Progress in Collaborative Improvement of High Quality, Yield, and Disease Resistance Breeding of Approved Rice Varieties in Guangdong from 2004 to 2022

Abstract

This article succinctly outlines the requirements for rice quality in Guangdong Province and the role of government regulatory policies in advancing high-quality rice breeding. By collecting the regional trial data of 1 101 rice varieties approved by Guangdong Province from 2004 to 2022, the number of varieties meeting the national or ministerial standards approved in each year were counted, and the progress of high-quality rice breeding in Guangdong was evaluated from the perspectives of quality index, resistance and yield. From 2004 to 2022, 106 varieties (combinations) meeting the quality of national standard (ministerial standard) (9.63% of all approved varieties) level Ⅰ and 320 varieties (combinations) reaching the quality of national standard (ministerial standard) (29.06%) level Ⅱ were approved by Guangdong. Notably, early season varieties exhibited lower quality rates compared with late season varieties. For rice quality traits, early-season trial varieties displayed lower compliance rates in the quality of national standard (ministerial standard) level Ⅱ, with chalkiness and chalky grain rate of 41.8% and 43.5%, respectively; the amylose content compliance rate in early-season trial varieties was only 37.32%, indicating that key improvements should be conducted in these three areas for new variety breeding. The average yield of rice varieties with quality meeting national standard level Ⅱ or above has consistently risen, indicating synergistic improvements in yield and rice quality during the high-quality rice breeding in Guangdong. Varieties meeting the national standard (ministerial standard) level Ⅱ or above also showed promising resistance rates against rice blast disease (85% at medium resistance or above) and bacterial blight disease (22.2% at medium resistance or above). Generally, while the percentage of hybrid rice varieties meeting high-quality standards is increasing, there is still a notable gap compared to conventional rice breeding. The proportion of high-quality rice varieties in Guangdong has been steadily growing, with a positive trend in "excellent, abundant and resistant" varieties. However, further optimization is possible. To cultivate high-quality rice varieties with double resistances, efforts should be put to enhance resistance to bacterial wilt disease. The evaluation and utilization of specific germplasm resources like local varieties should be increased to diversify the genetic background. This approach helps avoid variety homogenization, improves disease and stress resistance and strengthens the synergy between traditional and molecular breeding, enhancing overall breeding efficiency.

Keywords

• guangdong
• rice breeding
• rice quality
• resistance
• yield
• improvement