Production and genetic improvement of minor cereals in China

China is a leading country in the production of several minor cereals such as foxtail millet,Job's tears,naked oat,and naked barley.Sorghum and proso millet have also contributed greatly to Chinese agriculture.Foxtail millet,sorghum,barley,and proso millet were widely grown as major crops 60 years ago,and the reduction in their cultivation area reflects historical changes in Chinese agriculture over the past decades.Systematic germplasm collections from the 1950 s to the 1990 s gathered more than 66,690 accessions of these minor cereals,and for some of them,the Chinese germplasm collections are the largest in the world;for example,the 27,700 accessions of foxtail millet.Germplasm evaluations of each cereal species have focused mainly on drought tolerance,nutritional quality,and resistance to their main diseases.Comparisons among lines and selection of those with desirable traits were the main breeding methods for minor cereals in the 1950 s and 1960 s,but these methods were replaced by crossbreeding in the 1970 s.Newly developed cultivars have greatly changed the production situation,and many super cultivars have become milestones in crop breeding history.In this review,we describe the distribution and ecoregions,origin and domestication,and landmark varieties of several minor cereals in China.Nearly all of the minor cereals are drought-tolerant and fertilizer-efficient.The requirements for environmentally friendly crops and a more diverse food supply for humans and animals provide new opportunities to cultivate minor cereals in the drier and warmer environmental conditions that are predicted in the future.

Population genetic insights into the conservation of common walnut(Juglans regia)in Central Asia

The common walnut(Juglans regia)is one of the most economically important nut trees cultivated worldwide.Despite its importance,no comprehensive evaluation of walnut tree population genetics has been undertaken across the range where it originated,Central Asia.In this study,we investigated the genetic diversity and population structure of 1082 individuals from 46 populations across Central Asia.We found moderate genetic diversity of J.regia across Central Asia,with 46 populations clustered into three groups with a weak relationship between genetic and geographic distance.Our findings reveal that the western Himalaya might be the core region of common walnut genetic diversity in Central Asia and that,except for two populations in Gongliu Wild Walnut Valley,humans might have introduced walnut populations to Xinjiang,China.The observed distribution of the genetic landscape has probably been affected by historical climate fluctuation,breeding system,and prolonged anthropogenic activity.We propose the conservation of the core genetic diversity resources in the western Himalaya and pay special attention to populations from Gongliu in Xinjiang.These findings enhance our understanding of the genetic variation throughout the distribution range of J.regia in Central Asia,which will provide a key prerequisite for evidence-based conservation and management.