Effect of recurrent selection on the variability of the UENF-14 popcorn population

Abstract This study aimed to evaluate the effect of recurrent selection on the genetic variability of UENF-14 population after six selections. Two hundred and ten half-sib families were evaluated in two environments in the state of Rio de Janeiro, using incomplete randomized blocks design with treatments arranged in replication within "Sets". There was significant effect for Families within the "Set" (F)/S, proving that there is enough genetic variability to be exploited in the popcorn breeding program of UENF. The significance for the source of variation Environment (E) shows that the environments were distinct enough to promote differences between the evaluated characteristics. It was found that for both characteristics of greatest interest, GY and PE, the magnitude of the additive variance remains with close values in advanced cycles of UENF-14 population, indicating that variability remains, with no evidence of decreases in advanced cycles. This is concluded by the longevity of UENF breeding program.

摘要 本研究旨在评估经六轮轮回选择后，轮回选择对UENF-14群体遗传变异的影响。本研究以里约热内卢州两个环境下的210个半同胞家系（half-sib families）为试验材料，采用不完全随机区组设计，将处理安排于“组”内进行重复。“组”内家系（F/S）的效应达到显著水平，证明UENF的爆米花育种项目中存在充足可被利用的遗传变异。环境（E）变异来源的显著性结果表明，供试环境间差异足够显著，可使所评估的性状表现出差异。研究发现，针对两个最受关注的性状——籽粒产量（grain yield, GY）与膨化体积（popping expansion, PE），UENF-14群体在高级轮回周期中的加性方差始终维持在相近水平，表明其遗传变异并未出现衰减，高级选择周期仍可保留遗传多样性。这一结果印证了UENF育种项目的长期可持续性。