Phaeolus vulgaris Cv. rosecoco-glp-2 seed contaminatoin and infection by Colletotrichum lindemuthianum (SACC & MAGN) BRI & CAV., and implications on disease incidence and severity
Abstract
Surveys were conducted in several locations in Kisii, Kiambu and Meru districts, during which seeds the common bean (Phaseolus vulgaris) L. cv. Rose Coco-GLP-2 were collected from the small-scale farmers. The visual observation test and rolled paper towel, agar plate and blotter tests as recommended by the International Association of Seed Testing were applied to 38 samples. About 53% of the samples assessed by visual observation were contaminated by C. lindemthianum with an average infection of 0.34% (range 0.0-4.5%). The rolled paper towel test detected by C. lindemthianum in about 7.4% of the samples, with mean infection level of 1.2% (range 0.9-10.0%). Of the samples assessed by the agar plate test, 61% were contaminated with by C. lindemthianum, with an infection range of 0.0-4.25%. The blotter test recorded the disease from 32.0% of the samples, with a mean infection of 0.32% (range 0.0-1.50%).
Inoculations of beans with by C. lindemthianum 2 weeks after emergence gave significantly high levels of seed infection compared to seed infections attained when plants were inoculated at 4 and 6 weeks after emergence, pod filling stage and maturity. Seed infection was between 0.5% -24.1% and 0.9%-38.8% during the short and long rains respectively.
Planting of seeds with varying levels of by C. lindemthianum infection in the field produced significant levels of anthracnose incidence, severity on leaves and pods, measured at AUDP-AI, AUDPC-ASCL and AUDPC-ASP respectively at Kabete and Tigoni. There was significant and positive correlations between level of seed-borne by C. lindemthianum infection and AUDPC-AI, AUDPC-ASL and AUDPC-ASP.
Yields/ha, number of pods/plant and 100-seed weight were significantly low in plots sown with farmers’ seeds with pathogen free seeds and certified seeds. Negative and significant correlations were established between yields/ha, number of pods/plant and 100-seed weight and AUDPC-Ai, AUDPC-ASL and AUDPC-ASP. The reduction in yields was mainly as a result of reduction in number of pods and 100-seed weight.
Field studies were carried out to determine the relationship between time of inoculation and anthracnose incidence and severity on bean plants, expressed of AUDPC. Significantly high AUDPC values were recorded in plots inoculated with by C. lindemthianum at 2 weeks after emergence, compared to AUDPC recorded in plots receiving other treatments. Correlation time of inoculation and AUDPC-AI, AUDPC-ASL and AUDPC-ASP were not significant/
Yields/ha, number of pods/plant and 100-seed weight were all significantly reduced in plots inoculated with Yields/ha, at 2, 4 and 6 weeks after emergence and pod filling stage during significant correlations between yields/ha, number of pods/plant significant correlations between AUDPC-AI, AUDPC-ASL and AUDPC-ASP. The reduction in yields was mainly as a result of reduction in the number of pods and 100-seed weight.
Field studies were carried out to determine the relationship between time of inoculation and anthracnose incidence and severity on bean plants, expressed as AUDPC. Significantly high AUDPC values were recorded in plots inoculated with C. lindemthianum at 2 weeks after emergence, compared to AUDPC recorded in plots receiving other treatments. Correlations time of inoculation and AUDPC-AI, AUDPC-ASL and AUDPC-ASP were not significant.
Yields/ha, number of pods/plant and 100-seed weight were all significantly reduced in plots with
C. lindemthianum 2, 4 and 6 weeks after emergence and pod filling stage during both the short and long rains seasons. There were negative and significant correlations between yields/ha, number of pods/plant and 100-seed weight and AUDPC-AI, AUDPC-ASL and AUDPC-ASP and number of seeds/pod was observed. The reduction in yields was mainly as a result of reduction of pods and 100-seed weight.
Citation
M.Sc ( Plant Pathology)Sponsorhip
University of NairobiPublisher
Faculty of Agriculture, University of Nairobi
Description
M.Sc thesis