THE ASSOCIATION OF GENES-CONTROLLING CARYOPSIS TRAITS WITH GRAIN MOLD RESISTANCE IN SORGHUM

Four parental cultivars with distinct characteristics and gene markers for caryopsis traits were used as a base population to generate F1, F2, and BC1 populations at College Station, TX. These populations were evaluated for grain mold resistance at College Station, TX, in 1990, and at Namulonge and Serere Research Stations in Uganda, in 1991. The presence of a pigmented testa (B1-B2-), a red pericarp (R-Y-), a thin mesocarp (Z-), and an intensifier gene (I-) were all dominantly inherited. A pigmented testa was the single most important trait conferring grain mold resistance. The red pericarp trait also conferred grain mold resistance, though not as greatly. The effect of a red pericarp was enhanced by the presence of the intensifier gene. The effects of both a pigmented testa and a red pericarp were additive. Mesocarp thickness did not play a significant role in grain mold resistance. College Station and Serere were suitable locations for grain mold evaluation.