Yam is a tuber cultivated mainly in West Africa. Its culture faces biological and non-biological constraints of climatic types especially. The increasingly high temperatures as well as the bad spatio-temporal distribution accentuate the aridity of the grounds which considerably disturb the development even the production of yam. The objective of this study was to compare the morphophysiological adaptation responses of yam morphotypes subjected to water stress and to determine the portion of the seedling and the water regime suitable for a cultivation of yam in semi-arid zones. even arid. To do this, two morphotypes of yam «waogo» (Dioscorea alata) and «nyù» (D. cayenensis - D. rotundata complex) were grown in pots in real conditions. The tubers of each morphotype were divided into three portions and then subjected to three water regimes. Environmental and morphophysiological parameters were noted during the study.For all the parameters studied, the results show that the «nyù» is more tolerant of water deficit than the «waogo» with a larger root biomass and leaf area and lower transpiration. This study reveals that depending on the portion of the seed used and water regime, «nyù» and «waogo» have differentiated behaviors.

This study was conducted to evaluate the morphological and agronomic performance of ten varieties of sweet potato grown in Bongor in Chad during the dry season. The average length of internodes of the main stem and means the collar diameters were measured and maximum growth rates associates were determined, the length and diameter of tuber were measured, the number of tuber per plant were recorded tuber yield, the diameter/length ratio of the tuber, the average weight of tuber and dry matter aboveground biomass were determined. The results, it appears that varieties BF 59 and BF 40 have the longest and varieties BF 108 and TIB have diameters in the larger collar internodes. The highest growth rates were noted between the 37th and 51st JAP and between the 23rd and 72nd JAP respectively for the length of internodes and the collar diameter. For agronomic parameters, variety BF 108 was more effective for most of the studied parameters. This variety seems interesting for the selection of work.

The objective of this study was to highlight the physiological, morphological and agronomic performance of varieties and descendants of sesame (Sesamum indicum) grown in Burkina Faso. Experimentation was conducted at the Gampela educational agro station located at 12