Caracterização de genótipos mutantes de arroz para tolerância à salinidade no início do estádio vegetativo e produtividade de grãos

Abstract

Cultivated since the beginning of plant domestication, rice (Oryza sativa L.) is one of the most important cereals in the world, being a staple food for more than half of the world's population. However, the demand for food is being elevated due to the constant population growth, and forecasts indicate the intensification of climate change, potentiating the incidence of abiotic stresses such as salinity, which cause reduced yields and threaten food security. Rice is most sensitive to salinity at the seedling and reproductive stages. Excess salt causes osmotic stress, which reduces water uptake, and ionic stress, which affects the entire metabolism of the plant. Therefore, the development of new rice cultivars with higher yield and stable under salinity conditions is one of the main goals of rice breeding. The success of plant breeding depends on the presence of genetic variability, which has become increasingly narrow due to the strong selection pressure for more productive rice cultivars. Mutation induction using gamma radiation has been routinely applied to create genetic variability in rice. In this sense, the objective of this study was to characterize mutant genotypes, in M5 and M6 generations, for salinity tolerance at seedling stage and yield. Mutation induction enabled the creation of genetic variability for salinity tolerance in seedlings as well as for yield in rice. Based on the morphological parameters evaluated, mutants with higher salinity tolerance in seedling stage than BRS Pampeira were identified. Similarly, mutants more productive than the original cultivar were also detected.