Evaluating agronomic traits and selection of low N-tolerant maize hybrids in Indonesia

Nitrogen is one of the macro elements that maize needs. Nitrogen deficiency will affect maize's growth and grain yield. This study aimed to determine hybrid maize's growth, grain yield, and tolerance to low N conditions. This research was conducted at the Indonesian Cereal Testing Instrument Standard Institute in Maros, South Sulawesi, Indonesia, from July to November 2022. A nested design was applied with eleven hybrid maize genotypes and three N fertilization levels (N0 = 0 kg N ha^-1, N1 = 100 kg N ha^-1, and N2 = 200 kg N ha^-1) as treatments, replicated three times. Growth and grain yield traits were measured. An analysis of variance was used to determine the effect of fertilization level on growth. Eberhart and Russell stability analysis and the Stress Tolerance Index (STI) were used to determine hybrid maize tolerance and yield stability across the three fertilization levels. The findings indicated that the reduction in nitrogen fertilizer level affected maize agronomic performance and yield reduction. HLN 09 exhibited a mean yield of 7.68 t ha^-1, surpassing the overall hybrid mean of 7.21 t ha^-1. HLN 09 also demonstrated moderate stress tolerance at N2-N1, N2-N0, and N1-N0 and was characterized as a stable hybrid with regression coefficient (bi) = 0.99 and deviation from regression (s²di) = -0.22. The HLN 09 maize hybrid was a hybrid maize with good tolerance to low N conditions and high stability and yield.