02151naa a2200217 a 450000100080000000500110000800800410001910000150006024500930007526000090016852014500017770000170162770000170164470000160166170000140167770000250169170000140171670000150173070000160174577301720176116373302009-02-03       2008    bl uuuu     u00u1 u    #d1 aMUTEGI, R.  aField evaluation of cassava varieties under drought stress in Kenia, Tanzania and Ghana.  c2008  aA collaborative project is underway between IITA, CIAT, EMBRAPA, Cornell University and the NARS of Tanzania, Kenya and Ghana to identify the physiological and genetic traits that make cassava one of the most drought tolerant crops. This involves firstly the evaluation under drought stress conditions in Tanzania (Hombolo), Kenya (Kiboko) and Ghana (Tamale) of local varieties and a selection of genotypes from IITA, with contrasting responses to drought stress; and secondly the phenotyping, at the same sites, of two mapping populations (MCOL 1734 x VEN 77; MCOL 1468 x BRA 255) and self progeny (MCOL 1734) developed at CIAT. Currently 31 genotypes are being evaluated in a replicated trial with irrigated and non-irrigated treatments in Kenya, and ten local varieties are being evaluated in a similar experiment in Tanzania. Methodologies for physiologycal evaluation are being tested, and include stomatal conductance, leaf retention, stem, leaf and petiole starch content, ABA and yield parameters. The in vitro mapping populations are being hardened in Kenya, Tanzania and Ghana. The project has a large capacity buiding component, both for evaluating the response to drought, and in receiving and hardening in vitro cassava plantlets. Protocols for hardening and rapid micro-propagation of in vitro cassava plantlets have been developed. Genotyping of the mapping populations is underway using approximately 200 polymorphic SSR markers.1 aFERGUSON, M.1 aMAASS, B. L.1 aMKAMILO, G.1 aKAMAU, J.1 aADJEBENG-DANQUAH, J.1 aALVES, A.1 aSETTER, T.1 aFREGENE, M.  tIn: CGIAR GENERATION CHALLENGE PROGRAMME ANNUAL RESEARCH MEETING, 2008, Bangkok, Thailand. Poster abstracts... Mexico, DF: Generation Challenge Programme, 2008. p. 54.