Evaluation of Eggplant (Solanum spp) Genotypes for Proline Accumulation in Drought Conditions of Ghana

Sixteen (16) genotypes of eggplant (Solanum spp) were grown over two years in the Coastal and Sudan Savannah areas of Ghana to identify proline accumulation response patterns of the genotypes under dry season and drought-stressed conditions of Ghana. The experiment was conducted at Savanna Agricultural Research Institute (SARI) experimental farm, Manga, Bawku (Sudan Savannah Agro-ecology), and University of Ghana, Legon, Accra, experimental farm (Coastal Savannah Agro-ecology). At each agro-ecology, leaf samples of the genotypes were collected at the flowering stages of growth, dried, milled and assayed for their proline levels. The proline data for each location and season for the two year period were separately analyzed by general analysis of variance (ANOVA), for the estimation of the variation among the genotypes in proline accumulation. Proline which confers tolerance of the crop to variable seasonal and drought-stressed conditions varied significantly, due to the genotype and genotype x environment interaction effects on its accumulation. The eggplant genotypes were observed to develop internal complementary drought survival mechanisms, by lowering leaf relative water contents (LRWC) and increasing proline content, thereby enabling plants to withstand periodic drought better. The genotypes A3, A4, A8, A9F, A10 and Bawku1 accumulated higher levels of proline under dry season and drought-stressed conditions of the Coastal and Sudan savannahs, with the associated high temperatures across locations. These genotypes could be selected on the basis of proline accumulation, for improved drought tolerance of the crop, and should be incorporated in eggplant drought tolerant improvement programmes in Ghana.