Drought tolerance index of selected local varieties in maize: an integration of agrohistological, proline content, and yield under field capacity

Drought stress exacerbated by climate change severely compromises crop productivity and global food security, particularly in maize-dependent regions. To mitigate drought stress, a method based on local maize varieties and field capacity management can be the appropriate solution. Field capacity (FC) defined as the maximum water content soil retains after drainage serves as a key parameter for drought stress evaluation. Therefore, this study aimed: (1) to investigate the effect of local varieties, FC, and the interactions on agrohistological, proline, and maize yield, and (2) to find drought-tolerant local varieties of maize crops at a specific FC. This study was carried out using a factorial Randomized Block Design. The first factor was selected local varieties from North Sumatra (BI-3, SB-5, DS-2, MN-3, and hybrids as a comparison), and the second factor was FC (20, 40, 60, 80, 100%). This study was repeated three replicates and conducted in farmers' fields from June to October 2023 in a modified greenhouse. The parameters were analyzed by ANOVA and continued with DMRT at 5% level through IBM SPSS. Heritability, drought tolerance index, and Pearson correlation analysis were calculated. The results showed that the local variety DS-2 (Deli Serdang) had a higher level of drought tolerance (0.595), as characterized by an increase in agrohistological, proline, and yield reaching 1,385.24 kg ha−1. A 80% FC showed the lowest inhibition to agrohistological and proline, indicating the potential to be tolerated and support maize yield. The interaction of DS-2 with FC-80% had great potential to be applied to dryland.