Primary Study On Genetic Diversity And Productivity Of Limpograss (Hemarthria Compressa) Germplasm From Southwest China

In the paper, the genetic diversity of 57 limpograss (Hemarthria compressa) materials collected from different populations in southwest China was studied at the level of morphology and isozyme. In addition, we chose 20 better materials from all materials to value their productivity, in order to discover excellent germplasm as primary materials to breed new variety. The results showed as follows:1 Most of limpograss live in wet environment such as riverside, paddyfield, and humid farmland. At the same time, minority can be discovered in more drouthy hillside. Limpograss investigated and studied distribute at the altitude of 40m to 1650m in southwest China, which can adapt to different soil texture such as loam, clay, sand etc. Limpograss often accompany warm-season grass such as Cynodon dactylon, Erwmochloa ophiuroides, Paspalum urvillei, and it would be dominant in sand and clay.2 The genetic background of limpograss in southwest China is complex and the ecologic types are rich. There are great morphologic variation among different populations on leaf colour, stem thickness, plant height and creep trait. The leaf length ranges from 11.2cm to 27.1cm. The leaf width ranges from 0.465cm to 0.729cm.The sheath length ranges from 3.3cm to 6.1cm. The internode length ranges from 4.7cm to 13.2cm. The stem thickness ranges from 0.199cm to 0.414cm. The minimum of relative height is 33cm, the maxmum is 67cm. The minimum of absolute height is 35cm, the maxmum is 79cm. The rate of tassel has significant variance among different populations. 12.3% materials don't tassel. The rate of 14.0% materials is less than 5%.The rate of 42.1% materials range from 5% to 30%. The number is from 30% to 50% in 28.1%materials and more than 50% in 3.5% materials only.3 The limpograss materials are divided into three morphologic types as fine-low type, thickset-low type, high-horrent type, by means of clustering analysis. The thickset-low type has the characteristic of wide and long leaf, short internode and strong stem. Thehigh-horrent type has the characteristic of thin and long leaf, long internode and high and horrent plant. The two type materials can be as primary materials to breed new forage variety. The fine-low type has the characteristic of thin and short leaf, fine stem, short internode and low plant, so which can be as primary materials to breed soil and water preservation plant.4 The polymorphism of peroxidase isozyme are abundant on limpograss. There were 11 bands migrated into three regions with Rf value 0.037-0.176, 0.560-0.736 and 0.937 from cathode to anode. The three bands with Rf value 0.069, 0.610, 0.937 existed on all materials and had significant difference on width and colour darkness among them. The bands of materials from Guizhou province were less than other materials, which had not the bands with Rf value 0.128, 0.176, 0.560, 0.648 and 0.736. The clustering analysis showed that the isozyme patterns were consistent with geographical distribution.5 We valued the productivity of 20 better materials, the result showed as follows: H002, H029, 2003-6 belong to high-horrent type had higher yield of fresh grass and hay. HO 19, H031 belong to thickset-low type had high yield of fresh grass, but the yield of hay was lower. H047 belong to fine-low type had lower yield of fresh grass, but which content of dry matter was very high. The materials were more excellent and could be as good germplasm for breeding. Especially, H002 had richest leaf and highest yield of fresh grass and hay, and 2003-6 had highest content of crude protein.