Characterization of phenotypic diversity, yield and response to drought stress in a collection of Rhodes grass (Chloris gayana Kunth) accessions

Abstract

Information on available diversity and drought resistance among Chloris gayana accessions would offer considerable potential to select genotypes to alleviate the feed inadequacy that constrains livestock production in dry tropical areas. A collection of 62 C. gayana accessions from the genebank of the International Livestock Research Institute in Ethiopia was characterized using a set of 30 morphological, 4 phenological and 8 agronomic traits to assess diversity within the collection and to select promising accessions for use as livestock feed. In parallel, an experiment was conducted to assess the ability of these C. gayana accessions to maintain productivity under drought stress. The screened collection of C. gayana accessions proved to be highly diverse in terms of morphology and phenology, agronomic potential and drought response. Six morphological groups were described which differ in many characteristics, ranging from general growth habit to specific inflorescence parameters. Large variability was measured in dry matter production, varying not only in total amount (400–2100 g m −2 ) and leaf contribution to total plant mass (66–96% of dry matter), but also in the growth pattern observed over three harvests. Accessions belonging to identical morphological, agronomic or drought-response groups were found to originate from a wide range of environments. Promising accessions for different uses and environments were identified and should be further evaluated across seasons and in multilocational experiments.