Publications by authors named "Xinxiang A"

pv. (), the causal agent of bacterial leaf blight (BLB), is one of the most destructive bacterial pathogens in rice production worldwide. Although several complete genome sequences of strains have been released in public databases, they are mainly isolated from low-altitude rice cultivating areas.

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Background: Understanding and identifying the factors responsible for genetic differentiation is of fundamental importance for efficient utilization and conservation of traditional rice landraces. In this study, we examined the spatial genetic differentiation of 594 individuals sampled from 28 locations in Yunnan Province, China, covering a wide geographic distribution and diverse growing conditions. All 594 accessions were studied using ten unlinked target genes and 48 microsatellite loci, and the representative 108 accessions from the whole collection were sampled for resequencing.

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Traditional rice landraces grown under on-farm conservation conditions by indigenous farmers are extremely important for future crop improvement. However, little is known about how the natural selection and agriculture practices of indigenous farmers interact to shape and change the population genetics of rice landraces grown under on-farm conservation conditions during the domestication. In this study, we sequenced DNA from 108 core on-farm conserved rice landraces collected from the ethnic minority regions of Yunnan, China, including 56 accessions collected in 1980 and 52 accessions collected in 2007 and obtained 2,771,245 of credible SNPs.

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Rice landraces, a genetic reservoir for varietal improvement, are developed by farmers through artificial selection during the long-term domestication process. To efficiently conserve, manage, and use such germplasm resources, an understanding of the genetic structure and differentiation of local rice landraces is required. In this study, we analyzed 188 accessions of rice landraces collected from localities across an altitudinal gradient from 425 to 2, 274 m above sea level in Yunnan Province, China using ten target genes and 48 SSR markers.

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Diachronic analysis showed no significant changes in the level of genetic diversity occurred over the past 27 years' domestication, which indicated genetic diversity was successfully maintained under on-farm conservation. Rice (Oryza sativa L.) is one of the earliest domesticated crop species.

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Article Synopsis
  • On-farm conservation of crop landraces, specifically for paddy rice, wheat, and maize, is gaining attention as a way to preserve plant genetic diversity, compared to traditional conservation methods.
  • A comprehensive survey conducted in Yunnan Province covered 306 villages and revealed significant loss of landrace varieties, with 44.8% of villages losing paddy rice, 77.5% losing wheat, and 37.3% losing maize.
  • The survey identified a total of 901 collected landraces, highlighting great diversity in varieties across different ethnic groups, with paddy rice showing the most variability, influenced by local culture and customs.
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To reveal the genetic variation of rice paddy landraces across 30 years, we compared the genetic variation of between 6 paddy rice landraces grown in Yuanyang Hani's terraced fields in Yuanyang County, Yunnan Province in the 1970s (past-grown landraces) and 6 paired ones that have been grown during the past decade (current-grown landraces) using 60 SSR markers. The results showed that one to four alleles were amplified in 60 loci and 159 alleles in all the landraces tested. The number of alleles from the current-grown landraces decreased by 7 alleles compared to the past-grown landraces.

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