Effect of Aqueous Extracts of Acacia gourmaensis A. Chev and Eclipta alba (L.) Hassk. on Seed Health, Seedling Vigour and Grain Yield of Sorghum and Pearl Millet

摘要

Antifungal activity against several fungi infecting sorghum and pearl millet seeds was investigated in aqueous extracts of Acacia gourmaensis (bark) and Eclipta alba (whole plant). The effect of plant extracts in the management of the fungi Fusarium moniliforme, Curvularia lunata, Phoma sorghina, Colletotrichum graminicola and Exserohilum rostratum was assessed using the following parameters: post-treatment seed infection rate, emergence, mortality and vigour of seedlings and grain yield. Both plantextracts were efficient in controlling P. sorghina, F. moniliforme and C. lunata in pearl millet seeds where infections were reduced by 56-86%. In sorghum seeds, both extracts also reduced P. sorghina infections by 27-72% but only extracts from A. gourmaensis controlled C. graminicola with 69% decrease in seed infection. In addition to promoting seed health, all plants extracts favoured seedling emergence, especially in sorghum where proportions of emerged seeds (70-80%) were significantly higher than that of non-treated seeds (66%). Higher seedling vigour was also induced upon seed treatments in either sorghum (7.1-8.3) or pearl millet (7.4-8.4) compared to non-treated seeds (4.3 and 6.3, respectively). The overall beneficial effects of seed treatments with plant extracts resulted in the increase in grain yield. Treatment of the seeds with extracts from E. alba led to the highest yields in both sorghum (2.5 vs. 1.5 t ha-1 for non-treated seeds) and pearl millet (1.6 vs. 1.3 t ha-1). Altogether, plantextracts from A. gourmaensis and E. alba showed fungicidal activities and may be used for controlling major sorghum and pearl millet seed-borne fungi.