Mutant breeding of a Japanese traditional black rice cultivar Yayoi-murasaki to improve seed shattering trait

Abstract

Yayoi-murasaki is a traditional black sticky rice cultivar, which has long been grown locally in Tokushima prefecture in Japan for celebratory or religious occasions. This cultivar is characterized by late heading and easy seed shattering habits compared with modern Japanese rice cultivars, resulting in low yield performance. Severe seed shattering has been the major concern, especially under typhoon attacks. Therefore, mutant breeding using γ-ray was undertaken to mitigate seed shattering trait. Several lines selected for reduced seed shattering exhibited various phenotypes for seed shattering, fertility, and panicle morphology. These lines are a good resource for the improvement of Yayoi-murasaki and can be useful to understand the molecular mechanism of seed shattering trait in rice.