A set of thirty-six wheat cultivars were grown for two consecutive years under low and high nitrogen conditions. The interactions of cultivars with different environmental factors were shown to be highly significant for most of the studied traits, suggesting the presence of wider genetic variability which may be utilized for the genetic improvement of desired trait(s). Three cultivars, i.e., RAJ 4037, DBW 39 and GW 322, were selected based on three selection indices, i.e., tolerance index (TOL), stress susceptibility index (SSI), and yield stability index (YSI), while two cultivars, HD 2967 and MACS 6478, were selected based on all four selection indices which were common in both of the study years. According to Kendall’s concordance coefficient, the consistency of geometric mean productivity (GMP) was found to be highest (0.778), followed by YSI (0.556), SSI (0.472), and TOL (0.200). Due to the high consistency of GMP followed by YSI and SSI, the three selection indices could be utilized as a selection tool in the identification of high-yielding genotypes under low nitrogen conditions. The GMP and YSI selection indices had a positive and significant correlation with grain yield, whereas TOL and SSI exhibited a significant but negative correlation with grain yield under both high and low nitrogen conditions in both years. The common tolerant genotypes identified through different selection indices could be utilized as potential donors in active breeding programs to incorporate the low nitrogen tolerant genes to develop high-yielding wheat varieties for low nitrogen conditions. The study also helps in understanding the physiological basis of tolerance in high-yielding wheat genotypes under low nitrogen conditions.

中文翻译：

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利用多变量筛选方法鉴定低氮耐性小麦品种

在低氮和高氮条件下，连续三年种植了36个小麦品种。对于大多数研究的性状，品种与不同环境因素的相互作用显示出高度重要的意义，这表明存在更广泛的遗传变异性，可用于所需性状的遗传改良。根据三个选择指数，即耐性指数（TOL），胁迫敏感性指数（SSI）和产量稳定性指数（YSI），选择了三个品种，即RAJ 4037，DBW 39和GW 322，而两个品种为HD基于两个研究年度中共有的所有四个选择指数选择了2967和MACS 6478。根据肯德尔的一致性系数，发现几何平均生产率（GMP）的一致性最高（0.778），其次是YSI（0.556），SSI（0.472）和TOL（0.200）。由于GMP紧随YSI和SSI之后具有很高的一致性，因此可以在低氮条件下将这三个选择指数用作选择工具来鉴定高产基因型。在高氮和低氮条件下，两年中GMP和YSI选择指数与籽粒产量成正相关，而TOL和SSI与籽粒产量成显着但负相关。通过不同选择指数确定的常见耐性基因型可以用作主动育种计划中的潜在供体，以整合低氮耐性基因，从而为低氮条件开发高产小麦品种。