Growth Characteristics of Selected Dinitroaniline-Resistant and -Susceptible Goosegrass (Eleusine indica) Population

Abstract

Growth and development of selected dinitroaniline-resistant (DR) and -susceptible (DS) goosegrass populations were compared in field studies in replacement series, in association with cotton, and under noncompetitive conditions. The DR ‘Florence’ (FR) and DS ‘Orangeburg’ (OS) populations were similar in competitiveness as indicated by relative yields (RY) and relative crowding coefficients (RCC) for vegetative and reproductive biomass production in a replacement series. Relative growth of the FR and DS ‘Anderson’ (AS) populations in replacement series was similar when vegetative biomass was considered, but reproductive biomass of the AS population declined as proportion of FR population increased. RCC values also indicated that the FR population interfered with reproductive development of the AS population. In field studies, the FR population produced greater vegetative biomass than either DS population, while similar reproductive biomass occurred for the FR and OS populations. Inflorescence dry weights were greater for the FR than the AS population under noncompetitive conditions and in cotton, but were greater for the AS population in replacement series studies. The competitiveness of DR and DS goosegrass biotypes appears to be more related to growth characteristics of individual populations than to response to dinitroaniline herbicides.