[Objective]This study aimed to clarify the spatial patterns of comparative advantage of watermelon production in Guangxi Zhuang Autonomous Region, to pro-vide theoretical basis for the development of watermelon industry in China. [Method] Based on the agricultural statistics data of Guangxi and al over China, yield com-parative advantage （YCA） index, efficiency comparative advantage （ECA） index, scale comparative advantage （SCA） index, concentration ratio comparative advantage （CRCA） index, comprehensive comparative advantage （CCA） index, ratio of yield per unit area （RYPA） index and sowing area ratio （SAR） index were established and calculated to determine the watermelon production comparative advantages in 31 provinces （cities） in China. Spacial patterns of the comparative advantages were produced by using GIS software. [Result] Nine provinces Shandong, Henan, Anhui, Hebei, Hubei, Jiangsu, Hunan, Zhejiang and Guangxi were the dominant regions in watermelon production al over the country. The Central and Eastern China showed the integrated comparative advantage in watermelon production, while the Southern, Northeastern, Northern and Northwestern China can be considered as the potential places for watermelon production in future. Southwest China gave more priority to watermelon production, so the comparative advantages kept increasing here. [Con-clusion] Based on this study, watermelon production should be a prior consideration among the agricultural products in Guangxi. Related measures should be developed to optimize the regional distribution of watermelon in Guangxi and China to promote healthy competition in watermelon production.
[Objective] This study aimed to analyze the morphological diversity of red- seed watermelon （Citrullus lanatus ssp. vulgaris var. megalaspermus Lin et Chao） germplasm resources. [Method] Multiple cluster analysis and principal components analysis on the morphological traits of 51 red-seed watermelon germplasm resources were carried out. [Result] The coefficient of variations （CVs） of 39 morphological traits in 51 red-seed watermelon idioplasm resources ranged from 5.37% to 66.95%, with an average of 22.87%. The average of Shannon diversity information indices was 1.55. Among them, the Shannon diversity information index of seed length was the highest （2.16） and that of seed shell figure pattern was the lowest （0.32）. In ad- dition, the morphological diversity information indices of quantity characters were higher than that of quality characters. The principal components analysis revealed that the variance contribution rates of the first, second and third principal compo- nents were 19.49%, 15.32% and 9.55%, respectively. Cluster analysis divided the 51 materials into three broad branches based on the morphological traits. There was only one material in the fist branch and two in the second branch, and all the three materials were wild. The other 48 materials were divided into the third branch and all of them were cultivars. [Conclusion] This study provided a theoretical basis for the protection and utilization of red-seed watermelon resources.
