Caracterização por linhagens, mapeamento por associação e controle genético para resistência às doenças foliares em milho no Oeste do Paraná

Abstract

The work aimed to characterize common corn strains for resistance to main leaf diseases and to suggest crosses based on the genetic diversity detected in SNP markers, besides to identify genomic regions and to study of control involved in the resistance of white leaf spot (WLS) and northern leaf blight (NLB). For genetic diversity, the 72 maize lines were genotyped with SNP markers using the 650K Platform (Affymetrix®) and quantified using the Tocher and UPGMA methods. For the characterization, the experiment was conducted in a randomized complete block design with three repetitions. The genotypic values of the main diseases were predicted using by the procedure of REML / BLUP. For association mapping, 72 maize lines genotyped for SNP markers were associated with genotypic values of WLS and NLB. For the study of genetic control, the experiment was conducted in the agricultural year 2016 and it was composed of a randomized block design with three replications, being estimates based on the analysis of the variances of the segregating and nonsegregating generations. According to the results, the existence of genetic variability was detected among maize lines and this way, with the data of the distances through the molecular markers, it is possible to orient the crosses accurately, aiming at genetically resistant genotypes to the foliar diseases. The use of association mapping may be an efficient strategy in the selection of WLS and NLB resistant genotypes, without the need for crosses. With genetic control studies, inheritances of the quantitative type allied with the high restricted heritabilities of WLS and NLB, allow good selection efficiency and satisfactory selection gains.