Self-compatibility in 'Paloma' Indian ricegrass

Abstract

A species' mode of reproduction must be understood before initiating a breeding program. Indian ricegrass [Oryzopsis hymenoides (Roem. & Schult.) Ricker] flowers may be effectively cleistogamous or chasmogamous, but the floral structures are most consistent with self-pollination than cross-pollination. Results of a field study comparing seed production of isolated and open-pollinated 'Paloma' panicles indicate that self-incompatibility is not important. These observations suggest Indian ricegrass is primarily self-pollinated. Because Indian ricegrass has diffuse panicles and small flowers, it is difficult to make large numbers of controlled crosses. Only one seed is produced per emasculation. Furthermore, any hybrid seed produced will be difficult to germinate because of persistent seed dormancy in this species. Thus, plant breeding methods traditionally used for self-pollinated crops, which rely on artificial hybridization, would be inappropriate at this time. Collecting and evaluating native accessions should be a more effective initial strategy.