Miriam Wanjiku Mbiyu is an agricultural research professional with over 15 years’ experience in potato research and development gained while working at Kenya Agricultural and Livestock Research Organization (KARO) and Agricultural Development Corporation (ADC). She obtained her MSc degree in Biotechnology in 2006 and a BSc in Chemistry in 2006. She has worked on projects in crop protection, agronomy, germplasm management and evaluation, breeding, socio-economics and technology transfer. As a result, she has built capacity in designing and setting up of laboratory, screen/greenhouse and field experiments; and indexing of plant diseases using serological techniques. She is competent in collecting and collating research data, as well as compiling and preparing field and laboratory reports, administering experimental protocols and schedules, maintaining laboratory and field note books and writing standard operating procedures and complying with them. She has good organizational and project management skills. She has authored/coauthored 11 publications in refereed journals and 39 abstracts/conference papers proceedings and won two research grants. She is master trainer of Trainers of Trainers and farmers on seed and ware potato production and disease management.
Abstract
Potato cyst nematodes is a significant constraint to potato production in Kenya. Therefore, a study was carried out with the aim of determining the diversity of PCN populations in the country; site specific factors that contribute to spread and build-up in population density; relative yield loss caused by the pest; and the efficacy and active ingredients of selected botanical pesticides in PCN management. All the samples from Nyandarua, Nakuru and Meru counties gave amplicons of 434bp that are specific for G. rostochiensis. The fixation index (Fst) ranged from 0.021 to 0.048. Cyst counts were higher (302 cysts/ 300 g) in farms with more than one crop cycle compared to farms where one crop cycle was grown per year (38.5 cyst/300 g soil). Over 80% of the farmers used farm saved seed tubers and grew cultivar Shangi that is susceptible to PCN. Potato cyst nematodes reproduced more on Desiree and Shangi varieties than on variety Manitou. Relative yield losses were significantly reduced in potato varieties treated with PCN control products over the untreated control plots. Application of hexane extracts from ginger, garlic and Mexican sunflower resulted in a significant (P<0.05) increase in juveniles mortality and loss of egg viability resulting in potato yield increase. The ginger extract (100 mg/ml), had an inhibitory effect on multiplication of the nematodes and was rated as the most potent in reducing numbers of PCN. G. rostochiensis was the predominant species within the study area with limited genetic variation among the populations studied. Factors that were contributing to spread and buildup of potato cyst nematodes include cropping practices and soil types. There is need to deploy integrated management approaches so as to reduce the spread and build-up of PCN.
Research Supervisors
Prof. Maina Muiru Prof. John Kimenju Dr. Moses Nyongesa Dr. Solveig Haukeland
