Nonrandom mating experimental design. To map loci that control female-mediated nonrandom mating, pollen from Van-0 and Col-NPTII strains are placed in competition on RIL pistils. Thus, differences in siring success can be attributed to maternal genotypes, detectable as QTLs. To map loci that control male-mediated nonrandom mating, pollen from Col-NPTII is placed in competition with RIL pollen on Van-0 pistils. Thus, differences in siring success can be attributed to paternal genotypes, detectable as QTLs.