Indirect selection for drought tolerance in maize through agronomic and seeds traits

Abstract

High prolificacy, stay green, and a reduced anthesis-silking interval are among the traits most used for indirect selection for drought tolerance. The objective of this research was to evaluate five maize lines from the maize breeding program of the company Geneseeds Recursos Genéticos Ltda, to drought tolerance, grown at four plant population sizes, 40, 60, 80 and 100 thousand plants ha-1. In these conditions, the following traits were evaluated: prolificacy, stay green and interval between female and male flowering, which are indirectly related to drought tolerance. The physiological quality of seeds and expression of the enzymes alpha amylase, esterase, catalase, superoxide dismutase, alcohol dehydrogenase, malate dehydrogenase, and heat resistant proteins were also evaluated. The experiment was conducted in a randomized block design in a split plot layout. Differences were observed between the lines for all traits analyzed. Lines 63, 64 and 91 showed the greatest yields and prolificacy, and lines 63, 64, 54 and 91 had the lowest intervals between male and female flowering. No effetc of plant population on the physiological quality of maize seeds was detected, and the highest values of germination and seed vigor were observed in lines 64, 44 and 91. Lines 63, 64 and 91 are considered as promising for drought tolerance.