Galvão K S C, Ramos H C C, Santos P H A D, Entringer G C, Vettorazzi J C F, Pereira M G
Laboratório de Genética e Melhoramento Vegetal, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminence, Campos de Goytacazes, RJ, Brasil.
Laboratório de Genética e Melhoramento Vegetal, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminence, Campos de Goytacazes, RJ, Brasil
Genet Mol Res. 2015 Jul 3;14(3):7344-55. doi: 10.4238/2015.July.3.10.
This study aimed to improve grain yield in the full-sib reciprocal recurrent selection program of maize from the North Fluminense State University. In the current phase of the program, the goal is to maintain, or even increase, the genetic variability within and among populations, in order to increase heterosis of the 13th cycle of reciprocal recurrent selection. Microsatellite expressed sequence tags (EST-SSRs) were used as a tool to assist the maximization step of genetic variability, targeting the functional genome. Eighty S1 progenies of the 13th recur-rent selection cycle, 40 from each population (CIMMYT and Piranão), were analyzed using 20 EST-SSR loci. Genetic diversity, observed heterozygosity, information content of polymorphism, and inbreeding co-efficient were estimated. Subsequently, analysis of genetic dissimilarity, molecular variance, and a graphical dispersion of genotypes were conducted. The number of alleles in the CIMMYT population ranged from 1 to 6, while in the Piranão population the range was from 2 to 8, with a mean of 3.65 and 4.35, respectively. As evidenced by the number of alleles, the Shannon index showed greater diversity for the Piranão population (1.04) in relation to the CIMMYT population (0.89). The genic SSR markers were effective in clustering genotypes into their respective populations before selection and an increase in the variation between populations after selection was observed. The results indicate that the study populations have expressive genetic diversity, which cor-responds to the functional genome, indicating that this strategy may contribute to genetic gain, especially in association with the grain yield of future hybrids.
本研究旨在提高北弗卢米嫩塞州立大学玉米全同胞轮回选择计划中的谷物产量。在该计划的当前阶段，目标是维持甚至增加群体内部和群体之间的遗传变异性，以提高第13轮轮回选择的杂种优势。微卫星表达序列标签（EST-SSR）被用作一种工具，以辅助针对功能基因组的遗传变异性最大化步骤。使用20个EST-SSR位点对第13轮轮回选择周期的80个S1后代进行了分析，每个群体（国际玉米小麦改良中心和皮拉诺）各40个。估计了遗传多样性、观察到的杂合度、多态性信息含量和近交系数。随后，进行了遗传差异分析、分子方差分析和基因型的图形分散分析。国际玉米小麦改良中心群体中的等位基因数量范围为1至6，而皮拉诺群体中的范围为2至8，平均分别为3.65和4.35。从等位基因数量可以看出，香农指数显示皮拉诺群体（1.04）相对于国际玉米小麦改良中心群体（0.89）具有更大的多样性。基因SSR标记在选择前有效地将基因型聚类到各自的群体中，并且观察到选择后群体间的变异增加。结果表明，研究群体具有显著的遗传多样性，这与功能基因组相对应，表明该策略可能有助于遗传增益，特别是与未来杂交种的谷物产量相关。
