Characterization of meadow × smooth bromegrass hybrid populations using morphological characteristics

Abstract

Three hybrid populations between meadow bromegrass (Bromus riparius Rehm.) and smooth bromegrass (Bromus inermis Leyss.) have been developed using recurrent selection for vigor, uniformity of growth and floret fertility. The objective of this study was to use morphological characters to characterize the three hybrid populations (S-9197, S-9073, and S-9183) and the two parental species. Tiller heights did not differ among the hybrids and the parental species. Leaf-to-stem ratio of the hybrids was intermediate to that of the parents. Tiller density, panicle density and dry matter yield of the hybrids were more similar to those of smooth bromegrass. Leaf pubescence densities of the hybrids were higher than the parental species, but pubescence lengths closely resembled meadow bromegrass. Leaf area index (LAI) of the hybrids was lower than smooth bromegrass, and resembled meadow bromegrass. Lowest brown leaf spot ratings were observed in meadow bromegrass, while the hybrids were similar to smooth bromegrass. In general, the hybrid populations showed some individual characteristics similar to each of the parental species and, thus, can be characterized as being intermediate to the parental species. Furthermore, several of the differences among the hybrid populations can be attributed to the selection criteria that were used to develop these populations. Key words: Bromus, smooth bromegrass, meadow bromegrass, hybrid bromegrass, morphological characteristics