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Abstract
Developing hybrids of guineagrass (Panicum maximum Jacq.) is difficult mainly because its reproduction is by apomixis. Utilizing sexual female plants and facultative apomictic genotypes, the following crosses were developed at the USDA-ARS, Tropical Agriculture Research Station (TARS): GH-101 (Tift SPM 92 χ PI 3622); GH-102 (Tift 49 χ CI AT 604); GH-103 (Tift 49 χ PI 3622); and BPIH-104, a Brachiaria purpurascens χ P. coloratum interspecific hybrid. In a randomized split-plot design with four replications, the four hybrids, common guineagrass, and cultivar Tobiata (a P. maximum introduction), were evaluated in terms of dry matter yield (DMY) and a series of agronomic characters at 4-, 6-, and 8-wk cutting intervals (CI) during the period of one year at the Isabela ARS farm. On the average, the genotypes DM production increased 60% from the 4- to 6-wk CI and 44% from the 6- to the 8-wk CI. Tobiata and GH-104 were the top yielders with over 38 and 39 t/ha/yr, respectively. These yields are significantly higher than those reported in the tropics for common guineagrass and comparable to yields produced by napiergrass (Pennisetum purpureum Schum.).