Genomic footprints of Kam Sweet Rice domestication indicate possible migration routes of theDongpeople inChina andprovide resources for future rice breeding

The Dong people are one of China’s 55 recognized ethnic minorities,but there has been a long-standing debate about their origins.In this study,we performed whole-genome resequencing of Kam Sweet Rice(KSR),a valuable,rare,and ancient rice landrace unique to the Dong people.Through comparative genomic analyses of KSR and other rice landraces from south of the Yangtze River Basin in China,we provide evidence that the ancestors of the Dong people likely originated from the southeast coast of China at least 1000 years ago.Alien introgression and admixture in KSR demonstrated multiple migration events in the history of the Dong people.Genomic footprints of domestication demonstrated characteristics of KSR that arose from artificial selection and geographical adaptation by the Dong people.The key genes GS3,Hd1,and DPS1(related to agronomic traits)and LTG1 and MYBS3(related to cold tolerance)were identified as domestication targets,reflecting crop improvement and changes in the geographical environment of the Dong people during migration.A genome-wide association study revealed a candidate yield-associated gene,Os01g0923300,a specific haplotype in KSR that is important for regulating grain number per panicle.RNA-sequencing and quantitative reverse transcription-PCR results showed that this gene was more highly expressed in KSR than in ancestral populations,indicating that it may have great value in increasing yield potential in other rice accessions.In summary,our work develops a novel approach for studying human civilization and migration patterns and provides valuable genomic datasets and resources for future breeding of high-yield and climate-resilient rice varieties.

Fast integration and accumulation of beneficial breeding alleles through an AB–NAMIC strategy in wheat

Wheat(Triticum aestivum)is among the most important staple crops for safeguarding the food security of the growing world population.To bridge the gap between genebank diversity and breeding programs,we developed an advanced backcross-nested association mapping plus inter-crossed population(AB-NAMIC)by crossing three popular wheat cultivars as recurrent founders to 20 germplasm lines from a mini core collection.Selective backcrossing combined with selection against undesirable traits and extensive crossing within and between sub-populations created new opportunities to detect unknown genes and increase the frequency of beneficial alleles in the AB-NAMIC population.We performed phenotyping of 590 AB-NAMIC lines and a natural panel of 476 cultivars for six consecutive growing seasons and genotyped these 1066 lines with a 660K SNP array.Genome-wide association studies of both panels for plant development and yield traits demonstrated improved power to detect rare alleles and loci with medium genetic effects in AB-NAMIC.Notably,genome-wide association studies in AB-NAMIC detected the candidate gene TaSWEET6-7B(TraesCS7B03G1216700),which has high homology to the rice SWEET6b gene and exerts strong effects on adaptation and yield traits.The commercial release of two derived AB-NAMIC lines attests to its direct applicability in wheat improvement.Valuable information on genome-wide association studymapping,candidate genes,and their haplotypes for breeding traits are available through WheatGAB.Our research provides an excellent framework for fast-tracking exploration and accumulation of beneficial alleles stored in genebanks.