Accelerating the development of japonica hybrid rice in China

摘要

This paper reviews the detailed process of developing japonica hybrid rice in China and discusses breeding achievements with cytoplasmic male sterile (CMS)lines, photoperiod-sensitive genetic male sterile (PGMS) lines, as well as threeline and two-line japonica hybrid rice. Evidence shows the periodic breakthroughs of japonica hybrid rice breeding that have occurred since 2000. To overcome the weaknesses in developing japonica hybrid rice, we suggest the following plans to accelerate development. (1) Strengthen standard heterosis with the main aims of increasing panicles and seed set, improving grain quality by reducing chalky rate and chalkiness and increasing resistance to stripe leaf blight and false smut. (2) Because japonica hybrid rice has a relatively stronger photosensitivity to growth and narrower adaptability than indica hybrid rice, several types of varieties should be bred to satisfy the needs of different ecological regions, including early-season and middle-season japonica hybrid rice suitable for northern China; middle-season, late-maturing middle-season, and late-season japonica hybrid rice suitable for southern China; and single-season japonica hybrid rice suitable for the southwest plateau of China. Varieties with drought or salinity and alkalinity tolerance are also needed. (3) New types of male sterile lines with better early flowering, high outcrossing, and stable sterility should be bred. Parent multiplication and hybrid seed production must be strictly carried out to increase yield and secure the purity. (4) Cultivation technologies for new hybrid rice combinations should be developed simultaneously for different regions to achieve high yield potential, improve grain quality, and save cost.(5) Nationwide cooperation should be organized, research investment should be increased, and annual regular meetings should be held.