Effectiveness of the Nyanga Seed Potato Quarantine Area for the Production of AA Grade Potato (Solanum tuberosum L.) Seed in Zimbabwe

Abstract

In Zimbabwe, potato (Solanum tuberosum L.) is becoming a major staple food due to increasing uptake of products such as French fries and crisps. The availability of good quality seed has been a major challenge and potato farmers have resorted to farmer based seed systems where potato varieties listed in the official variety catalogue were becoming unpopular. Those varieties perceived to be popular were not on the official seed production program. Farmers were claiming that the quality of seed from the official seed program was affecting their yields. This, coupled with an increase in complaints received by the Seed Certifying Authority on the quality of potato seed necessitated this study to investigate the suitability of continued use of the designated Nyanga Seed Potato Quarantine Area (SPQA) for the production of foundation and AA grade seed. The study monitored the prevalence of scheduled pests and diseases of the SPQA and characterized existing planting material for purity and compliance to the statutory requirements. The objective was to derive policy implications on the continued use of the Nyanga SPQA as a seed potato quarantine designated production area.The study was comprised of a longitudinal survey, regular seed crop inspections in the SPQA and field trials at ART Farm in Harare and Divonia farm in Acturus, from January 2012 to December 2014. A total of 59 ha out of 876 ha registered for inspection and a total of 199.2mt of seed was rejected during 2012, 2013 and 2014 production seasons in the SPQA. The production systems found in the SPQA affected the quality of seed being produced in the area but the seed certification scheme was managing to control the quality of seed that enters into the seed market. The bacterium Ralstonia solanacearum was detected at five farms out of 22 farms and Clavibacter michiganensis subsp. sepedonicum was detected at one farm out of 22 farms. The detected diseases were concentrated on a portion of six neighbouring farms. This resulted in the recommendation for suspension of those farms from production of seed until research establishes total eradication of the diseases in the areas. Overall the study concludes that the SPQA is still functioning in the exclusion of diseases of quarantine importance.