Analysis Of Biological Character And Combining Ability On Different Alfalfa Hybrid Combination F₁ Generation

Studies on the mechanism of male sterility and applications of hybrid seedcan effectively improve the yield, resistance and quality of alfalfa,which have great significances to the development of alfalfa industry. We used male sterile line MS-GN as the female parent, excellent varieties from abroad and china as male parent to configure 15 alfalfa cross combination. The objectives of this study were to provide considerable selections of hybrid combination and data base for breeding excellent alfalfa hybrid in the future. We analyzed biological characteristics and combining ability of their F1 generation, the main results were as follows:There were significant differences both in productivity and quality for 15 hybrid combinations F1 generation of alfalfa(P<0.05). Russia No.8×MS-GN had the highest plant height, acid detergent fiber and neutral detergent fiber contents. Chaoyang×MS-GN had the most branch numbers per plant. The grass yield of Longmu 803×MS-GN and Gongnong No.3×MS-GN were higher than other combinations. In addition, Longmu 803×MS-GN had higher protein content. The nitrogen-free-extract content of Russia No.4×MS-GN was the highest. Grey correlation analysis showed that the most influencing factors to comprehensive production value were branch number, HY/FY and CP. The comprehensive production value of Chaoyang×MS-GN was the highest, showing a wide range for planting, which followed by Magna-601×MS-GN, Pyramid×MS-GN, Gongnong No.3×MS-GN and Hopiand×MS-GN. On the contrary, Russia No.7×MS-GN was at the end rank with the worst comprehensive performance.The study on photosynthetic characteristics of the 9 alfalfa hybrid combinations F1 generation showed that daily variations in photosynthesis rate of other hybrid alfalfa were represented by two-peaked curves except combinations of Hopiand×MS-GN and Pyramid×MS-GN, Their photosynthetic rates in response to light intensity and CO2 concentration were simulated by non-rectangular hyperbola models. The hybrid combinations Hopiand×MS-GN,Pyramid×MS-GN and Magna-601×MS-GN showed wide ranges of light utilization. Shade-resistance combinations were CW306×MS-GN, Longmu803×MS-GN and WL-323×MS-GN, while Daye×MS-GN and Pyramid×MS-GN were more heliophilous; Hopiand×MS-GN,Pyramid×MS-GN and Daye×MS-GN had the largest light use efficiency and strong ability to use weak light. The CO2 utilization ability was stronger for combinations WL-323×MS-GN, Daye×MS-GN and CW306×MS-GN. The leaf physiological activities of Daye×MS-GN, Pyramid×MS-GN and Hopiand×MS-GN’s were higher, which provided more energy for plant growth.The analysis on combining ability of the 9 alfalfa hybrid combinations showed that forage yield traits were impacted both by the additive and non-additive genes effect. General combining ability of parents and special combining ability of combinations were, but not necessarily relevant. In addition to the female parent MS-GN, the male parent Hopland, Xin Jiang Daye, Pyramid, Magna-601 had stronger general combining ability. Combinations Daye×MS-GN, Hopiand×MS-GN and Pyramid×MS-GN had greater values of specific combining ability. In conclusion, strong advantaged combinations were Hopiand×MS-GN and Longmu 803×MS-GN preliminary.