Oliveira M A C, Duarte J B, Morello C L, Suassuna N D, Oliveira A B
Agência Goiana de Defesa Agropecuária, Itumbiara, GO, Brasil.
Setor de Melhoramento de Plantas, Escola de Agronomia, Universidade Federal de Goiás, Goiânia, GO, Brasil
Genet Mol Res. 2016 Sep 2;15(3):gmr8667. doi: 10.4238/gmr.15038667.
Ramulosis is one of the most aggressive diseases in cotton, and understanding the genetic control of its resistance is imperative for selecting superior cotton genotypes in breeding programs. This study analyzed the inheritance pattern of this resistance using chi-square goodness-of-fit tests to determine the phenotypic proportions of the F generation, and a mixed inheritance approach to jointly model major gene and polygenes effects. F, F, Rc, and Rc generations were obtained by crossing resistant (BRS Facual, CNPA 2984, or CNPA 2043) and susceptible (Delta Opal, CNPA 999, or CNPA 2161) genotypes, and were assessed under field conditions with artificial inoculation of the pathogen (Colletotrichum gossypii var. cephalosporioides). Genetic control of the trait varied among the crossings. For Delta Opal x BRS Facual and CNPA 2161 x BRS Facual, phenotypic segregations in the F generation did not differ from the expected proportions for the hypothesis of duplicate genes (15:1). For Delta Opal x CNPA 2043, the segregation did not differ from the expected proportions for dominant recessive epistasis (13:3). The hypothesis of genetic control by one major gene was supported only for the Delta Opal x CNPA 2043 crossing. Three other crossings showed evidence of polygenes in the inheritance of the trait. In conclusion, major genes and polygenes are likely involved in the genetic control of ramulosis resistance in cotton.
炭疽病是棉花中最具侵袭性的病害之一，了解其抗性的遗传控制对于在育种计划中选择优良棉花基因型至关重要。本研究使用卡方拟合优度检验分析了这种抗性的遗传模式，以确定F代的表型比例，并采用混合遗传方法联合建模主基因和多基因效应。通过将抗性基因型（BRS Facual、CNPA 2984或CNPA 2043）与感病基因型（Delta Opal、CNPA 999或CNPA 2161）杂交获得F、F、Rc和Rc代，并在田间条件下人工接种病原菌（棉炭疽病菌头孢变种）进行评估。该性状的遗传控制在不同杂交组合中有所不同。对于Delta Opal×BRS Facual和CNPA 2161×BRS Facual，F代的表型分离与重复基因假说的预期比例（15:1）没有差异。对于Delta Opal×CNPA 2043，分离与显性隐性上位性的预期比例（13:3）没有差异。仅在Delta Opal×CNPA 2043杂交中支持一个主基因进行遗传控制的假说。其他三个杂交组合显示该性状的遗传中有多基因的证据。总之，主基因和多基因可能参与了棉花炭疽病抗性的遗传控制。
