The main rice varieties in Thailand are Conventional Indica varieties. Pengshiluo 601, pengshiluo 602, pengshiluo 2, especially pengshiluo No.2, are widely used in northern rice region. This is a fragrant indica rice variety, and its planting area is more than 50%. KDML105 is an indica rice variety with slender, transparent and fragrant grains. It has been planted in Chiang Mai for 35 years and has a large planting area in China. It is a raw material for processing export rice. For new varieties bred by scientific research institutions, rice farmers will be invited to participate in the taste of rice quality, and the evaluation of rice farmers will be used as the basis for evaluating and approving the quality. What's more, Thailand insists on paying attention to seed production in rice technology promotion, and has set up 23 rice seed production centers throughout the country. The seed production centers purify and rejuvenate according to the technical requirements, and strictly carry out seed propagation to remove impurities and eliminate inferior quality, so as to maintain the excellent characteristics of rice varieties. Some varieties have been used for 50 years in production, but they are still favored by rice farmers and are the best raw materials for processing and exporting rice. At present, the key point of rice breeding in Thailand is to select varieties with high quality, less fertilizer and less medicine, strong disease resistance and insect resistance.

Thailand's rice is mainly conventional rice varieties, accounting for more than 98% of the rice varieties, and less than 2% of the hybrid rice varieties. However, due to the high yield of hybrid rice and the great economic benefits of seeds, the promotion of hybrid rice began to grow, but due to the relatively poor quality of hybrid rice, the promotion progress was slow. Before the 1960s, pure line selection was mainly used in rice breeding in Thailand to select the best from local farmers. The goal was to improve the quality of rice, especially the grain length. In the mid-1960s, hybrid breeding and mutation breeding were applied to rice breeding, mainly to select non photosensitive varieties suitable for irrigated rice areas, and to improve the yield per unit area and disease resistance and insect resistance of rice varieties from the International Rice Research Institute (IRRI). Hybrid rice has been studied since the early 1990s, but the progress is slow. At the end of 1990s, rice biotechnology research started. Scientists tried to introduce disease resistance genes through molecular technology. However, due to the safety issues, they are still in the stage of product test and observation. At present, rd6 (bred in 1977), KDML105 (bred in 1959), spr60 (bred in 1987), rd23 (bred in 1981) and rd10 (bred in 1981) are the main popularized varieties. In particular, KDML105 was bred from the local farmers in Thailand in 1959. It is drought resistant, acid and alkali resistant soil, and the rice grain is slender, transparent and delicious. It is very popular in the international market. This variety has been used in production for nearly 50 years, and still occupies a considerable proportion. The main reason is that the rice quality is excellent. However, due to the long-term cultivation, the varieties degenerated seriously and the disease resistance ability decreased. At present, the focus of research is to enhance the disease resistance. In addition, due to the small seed market and low profit, only a few agricultural companies are engaged in seed production and purification, and most of the seeds are purified by farmers themselves. Thailand is located in a tropical region with high temperature and high humidity, which causes serious diseases and insect pests, but at the same time, it needs to emphasize the quality of rice. Therefore, the breeding of resistant varieties has attracted great attention.

In terms of variety improvement, Thailand always pays attention to quality first. Only those who meet the quality standard can enter the market. Otherwise, no matter how much the yield is increased, it will not be used in production. In order to prevent the degradation of "Hom Mali / variety", Thailand's Rice Research Center and experimental station pay great attention to the purification and rejuvenation of varieties, and update every 2-3 years to ensure the quality of high-quality rice.