GENOTYPIC VARIATION AND ASSOCIATION MAPPING FOR AGRONOMIC TRAITS IN SET OF TEMPERATE-ADAPTED MAIZE LINES DEVELOPED BY DH AND SSD METHODS

BS39 is a broad-based population of tropical maize adapted to temperate environments that can provide useful and unique alleles to U.S. Corn Belt breeding programs. As the development of inbred lines demands several generations of self-pollination, doubled haploid (DH) technology has been used as an efficient alternative to speed up this process. Our objectives were to compare genetic parameters for plant height (PH), ear height (EH) and anthesis-silking interval (ASI) among the BS39-derived lines using Single Seed Descent (SSD) and DH methods and identify SNP markers associated with these traits. We developed four sets of 96 lines derived from BS39 and from a cross between BS39 and A427, a spontaneous haploid genome doubling (SHGD) donor, by DH and SSD methods. Lines were genotyped using genotype-by-sequencing and Diversity Array Technology Sequencing. We observed extensive genotypic variation for PH, EH and ASI in all sets of lines. Lines developed by SSD method had larger genotypic variation than those developed using the DH method. The DH lines associated with SHGD could reduce costs and time to complete the breeding cycle. We found nine significant SNPs related to PH and EH, and six out of them were linked to genes responsible for plant growth.