Rice Breeding Genetics.pdf

Rice genetics can benefit from studying rice domestication, which has greatly impacted rice genetics, but exploiting elite alleles from wild species and domesticated varieties for modern rice breeding is ongoing. Crop domestication, including rice, has been influenced by human civilization, with domesticated cultivars obtaining beneficial alleles from progenitors to adapt to local conditions. Asian cultivated rice, Oryza sativa, was domesticated from wild-rice species O. rufipogon, with two primary subspecies: indica and japonica. Uncovering the domestication process can provide a better understanding of artificial selection and propose a model for other crop species. Domestication genes, such as those controlling shattering, seed size, and grain quality, have been characterized, with archaeological evidence showing rice domestication began in China's Yangtze Valley 8,000-9,000 years ago. Genetic studies support the single-origin model, with the snowball model demonstrating the earlier critical domestication gene was introduced to other Asian regions, and the multiple-origin model proposing multiple mutations in divergent wild populations. Population genetics studies have identified selective sweeps, causing decreased genetic diversity, and comprehensive studies on rice genome variations have provided evidence for investigating phylogenetic relationships between cultivated and wild rice.