Effects Of Space Mutagenesis On Agronomic Traits And Nutrient Composition Of Deqin Alfalfa

Alfalfa(Medicago sativa L.)is an excellent leguminous forage widely distributed in the world.As a wild cultivar in Yunnan,Deqin alfalfa has special adaptability.Improving its yield and quality plays an important role in promoting the development of animal husbandry in Yunnan region.Space mutagenesis is the use of space with strong radiation,high vacuum,microgravity and other unknown factors to mutagenesis plant materials,in order to obtain excellent new varieties or special germplasm materials.In order to explore the effect of space mutagenesis on Deqin alfalfa,the germplasm resources of Deqin alfalfa with high yield,high quality and strong stress resistance were selected.In this study,Deqin alfalfa after space mutagenesis was used as experimental material,and Deqin alfalfa without space mutagenesis was used as control to study the emergence rate,growth period,agronomic traits and nutritional composition.The results showed that:The effect of spatial mutagenesis on seed germination of Deqin polysavone was not significant(P>0.05).(1)Spatial mutagenesis made the branching stage of alfalfa advance by 5 days,but there was no significant difference in other growth stages(P>0.05).(2)The variation coefficients of 15 agronomic traits ranged from 4.23%to 73.43%in the planting year of 2021.The coefficient of variation of branching number was the largest,while that of water content was the smallest.Spatial mutagenesis significantly increased the leaf area,leaf length,leaf width,petiole length,leaf number,stem diameter,branch,leaf weight,stem-leaf ratio,fresh grass yield and hay yield of Deqin alfalfa(P<0.05).(3)The variation coefficients of five nutritional components of Deqin alfalfa by spatial mutagenesis ranged from 9.33%to 16.11%.The coefficient of variation of crude fat content was the largest and that of crude protein content was the smallest.Spatial mutagenesis significantly increased the crude protein and ether extract contents of Deqin alfalfa(P<0.05).Spatial mutagenesis significantly decreased the acid detergent fiber content of Deqin alfalfa(P<0.05);Neutral detergent fiber content and ash content were increased,but there was no significant difference compared with the control(P>0.05).(4)Membership function analysis of agronomic characters of Deqin alfalfa by space mutagenesis showed that 4,6,10,16,17,28,39,43,54,56,69,71,82,83,84,89,90,92,110,111 were superior.The best characters were plant height,plant dwarf,leaf area increase,stem diameter increase,branch number increase,purple stem,grass yield increase,leaf number increase and growth rate increase.(5)The branch number,leaf number,fresh grass vield,dry matter,cude protein content,ether extract content and acid wash fiber of Deqin alfalfa in the next year(2022)were significantly increased compared with that in the next year(2021)(P<0.05).The plant height,leaf area,stem diameter,neutral detergent fiber content and ash content of Deqin alfalfa in the next year(2022)compared with that in the same year(2021),but there were no significant differences(P>0.05).(6)In this study,7 Deqin alfalfa mutant plants(6,28,39,56,90,110,111)were selected as excellent forage germplasm resources for further breeding.