Guizhou Province Hybrid Rice Production Application Evaluation

Rice is one of the staple crops in Guizhou, and the annual planting area is about 750,000 hm~2 in Guizhou province. The yield of rice is about 60 % of the total in the grain crops. With the extensive application of hybrid rice, the rice output increased greatly. However, such questions as what type of hybrid rice combinations in the production is dominant, and how they are distributed in different regions, can not be clear completely at present.From the viewpoint of different subspecies, hybrid rice can be divided into two types: indica hybrid rice and japonica hybrid rice, and indica hybrid rice is the major type in the current production of Guizhou province. Hybrid rice, according to the different types of male sterile line, could also be classified into two-line and three-line system.The three-line system refers to three lines, which are cytoplasm male sterile line (CMS, or A), maintainer (B) and restorer (R). The system is the leading type in current rice production. The CMS in terms of the difference in the origin of cytoplasm is classified into wild absorption (WA) such as Zhengshan 97A, Jin 23A, Indanicia type(as II-32A, You lA),Gang type from Gambia, west Africa(G46A),and D type from Dissi (D 62A, etc.), dwarf cytoplasmic male sterility (Xie-qing-zao A), etc.Many combinations in hybrid rice come from the same CMS or the same restorer. What is more, the parents in primitive variety are the same or rather relative to them. Based on different restorers, there are "Minghui63"( M63 system in short), "Minghui77"( M77 system in short), "Gui99"( 99 system in short), "Shuhui527"(R527 system in short) ", "Minghui86"(M86 system in short), "Enhui58"and so on.According to the growth period, the combination types in hybrid rice consist of early, middle and late-maturity.In addition, the two-line hybrid rice based on the difference in sterility of dual-purposemale genic sterile (DPMGS) line have two types which are thermo-sensitive-sterile line andphotoperiod sensitive -sterile rice, and the former is leading one in production.In recent years, most of parents in combination of hybrid rice had a better improvement onthe quality, yield, resistance to diseases or pests and the tolerance to cold stress through theefforts to breeders. The application of these improved combinations made a great progress inrice production. Because Guizhou is one of mountainous provinces, ecological condition isvery complex, so the ecosystem is characterized by such typical vertical-agriculture resultingn the types and combinations of hybrid rice are various. Besides, rice planting regions inGuizhou province where there are different or diversified in growth period of hybrid rice and(?) regional thermal condition could be classified into four main regions. The first region (I)...