Submitted to: International Grasslands Congress
Publication Type: Proceedings
Publication Acceptance Date: 6/8/1997
Publication Date: N/A
Interpretive Summary: Apomixis is an asexual form of reproduction in plants where seed produce without fertilization. It is a means of cloning plants by seed. There is considerable interest in apomixis as a tool for breeding and propagating superior plant types. Plants that reproduce by normal sexual reproduction occur in most apomictic species. However, these plants have received little attention. Buffelgrass, an important forage grass in southern Texa and northern Mexico, is predominantly apomictic; a limited number of sexual plants exist but little is known about their forage potential. An experiment was conducted to determine if these sexual plants have sufficient vigor and desirable traits for use in a grass breeding program. The sexual plants, their self-pollinated offspring, and first generation (F1) hybrids were compared to several apomictic plants and hybrids for different traits. The sexual self-pollinated progeny were less fertile and dless productive than their parents and both the sexual and apomictic hybrids. However, the sexual hybrids were as vigorous as the apomictic hybrids which suggests there is potential in breeding sexual buffelgrass.
Technical Abstract: Breeding apomictic grasses is based on either the direct selection of apomictic landraces or the hybridization of sexual and apomictic types and selection of apomictic F1 hybrids. Little is known about the potential of sexual hybrids as cultivars in apomictic species. To determine if method of reproduction (MOR) was related to plant vigor, parental, S1, and F1 hybrids of buffelgrass differing in method of reproduction (apomictic or sexual) were established in a common garden in 1994 and 1995. In both years severe inbreeding depression was observed in the S1 progeny as they were shorter, produced less biomass, and had low seed-set, when compared to the sexual parents or the F1 hybrids. In contrast, the apomictic and sexual F1 hybrids produced similar biomass, tiller numbers, and were similar in plant height. This study suggests that while severe inbreeding depression occurs in buffelgrass, sexual F1 hybrids are as vigorous as apomictic hybrids and could be considered for potential use as cultivars.