‘紫王子’海棠半同胞家系苗期表型特征分析

【目的】基于海棠种质基因库优良品种资源丰富的优势,开展了以‘紫王子’海棠(Malus‘Purple Prince’)为母本的自由授粉子代试验研究,探索其半同胞家系表型特征及育种成效。【方法】运用Shannon-Wiener(H'R)及Pielou(ER)等指数进行14个性状的表型多样性比较,采用频率分布函数法进行亲子代间性状变异趋势及超亲性分析,通过层次分析法(AHP)进行表型性状综合评价。【结果】在表型多样性方面,‘紫王子’海棠半同胞家系14个性状的H'R平均值比疑似父本群体提高了13%,其中地径生长量、分枝数、完全功能叶颜色的H'R和ER超过疑似父本群体23.8%~53.2%。在遗传改良方面,与疑似父本群体相比,半同胞家系中综合性状得分高的优株比例下降了37.0%,紫红叶优株和速生优株的比例分别下降了14.9%和37.5%,但枫叶型、分枝多、通直度高、耐热性强的优株比例分别增加了12.6%、48.3%、28.7%和18.5%;与母本相比,7.8%的优株综合性状得分超过母本;此外,有些单株综合得分略低于母本,但部分单一性状表现比较突出,如F113和F60优株的新叶为鲜见的亮红色,F35和F108优株的叶片为枫叶型,观赏效果佳。【结论】尽管自由授粉降低了优株比例,但有效扩大了子代群体的遗传基础,对部分性状的遗传改良具有明显的效果。

Analysis of phenotypic characteristics of the Malus 'Purple Prince' half-sib progenies at the seedling stage

Objective] In this project, experiment was conducted on the free pollination progeny of Malus ' Purple Prince' based on the advantages of the abundant resources in a crabapple germplasm bank. The goal of this study was to explore the phenotypic characteristics and breeding effectiveness of half-sib progenies.Method]The phenotypic diversity of 14 traits was compared using the value of Shannon-Wiener (H′R ) and Pielou indexes (ER ). The trends in variation and transgressive characteristics of traits between parents and progeny were analyzed using a frequency distribution func-tion. Subsequently, the comprehensive evaluation of phenotypic traits was conducted by the analytic hierarchy process (AHP). Result]In terms of phenotypic diversity, the average H′R of the 14 traits of the half-sib progenies increased by 13% compared to that of the possible paternal parent group. Among them, the H′R and ER of the ground diameter growth, branch number, heat resistance and mature leaf color increased by 23.8%-53.2%. Regarding genetic improvement, the proportion of excellent seedlings with high comprehensive scores in the half-sib progenies decreased by 37. 0% compared with the possible paternal parent group. The proportion of seedlings with purple-red colored leaves or a fast-growing charac-ter decreased by 14.9% and 37.5%, respectively. However, the proportion of seedlings with maple leaves, many branches, high seedling straightness, or high heat resistance increased by 12. 6%, 48. 3%, 28. 7% and 18. 5%, respectively. Compared with the maternal parent clones, the proportion of seedlings with high comprehensive scores increased by 7. 8%(12 seedlings). In addition, although the comprehensive score of some individual was slightly lower than that of the mater-nal parent clones, some single traits performed notably well. For example, the young leaves of F113 and F60 excellent seedlings were rarely bright red, the leaf type of F35 and F108 excellent seedlings as maple.Conclusions]Although free pollination reduced the proportion of excellent seedlings with high comprehensive scores, it effectively expanded the genetic basis of half-sib progenies. Furthermore, it had obvious effect on the genetic improvement of some single traits.