Genetic dissection of a reduced seed-shattering trait acquired in rice domestication.

Abstract

Asian rice (Oryza sativa L.) was domesticated from wild rice (O. rufipogon Griff.). During rice domestication, the wild characteristic of seed-shattering behaviour was suppressed, enabling an efficient harvest with increased yield. Rice, a stable food for humans, is one of the most important crops consumed by billions of people, especially in Asian countries. With advances in molecular genetic studies, genes or loci involved in reduced seed shattering via the inhibition of abscission layer formation have been identified. The mutations alone showed no inhibitory effect on abscission layer formation in the wild rice O. rufipogon, but their combination enabled a stepwise change in the degree of seed shattering, which may be associated with advances in harvesting tools. In the early stages of rice domestication, the closed panicle formation and slight inhibition of the abscission layer resulted in complementary effects that increased harvesting efficiency. Furthermore, common and distinct loci were found to contribute to reduced seed shattering in groups of rice cultivars, indicating that mutations at seed-shattering loci are important information for tracing the process of rice domestication.