Novel Population Structure for QTL Mapping in Maize. (5740)
Authors:
A.K. Singh* - University of Guelph, Canada E.A. Lee - University of Guelph, Canada M. Tollenaar - University of Guelph, Canada
Abstract:
Traditional quantitative trait loci (QTL) mapping population sizes are large, consisting of 150 – 300 recombinant inbred lines (RIL), so as to homogenize the effects of the rest of the genome. This reduces the within marker class variance thereby increasing the likelihood of QTL identification. One novel approach to reduce population sizes without loss of QTL detection power is to cross parents that are homogeneous for most of the genome. In theory, a pair of inbred lines derived from the same hybrid should have at least 50% of their alleles identical by descent (IBD), i.e. derived from the same parent. Using three families of six inbred lines and 15 sister line crosses each, we examined the extent and genome structure of IBD, and presence of phenotypic variation for grain yield and response of leaf photosynthesis to cold night time temperatures. Average IBD estimates across 45 sister line cross was ~65%, and ranged from 51.1 to 79.8%. In many cases, the non-IBD appear to be relatively small (less than 20 cM). For grain yield, significant genetic variation was detected in two of the three families. Three inbred lines from with in a family were crossed to CG102 and revealed significant genetic variation when evaluated for photosynthesis in response to cold during the grain filling period.
Speaker Information: Asheesh Singh, University of Guelph, Canada, Department of Plant Agriculture, Crop Science building, University of Guelph, Guelph, ON N1G2W1;
Phone: (519) 824 4120 ext58184; E-mail: [email protected]
Session Information: Monday, November 1, 2004, 1:00 PM-3:00 PM Presentation Start: 8:25 AM
Keywords: novel; QTL; mapping; maize
