Gain sensitivity of linear active networks

Imperial Users onl

The Mechanism of the Development and Maintenance of Sexual Dimorphism in the Dioecious Mulberry Plant (Morus alba)

Intersexual differentiation is crucial for the speciation and maintenance of dioecious plants, but the underlying mechanisms, including the genes involved, are still poorly understood. Here, we focused on a typical dioicous plant Morus alba, to explore the molecular footprints relevant to sex evolution by revealing the differentially expressed genes (DEGs) between two sexes and the testing signals of selection for these DEGs. From the results, we found a total of 1543 DEGs. Interestingly, 333 and 66 genes expression were detected only in male and female inflorescences, respectively. Using comparative transcriptomics, the expression of 841 genes were found to be significantly higher in male than in female inflorescences and were mainly enriched in defense-related pathways including the biosynthesis of phenylpropanoids, cutin, suberine and waxes. Meanwhile, the expression of 702 genes was female-biased and largely enriched in pathways related to growth and development, such as carbohydrate metabolism, auxin signaling and cellular responses. In addition, 16.7% and 17.6% signals of selection were significantly detected in female- and male-biased genes, respectively, suggesting their non-negligible role in evolution. Our findings expanded the understanding of the molecular basis of intersexual differentiation and contribute to further research on sex evolution in dioecious plants

Farmers Agronomic Practice in Management of the Tomato (Solanum lycopersicon L.) Yellow Leaf Curl Virus in Central Region of Ghana

The study assessed farmers’ awareness of the Tomato yellow leaf curl virus (TYLCV) disease and their agronomic and disease management practices in the Efutu municipality, Komenda-Edina-Eguafo-Abirem (KEEA), and Mfantseman districts which are leading tomato producing centres in the Central Region of Ghana. The study also surveyed the incidence and severity of the TYLCV disease in tomato fields across the three districts. Household data were collected using structured questionnaire from 150 respondents using multi-stage procedure, and analysed using descriptive statistics. Incidence (DI) and severity index (SI) of TYLCV disease were determined from forty (40) tomato fields selected from each of the three districts. The field data was subjected to analysis of variance (ANOVA) and the means separated with least significant difference (l.s.d) method at 5% level of probability.Majority of the farmers (92.6%) were aware of the TYLCVdisease and said it could cause yield losses rangingfrom less than 10% to over 41% but did not know the cause.Majority (60.4%) of the farmers managed the TYLCV disease in their farms mainly by applying insecticides (55.6%) and roguing of diseased plants (43.1%). About 60.7% of the farmers practiced mixed cropping, and most of them cultivated tomato in both the major and minor cropping seasons, using mainly an improved form of Solanum pimpinellifolium. The highest mean disease incidence and mean disease severity indices were recorded at KEEA (52.9±2.7%, 26.89±1.2%), followed by Efutu (49.5±1.19%, 25.29±0.9%), and Mfantseman (42.1±2.7%, 21.41±0.8%) respectively.In conclusion, TYLCV was highly prevalent in the study area, but infection was moderate due to the use of improved tomato variety. Â

Farmers Agronomic Practice in Management of the Tomato (Solanum lycopersicon L.) Yellow Leaf Curl Virus in Central Region of Ghana

The study assessed farmers’ awareness of the Tomato yellow leaf curl virus (TYLCV) disease and their agronomic and disease management practices in the Efutu municipality, Komenda-Edina-Eguafo-Abirem (KEEA), and Mfantseman districts which are leading tomato producing centres in the Central Region of Ghana. The study also surveyed the incidence and severity of the TYLCV disease in tomato fields across the three districts. Household data were collected using structured questionnaire from 150 respondents using multi-stage procedure, and analysed using descriptive statistics. Incidence (DI) and severity index (SI) of TYLCV disease were determined from forty (40) tomato fields selected from each of the three districts. The field data was subjected to analysis of variance (ANOVA) and the means separated with least significant difference (l.s.d) method at 5% level of probability.Majority of the farmers (92.6%) were aware of the TYLCVdisease and said it could cause yield losses rangingfrom less than 10% to over 41% but did not know the cause.Majority (60.4%) of the farmers managed the TYLCV disease in their farms mainly by applying insecticides (55.6%) and roguing of diseased plants (43.1%). About 60.7% of the farmers practiced mixed cropping, and most of them cultivated tomato in both the major and minor cropping seasons, using mainly an improved form of Solanum pimpinellifolium. The highest mean disease incidence and mean disease severity indices were recorded at KEEA (52.9±2.7%, 26.89±1.2%), followed by Efutu (49.5±1.19%, 25.29±0.9%), and Mfantseman (42.1±2.7%, 21.41±0.8%) respectively.In conclusion, TYLCV was highly prevalent in the study area, but infection was moderate due to the use of improved tomato variety. Â

