A mapping experiment has been carried out on the IMB94 recombinant inbred maize population seeking loci that confer tolerance to drought stress, UV-B stress, and the combination of both. The effects of drought, UV-B radiation, and the combination of both on four general traits in maize seedlings were measured under greenhouse conditions and analyzed using QTL Network and Chromoscan software. Trait measurements indicated a seasonal affect on growth which was adjusted for by standardizing trait data by the median of corresponding parental ‘check plants’. Non-adjusted and adjusted QTL Network analyses identified 19 QTLs with 5 epistatic interactions and 6 QTLs with 2 epistatic interactions, respectively while Chromoscan analysis identified 123 single locus QTLs. Results from these analyses suggest that QTLs for drought and UV-B tolerance exist across the entire genome and are somewhat more common than QTLs for tolerance to the combination of both stresses
