Genetic Diversity Research On Wild Species And Cultivating-varieties Of Corchorus

Jute is the important fiber crop for textile industry and paper manufacture.The experiments were divided in to three parts to study the genetic diversity.They are as fall: pollen grain,individual characters and molecular markers.At first , the structures and shapes of Corchorus including 10 Jute species were investigated by using scaning electron microscope (SEM ). It is can be based on the form,size and the outside wall of the pollen to identity the interspecific difference in Jute species. Second, Principal components(PC) of nine yield characters of 150 Jute varieties were analysed. We can use the result to analysis the difference on individual character.And the last,Genetic diversity and relationship of the 173 representive Jute varieties from oversea and our country, was evaluated according to SRAP markers which genomic DNAs were amplified with 35 SRAP primers. The 173 Jute varieties were clustered into different groups according to the similarity coefficient (Nei-li), which represented the genetic relationship of different varieties. The major results are as follow:(1) Pollen is a more conservative organ in the systematic development of the plant and the variation intensity of the pollen often marks the evolution level of this each. The consequence tell us that the pollen of the Jute are usually 3-colporate,subelliptic,elliptic,prolate and perprolate.They are 17.01~22.83μm×28.33~37.03μm in size.The exine ornamentanion ususlly displaied into reticulation. There are many differences among Jute species in shape,the length of colporate and the ratio of P/E.The pollen which as a part behaviors of the entire acrostichum can be stably hereditied to the descendant and it can be use to esplore the inheritable character of the crop and counted us a auxiliary guideline.The pollen morphology is of some significance for a better classification of the genus.(2) The results of the Principal components(PC) of nine yield characters of 150 Jute varieties are as follow: the first four PCs,which might be regarded as fiber yield component factor(51.22%),fiber and stem weight proportion factor (15.89%), stem diameter factor(11.00%) and fiber content of fresh stem factor(9.98%).The four account for 88.11% among the varieties. (3) At the level of L1(91%),all varieties were clustered into one major group and several single-variety groups.At the level of L2 (55%),the major group was clustered into one large group which include 163 varieties and a small groups with 21 varieties.(4) 2146 DNA bands which 2015 (93.89%) were polymorphic were amplified with 35 SRAP primers .(5) From the UPGMA cluster based on the genetic similarity (GS) , at the level of 91%, 173 kinds Jute varieties separated wild species and cultivaling-varieties. The result shows wild species have further relationship from cultivaling-varieties and their genotypes are quite different with the latter. There is certain genetic differences between the different groups of cultivating-varieties. In order to breeding new Jute varieties, hybridizing parents who have further relationship should be chose.(6) From the UPGMA cluster based on the genetic similarity (GS) , the study indicated that the genetic difference between the Jute varieties in our country was relative small, which can be improved through germplasm innovation. SRAP markers can apply abundant polymophism information at molecular level, which is a valid way to study genetic divesity and relationship of Jute species.The issues of DNA extraction quality in Jute, the establishment of SRAP reaction system,genetic diversities and genetic relationships among 173 Jute varieties were also discussed.