Phenotypic and molecular evaluation of maize (Zea may L.) genotypes under field conditions in the Volta region of Ghana

Maize streak disease (MSD) is the most devastating and destructive disease of maize (Zea mays L.) in sub-Saharan Africa (SSA). Field trials were conducted in the 2014 minor and 2015 major cropping seasons to screen 16 and 17 maize genotypes, respectively, for high yield and resistance to maize streak virus (MSV) infections. The plants were scored for disease severity at 4, 6, 8 and 10 weeks after planting (WAP) based on a 1-5 visual scale (1= No infection and 5= Very severe infection). Polymerase chain reaction (PCR) test was done to detect the presence of MSV in the diseased leaf samples in order to confirm field resistance. Both phenotypic and PCR test revealed that all the maize genotypes tested in the study were infected by MSV. There was a significant varietal effect on the incidence and severity of MSD in both the major and minor seasonal trials. Genotypes ‘Abontem’,’Aburohemaa’, ‘Akposoe’, ‘Dapango’, ‘Dorke’, ‘Etubi’, ‘Honampa’, ‘Mamaba’, ‘Obatanpa’, ‘Omankwa’ and PAN 12 showed mild disease symptoms during both major and minor cropping seasons. On the other hand, genotypes ‘Dormabin’, ‘Dzinu-Eve’, ‘Enibi’, Keta 60 and PAN 53 exhibited moderate to severe symptoms during the two cropping seasons. Incidence and severity of MSD were significantly higher in the minor season than in the major season, indicating a significant seasonal effect of MSV on the maize genotypes. The yield and yield components were observed to vary significantly among the different maize genotypes and between the cropping seasons with mean yields significantly higher in the major season than in the minor season. Genotypes ‘Abontem’, ‘Aburohemaa’, ‘Akposoe’, ‘Dorke’, ‘Etubi’, ‘Honampa’, ‘Omankwa’, ‘Obatanpa’ and PAN 12 (All improved varieties), which exhibited partial resistance to MSV infection gave high seed yields during both seasons. The improved maize genotypes that were high yielding and resistant to MSV infection should be evaluated for uniform yield trials on farmers’ fields towards their release as varieties to farmers

Studies on the use of Trichoderma harzianum and natural plant products in the management of Fusarium oxysporum f.sp. lycopersici on tomato

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Effect of three water treatments on growth of rice variety IR36

Rice (Oryza Sativa L.) variety IR36 was grown under three water treatments namely: saturated sand, water table held at 15cm below the sand surface and water table at 30 cm below the sand surface. The growth period was 6 weeks with plants harvested at two week intervals. Growth parameters measured included total number of roots, length of roots, shoot dry mass, root dry mass and number of tillers. Moisture content at a depth of about 3 cm below the surface of the sand was also determined. There were no significant differences in root dry mass for the treatments but shoot dry mass was significantly greater under the saturated treatment than under the 30 cm treatment but there was no significant difference between those under the saturated treatment and the 15 cm water table treatment. Length of roots greater than 30 cm long were significantly greater under the 30 cm treatment than the others but number of roots greater than 30 cm long were significantly greater under the saturated treatment than the others. Tiller numbers were significantly greater under the saturated treatment than under the 30 cm treatment. Generally growth was in the order saturated > 15 cm water treatment > 30 cm water table treatment. Water table control was able to sustain growth of rice over a period of six weeks after sowing, however growth under saturated conditions was better than the others