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：源自不同群体杂交的杂交咖啡植株选育，对育种项目的成功至关重要。本研究通过估算刚果咖啡（Coffea canephora）库伊卢变种与罗布斯塔杂交群体的群体内遗传参数，旨在明确最优选育策略。本试验采用北卡罗来纳II设计（North Caroline II）构建20个全同胞家系，并以随机完全区组设计进行田间种植，每个小区定植1株植株。试验测定的性状包括：营养生长势、锈病抗性、株高、冠幅投影直径、成熟时间及咖啡豆产量。显著的个体遗传方差与遗传力估计值证实了开展有效选育的可行性。在家系水平与单株水平开展的多性状选择指数分别实现了5%与40%的遗传增益。综上，即便数据存在不平衡性，杂交群体内的单株选育仍是选育优良个体以用于构建新杂交组合、培育品种克隆的可行策略，适用于刚果咖啡的育种项目。