To evaluate the genetic diversity and to clarify the genetic relationships of wild and cultivated soybeans growing in China, 21 wild soybean accessions and 27 cultivated soybean landraces were analysed by using the random amplified polymorphic DNA method. The data show that wild soybean has a higher genetic variation than cultivated soybean, indicating that genetic variation has been reduced by domestication of wild soybean. Based on Nei's genetic similarity coefficient, all the accessions were classified into two major clusters, corresponding to wild and cultivated varieties of soybean. Furthermore, within each species, the accessions tend to form sub‐clusters that are in agreement with their geographical origins, demonstrating that an extensive geographical genetic differentiation exists in both species. For cultivated soybean, the varieties from the same geographical region but with different seasonal types were found to have closer genetic relationships than varieties from different geographical regions but with the same seasonal type. This result indicates that geographical differentiation plays a key role in the genetic differentiation of both wild and cultivated soybeans. Cultivated soybean varieties with different seasonal types in a region might have been established mainly from the local genotypes.
Identifying the spatial patterns of fish diversity in streams is basic for the conservation and management of stream fishes. The “upstream–downstream” patterns in the taxonomic α‐diversity of stream fishes have been widely surveyed. However, the longitudinal patterns in the functional diversity and β‐diversity of stream fishes have been given less attention. In this study, we surveyed fishes along an upstream–downstream gradient in a headwater stream of the Qiantang River, China, and examined the longitudinal variations in fish diversity. Our aims were to assess whether the longitudinal patterns in fish diversity were consistent between the taxonomic and functional metrics and between the α‐ and β‐aspects of diversity. We found that both species richness and functional richness of fishes showed a hump‐shaped relationship with the distance from headwaters, while both taxonomic and functional β‐diversities presented the U‐shaped distributions along the river continuum. Functional diversity related more to the distance from headwaters than taxonomic diversity. Despite their similar relationship with the distance from headwaters, taxonomic and functional β‐diversities were dominated by species turnover and function nestedness components, respectively. Our results suggest that, along the river continuum in a subtropical stream, the α‐ and β‐aspects of fish diversity present different longitudinal variations. Although the taxonomic and functional diversity shows similar relationships with distance from headwaters, their spatial variations are driven by different ecological processes.
Aquaculture, especially of non-native species and translocated domestic species, is a greatly encouraged way of relieving the conflicts between food and economic demand and resource depletion. We herein summarized the introduction history of non-native fish for aquacultural use in China, including 105 species introduced from abroad and 61 species translocated domestically across river basins, which has brought great economic benefits but high ecological risks. Of these, one-fourth have successfully established wild populations in natural waters and 15% have successfully invaded. We presented specific examples of seven aquaculture species/taxa and three aquarium species/taxa to explain their outcomes. The notable economic benefits, complex species composition and strain selection of tilapias, carps and sturgeons may together facilitate their invasion, and result in fish diversity decline, genetic pollution, and loss of ecosystem service. We specifically reviewed invasion cases in lakes and reservoirs and found that lakes in western China and reservoirs made by major This article is a Sena De Silva paper. The Sena De Silva paper is an honorific title dedicated to the memory of Professor Sena De Silva, who was the founding editor of Reviews in Aquaculture and a globally renowned aquaculture scholar, pioneer and advocate. The title is awarded to high quality articles that excel in one, or more, of the following qualities: i) Novelty and originality; ii) Likelihood of direct positive impacts for the aquaculture sector, with keen focus on any of, or all three: environmental sustainability, economic viability, and social responsibility iii) Overall quality of scientific reasonings coupled with realworld applicability.
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