| In this paper, we screen and evaluate the production performance of Gannong No.3, HA-3, Eureka and their 29 hybrid progeny initially.Then we analyzed the genetic diversity, evaluate the resistance to trips, analyzed the yield and quality traits with gray systematic theory, estimated the general combining ability and Genetic Parameters of the selected excellent 16 alfalfa germplasms. Aim to determine the production performance and hereditary basis of 16 alfalfa germplasms and configurate excellent cross combinations,which can provide scientific basis for new alfalfa varieties breeding of high-yield, high-quality and strong insect-resistant in Northwest irrigation area. The resμlts as follows:We structured the AHP comprehensive evaluation model for the 29 alfalfa germplasms and selected 16 excellent alfalfa germplasms which included White flower 1#, Fast-growing 12#, White flower2#, White flower 3#, Fast-growing 11#, Fast-growing5#, Fast-growing 1#, Fast-growing 4#, Big leaf 2#, Fast-growing 15#, Fast-growing 20#, Fast-growing 19#, Fast-growing 26#, Erect type, Fast-growing 2#, Fast-growing17#.The above mentioned germplasms all perform better yield and quality.The tested alfalfa germplasms were classified into 5 major groups in the genetic similarity of 0.266. This first group included Fast-growing 1#, Fast-growing 11# and Fast-growing 12#,which perform high yield and good quality;the second group included Fast-growing 5#,Big leaf 2#, Fast-growing 26#, Erect type,HA-3, Fast-growing 15#, Fast-growing 17#, Fast-growing 20#, Fast-growing 19#, which perform better resistance to thrips;the third group included Fast-growing 4#, Gannong No.3,White flower 1#, White flower 2#, White flower 3#,which perform high general combining ability;the forth group and fifth group included Eureka and Fast-growing 2# respectively.Based on the damage indices, an evaluation test on resistance of Gannong No.3, HA-3, Eureka and their 16 hybrid progeny to thrips was carried out. Using cluster analysis, the resistance of tested alfalfa germplasms to thrips were clustered into 3 classes, there were 6 germplasms with the highest resistance(White flower1#,Fast-growing15#,Fast-growing12#,Fast-growing20#,HA-3 and Erect type alfalfa germplasms) and the mean of their damage indices was 50.66%,7 germplasms with the medium resistance(White flower3#, White flower2#, GannongNo.3,Fast-growing11#,Eureka, Fast-growing4#,Fast-growing1# and Fast-growing 5# alfalfa germplasms) and the mean of their damage indices was 69.01%, 6 germplasms with the lowest resistance Fast-growing 19#,Fast-growing 26#,Fast-growing2#, Fast-growing11#, Fast-growing17# and Big leaf 2# alfalfa germplasms) and the mean of their damage indices was 80.32%.Through field experiments, hay yield traits, crude protein(CP), neutral detergent fiber(NDF) and acid detergent fiber(ADF) of Gannong No.3, HA-3, Eureka and their 16 hybrid progeny were determined. Based on yield and nutrient quality characters, we structured the comprehensive evaluation model with gray systematic theory, Fast-growing 4# and White 3# are of high yield, high nitrogen and low fiber material, Fast-growing 12# is of high yield and high nitrogen material, Fast-growing 1# and White 1# are of high yield and middle nitrogen materials, Fast-growing 15# is of high yield and low fiber material, while White 2# is of middle yield and high nitrogen material. The above mentioned germplasms could be used as good alfalfa breeding materials after further transgenerational screening.Half-sib seeds of 16 excellent alfalfa germplasms and the three parents were selected as tested materials. General combining ability(GCA) and the broad-sense heritability(H2) of 16 germplasms combination for yield and quality were analyzed and evaluated. Cluster analysis was conducted based on GCA. The results showed that there were two strains with high general combining ability(white flower 3# and fast-growing4#) and eight strains with moderate general combining ability(fast-growing 15#, fast-growing 12#, white flower 1#,white flower 2# and fast-growing 1# etc.).These parents have the character of high yield and good quality and all can be used as a good parent which can participate in the next step cross breeding. The estimated of heritability in the broad are sequenced as RFV, hay yield, leaf-stem ratio, CP, branch number, internode length,plant height and growth rate.Comprehensiving the above results and using the theory of heterosis, we ongurateed 12 hybridized combinations from the selected 8 gemplasms which show high GCA of production performance and better resistance to trhips.There were 2 high-yield, good-quality and strong insect resistance hybridized combinations.they were ①White flower 1#×Fast-growing 15#×Fast-growing 12#, whose GCA was from 16.46 to 23.05; ②White flower 3#×Fast-growing 4#×Fast-growing 20#, whose GCA was from 0.13 to 37.73. There were 2 high yield and good quality hybridized combinations. They were ① White flower 3# ×Fast-growing 4#×Fast-growing1#, whose GCA was from 12.71 to 37.33; ②White flower 3# ×Fast-growing 4#×White flower 2#, whose GCA was from 18.18 to 37.33. There were 3 high yield and strong insect resistance hybridized combinations.They were ①White flower 1# ×Fast-growing 1#, whose GCA was from 12.71 to 16.46; ②White flower 1# ×Fast-growing 12#, whose GCA was from 16.46 to 20.38; ③Fast-growing 1#×Fast-growing 12#, whose GCA was from 12.71 to 20.38. There were 2 good quality and strong insect resistance hybridized combinations. They were ① Fast-growing 15#×Fast growing 20#, whose GCA was from 0.13 to 23.05; ② Fast growing 15#× White flower 2#, whose GCA was from 18.18 to 23.05. The above hybrid combinations can guide the next hybrids equipping of high yield, good quality, strong insect resistance alfalfa varieties, so as to improve the breeding efficiency. |
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