Evaluation Of The Biologic Traits, Agronomic Characters And Stress Tolerance For Five Forage Grasses

Grasses have a pivotal role in the development of livestock production and ecological protection. It exist a very rich diversity of the grass germplasm resources in our country. The systematic study of the biological traits, the agronomic characters, the drought resisitance and the salt tolerance and soon as the aspects above have been executed in the paper, so the aim is providing a base for further utiliation of grass germplasm and the breeding of new varieties. The main results obtained are as follows:(1) The grass species such as Elymus nutans Griseb, Bromus inermis Leyss, Elymus sibiricus L., Agropyron trachycaulum L. and Agropyron cristatum (L.) Gaertn as the test materials have been planted on the condition of cold and dryland farming area, and the production performance include morphological characteristics, phenological period, growth speed, over wintering rate, stem/leaf ratio, fresh/dry ratio and forage yield etc have been analyzed to inquire the effection of forage yield of different cutting time. The result showed that five species materials could over wintering as normal in cold dryland farming area (over wintering rate>90%); the fresh forage yield of test materials had significant differences (P<0.05), and the forage yield of different mowing time is as follows:Elymus sibiricus L.> Agropyron trachycaulum L.> Elymus nutans Griseb.> Bromus inermis Leyss.> Agropyron cristatum (L.) Gaertn; Agropyron trachycaulum L.and Elymus sibiricus L. among all of the five kinds materials had small stem/leaf ratio and large fresh/dry ratio in terms of yield or growth rate were the best while the Bromus inermis Leyss.and Elymus nutans Griseb.had bad Production performance.(2) Salt tolerance test were taken with paper using petri dish germination method and pot seedling cultivation method. The effect of salt stress on the seed germination and seedling growth of different grass species were evaluated and analyzed by membership function to provide theoretical reference for salt tolerance identification, salt tolerance breeding and saline alkali land cultivation. The results showed that the order of salt tolerance of5grass species was:Elymus nutans Griseb.> Agropyron trachycaulum L.>Elymus sibiricus L.> Bromus inermis Leyss.> Agropyron cristatum (L.) Gaertn.(3) The drought resistance experiment were executed, so that the content changes of chlorophyll fluorescence parameters, photosynthetic parameters, leaves electric conductivity, proline for different forages grasses under drought stress treatments were measured. The results showed that:the minimal fluorescence (Fo) and non-photochemical quenching coefficient (qN) of all the materials trended to rise gradually, but the maximal fluorescence (Fm), potential Photochemical efficiency (Fv/Fo) of photosystemII(PSII). maximal photochemical efficiency of PSII (Fv/Fm) and photochemical quenching coefficient (qP) declined gradually along with the aggravation of drought stress. The parameters above varyed with the different materials, the difference could be therefor used as the indexes for the identification and evaluation of drought resistance for the grass speices. Finally, the drought resistance of different grasses was analyzed and valuated using membership function, so the order of the five grasses drought resistance was:Elymus nutans Griseb> Bromus inermis Leyss> Agropyron trachycaulum L.,> Elymus sibiricus L.> Agropyron cristatum (L.) Gaertn.