Análise de qtl para produtividade no cruzamento de arroz epagri 108 (indica) x irat 122 (japonica) por marcadores SNPs.
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2016-08-12
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Universidade Federal de Goiás
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The rice (Oryza sativa) is a staple food for the majority of the world's population. One of the main challenges for the breeding programs of this crop is the increase of the yield potential of commercial cultivars. For the development of superior lines and cultivars is necessary to identify and incorporate superior alleles in genetic breeding programs. One of the alterna-tives for the identification of useful genetic variability is the crossing involving genetically unrelated parents, as well as genotyping and phenotyping the segregating populations de-rived from these crossings, and posterior analysis of QTL (Quantitative Trait Locus). This study aimed to identify genes associated with yield of grains in rice through Genotyping by Sequencing (GBS), field experiments and a posterior analysis of QTL involving 232 RIL’s (Recombinant Inbred Lines) derived from the inter-subspecific crossing Epagri 108 (indica) x IRAT 122 (japonica) in two locations (Goianira - State of Goias and Boa Vista - State of Roraima). For the QTL analysis it was mapped 2,382 SNP markers, which identified two QTLs for yield, both located on chromosome 6, exclusively for the experiment of Goianira. The average effects of allele substitutions were 1,365.20 kg.ha-1 and 1,075.49 kg.ha-1, and the proportions of the phenotypic variance explained by the QTLs were 18% and 29%, clas-sified as QTL of large effect. All favorable alleles for yield were derived from genitor IRAT 122. One of the QTL identified to the productivity showed interaction QTL x E, which was expected due to the high significance of interactions G x E detected in the joint analysis. For the experiment of Goianira was also analyzed the trait hundred grain weight, and it were found three QTLs on chromosomes 5, 6 and 12. The average effects of the allelic substitution for the hundred grain weight ranged from 0.12 to 0.14 grams. The proportions of the pheno-typic variance explained by the QTLs ranged from 6 to 8%. Approximately 84% of the QTLs for the hundred grain weight were obtained from the parent IRAT 122. In chromosomal regions identified QTLs for grain yield are contained two genes: the LOC_Os06g16870, a transposon En/Spm, and the LOC_Os06g33320 whose function remains unknown, but whose expression was almost exclusively found in the inflorescences of rice. For the hundred grain weight, the chromosome region of the QTL located on chromosome 5 is located in a linkage block with 82 genes that co-segregate, and whose putative functions include, among others, the adjustment of tillering, pollen formation, grain filling and resistance to abiotic stress. For the QTL located on chromosome 6 it was identified the gene LOC_Os06g16160, which the function still unassigned, but whose expression is located almost exclusively in the root. On chromosome 12, the QTL containing the gene LOC_Os12g41956 expresses a protein of the galactosyl-transferase family, which participates in the synthesis of the RFO’s (Raffinose Family of Oligosaccharides), regulating the levels of reserve oligosaccharides in seeds.
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SILVA, D. R. A. Análise de qtl para produtividade no cruzamento de arroz epagri 108 (indica) x irat 122 (japonica) por marcadores SNPs.. 2016. 89 f . Dissertação (Mestrado em Genética e Melhoramento de Plantas) - Universidade Federal de Goiás,Goiânia, 2016.