Identification And Photosynthetic Characteristics Analysis Of F₁ Hybrids Of Two Species Of Clover

Due to drought,cold and other natural conditions,it is difficult to promote large areas of Trifolium cultivation in Inner Mongolia.After several years of cultivation,T.ambiguum Bieb.has become a clover specie that has been fully adapted to the environment of Inner Mongolia.However,its nitrogen fixation ability is poor,seedling growth is slow and resistance to infertility is low.In order to compensate for these deficiencies,new varieties have been cultivated.Female plant part of T.ambiguum Bieb.(2n=6X=48)and male plant part of T.repens L.(2n= 4X=32),that has a strong ability of nitrogen fixation,were used for distant hybridization.Number of different varieties of hybrid F1 plants were obtained through the embryo rescue technology.Because these F1 hybrids are sterile,they need to be further cultivated to restore fertility.Two years after planting the hybrids and parents in the field,some plants restored fertility and vigor,new strains have been formed.According to the difference and stability of morphological characteristics,9 hybrids F1(A1,A2,B1,B2,C1,C2,Dl,D2,E1)with high germination rate and high seed setting rate were selected.With parents as control,their molecular genetics and photosynthetic characteristics were analyzed.The molecular genetics of 9 hybrids Fi were identified by ISSR molecular marker technique,and their photosynthetic capacity was determined by LI-6400 photosynthesis apparatus.The main results are as follows:(1)There were significant differences on the molecular level between the F1 hybrids and the parents,and their genetic traits were closer to the T.ambiguum Bieb.,and the genetic information of the female parent was expressed to a higher degree.(2)The maximum net photosynthetic rate of T.ambiguum Bieb.and T.repens L.and 9 hybrids was Bl>Al>B2>Ta>D1>A2>C2>D2>E1>C1>Tr.Under high light conditions the photosynthetic capacity of white clover was the weakest and the photosynthetic capacity of some hybrids of F1 hybrids showed super-character.(3)The hyperbolic curve correction model is more suitable for fitting photosynthetic-light response curves of T.ambiguum Bieb.,T.repens L.and their 9 hybrids F1.