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By the methods of phenotypic identification and SRAP markers amplif cation, the genetic diversities of fourty wild H. compressa clones from southwest China were assessed and classified. The results showed as follows: The phenotypic variations were rich among H. com pressa clones, and the variation coefficient of the phenotypic traits ranged from 12. 9 % - 57. 0 % . Through the cluster analysis based on phenotypic traits, the clones with obvious genetic differences could be distinguished. The tested 40 H. compressa clones could be clustered into three groups, two cloners( H019 and H054) in A group without earring and flower, two cloners( H002 and H050) in B group with long intemode, long stem, long inflorescence, other 36 clones in C group. After the amplication with 15 pairs of SRAP primers, a total of 314 fragments were detected, among which, 290 fragments were polymorphic, accounting for 92. 4 % of the total. The amplified fragments and polymorphic fragments per pair primer combination were averagely 20. 9 and 19. 0, respectively. Polymorphic information content ( PIC) was from 0. 351 to 0. 499, with average of 0. 443, and the similarity coefficient of 40 accessions ranged from 0. 639 to 0. 949. These results suggested that there was rich genetic diversity among the wild resources of H. compressa clones tested. At the genetic similarity coefficient of 0. 730, the H. compressa clones could be classified into three classes, 36 clones belonged to C class, B class included three clones, namely H050, H052 and H053 , and A class had H029 only. The relationship between morphological and SRAP-based genetic distance wasn ' t significant by mental test. [ABSTRACT FROM AUTHOR]

The rapid development of electronic devices？ wireless communication technologies and low frequency Radar systems bring forward requirements on broadband thin microwave absorbers working at low frequencies. However ？ existing microwave absorbers are usually of poor performance in low frequency waveband. Tn recent years？ considerable efforts were made on high performance low frequency microwave absorbers by researchers all over the world. These efforts focus on various high magnetic permeability absorbents for thin absorbing coatings ？ and the emerging met am ate rial absorbers. This paper is devoted to cover the main progress on the above aspects. [ABSTRACT FROM AUTHOR]

The resistances to ergot of 56 accessions from Qinghai-Tibet plateau were evaluated under the field condition. The results showed that the resistances to ergot of germplasm were quite different and the disease incidence ranged from 0%-95% with means of 27.68%.The resistance types were divided based on the disease index( DI) calculated with the disease incidence and class of disease. The proportion of the different resistance types were 41.07% high resistance, 19.64% resistance, 30.36% medium resistance, 8.93% sensibility, 0% high sensibility, respectively. The result of statistical analysis indicated that most of the germplasm showed the resistance to ergot. In addition, the correlations between the disease parameters and economical characters including plant length, inflorescence length, leaf length and leaf width showed the low correlation. The result of the study would supply an important information for the resistive breeding of Elymus nutans. [ABSTRACT FROM AUTHOR]