Yield Testing of Newly Improved Soft White Rice and Glutinous Rice Lines

Competition among soft fragrant rice in the world market has intensified. While Thai Hom Mali rice still commands a high price in the world market, soft fragrant rice and soft rice from Vietnam and Cambodia are much cheaper than Thai Hom Mali Rice and Thai Aromatic Rice. It is clear that Vietnam has succeeded in breeding soft fragrant rice from Soc Trang that won first prize at the World's Best Rice contest in 2018. This variety, named ST24, is a soft fragrant rice with very good physical properties: its grains are slender, averaging 7.8 mm long, and clear like basmati, but do not elongate when cooked. Importantly, it has a short maturity, can be grown all year, and has a yield as high as 1.36 tons/rai (from a report that could not confirm the amount of chemical fertilizer used in production), raising the question of which Thai fragrant variety can compete with ST24.

Breeding soft fragrant rice is one of the important targets of the Center of Excellence for Precision Rice Breeding, through cooperation between the Rice Science Center, Kasetsart University, and the National Center for Genetic Engineering and Biotechnology (BIOTEC).

For an appropriate academic comparison, 7 newly improved photoperiod-insensitive soft fragrant lines, both glutinous and non-glutinous, were tested for quality and yield: Hom Malai Man, Hom Naka (glutinous), Hom Jinda, RD47 blast-resistant No. 2 (RD47-BB-2), RD47 blast-resistant No. 3 (RD47-BB-3), Hom Nin 9997 and Pin Kaset 1. They were grown for yield testing together with various commercial varieties, namely RD43, RD79 (non-fragrant soft rice), Pathum Thani 1 and Hom Suphan, at the Rice Experiment Station, Kasetsart University, Kamphaeng Saen, in the 2020 off-season (March–July 2020), under organic and GAP systems, to compare rice varieties suited to promoting to farmers for growing for Thai rice export to the world market. The goal was to obtain rice with good plant type, resistance to unfavorable environments, good cooking quality, glutinous or soft-textured, high yield and short to medium harvest age.

Results and discussion In the yield comparison, in the organic field the newly improved Hom Malai Man had a yield of 572 kg/rai, more than RD43 (347 kg/rai), and in the chemical field Hom Malai Man yielded 524 kg/rai, likewise more than RD43 (275 kg/rai), showing that Hom Malai Man has good potential to compete with soft fragrant rice from Vietnam in the world rice market. However, the other test lines could not yet be harvested because they have a longer harvest age than the 3 varieties above.