As a major source of food, cassava （Manihot esculenta Crantz） is an important root crop in the tropics and subtropics of Africa and Latin America, and serves as raw material for the production of starches and bioeth...As a major source of food, cassava （Manihot esculenta Crantz） is an important root crop in the tropics and subtropics of Africa and Latin America, and serves as raw material for the production of starches and bioethanol in tropical Asia. Cassava improvement through genetic engineering not only overcomes the high heterozygosity and serious trait separation that occurs in its traditional breeding, but also quickly achieves improved target traits. Since the first report on genetic transfor- mation in cassava in 1996, the technology has gradually matured over almost 15 years of development and has overcome cassava genotype constraints, changing from mode cultivars to farmer-preferred ones. Significant progress has been made in terms of an increased resistance to pests and diseases, biofortification, and improved starch quality, building on the fundamental knowledge and technologies related to planting, nutrition, and the processing of this important food crop that has often been neglected. Therefore.cassava has great potential-in food security and bioenergy development worldwide.展开更多
Climate variability as occasioned by conditions such as extreme rainfall and temperature, rainfall cessation, and irregular temperatures has considerable impact on crop yield and food security. This study develops a p...Climate variability as occasioned by conditions such as extreme rainfall and temperature, rainfall cessation, and irregular temperatures has considerable impact on crop yield and food security. This study develops a predictive model for cassava yield (Manihot esculenta Crantz) amidst climate variability in rainfed zone of Enugu State, Nigeria. This study utilized data of climate variables and tonnage of cassava yield spanning from 1971 to 2012;as well as information from a questionnaire and focus group discussion from farmers across two seasons in 2023 respectively. Regression analysis was employed to develop the predictive model equation for seasonal climate variability and cassava yield. The rainfall and temperature anomalies, decadal change in trend of cassava yield and opinion of farmers on changes in rainfall season were also computed in the study. The result shows the following relationship between cassava and all the climatic variables: R2 = 0.939;P = 0.00514;Cassava and key climatic variables: R2 = 0.560;P = 0.007. The result implies that seasonal rainfall, temperature, relative humidity, sunshine hours and radiation parameters are key climatic variables in cassava production. This is supported by computed rainfall and temperature anomalies which range from −478.5 to 517.8 mm as well as −1.2˚C to 2.3˚C over the years. The questionnaire and focus group identified that farmers experienced at one time or another, late onset of rain, early onset of rain or rainfall cessation over the years. The farmers are not particularly sure of rainfall and temperature characteristics at any point in time. The implication of the result of this study is that rainfall and temperature parameters determine the farming season and quantity of productivity. Hence, there is urgent need to address the situation through effective and quality weather forecasting network which will help stem food insecurity in the study area and Nigeria at large. The study made recommendations such as a comprehensive early warning system on clim展开更多
基金supported by the National Key Basic Research Program of China(No.2010CB126605)National High Technology Research and Development Program(No. 2009AA10Z102)+2 种基金the earmarked fund for the China Agriculture Research System(nycytx-17)the Chinese Academy of Sciences (No.KSCX2-EW-J-12)Shanghai Landscape and City Administration(No.G102410)
文摘As a major source of food, cassava （Manihot esculenta Crantz） is an important root crop in the tropics and subtropics of Africa and Latin America, and serves as raw material for the production of starches and bioethanol in tropical Asia. Cassava improvement through genetic engineering not only overcomes the high heterozygosity and serious trait separation that occurs in its traditional breeding, but also quickly achieves improved target traits. Since the first report on genetic transfor- mation in cassava in 1996, the technology has gradually matured over almost 15 years of development and has overcome cassava genotype constraints, changing from mode cultivars to farmer-preferred ones. Significant progress has been made in terms of an increased resistance to pests and diseases, biofortification, and improved starch quality, building on the fundamental knowledge and technologies related to planting, nutrition, and the processing of this important food crop that has often been neglected. Therefore.cassava has great potential-in food security and bioenergy development worldwide.
文摘Climate variability as occasioned by conditions such as extreme rainfall and temperature, rainfall cessation, and irregular temperatures has considerable impact on crop yield and food security. This study develops a predictive model for cassava yield (Manihot esculenta Crantz) amidst climate variability in rainfed zone of Enugu State, Nigeria. This study utilized data of climate variables and tonnage of cassava yield spanning from 1971 to 2012;as well as information from a questionnaire and focus group discussion from farmers across two seasons in 2023 respectively. Regression analysis was employed to develop the predictive model equation for seasonal climate variability and cassava yield. The rainfall and temperature anomalies, decadal change in trend of cassava yield and opinion of farmers on changes in rainfall season were also computed in the study. The result shows the following relationship between cassava and all the climatic variables: R2 = 0.939;P = 0.00514;Cassava and key climatic variables: R2 = 0.560;P = 0.007. The result implies that seasonal rainfall, temperature, relative humidity, sunshine hours and radiation parameters are key climatic variables in cassava production. This is supported by computed rainfall and temperature anomalies which range from −478.5 to 517.8 mm as well as −1.2˚C to 2.3˚C over the years. The questionnaire and focus group identified that farmers experienced at one time or another, late onset of rain, early onset of rain or rainfall cessation over the years. The farmers are not particularly sure of rainfall and temperature characteristics at any point in time. The implication of the result of this study is that rainfall and temperature parameters determine the farming season and quantity of productivity. Hence, there is urgent need to address the situation through effective and quality weather forecasting network which will help stem food insecurity in the study area and Nigeria at large. The study made recommendations such as a comprehensive early warning system on clim
