FORAGE YIELD, QUALITY, AND FERTILITY OF SORGHUM X SUDAN GRASS HYBRIDSIN A1 AND A3 CYTOPLASM

Currently, no information is available comparing the agronomic perform ance of A1 and A3 cytoplasms in sorghum x sudangrass [Sorghum bicolor (L.) Moench] hybrids. The objectives of this study were to compare the effects of Al and A3 cytoplasm on the maturity, fertility, height, fo rage yield, and forage quality of sorghum x sudangrass hybrids. In 198 9, pollen from a bulk of eight sudangrass populations was used to poll inate four sorghum lines that had been mule-sterilized in both A1 and A3 cytoplasm. Hybrids were grown at the Univ. of Nebraska Field Labora tory, Ithaca, NE, in 1990 and 1991, in a split-plot design with inbred s (females) treated as whole plots and cytoplasms treated as subplots. The soil was a Sharpsburg silty clay loam (fine montmorillonitic, mes ic Typic Agriudoll). Cytoplasm had no effect on days to 50% anthesis, height, forage yield, in vitro dry matter disappearance (IVDMD), or cr ude protein. Seed set under selfing bags (fertility restoration) in A3 hybrids was observed, with interaction among A3 cytoplasm sources and lines.