Mapeamento de QTL para caracteres de importância agronômica em arroz no cruzamento Araguaia X Maninjau
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2020-09-30
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Universidade Federal de Goiás
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The productivity of the main food crops will not be sufficient to meet the anticipated demands for food. Rice (Oryza sativa L.) is the main food for a large part of the world population, and increasing its productivity has been one of the main objectives of breeding programs in the world, with the aim of developing rice cultivars with greater productive potential and production stability than those available today. Adaptability and stability studies, together with the mapping of QTL (Quantitative Trait Loci) aiming at the discovery of markers for assisted selection, can boost the obtaining of commercial cultivars that meet the demand for rice grain production. This work aimed to identify: 1) Recombinant Inbred Lines (RILs) productive, with greater adaptability and stability, and 2) QTLs related to important agronomic characters in a population of RILs from the interspecific crossing Araguaia x Maninjau. The adaptability and stability analysis was performed in two locations (Boa Vista - RR and Goianira - GO) to obtain phenotypic data of four agronomic traits and identification of superior inbred lines. The RILs and the genitors were genotyped by the DArTseq methodology to obtain SNPs markers and silico DArTs for the QTL mapping. After consolidating the data from the field and genotyping experiments, the QTLs analysis was performed considering 234 RILs and 8,911 SNPs and DArTs by the multiple interval mapping method, with LOD≥ 3.0. The interspecific crossing generated enough variability to select superior inbred lines and favorable alleles for QTL mapping. The Goianira experiment showed the most productive RILs (average of 6,455 kg/ha) and the most resistant to lodging (average score of 1.7), while the Boa Vista experiment showed precocious RILs (average of 72.1 days until flowering) and lower plants (average height of 106.51 cm). The genitor Maninjau had a better phenotypic performance
for productivity, while Araguaia was more precocious, lower and resistant to lodging. Two line stood out for performing well in different environments for multiple characters. Twenty-two significant QTLs (LOD≥ 3.0) were identified, six for grain yield, five for days to flowering and 11 for plant height, with explained phenotypic variation ranging from 3.94% to 35.36 The QTL PTHT12 for plant height had stability between environments. The QTL mapping confirmed that the genitor Maninjau was the donor of 66.6% of the favorable alleles to increase grain productivity, and that Araguaia was the donor of 100% of the favorable alleles for early flowering and 63.3% for size low in RILs. The line with the best performance are indicated to continue in the breeding program. Potential markers were identified for grain yield, flowering and plant height, and are indicated for the validation step for use in the assisted selection routine of rice breeding programs in Brazil
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SANTOS, J. F. F. Mapeamento de QTL para caracteres de importância agronômica em arroz no cruzamento Araguaia X Maninjau. 2020. 124 f. Dissertação (Mestrado em Genética e Melhoramento de Plantas) - Universidade Federal de Goiás, Goiânia, 2020.