Mathematical models have been widely employed for the simulation of growth dynamics of annual crops,thereby performing yield prediction,but not for fruit tree species such as jujube tree(Zizyphus jujuba).The objective...Mathematical models have been widely employed for the simulation of growth dynamics of annual crops,thereby performing yield prediction,but not for fruit tree species such as jujube tree(Zizyphus jujuba).The objectives of this study were to investigate the potential use of a modified WOFOST model for predicting jujube yield by introducing tree age as a key parameter.The model was established using data collected from dedicated field experiments performed in 2016-2018.Simulated growth dynamics of dry weights of leaves,stems,fruits,total biomass and leaf area index(LAI) agreed well with measured values,showing root mean square error(RMSE) values of 0.143,0.333,0.366,0.624 t ha^-1 and 0.19,and R2 values of 0.947,0.976,0.985,0.986 and 0.95,respectively.Simulated phenological development stages for emergence,anthesis and maturity were 2,3 and 3 days earlier than the observed values,respectively.In addition,in order to predict the yields of trees with different ages,the weight of new organs(initial buds and roots) in each growing season was introduced as the initial total dry weight(TDWI),which was calculated as averaged,fitted and optimized values of trees with the same age.The results showed the evolution of the simulated LAI and yields profiled in response to the changes in TDWI.The modelling performance was significantly improved when it considered TDWI integrated with tree age,showing good global(R2≥0.856,RMSE≤0.68 t ha^-1) and local accuracies(mean R2≥0.43,RMSE≤0.70 t ha^-1).Furthermore,the optimized TDWI exhibited the highest precision,with globally validated R2 of 0.891 and RMSE of 0.591 t ha^-1,and local mean R2 of 0.57 and RMSE of 0.66 t ha^-1,respectively.The proposed model was not only verified with the confidence to accurately predict yields of jujube,but it can also provide a fundamental strategy for simulating the growth of other fruit trees.展开更多
Apple occupies a dominant position in fruit production globally, and has become the main income source of local smallholder farmers in Luochuan County in the Loess Plateau area, one of the largest apple production are...Apple occupies a dominant position in fruit production globally, and has become the main income source of local smallholder farmers in Luochuan County in the Loess Plateau area, one of the largest apple production areas in China. However, the annual productivity of apple orchards in this region remains low and has gradually declined over the years. The distinction and correlation of production constraints can contribute to the promotion of apple orchard productivity and the development of a sustainable orchard system. In the present study, survey data from 71 smallholder farmers were analyzed using a yield gap model to distinguish the production constraints and determine their correlation with the yield gap based on the structural equation model(SEM). The results indicated that the average apple yield in Luochuan County was 29.9 t ha^–1 yr^–1, while the attainable yield(Yatt;the highest yield obtained from the on-farm surveys) was 58.1 t ha^–1 yr^–1. The average explained and unexplainable yield gaps were 26.3 and 1.87 t ha^–1 yr^–1. According to the boundary line analysis, crop load,number of sprayings and base fertilizer N were the top three constraints on apple production in 9.8, 7.8 and 7.8% of the plots, respectively. Among the production constraints, crop load and fruit weight affected apple yield through direct pathways,whereas other constraints influenced apple yield through an indirect pathway based on the SEM, explaining 51% of the yield variance by all the main production constraints. These results can improve the current understanding of production constraints and contribute to the development of management strategies and policies for improving apple yield.展开更多
Tropical fruit trees constitute important biological resources in the global agrobiodiversity context. Unlike the tropical fruit trees of American and Asian origin, indigenous fruit trees (IFT) of tropical Africa have...Tropical fruit trees constitute important biological resources in the global agrobiodiversity context. Unlike the tropical fruit trees of American and Asian origin, indigenous fruit trees (IFT) of tropical Africa have scarcely achieved the status of international recognition in commodity markets and research arena outside Africa. This paper presented a critical review of the status of IFT in the Tropical African sub-regions (of West Africa, Central Africa, East Africa, Southern Africa and the Indian Ocean Islands) in relation to the introduced naturalised fruit trees from tropical America and Asia, threats to the diversity and sustainable use of IFT, analysis of the opportunities and challenges of developing IFT, as well as targets for crop improvement of the rich IFT of Tropical Africa. Domestication programme via relevant vegetative propagation techniques for priority IFT of the sub-regions was examined and advocated, in addition to the adoption of complementary conservation strategies, including Field GeneBanks in the management of the continent’s IFT diversity.展开更多
