da Cunha K S, Pereira M G, Gonçalves L S A, Berilli A P C G, de Oliveira E C, Ramos H C C, do Amaral Júnior A T
Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, Brasil.
Genet Mol Res. 2012 Sep 25;11(3):3398-408. doi: 10.4238/2012.September.25.8.
We estimated the genetic gains of the 12th cycle of reciprocal recurrent selection for maize traits of agronomic interest. We used 23 ISSR molecular markers in an attempt to maximize genetic variability among and within populations based on selection of S(1) progenies. To this end, 138 full-sib families were evaluated in a randomized block design in two environments (the municipalities of Campos dos Goytacazes and Itaocara, in the State of Rio de Janeiro, Brazil), with replications within sets. Direct selection for grain yield was used for the selection of the families. To assess genetic diversity among and within populations, we examined plants produced from part of the S(1s) seeds from the parents that originated the 42 full-sib families that were selected from the agronomic traits. Direct selection for grain yield provided good gains for the traits evaluated, with estimated improvement of -0.87 days for days to flowering, 0.35 plants, 1.79 ears per plot, 0.58 g per 100-grain weight, 308.21 g ear weight per plot, and 261.83 kg/ha grain yield. Application of molecular markers at the stage of superior progeny selection led to increased genetic distance among populations, which is a very important factor for utilization of heterosis and providing greater longevity to the reciprocal recurrent selection program.
我们估算了玉米农艺性状第12轮互交轮回选择的遗传增益。我们使用23个ISSR分子标记，试图基于S(1)后代的选择，使群体间和群体内的遗传变异性最大化。为此，在巴西里约热内卢州的坎波斯-多斯戈伊塔卡泽斯市和伊塔奥卡拉市这两个环境中，以随机区组设计对138个全同胞家系进行了评估，每组内有重复。对家系的选择采用了对籽粒产量的直接选择。为了评估群体间和群体内的遗传多样性，我们检查了由42个从农艺性状中选出的全同胞家系的亲本的部分S(1s)种子所产生的植株。对籽粒产量的直接选择为所评估的性状带来了良好的增益，开花天数估计改善了-0.87天，植株数增加了0.35株，每小区果穗数增加了1.79个，百粒重增加了0.58克，每小区果穗重增加了308.21克，籽粒产量增加了261.83千克/公顷。在优良后代选择阶段应用分子标记导致群体间遗传距离增加，这是利用杂种优势和使互交轮回选择计划具有更长寿命的一个非常重要的因素。
