Pathogenicity of pythium species on hosts associated with bean-based cropping system in south western Uganda

Research PaperA pathosystem is a subsystem of an ecosystem and is characterised by the phenomenon of parasitism. The bean-Pythium pathosystem consists of the host (bean), the pathogen (Pythium) and their host-pathogen relation. Of interest is how the pathogen causes pathogenicity on other crops and beans. To investigate this, screen house experiments were set up to test the pathogenicity of Pythium species derived from bean and other crops grown in association with beans. Pathogenicity was tested on maize (Zea mays), millet (Eleusine corcana), sorghum (Sorghum bicolor), peas (Pisum satium), susceptible bean variety (CAL 96) and resistant bean variety (RWR 719). The results indicated that distinct symptoms were observed in the roots and shoots of test crop species which are characteristic of Pythium infection. For instance peas had brownish watery stems and roots Also bean-derived pathogenic Pythium spp. were found to be more virulent than Pythium spp. derived from other crop species.Sorghum and peas had the highest disease scores upon infection by Pythium spp. We can conclude that there is cross pathogenicity among Pythium spp. especially affecting sorghum and peas. This phenomenon may account for the current root rot epiphytotics in south western Uganda and other similar agroecologies. An integrated disease management strategy that will deploy multi-non hosts to Pythium root rot is recommended.A pathosystem is a subsystem of an ecosystem and is characterised by the phenomenon of parasitism. The bean-Pythium pathosystem consists of the host (bean), the pathogen (Pythium) and their host-pathogen relation. Of interest is how the pathogen causes pathogenicity on other crops and beans. To investigate this, screen house experiments were set up to test the pathogenicity of Pythium species derived from bean and other crops grown in association with beans. Pathogenicity was tested on maize (Zea mays), millet (Eleusine corcana), sorghum (Sorghum bicolor), peas (Pisum satium), susceptible bean variety (CAL 96) and resistant bean variety (RWR 719). The results indicated that distinct symptoms were observed in the roots and shoots of test crop species which are characteristic of Pythium infection. For instance peas had brownish watery stems and roots Also bean-derived pathogenic Pythium spp. were found to be more virulent than Pythium spp. derived from other crop species.Sorghum and peas had the highest disease scores upon infection by Pythium spp. We can conclude that there is cross pathogenicity among Pythium spp. especially affecting sorghum and peas. This phenomenon may account for the current root rot epiphytotics in south western Uganda and other similar agroecologies. An integrated disease management strategy that will deploy multi-non hosts to Pythium root rot is recommended

The Role of mixed cropping systems on bean root rot epidemics in south western Uganda

Research PaperIn south western Uganda, beans are largely grown as intercrops with sorghum, maize, sweet potato and potato . Continuous cropping of beans, has increased bean root rot epidemics. Since some of the root rot causing organisms are known to affect other crops, there was need to investigate the role they may be playing in the current root rot epidemics. Surveys were carried out in Kabale district in order to establish the incidence of root rot on other crops grown in association with beans. Plant samples for isolation of Pythium, the main causative agent of root rot were also collected. Results indicated that potato had a high root rot incidence while maize had a low root rot incidence. Also, sorghum and peas had root rot symptoms. Out of the 142 Pythium isolates collected, 21 different Pythium species were identified by ITS-DNA sequencing. Fifteen new Pythium species not previously identified in the region were found. This study finds evidence that diverse crop species associated with beans may be playing a role in bean root rot epidemics.In south western Uganda, beans are largely grown as intercrops with sorghum, maize, sweet potato and potato . Continuous cropping of beans, has increased bean root rot epidemics. Since some of the root rot causing organisms are known to affect other crops, there was need to investigate the role they may be playing in the current root rot epidemics. Surveys were carried out in Kabale district in order to establish the incidence of root rot on other crops grown in association with beans. Plant samples for isolation of Pythium, the main causative agent of root rot were also collected. Results indicated that potato had a high root rot incidence while maize had a low root rot incidence. Also, sorghum and peas had root rot symptoms. Out of the 142 Pythium isolates collected, 21 different Pythium species were identified by ITS-DNA sequencing. Fifteen new Pythium species not previously identified in the region were found. This study finds evidence that diverse crop species associated with beans may be playing a role in bean root rot epidemics

The Effect of Water Quality on Aquaculture Productivity in Ibanda District, Uganda

Water quality plays a substantial role in maximizing fish productivity. Despite the efforts made by government to improve fish production, there are general complaints about the small size of fish produced in aquaculture systems. This study was conducted in order to assess the effect of water quality on aquaculture productivity in Ibanda District, Uganda. The specific objectives were to examine the status of water quality parameters (temperature, turbidity, pH, alkalinity, Ammonia content, hardness, Carbon dioxide content, and Iron content) and assess their effect on fish pond productivity. Using data from fish farmers and water samples taken from 25 restocked fish ponds in ten sub-counties, the study revealed that of the eight water quality parameters examined only four (average turbidity, alkalinity, hardness, and Carbon dioxide content) were within the acceptable ranges, while Ammonia content, temperature, pH, and Iron content were slightly outside the recommended ranges. In addition, the study revealed that water quality parameters such as temperature, pH, and Ammonia Carbon dioxide, and Iron content had a significant effect on the weight and size of both tilapia and catfish. The study concluded that certain water quality parameters have a detrimental effect on fish farming. There is a need to educate fish farmers on how to maintain water quality at suitable levels in order to improve fish farm productivity in Ibanda district