EVALUATION OF CORN HYBRIDS UNDER CONTRASTING WATER AVAILABILITY CONDITIONS

ABSTRACT The current study aimed to assess adaptability and stability of corn hybrids regarding grain yields when sown in three different seasons in the Brazilian cerrado. The research was carried out at the Experimental Farm of the IF Goiano, campus in Ceres - GO. Pre-sowing fertilization was made with 20 kg ha-1 of nitrogen, 150 kg ha-1 of phosphorus and 80 kg ha-1 of potassium (04-30-16 formulation). Data were analyzed in a random block experimental design. We assessed tem corn hybrids (Truck, Fórmula, P30F53, P3646H, P30F35H, AGN 30A77H, AGN 30A37H, AG 8088PRO, DKB 390 and DKB Bi9440) in three sowing seasons (Nov. 18, 2011; Jan. 31, 2012 and Feb. 20, 2012) with three replications. Harvests were held on Apr. 4, 2012; Jun. 10, 2012 and Jul. 1, 2012. Each hybrid was assessed on yielding; and a graphical analysis was made to contrast hybrids and sowing seasons regarding stability and adaptability. Results showed a significant effect of the interaction between hybrids and sowing times. Therefore, we may state that the best hybrid in an environment would not be necessarily good in another. Thereby, we can infer that drought and corn genetic variability have diverse behaviors in each season. Over the two-dimensional graphics generated by GGE Biplot method, we observed an increased adaptability of AGN 30A77H when sown on Nov. 18, 2011 and on Jan. 31, 2012, followed by Fórmula; however, for P30F35H, it was on Feb. 20, 2012.摘要 本研究旨在评估玉米杂交品种在巴西塞拉多（Cerrado）地区三个不同播期下的籽粒产量适应性与稳定性。试验于戈亚斯州（Goiás，缩写GO）塞雷斯（Ceres）校区的戈亚诺联邦教育科技学院（IF Goiano）实验农场开展。基肥施用方案为每公顷施氮肥20 kg、磷肥150 kg、钾肥80 kg，肥料配比为04-30-16（N-P₂O₅-K₂O）。试验采用随机区组设计对数据进行统计分析，共评估10个玉米杂交品种（Truck、Fórmula、P30F53、P3646H、P30F35H、AGN 30A77H、AGN 30A37H、AG 8088PRO、DKB 390及DKB Bi9440），设置3个播期（2011年11月18日、2012年1月31日、2012年2月20日），每个处理重复3次。收获时间分别为2012年4月4日、2012年6月10日及2012年7月1日。对各品种的籽粒产量进行测定，并通过图形分析对比不同品种与播期的稳定性与适应性。结果表明，品种与播期的交互效应达显著水平。由此可见，在某一环境下表现最优的品种，未必适用于其他环境。据此可推断，干旱胁迫与玉米遗传变异在不同播期下表现出差异化响应。通过GGE双标图（GGE Biplot）方法生成的二维可视化图形分析结果显示，AGN 30A77H在2011年11月18日、2012年1月31日两个播期下的适应性最优，其次为Fórmula；而P30F35H的最优播期则为2012年2月20日。