Mapeamento de regiões genômicas associadas a caracteres de raízes em genótipos de arroz

Abstract

Rice (Oryza sativa L.) is a staple food for more than half of the world's population, especially for low-income people. In Brazil, this crop plays an important role in terms of consumption, production and economy. In recent years, yield and total rice production have reached a plateau in some countries, while population continues to increase, representing a challenge for researchers and breeders. Yield is determined by its components, which are the main targets of genetic improvement. Root system is another key parameter for rice yield, as it is responsible for uptake water. This trait also acts on absorption and transportation of nutrients from soil, in addition to other functions directly linked to yield. Understanding molecular basis of root traits in rice is one of the strategies to help plant breeders overcome challenges and reach the ultimate goal. Within this perspective, the objective of this research was to map genome regions responsible for root dry weight and length in rice. Genome-wide association study was applied using 7098 SNPs (single nucleotide polymorphism) markers and a collection of 188 rice genotypes grown in Brazil. Six SNPs markers for root length and three markers for root dry weight were detected. Genes encoding MYB transcription factor, Cinnamyl Alcohol Dehydrogenase and Cdk-Activating Kinase, among others, were found associated to root length. Amidst the genes related to root dry weight, those encoding Cellulose synthase, Lipid Transfer Protein, Receptor-Like Cytoplasmic Kinase and CCCH-type zinc finger protein associated to drought tolerance were identified.