Climate Change and Agriculture - Batch 1

Prevalence of Virus Diseases, Distribution and Characterization of Viruses Infecting Cucurbit Crops in Six Agro-Ecological Zones in Côte D’ivoire

2022-05-13T09:33:48Z

Prevalence of Virus Diseases, Distribution and Characterization of Viruses Infecting Cucurbit Crops in Six Agro-Ecological Zones in Côte D’ivoire Kone, Nahoua Viral diseases are a worldwide problem of cucurbits and a major limiting factor for they production. A field survey was conducted through six agro-ecological zones of Côte d’Ivoire during the dry and rainy seasons in 2014 to assess disease prevalence and severity, identify associated viruses, and evaluate the effect of temperature and growing seasons on virus diseases. Viruses were detected on sampled leaves displaying virus-like symptoms using double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and reverse transcription polymerase chain reaction (RT-PCR). The phylogenetic relationships of the new detected virus were also studied. High disease prevalence and severity was observed in both dry and rainy seasons. Significant difference (P < 0.05) was observed in rainy season varying between 0.6% and 56.8%. Cucumber mosaic virus (CMV), Zucchini yellow mosaic virus (ZYMV) and Papaya ringspot virus (PRSV) were detected out of five. CMV was more prevalent in dry season at an incidence of 31.5% whereas ZYMV was more prevalent in rainy season at an incidence of 34.3%. Pepo aphid borne yellows virus (PABYV) was detected by RT-PCR in Côte d’Ivoire as a Polerovirus based on the sequence similarity and phylogenetic analyses. CMV was detected at significantly enhanced levels in plants when co-infected with ZYMV; plant height was reduced compared to the single infection at 20°C and 25°C. During growing seasons, high incidence and severity were recorded with the highest mean disease severity in growing season 2. It is concluded that co-infection with ZYMV enhance the titer of CMV, which could have epidemiological significance. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use and the University of Cape Coast in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Climate Change and Agriculture

Effect of Temperature on Population Dynamics of Meloidogyne Spp. and Fusarium Spp. Infesting Sweet Pepper in Niger

2021-08-05T13:10:38Z

Effect of Temperature on Population Dynamics of Meloidogyne Spp. and Fusarium Spp. Infesting Sweet Pepper in Niger Boubacar Toukal, Assoumana Meloidogyne spp. and Fusarium spp. cause wilt disease in sweet pepper and result in decline of its production. Other limiting factors of sweet pepper production are inappropriate agronomic practices and lack of effective climate adaptation strategies. The aim of this study was to investigate on one hand, how farmers perceive climate change and their access to agricultural extension services and, on the other hand the distribution and identification of causal agents of wilt disease and also to find out the effect of temperature on the co-infection of pathogens on sweet pepper. The results revealed that the perception of farmers on rainfall patterns do not match with past meteorological records. Respondents indicated that there is an increase in temperature which is in agreement with climatic data evidence. Crop diversification was found as the major adaptation strategy to climate variability. The lack of sufficient access to information is the constraints that hindered farmers to adapt effectively. The incidence of the Meloidogyne spp. was 100% in both districts while the occurrence of Fusarium spp. was 80.32% and 62.23% in Diffa and Aguie respectively. Based on morphological and molecular characterization, three pathogens were identified in sweet pepper; Meloidogyne enterolobii, Meloidogyne incognita and Fusarium solani. The sequential and concomitant inoculation of the fungus and/ or the nematode did not cause the sudden death of sweet pepper plants as observed in the field. It only resulted in significant increase in yellowing in leaves and high nematode and fungal reproduction in inoculated plants in comparison to the uninoculated plants. Temperature greatly influenced the reproduction capacity of M. enterolobii and F. solani. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use and the University of Cape Coast in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Climate Change and Agriculture

Effects of Harvesting Times and Fertilizer Application on Cassava Yield and Quality in Rainforest and Guinea Savanna Agroecological Zones of Nigeria

2021-08-05T13:10:38Z

Effects of Harvesting Times and Fertilizer Application on Cassava Yield and Quality in Rainforest and Guinea Savanna Agroecological Zones of Nigeria Sobamowo, Jumoke Omowunmi Farmers desire to harvest cassava roots with high total dry matter and of good quality at shorter times. However, they have limited knowledge regarding combinations of improved varieties and right types and rates of fertilizer application that are most suitable for their agro ecological zones. The study was carried out to quantify total dry matter and root quality response of six cassava varieties to fertilizer application and intra-annual rainfall variability in two agro-ecological zones of Nigeria. Two field experiments were conducted at Oke-oyi and Ikenne. Three inorganic NPK fertilizer types were applied at two rates to six cassava varieties in a split split plot arrangement with three replicates. In each experiment cassava was harvested destructively at 6, 8, 10 and 12 MAP. Data on yield and quality parameters were analyzed using SAS, means separation by LSD 5%. The results revealed that fertilizer application significantly increased all the parameters measured at Ikenne (at both experimental sites) except fresh storage root weight and dry matter content at Oke-oyi. TME 419 had higher starch content at Ikenne while TMS 96/1632 had significant higher starch content at Oke-oyi. Cyanide potential was highest in TMS 96/1632 and TMS 30572 at 12 MAP at Oke-oyi and Ikenne respectively. NPK 12-12-17 was observed to perform better than other fertilizer types. This study showed that application of NPK 12-12-17 fertilizer at 300 kg ha-1 to cassava varieties TME 419 and TMS 98/0505 at study sites, increased total dry matter root yield, starch content and showed low cyanide potential. Farmers who plant these two cassava varieties either for food or for industrial purposes at the two sites will earn higher income. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use and the University of Cape Coast in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Climate Change and Agriculture

Greenhouse Gas Emissions from Ferric Luvisols under Nitrogen Fertilization in Northern Ghana

2021-08-05T13:10:38Z

Greenhouse Gas Emissions from Ferric Luvisols under Nitrogen Fertilization in Northern Ghana Atakora, Williams Kwame Carbon dioxide and nitrous oxide are two important greenhouse gas that contribute to global warming. Farmers in Northern Ghana rely on mineral fertilizers mainly sulphate of ammonia, urea and NPK compound fertilizers to boost crop production due to low soil fertility. A study was conducted on Ferric Luvisols in Akukayilli in the Tolon District of the Northern Region of Ghana to assess the influence of physic-chemical properties and environmental factors (soil temperature and soil moisture characteristics) on CO2, N2O, NO NO2 emissions. A randomized complete block design with three replications was used. Two nitrogenous fertilizer sources, sulphate of ammonia and urea at two rates of 60 and 120 kg N ha-1 y-1 and NPK (60-40-40) were used. Maize was the test crop, using the variety omankwa. The fate of excess N fertilizer in the soils were determined by 15N procedures. Application of NPK 60-40-40, sulphate of ammonia 60 and urea 60 kg ha-1 y-1 produced substantial maize yield with minimum production of CO2 and N2O. A nitrous oxide emission factor (EF) of 0.15 % has been established for the Northern savanna zone of Ghana. A large substrate availability (120 kg N ha-1 y-1) was found to contribute to the high emission of greenhouse gases, however, the levels of the greenhouse gases observed in this study are below the threshold that will lead to global warming. Observed δ15N values of N2O proved that the application of the compound fertilizer NPK fixed higher nitrogen in the soil than sulphate of ammonia and urea. Water filled pore spaces directly correlated with increase in emission of N gases. It is recommended that the emission factor be assessed for soils of other agro-climatic zone. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use and the University of Cape Coast in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Climate Change and Agriculture