Breeding trials in water-stress conditions: identification of sensitive traits in early stages and characterization of a tropical maize public panel

Abstract

Abstract One of the major goals of modern agriculture is to achieve increased crop yield using less water. Despite the significant advances in genomics, a phenotypic characterization efficient is essential for the success of a modern breeding program, which wants to speed up the genetic gains by deploying selection in the early stages. Thus, this study aimed to identify which traits are most important to discriminate the maize genotypes to support early selection under contrasting water availability conditions. For this, we used a public diversity panel consisting of 360 tropical maize inbred lines, involving two conditions, well-watered (WW) and water-stress (WS), in eight trials. Evaluations were carried out in the phenological stage V6 for shoot and root traits. There was a significant variation in the panel performance, mainly for root traits under WS conditions, composing six clusters. However, the traits showed a similar pattern of clustering evidenced by principal components in WW and WS conditions. Moreover, a strong relationship was found among the roots' length, surface area, and volume. Based on this, we suggest discarding the most error-prone ones. Our results showed via Redundancy Analysis (RDA) that plant height, stalk diameter, and lateral roots length are traits more sensitive to WS and, therefore, may be considered in early selection in breeding programs aiming for water use efficiency.