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The phenology of Malian sorghum varieties was studied to understand the impact of climate constraints on their cycle duration. We hypothesized that with recent droughts, farmers had shifted to varieties with shorter cycle durations. The studied gemplasme was drawn from two different collections: one made in 1978 and the other in 2000. A phenology model adapted for photoperiod-sensitive sorghums was used to predict cultivar behaviour in their original environment as a function of latitude and rainfall regimes. The average cycle duration of the ecotypes changed little in 20 years. This point negates our assumption, because the rainfall deficit did not result in a shortening of the average cycle duration of the sorghums. A vast majority of ecotypes from humid areas were found to be photoperiod sensitive. This trait allows for optimal use of water supply by the crop and most importantly to evading specific biotic constraints (mold, bird pressure). As one moves towards the northern, drier areas, both late- and early-maturing ecotypes are encountered. This diversity is an important element in securing production in arid regions. Genetic diversity appears to be an important factor in the resilience of the cropping systems in areas with higher climatic risks. This work can guide the breeding programs in defining ideotypes specifically adapted to the range of climatic environments of the area.