Selection of corn inbred lines, testers, and hybrids adapted to second-crop environments

Abstract: The objective of this work was to evaluate the yield performance, adaptability, and stability of corn (Zea mays) topcross hybrids in nine environments in Brazil, in order to select inbred lines, testers, and promising hybrid combinations for these environments in the second crop season. The trials were carried out during the second crop season of 2017, in six sites in the state of Paraná and three in the state of Mato Grosso do Sul, Brazil. Sixty-six single-cross hybrids, made up of 33 inbred lines crossed with two testers, were evaluated. The stability of the genotypes was assessed by the Schmidt & Cruz method and by the additive main effects and multiplicative interaction (AMMI) methodology. In addition, the genetic parameters and the general combining ability of the testers were estimated. Tester 2 is the most adapted to discriminate inbred lines in the second-crop environments. Inbred lines 12, 21, 23, and 32 are recommended for obtaining hybrids to be cultivated in the second crop season due to their good adaptability and stability and high yield in the crosses in which they participated. The HS123, HS223, and HS232 hybrids present the best performance and are the most recommended for the second-crop environments.

摘要：本研究旨在评估巴西9个试验环境下玉米（Zea mays）顶交杂交种的产量表现、适应性与稳定性，以期为巴西第二季作物种植环境筛选适宜的自交系、测验种及优良杂交组合。试验于2017年第二季作物季开展，共设置9个试验点，其中巴拉那州（Paraná）6个、南马托格罗索州（Mato Grosso do Sul）3个。本次试验共评估66个单交杂交种，均由33个自交系与2个测验种组配得到。基因型稳定性分别通过施密特-克鲁兹（Schmidt & Cruz）法与加性主效应和乘性互作（AMMI）法进行分析。此外，本研究还估算了相关遗传参数及测验种的一般配合力。结果表明，测验种2最适合在第二季作物环境中区分自交系；自交系12、21、23及32因具备良好的适应性与稳定性，且在参与组配的杂交组合中表现出较高产量，推荐用于组配适合第二季作物种植的杂交种；杂交种HS123、HS223与HS232表现最优，是最适合推广至第二季作物环境的优良组合。