TORELANCE LEVEL OF DIFFERENT CABBAGE VARIETIES TO BLACK ROT BY: MUNENE DAVID M. A22/0081/2009

1. TORELANCE LEVEL OF DIFFERENT CABBAGE VARIETIES TO BLACK ROT BY: MUNENE DAVID M. A22/0081/2009 SUPERVISOR: PROF. DANIEL MUKUNYA

2. Introduction • Cabbage is the most valued and the most used vegetable in the world • Of all the crucifers, cabbages are the most affected by black rot caused by a bacteria Xanthomonas campestris pv campestris • Different seed companies have breed for resistant varieties (F1) but farmers are still suffering losses related to black rot • This means there is a need to evaluate the most resistant variety that can minimize losses encountered by the farmers around Kabete

3. Problem statement and justification • Despite breeders effort to breed for resistant varieties of cabbage, black rot disease has remained to be a threat in most parts of the world, especially in small scale • Production(21MT/ Ha) has remained much lower than the yield potential (26-75 MT/Ha depending on variety) despite high demand, good market prices and health benefits associated with cabbages • Infected cabbages are also prone to other pathogens leading to high storage losses • This is as result of break down of resistant gene following the continued mutation of the bacteria over time

4. OBJECTIVES General objective; • Evaluation of the most tolerant cabbage varieties against black rot commonly grown in Kenya Specific objective; • Determine the incidence of black rot in different cabbage varieties

5. Materials • Four cabbage varieties- Riana, Fanaka F1, Pructor F1, Queen F1 • 1 kg DAP • 2kg CAN • pesticides • 70% alcohol(100ml) • 3% Sodium hypochlorite (50ml) • Sterile distilled water • Empty Petri dishes • 12 plates of nutrient agar • Wire loop • Spirit lamp • 12 universal bottles • Clean distilled water • Teat pipette/ dropper

6. Methodology • Planting and establishment of cabbages in the field • Collection of young black rot infected cabbage material from the field station for bacterial isolation in the laboratory • Isolation of bacteria using aseptic method • Sub-culturing of bacteria to produce clean pure colonies • Serial dilution to achieve different numbers of colony forming units(c.f.u) • Bacterial inoculation to cabbage plants • Data collection

7. Reference • Bacteriology exercise book, fourth year, isolation of bacteria • http://go.warwick.ac.uk/wrap • Edward J. Sikora, Extension Plant Pathologist, Professor, Entomology and Plant Pathology, Auburn University • International Rules for Seed Testing Annexe to Chapter 7: Seed Health Testing Methods • HCDA ( Horticulture Crop Development Authority), 2007 Report • http://dx.doi.org/10.1094/PDIS-94-3-0298 • Massomo SMS, Mabagala RB, Swai IS, Hockenhull J, Mortensen CN . “Evaluation of varietal resistance in cabbage against the black rot pathogen, Xanthomonas campestris pv. campestris in Tanzania.” Crop Protection 23,4(2004): 315-325. • Chupp C. “Black rot of cabbage.” Manual of Vegetable Plant Diseases. New Delhi, India : Discovery Publishing House, 2006. p. 132-133 • Williams PH. "Black rot: a continuing threat to world crucifers." Plant Disease 64.8 (1980): 736-742. • "Black rot of cabbage and other crucifers." Integrated Pest Management. University of Illinois Extension. Dec 1999.

8. Work plan

9. THANK YOU FOR YOUR AUDIENCE