Identificação de variáveis discriminativas em milho tropical para estudos envolvendo condições contrastantes de suprimento de água

Abstract

Hydric deficit is the main abiotic factor responsible for losses in corn cultivation. Studies involving such stress face many challenges, considering that the experimental conditions must be meticulously managed and the variables involved are highly complex. With this, the need arises to study variables that present greater discriminative power in the corn crop under hydric deficit to subsidize future studies in these conditions. Thus, the objective of this work was to identify relevant and discriminative variables for studies in contrasting conditions of water supply. For this, a panel with 360 tropical corn lineages was used. The experiments were conducted in 2020 and 2021 in the experimental area of ​​the Federal University of Ceará. Two experimental conditions were imposed: ideal water supply (AI) and hydric deficit (DH), four for each condition, in the row × column experimental design. Phenotypic evaluations were performed when most of the plants reached the phenological stage V6. The aerial part variables were: plant height (AP), stem diameter (DC), number of leaves, chlorophyll content (SPAD) and dry mass (MSPA). And the root variables were: lengths of lateral (CRL) and axial roots (CRA), superficial area of lateral (ASRL) and axial roots (ASRA), volume of lateral (VRL) and axial roots (VRA), convex area of root system (ACR) and root dry mass (MSR). Allowed to observe the effects of DH to the variables studied, becoming it notorious that the variables of the classes of axial and lateral roots (length, superficial area and volume) showed greater discriminative power, presenting high correlation each other, enabling discard, keeping the variable length, in both classes, for practicality. However, when analyzing the heritabilities of the variables studied, it was noticed that the highest averages were for AP, MSPA and DC in AI; and MSPA, CRA and DC in HD. It is concluded that the variables of the axial and lateral root classes were classified as discriminative. And the variables indicated to subsidize future studies were: AP, MSPA and DC in AI; and MSPA, CRA and DC in DH.