Karyotype Analysis And Evolutionary Trends On Corylus. Avellana L. And C. Heterophylla Fisch

The fourty hazelnut germplasms from the hazelnut germplasms pool of Shandong Agricultural University were taken as the experimental materials in this paper.The conventional squashed method was improved and the somatic-cell-chromosomes of hazelnut were studied. Through identification of chromosome numbers, analysis of karyotypes and exploration of effective approach of karyotype analysis of hazelnut germplasms, the aim of this paper was to provide the basic cytology data of hazelnut germplasms The main study results were as follows:1. According to existing plant cytological achievements, the study methods of chromosome was improved and a set of simple, economical and efficient karyotype analysis method was explored. The new shoots were collected in clear days in April or May of the Spring from 11:00 AM to16:00 PM. The young leaves should be divested. Tender tissues were pretreated with saturated 1,4 dichlorobenzene solution for 2-3h, fixed in freshly prepared Carnoy's fixed liquid(1:2 acetic-alcohol)for 2-24h., hydrolyzed in the mixed solution(HCL:95%alcohol=1:1)for 10 min at room temperature and stained with improved fuchsin solution.Squashing, microscopic examination and measurement were then carried on.The pairing and arrangements of chromosomes were made using Adobe photoshop and Auto CAD.2. The results showed that all the chromosomes of hazelnut germplasms were diploid and the number is 22 ; The actural length of chromosomes belonging to small chromosomes. The main member of karyotype was m chromosome and only a few chromosomes also have sm chromosomes. The ratio of the longest chromosome and the shortest chromosome more than 2 but less than 4 was 72.5%. There were no chromosomes of the arm ratio more than 2. As to relative length, the main member of karyotype were S chromosome,M chromosome and L chromosome except H8 which karyotype was M chromosome and L chromosome and B-9 which karyotype was M chromosome alone. The varation of asymmetric coefficient ranged 56%- 60.34%.The karyotype of the most hazelnut germplasms belonged to 1A and 1B type except that of B-23 which was 2B type. There was great similarity of karyotype among the germplasms.So the hazelnut is a little symmetry type.3. The result from cluster analysis and comparing the characteristic among fourty hazelnut germplasms showed that C. avellana L. is further evolved than C. heterophylla Fisch.; C. avellana L. had the close relation to H2,H4, and the distant relation to H8,7#. The famliies of C. heterophylla Fisch. and interspecific hybrids of C. heterophylla Fisch.×C. avellana L. had clearly evolves and mutates. There were two condition as follows:Some germplasms , such as 84-237,T20,81-23,M1,85-119 and so on, had the close evolves to C. heterophylla Fisch. and the distant relation to C. avellana L.; Others , B-23,84-226,84-263,T6 et al, showed the close relation to C. avellana L.and the distant relation to C. heterophylla Fisch..The distinction of the evolution trend and relationship among the family of C. heterophylla Fisch. and Interspecific Hybrid Cultivars was not clearly ,although the most of Interspecific Hybrid Cultivars had a further evolution than the family of C. heterophylla Fisch.. These germplasms had taken place the larger variation, and 84-226,B-23 had the largest variation.