Genetics and Mapping of Multiflorous Spikelet in Hexaploid Oat

The formation of naked grains is directly associated with the development of a multiflorous spikelet in hexaploid oat. The objectives of this study were to determine the genetics of multiflorous spikelet and to identify molecular markers linked to this character in hexaploid oat. A genetic population of recombinant inbred lines (RILs) developed from a simple cross between the oat lines UFRGS 01B7114-1-3 (normal spikelet) and UFRGS 006013-1 (multiflorous spikelet) was analyzed in this study. Parental and recombinant inbred lines were evaluated for multiflorous spikelet in field tests during the growing seasons of 2012 and 2013 in southern Brazil. DNAs extracted from F_5:6 plants were assayed with 6,000 genome-wide single nucleotide polymorphism (SNP) markers using a genotyping platform developed for oat. Multiflorous spikelet in the evaluated population was controlled by one major gene, with multiflorous spikelet lines carrying Mf1Mf1 and normal spikelet lines carrying mf1mf1 alleles. The SNP marker ‘GMI_ES17_c5923_221’ showed high association with the multiflorous/spikelet phenotype. In 2012, the genetic distance between the marker GMI_ES17_c5923_221 and the locus Mf1 was 1.8 cM, while in 2013 the genetic distance was 3.5 cM. However, we could not map the SNP marker GMI_ES17_c5923_221 to any of the 42 linkage groups formed in the UFRGS 01B7114-1-3 x UFRGS 006013-1 mapping population. Further studies will confirm the association of this marker with multiflorous spikelet in different populations and also investigate the potential of use this marker in breeding naked oat cultivars.