected. Examination using diversity index on different botanical types indicated that the genetic variation available in the entire collection has been preserved in the mini core collection. Statistics showed that there was no significant difference on variation between the mini core and core collections among the 25 phenotypic traits. This mini core collection provides an effective mechanism for the proper exploitation of peanut germpIasm resources for the genetic improvement of this crop. Test and evaluation of fatty acids among the 298 accessions of the mini core collection indicated that the mini core collection was available for finding genetic resource with high oleat. 7 accessions with oleat higher than 60% were evaluated and some of them have low palmitic acid and elite agronomic traits.