基金supported by the National Natural Science Foundation of China(41561088 and 61501314)the Science&Technology Nova Program of Xinjiang Production and Construction Corps,China(2018CB020)
文摘Mathematical models have been widely employed for the simulation of growth dynamics of annual crops,thereby performing yield prediction,but not for fruit tree species such as jujube tree(Zizyphus jujuba).The objectives of this study were to investigate the potential use of a modified WOFOST model for predicting jujube yield by introducing tree age as a key parameter.The model was established using data collected from dedicated field experiments performed in 2016-2018.Simulated growth dynamics of dry weights of leaves,stems,fruits,total biomass and leaf area index(LAI) agreed well with measured values,showing root mean square error(RMSE) values of 0.143,0.333,0.366,0.624 t ha^-1 and 0.19,and R2 values of 0.947,0.976,0.985,0.986 and 0.95,respectively.Simulated phenological development stages for emergence,anthesis and maturity were 2,3 and 3 days earlier than the observed values,respectively.In addition,in order to predict the yields of trees with different ages,the weight of new organs(initial buds and roots) in each growing season was introduced as the initial total dry weight(TDWI),which was calculated as averaged,fitted and optimized values of trees with the same age.The results showed the evolution of the simulated LAI and yields profiled in response to the changes in TDWI.The modelling performance was significantly improved when it considered TDWI integrated with tree age,showing good global(R2≥0.856,RMSE≤0.68 t ha^-1) and local accuracies(mean R2≥0.43,RMSE≤0.70 t ha^-1).Furthermore,the optimized TDWI exhibited the highest precision,with globally validated R2 of 0.891 and RMSE of 0.591 t ha^-1,and local mean R2 of 0.57 and RMSE of 0.66 t ha^-1,respectively.The proposed model was not only verified with the confidence to accurately predict yields of jujube,but it can also provide a fundamental strategy for simulating the growth of other fruit trees.
基金funded by the National Key Research and Development Program of China (2016YFD0201137 and 2016YFE0101100)the Innovative Group Grant of the National Science Foundation of China (31421092)
文摘Apple occupies a dominant position in fruit production globally, and has become the main income source of local smallholder farmers in Luochuan County in the Loess Plateau area, one of the largest apple production areas in China. However, the annual productivity of apple orchards in this region remains low and has gradually declined over the years. The distinction and correlation of production constraints can contribute to the promotion of apple orchard productivity and the development of a sustainable orchard system. In the present study, survey data from 71 smallholder farmers were analyzed using a yield gap model to distinguish the production constraints and determine their correlation with the yield gap based on the structural equation model(SEM). The results indicated that the average apple yield in Luochuan County was 29.9 t ha^–1 yr^–1, while the attainable yield(Yatt;the highest yield obtained from the on-farm surveys) was 58.1 t ha^–1 yr^–1. The average explained and unexplainable yield gaps were 26.3 and 1.87 t ha^–1 yr^–1. According to the boundary line analysis, crop load,number of sprayings and base fertilizer N were the top three constraints on apple production in 9.8, 7.8 and 7.8% of the plots, respectively. Among the production constraints, crop load and fruit weight affected apple yield through direct pathways,whereas other constraints influenced apple yield through an indirect pathway based on the SEM, explaining 51% of the yield variance by all the main production constraints. These results can improve the current understanding of production constraints and contribute to the development of management strategies and policies for improving apple yield.
文摘Tropical fruit trees constitute important biological resources in the global agrobiodiversity context. Unlike the tropical fruit trees of American and Asian origin, indigenous fruit trees (IFT) of tropical Africa have scarcely achieved the status of international recognition in commodity markets and research arena outside Africa. This paper presented a critical review of the status of IFT in the Tropical African sub-regions (of West Africa, Central Africa, East Africa, Southern Africa and the Indian Ocean Islands) in relation to the introduced naturalised fruit trees from tropical America and Asia, threats to the diversity and sustainable use of IFT, analysis of the opportunities and challenges of developing IFT, as well as targets for crop improvement of the rich IFT of Tropical Africa. Domestication programme via relevant vegetative propagation techniques for priority IFT of the sub-regions was examined and advocated, in addition to the adoption of complementary conservation strategies, including Field GeneBanks in the management of the continent’s IFT diversity.
