Changes in the rice grain quality of different high-quality rice varieties released in southern China from 2007 to 2017

Abstract

High-quality rice varieties are planted widely in southern China. However, the changes in grain quality in the different high-quality rice varieties released in recent years are unclear. This study compared the grain quality changes and status of those varieties and presented proposals for future breeding. In the past 11 years, high-quality indica has significantly improved chalky rice rate (CRR), chalkiness degree (CD) but decreased head rice rate (HRR); amylose content (AC), gel consistency (GC) and length-to-width ratio (LWR) were improved only in indica hybrid rice. Most high-quality rice varieties grown in southern China are primarily indica rice. In contrast to indica rice, japonica rice had increased milling recovery, cooking and eating qualities (CEQ), but worsened significantly the physical appearance. For japonica rice, hybrid varieties exhibited a marked improvement in the rice quality for lower AC, higher GC and LWR compared with inbred varieties. A higher grain quality was observed in inbred varieties for indica rice due to lower CRR, CD and AC, higher HRR and GC. Our results suggested that we should be focused on improving the physical appearance quality for japonica rice and milling recovery, particularly CEQ for indica rice, for future high-quality rice breeding.