Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Laboratório de Melhoramento Genético Vegetal, Av. Alberto Lamego, 2000, 28013-602 Campos dos Goytacazes, Rio de Janeiro, RJ, Brazil.
An Acad Bras Cienc. 2023 May 19;95(1):e20220468. doi: 10.1590/0001-3765202320220468. eCollection 2023.
This study aimed to characterize papaya lines via microsatellite markers, and select genotypes based on the fixation index in order to promote the genetic purification of important commercial hybrids parent lines. Overall, 400 genotypes from three parental lines (JS-12, SS-72/12, and Sekati) were genotyped. Expected (HE), observed (HO) heterozygosity, and fixation index (F), were estimated. Genetic distances were estimated using an unweighted index, which was graphically presented via cluster analysis using the UPGMA and PCoA. Intra-genotypic variability was detected in both JS-12 and Sekati lines, while an absence of it was observed in SS-72/12. Such variability may positively contribute to the fitting of 'UENF/Caliman 01' and 'UC-10' hybrids into the traits of commercial interest how size and weight fruit. Regarding the fixation index, 293 genotypes showed maximum values (F=1) facilitating the genotypes selection process. Concerning population analysis, a close proximity between heterotic group 'Formosa' lines was observed, while a greater distance among 'Solo' group ones, and this enables systematic exploitation of such material. The fixation index maximum enabled the 80 genotypes selection thereby contributing to the parents genetic purification, since, the selected genotypes will be used in future hybridization steps to generate hybrids fitted into the traits of commercial interest.
本研究旨在通过微卫星标记对番木瓜品系进行特征分析，并根据固定指数选择基因型，以促进重要商业杂交亲本系的遗传纯化。本研究共对来自三个亲本系（JS-12、SS-72/12 和 Sekati）的 400 个基因型进行了基因分型。估计了期望杂合度（HE）、观测杂合度（HO）和固定指数（F）。使用无权重指数估计遗传距离，并通过 UPGMA 和 PCoA 聚类分析以图形方式展示。在 JS-12 和 Sekati 系中检测到了种内变异性，而在 SS-72/12 系中则没有。这种变异性可能对“UENF/Caliman 01”和“UC-10”杂种适应商业利益相关性状（如大小和重量）产生积极贡献。关于固定指数，有 293 个基因型表现出最大值（F=1），这有利于基因型选择过程。关于群体分析，观察到杂种群“Formosa”系之间的亲缘关系较近，而“Solo”群之间的亲缘关系较远，这使得对这种材料进行系统开发成为可能。最大固定指数使 80 个基因型得以选择，从而有助于亲本的遗传纯化，因为所选的基因型将用于未来的杂交步骤，以生成适应商业利益相关性状的杂种。
