RFLP MAPPING OF THE SUGARY ENHANCER1 GENE IN MAIZE

xRFLP marker data from an F-2:3 population derived from a cross betwee n a sugary1 (su1) and a sugary enhancer1 (su1, sel) inbred were used t o construct a genetic linkage map of maize. This map includes 93 segre gating marker loci distributed throughout the maize genome, providing a saturated linkage map that is suitable for linkage analysis with qua ntitative trait loci (QTL). This population, which has been immortaliz ed in the form ofsibbed F-2:3 families, was derived from each of the 2 14 F-2 plants and along with probe data are available to the scientifi c community. QTL analysis for kernel sucrose (the primary form of suga r) concentration at 20 days after pollination (DAP) uncovered the segr egation of seven major QTL influencing sucrose concentration; a locus linked to umc36a described the greatest proportion of the variation (2 4.7%). Since maltose concentration has previously been reported to be associated with the sel phenotype, an analysis of probe associations w ith maltose concentration at 40 DAP was also conducted. The highly sig nificant association of umc36a with maltose and sucrose concentrations provided evidence that this probe is linked to se1. Phenotypic evalua tion for the sel genotype in each F-2:3 family enabled us to map the g ene 12.1 cM distal to umc36a. In contrast to previous work where sel w as reported to be located on chromosome four, our data strongly sugges t that the sugary enhancer1 locus maps on the the distal portion of th e long arm of chromosome 2 in the maize genome.