Selection and genetic parameters for interpopulation hybrids between kouilou and robusta coffee

ABSTRACT Selection of hybrid coffee plants coming from crosses between divergent populations is particularly relevant for the success of breeding programs. This study aimed to outline the best selection strategy in a hybrid population of Coffea canephora var. kouilou and robusta by estimating intrapopulation genetic parameters. Twenty full-sib progenies obtained by North Caroline II were installed in a randomized complete blocks design, with one plant per elementary plot. The following traits were evaluated: vegetative vigor, reaction to rust, plant height, diameter of canopy projection, maturity time, and bean yield. Significant individual genotypic variance and heritability estimates lead to an effective selection. The multi-trait selection index carried out between progenies and at individual level provided 5% and 40% gain, respectively. Thus, intrapopulation selection in a hybrid population is a viable strategy for the selection of superior individuals to compose new crosses and clones for cultivars in the breeding program of C. canephora, even with unbalanced data.

摘要：针对源自遗传分化种群杂交所得的杂交咖啡植株开展选择，对咖啡育种项目的成功至关重要。本研究通过估算群体内遗传参数，旨在拟定刚果咖啡（Coffea canephora）库伊卢变种与罗布斯塔杂交群体的最优选择策略。本研究采用北卡罗来纳II设计（North Caroline II）构建了20个全同胞家系，并以随机完全区组设计开展田间试验，每个小区种植1株植株。本试验测定的性状包括：营养生长势、抗锈病性、株高、冠幅投影直径、成熟期以及咖啡豆产量。显著的个体基因型方差与遗传力估计值表明，该群体可开展有效的选择育种。在家系水平与单株水平实施的多性状选择指数选择，分别获得了5%与40%的遗传增益。综上，即便存在数据不平衡的情况，杂交群体内的群体选择仍是选育优良单株的可行策略，可用于组配新的杂交组合以及培育栽培品种所需的无性系，适用于刚果咖啡的育种项目。