Research On Cytology And Genetic Mark Among Buckwheat Species In West Of Sichuan

Buckwheat is the genus of Fagopyrum, family of Polygonaceae, an annual herbaceous plant. Buckwheat is a multipurpose crop used for food, feed, medicine and manure. Cross (1913) firstly reported the phylogenetic relationships among Chinese buckwheat. And then many researchers throw into buckwheat research.It was acceptable that the original centre of buckwheat is southwest of China. In this experiment, we collect 12 species of buckwheat from Aba, Xichang, Yaan, of Sichuan province. In order to investigate these species' genetic relationship and evolutional tendency, we use the methods from morphology, karyogroup analysis, isoenzyme and ISSR. This foundational work could provide useful information for the breeding and genetic improvement of buckwheat. The research results obtained as follows:1. Investigation of buckwheat distribution state that wild buckwheat species widely distribute Aba state, especially approximately 900-3600 m altitude, and mostly at cool area of 1500-2500 m altitude; meanwhile, this distribution was isolated by high mountains, such as Zhegu, Balangshan, Tiejinhaizi mountain in Aba state.2. Morphological characteristics state that the difference buckwheat include plant height, stem thickness, node number, branch, phylliform, inflorescence types, pedicel, pistil number, bloom, size and 1000- kernel weight of seeds. The results obtained as follows: (1) semi-erect group plant may be the intermediate between erect group and grovel type. (2) Fagopyrum wenchuanense and Fagopyrum qiangcai's morphological characteristics is prominently different from other species, consequently, there would be new species. (3) Fagopyrum crispatofolium would be a subspecies of Fagopyrum densovillosum. (4) F.gracilipes var.odontopterum consists of red and white strains. It is unclear the relationship of these two types.3. It was firstly reported that the karyotype of F.crispatofolium, F.gracilipes var.odontopterum, F.wenchuanense, F.qiangcai and contrast with other studied species. (1) F.gracilipes var.odontopterum, F.wenchuanense and F.qiangcai are diploid, their all chromosome number is 2n=2x=16; F.densovillosum is tetraploid, its chromosome number is 2n=4x=32. (2) In the different times of the chromosome level, buckwheat karyotype variation and buckwheat closely related. In times of the same chromosome level, buckwheat diploid karyotype variations smaller, tetraploid karyotype variation larger. Buckwheat karyotype evolution trend is symmetrical to develop in the direction of asymmetry.4. We analysis 12 species from west of Sichuan using the methods of isoenzyme of POD, EST, SOD. (1) F.wenchuanense was the first group from the dendrogram. This species was significant distinct genetic differentiation from other groups. Nei-Li similarity coefficient (GS) exists between 0.3333 and 0.5833. (2)Three species of F.cymosum from Aba, Xichang, Yaan was the second group from the dendrogram. Nei-Li similarity coefficient exists between 0.0833 and 0.2500. It was demonstrated that geography differences of genetics exist in these species. (3) F.esculentum and F.tataricum was also the second group. This indicates these three species appeared to be more related. F.cymosum and F.tataricum's Nei-Li similarity coefficient (GS) exists between 0.2917 and 0.2917. But F.cymosum and F.esculentum exists between 0.3750-0.4583. These data indicates that between F.cymosum and F.tataricum is more closely compared to F.esculentum and F.cymosum. This review was supported by Sharma and Luo Dingze.5. The 18 primers produced 231 clear and easily scored bands through ISSR marker amplification in the 12 species studied, The GS value in 12 accessions studied was between 0.1818 and 0.5238, F.crispatofolium and F.densovillosum's genetic distance is minimum to 0.1818, indicating these two species are the nearest evolutionary relationship. From the dendrogram, three groups were classified. F.wenchuanense and F.qiangcai are the first group; F.tataricum, F.esculentum, F.cymosum are the second group. F.densovillosum F.gracilipes var.odontopterum (red and white), F.gracilipes and F.crispatofolium are the third group. F.gracilipes and F.densovillosum could be the peer stage of primary evolution, and the evolution process may be from F.gracilipes to F.gracilipes var.odontopterum (white), from F.densovillosum to F.crispatofolium and F.gracilipes var.odontopterum (red). From ISSR molecular marker, F.cymosum, F.tataricum and F.esculentum are the second group in the dendrogram, indicating F.tataricum is more closely to F.cymosum.