Developing Cultivation Practices To Combat Early Drought Challenges: The Case Of Sorghum In Mali

ABSTRACT

Rainfall variability and early season drought are among the most severe consequences of climate change in the Sahelian zone of Mali in West Africa that affect the production of key staple crops such as Sorghum (Sorghum bicolor (L.) Moench). Therefore, a three-step research was conducted with trials in the laboratory, pots and field to improve seed germination and reduce crop establishment failure. The experiments were set up to evaluate the effects of heat and drought stress, priming of seeds and the zaï pits practice on the performance of nine sorghum varieties. During all steps, a wide series of recognized germination performance indicators were used to assess in promising varieties and pre-seed treatments (hydro or osmo-priming) in laboratory and pot trials for their impact on crop yield. The findings showed that the varieties Banidoka, CSM63E and Saba-tienda performed best under heat and drought stress conditions. Hydro-priming in tepid or hot water was an effective technique to improve seed germination and seedling growth parameters in general. Water derived from the river or well was most effective for hydro-priming whilst a hydro-priming duration of 8 hours at room temperature (25 ºC) equaled the effect of 20 minutes priming in hot water (70 oC), but in both cases, treated seeds had to be immediately sown. Osmo-priming with 50 ppm of KH2PO4 or 100 ppm of K2SiO3 significantly improved seed germination and seedling growth in early drought conditions. A combination of priming and the zaï pits practice, which involves an application of organic matter, increased grain yield by 34% and straw yield by 42% over the control without priming and sown on the ridge.