Paper presented at the 52nd CFCS Annual Meeting, Guadeloupe, July 10-16, 2016 Main results Pre-harvest Variety differences were observed for plant height, leaf length and leaf width. However, there did not appear to be any effect on these parameters due to the water treatments. Harvest No significant difference was observed among the varieties for fresh leaf weights. Significant variety x treatment (p < 0.05) interactions were observed for total fresh root weight; total number of roots and total number of marketable roots. Maracas Bluestick yielded total fresh root weight of 1,500.0 ± 120.7 g per plant under water regime 1 compared to 925.0 ± 120.7 g under water regime 2. Comparative values for the other 4 varieties regimes 1 and 2, respectively were Butterstick (633.3 ± 139.4 and 550 ± 120.7); Maracas Blackstick (458.7 ± 120.7 and 725 ± 120.7); Mmex 59 (787.5 ± 120.7 and 543.7 ± 120.7) and Pickney Muma (337.5 ± 120.7 and 368.7 ± 120.7). Maracas BlueStick had Total Root number of 9.8 ± 1.19 per plant under regime 1 compared to 5.3 ± 1.19 under water regime 2. Comparative values for the other 4 varieties regimes 1 and 2, respectively were Butterstick (7.0 ±1.37 and 6.5 ± 1.19); Maracas Blackstick (5.5 ±1.19 and 9.5 ±1.19); Mmex 59 (7.0 ±1.19 and 4.3 ±1.19) and Pickney Muma (4.8 ± 1.19 and 6.5 ± 1.19). Maracas BlueStick had marketable Root number of 7.3 ± 0.89 per plant under regime 1 compared to 4.0 ± 0.89 under water regime 2. Comparative values for the other 4 varieties regimes 1 and 2, respectively were Butterstick (5.3 ± 1.03 and 3.8 ± 0.89); Maracas Blackstick (3.0 ± 0.89 and 5.5 ± 0.89); Mmex 59 (4.3 ± 0.89 and 3.3 ± 0.89) and Pickney Muma (1.5 ± 0.89 and 4.3 ± 0.89). Significant differeces (p <0.05) were observed among varieties for total fresh marketable root weight and total number of roots. Marketable fresh root weight of Maracas Bluestick for both regimes 1 and 2 was significantly higher than for the other 4 varieties. Conclusion Based on the performance of Maracas Bluestick under water regime 2 (water stress), it is concluded that the variety has the potential for good production in areas prone to drought (water stress). The next step would be field evaluations to assess the varieties under field conditions. Acknowledgement: The support of the Intra-ACP Agriculture Policy Programme funded by the European Union under the 10th EDF facility for the study is highly acknowledged. Bibliografic references Alves A A C. 2002. Cassava Botany and Physiology. In: Hillocks R J, Thresh J M and Bellotti A C (eds) Cassava: Biology, Production and utilization. Wallingford: CABI Publishing pp.67-89 El-Sharkawy M A. 2006. International research on cassava photosynthesis, productivity, eco-physiology, and responses to environmental stresses in the tropics. Photosynthetica 44:481-512 Lenis J I, Calle F, Ceballos H, Cock, J H, Jaramillo, G and Perez, J C. 2006. Leaf retention and cassava productivity. Field Crops Research 95:126-134 Lynam J and Romanoff S. 1992. Cassava and African food security: some ethnographic examples. Ecol. Food Nutr 27: 29-41
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