Official release of eight cassava varieties in the Lake zone of Tanzania Kulembeka HP, Jeremiah SC, Mkamilo G, Ngendello T, Ndyetabula I, Merumba S.M, Legg JP and Kanju EE.

Importance of cassava Tanzania is 4th cassava producer in Africa Total root production is 7 M tons from 670,000 ha Cassava is 2nd most important staple after maize Of the total cassava production in Tanzania (7M tons), Lake zone contributes about 40%

Fig. Cassava production (MT) in each zone in 2007/2008

Major biotic constraints in the Lake zone Cassava yields lake zone 7.3 t/ha, national average 10.5 tons/ha (FAO, 2007) Low yields were mainly due to susceptibility of local varieties to major diseases and pests: CMD, CBB and CGM The emergence of CMD pandemic in Lake zone in 1998 wiped out all cassava varieties resulting into food crisis Five varieties in the pipeline for official realease in 2005 also succumbed to CMD_UgV

Yield losses up to 100%

Mitigation of CMD pandemic To address CMD pandemic about 900 breeding line were introduced from Uganda in 2001 with support from IITA, EARNET, GOT and USAID-OFDA Introduced through open quarantine facility and put under inspection for one year Materials screened against CMD-UgV, root yield and other root traits with the support of USAID-OFDA and GOT Participatory evaluation resulted into identification of 8 (eight) promising lines for high yield, resistance to CMD and other farmer preferred traits

Participatory variety selection

Application for official Release In May 2008 proposal for official release of eight promising was submitted to Tanzania Official Seed Certification Institute (TOSCI) TOSCI conducted National Performance Trial (NPT) and Distinctiveness Uniformity and Stability (DUS) test, NPT and DUS results were presented and discussed at NPT Technical Committee and National Variety Release Committee in December 2009 All eight varieties were accepted for official release on 22nd December 2009. NPT and DUS were supported by AGRA

Name under which tested Description of Released varieties Name under which tested Proposed names Merits MM96/8450 Kyaka Yield potential (22t/ha); CMD resistant, CGM tolerance, CBB tolerance, Maturity (11-12 months), bitter MM96/4684 Mkombozi Yield potential (20t/ha); CMD resistant, CGM tolerance, Maturity (10-12 months), good mealing quality, sweet MM96/5725 Nyakafuro Yield potential (20t/ha); CMD resistant, CGM tolerance, Maturity (10-12 months) MM96/3075B Belinde Yield potential (20t/ha); CMD resistant, CGM tolerance, Maturity (9-12 months), good for intercropping, sweet MM96/4619 Meremeta Yield potential (20t/ha); CMD resistant, CGM tolerance, Maturity (9-12 months), sweet MM96/8233 Rangi mbili Yield potential (23t/ha); CMD resistant, CGM tolerance, Maturity (10-12 months), sweet 95NA/00063 Kasala Yield potential (22t/ha); CMD resistant, CGM tolerance, Maturity (11-12 months), sweet, mealy TMS191/0067 Suma Yield potential (17t/ha); CMD resistant, CGM tolerance, Maturity (10-12 months), good for intercropping, sweet

Dissemination By support of BMGF through GLCI project and SIDO (MUVI project) the released varieties have been widely disseminated to farmers in the Lake zone of Tanzania particularly in: Bukoba, Muleba, Biharamulo, Misenyi, Misungwi, Ukerewe, Bunda, Musoma, Kwimba, Geita and Serengeti districts

Cassava Multiplication

CHALLENGES By the time the eight varieties were released for resistance to CMD-UgV, CBSD was not important in the Lake zone. Most of the released varieties succumb to CBSD infection therefore increasingly threatening cassava production and food security in Lake zone. Current efforts are geared towards breeding for dual resistance to CMD and CBSD

ACKNOWLEDGEMENT IITA USAID-OFDA EARRNET AGRA TOSCI GOVERNMENT OF TANZANIA CASSAVA RESEARCH TEAM FARMERS GCP21-II

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