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 1950s to the 1990s 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 1950s and 1960s, but these methods were replaced by crossbreeding in the 1970s. 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.