Individual selection of the first backcross generation of passion fruit potentially resistant to the fruit woodiness disease

Abstract The REML/BLUP procedure has been successfully used for genetic progress through individual selection of high-yielding passion fruit genotypes resistant to the Cowpea aphid-borne mosaic virus. This study was thus developed to estimate genetic parameters and predict the gain obtained from individual selection of genotypes in a population derived from backcrosses in passion fruit. The experiment was set up as a randomized block design with four replicates, involving five full-sib families (genotypes from the first backcross). Variance components and the genetic values were estimated for eight agronomic traits via the REML/BLUP procedure. For all traits, genotypic variance between the genotypes from the first backcross showed little contribution to the phenotypic variance. The low heritability estimates obtained for the traits are overcome via individual BLUP estimates. Therefore, it was possible to obtain considerable gains with individual selection for the variables fruit length, average fruit weight, and pulp weight (19.50 to 14.04%; 22.93 to 17.97%; and 10.08 to 7.95%, respectively). For the traits showing lower gains, it is possible to obtain gains indirectly by selecting genotypes for correlated traits. Because this population derives from the first backcross generation, agronomic traits still must be recovered.

摘要 限制性最大似然估计/最佳线性无偏预测（REML/BLUP）流程已成功应用于通过对高产且抗豇豆蚜传花叶病毒（Cowpea aphid-borne mosaic virus）的西番莲基因型开展个体选择以实现遗传进展。本研究旨在估算西番莲回交衍生群体中基因型个体选择的遗传参数，并预测其选择增益。本试验采用随机区组设计，设置4次重复，共包含5个全同胞家系（即来自第一次回交的基因型）。本研究通过REML/BLUP流程，对8个农艺性状的方差组分与遗传值进行了估算。对于所有性状，第一次回交所得基因型间的遗传方差对表型方差的贡献均较小。尽管这些性状的遗传力估算值较低，但通过个体BLUP估算可有效弥补这一局限。因此，对果长、平均单果重及果肉重量开展个体选择，可获得可观的选择增益（分别为19.50%至14.04%、22.93%至17.97%及10.08%至7.95%）。对于增益较低的性状，可通过选择相关性状的基因型实现间接选择增益。由于该群体源自第一次回交世代，其农艺性状仍有待进一步恢复与改良。