DEVELOPMENT OF POST-FLOWERING DROUGHT TOLERANT SORGHUM HYBRIDS FOR THE SAHELIAN ZONE

Sorghum is the fourth most produced cereal in Mali following maize, rice and millet. It is grown either in rainfed conditions or in flood recession conditions in lakes, ponds or along the Niger and Senegal rivers. However, its yield (829 kg/ha) remains low due to various abiotic and biotic constraints, including the effects of post flowering drought. One of the limiting factors of its production in the Sahelian zone remains the very frequent post-flowering drought. Data collected from Mali's meteorological stations from Niono to Sikasso indicates a prevalence of drought in every other year between 1950 and 2015. The development of post-flowering drought-tolerant sorghum hybrids is one of the best approaches to increase the level of sorghum productivity and production in the Sahelian zone, which is often affected by the effect of drought. Thus, A/B lines (sterility maintainer) and R lines (fertility restorer) with the "stay green" trait have been developed in Mali . The objective is to ensure food security and income of farmers in the Sahelian zone of Mali through the development and dissemination of sorghum hybrids tolerant to post -flowering drought . Thirty-eight (38) hybrids from combinations between the different groups of parents were compared to 2 controls in a 2-replication Alpha lattice design. The study was conducted at the Kolombada Agricultural Research Substation and the Cinzana Agricultural Research Station). The characteristics analyzed were plant height, number of green leaves at physiological maturity and grain yield. The evaluation showed through statistical analysis, significant différences between hybrids for plant height, number of green leaves and grain yield. The average plant height varied from 250 to 130 cm in Kolombada against 317 to 117 cm in Cinzana . The number of green leaves at physiological maturity varied from 4 to 7 in Kolombada and from 3 to 6 in Cinzana . In Kolombada, grain yield varied from 915 kg/ha to 4841 kg/ha against 363 kg/ha to 3503 kg/ha in Cinzana. The gain in grain yield of the hybrids compared to the best hybrid control Fadda varied from 25 to 106%, thus confirming the performance of the new hybrids compared to the hybrids in diffusion. The results of the drought indices (GMP and YSI) made it possible to distinguish twenty-one new hybrids tolerant to post-flowering drought. The identified hybrids will thus be evaluated in areas with low rainfall.