Study On Classification And Evaluation Of Wild Iris Native To Northeast China

China is known as an important distribution center of the genus Iris, with 65 species, occupied one-fifth of global Iris species. There were 19 species, two variants and two forma of wild Iris in northeast China recorded in previous literatures, occupied one-third of Chinese Iris species, which is known as an important distribution center of China. These resources are important germplasm for improving cold and drought resistance to Iris cultivars. In this study, the genus Iris native to northeast China was investigated comprehensively and systematically, geographic distribution, habitation, population quantity, growth situation and the main accom panying plants of most species has preliminary understandings. On this basis, We carried out four studies, which including germplasm identification, phylogenetic classification, chromosome number and karyotype, comprehensive assessment. Main results for this study are as follows:Twenty-eight investigation sites were selected by us for investigating wild Iris resources in Liaoning, fifty-five investigation sites were selected by us for investigating in northeast China. We selected twenty-eight sites in Liaoning, which has the largest count of wild Iris species in northeast China, according to climate variability and geomorphic feature in Liaoning the distribution regularities of wild Iris resources was analyzed after the investigation, twenty-seven sites were selected in Jilin, Heilongjiang and Inner Mongolia Autonomous Region. In each sites, we selected phytocoenosium with little human interference, population quantity, habitat and associated plantsthe of Iris species native to this site was investigated and recorded.132 accessions were collected during the investigation, including 53 accessions from Liaoning,79 accessions from Jilin, Heilongjiang and Inner Mongolia Autonomous Region. According to previous literatures and the specimens stored at Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang,132 accessions were classified into 17 species,3 variants,4 forms and five unknown accessions, including I. dichotoma, I. lacteal, I. tigridia, I. tenuifolia, I. ventricosa, I. kobayashii, I. rossii, I. minutoaurea, I. setosa, I. ensata and I.laevigata, These species with significant difference on morphological characteristics, species identification was relatively easy, but I. sangguinea and I. typhifolia, I. ruthenica and I. uniflora, I. mandshurica and I. bloudowii, the morphological characteristics between each pair of them was similar, species identification was relatively difficult, they must be grown in one place to observe, to understanding of interspecific differences directly on the vision; three variants including; four forms including I. dichotoma f. alba, I. laevigata f. alba, I. sangguinea f. alba,I. lactea and I. tigridia, the leaves is very narrow.The chloroplast DNA fragments ndhF of 32 accessions (17 species,3 variants,1 forms and two unknown accessions) were analyzed for phylogenetic relationships among the genus by the Maximum parsimony (MP) and Bayesian inference (BI) analysis. Dietes robinsoniana and Moraea pritzeliana were used as outgroups. Two methods of analysis are shown in this study involves northeast Iris taxa constitute a single system. This taxa was divided into three categories, including Subgen. Pardanthopsis, Subgen. Limniris, Subgen. Iris. The result and now use the classification system perfectly. The phylogenetic tree clustering results of the two basic consistent, but BI tree's approval rating higher than MP tree. In the morphologically similar species are two together, show very close relatives, the species and varieties are at a higher approval rating in a first, the same down the material comes from the different groups are gathered for a first, a clustering phenomenon did not appear across. Reference molecular systematics research results, combined with the morphological features and previous literature,I. koreana Nakai and I. typhifolia, which grown in the arid environment.The root tips of Iris species (15 species,3 variants,1 form and one unknown accessions) were used to study chromosome number and karyotypes with the conventional pressing plate method. The chromosome number and karyotypes of 5 Iris species was reported for the first time, including I. ventricosa, I. kobayashii, I. rossii, I. minutoaurea and I. typhifolia. Most of the remaining species and reported the same chromosome number, karyotype of but is a little different, a few species of chromosome number is different from previous reports. In this study, the results of karyotypes of I. ruthenica I. uniflora and I. uniflora var. caricina were 2n=42; I. sangguinea and I. typhifolia were 2n=28; I. tigridia and I. tigridia var. fortis were 2n=18, but I. tigridia, the leaves is very narrow was 2n=20, the results were consistent with Jinmei Lu.According to the research results of morphology, molecular systematics and cytology, combining the result of investigation, we suggest that the classification status of should be reserved;I. kobayashii and I. ventricosa could have a near relationship among the genus Iris native to northeast China.According to the difference of morphological characteristics and growth habit among the genus Iris native to northeast China, they were divided into two categories, including short-bush and blossom in spring, height-bush and blossom in summer. The comprehensive assessment of them respectively used AHP. The evaluation results show that among the short-bush and blossom in spring, which score from high to low: I. tigridia, I.uniflora var. caricina, I. uniflora, I. ruthenica, I. mandshurica, I. bloudowii, I. kobayashii, I. tenuifolia, I. minutoaurea, I. rossii; height-bush and blossom in summer, which score from high to low:I. ensata, I. typhifolia, I. ventricosa, I. laevigata, I. dichotoma, I. sangguinea, I. lactea var. chinensis, I. setosa.The distribution and population of I. tigridia, I. uniflora var. caricina and I. ensata was very large, so we suggest to introduce them to urban gardening; I. typhifolia has high ornamental value, but the population of it was less, we suggest that the study of on reproductive biology and breeding should be developed. We hope cultivar group of I, typhifolia could be developed, which has high value of ornamental and reproduction rate.