Analysis Of Nutrient Composition And EST-SSR Genetic Diversity Of Asparagus Germplasm Resources

Asparagus is one of the most important vegetable crops in the world,known as "one of the top ten famous dishes in the word","King of vegetables." Asparagus germplasm is the basis of asparagus breeding and industry development.China is the biggest asparagus producer in the world.However asparagus research started very late in China,many problems exist in asparagus production,such as the lack of good varieties,seeds market chaos,the lack of information of germplasm resources genetic background,parental selection aimless,research is far behind the demand of production.Thus asparagus germplasm collection and evaluation is of great significance to promote asparagus breeding and production.In this study,46 asparagus germplasms collected by our laboratory were used to analyze the contents of macronutrients in roots,stalks,leaves,spears and the contents of mineral nutrients in spears.The nutritional quality of asparagus was evaluated by 10 nutritional indicators.And their genetic diversity was also analyzed by EST-SSR molecular marker technique.The research results from this study are as follows:1.Nitrogen,phosphorus average content in different organs of asparagus was spear>root>leaf>stalks.Potassium average content was spear>stalks>leaf>root Calcium average content was spear>root>stalks>leaf.Magnesium average content was root>spear>stalks>leaf.The average content of the five elements above was higher in asparagus spears than in other parts.Nitrogen content range in spear was 40.68~87.85 g/kg,phosphorus of content range was2.33~15.24 g/kg,potassium of content range was 36.15~76.97 g/kg,calcium of content range was 4.45~27.61 g/kg,magnesium of content range was 1.08~6.08 g/kg.Apollo had the highest nitrogen content,Purple Passion had the highest phosphorus content,Pacific Endeavour had the highest potassium content,The variation range of the calcium,magnesium element was different.Purple Passion had the highest calcium content and the magnesium content of UC157、JK107were over 5 g/kg.The results showed that the distribution of nitrogen,phosphorus,potassium,calcium,magnesium in asparagus was specific among organs and cultivars.2.The nutritional quality and the degree of variation in nutritional quality among different asparagus germplasm resources were very different.Among these 46 asparagus germplasms,Pacific Purple、Backlim、JK106、Pacific Green、Gijnlim、JK104、Jinglvlu number 1、Champion、Jingzilu number 2 were of the best comprehensive nutritional qualitiy.Pacific Purple had the highest average membership function value at 0.498.3.EST-SSR molecular markers were developed based on EST sequences from NCBI database.Total 31 pairs of high polymorphism primers were selected to analyze the genetic diversity of asparagus.The similarity coefficient of 46 asparagus germplasm ranged from 0.32~0.90,and the average similarity coefficient was 0.72,which indicated that the difference between germplasm was weak.UPGMA cluster analysis showed that 46 species of asparagus germplasm were grouped into five groups at the genetic similarity coefficient of 0.70.The first group included 37 different asparagus germplasm from different sources:UC157,Atlas,Grande,Purple Passion,Jersey giant asparagus,Jersey Supreme,Apollo,NJ1189,NJ1123 from USA;Avalim,Backlim,Gijnlim,Grolim,Fortems,Tallems from the Netherlands;Pacific Purple,Pacific Challenger 1,Pacific Challenger 2,Pacific Endeavor,Pacific Crusader,Pacific peak,Pacific Green from New Zealand;Jinggang 701,Jingganghong,JK101,JK02,JK103,JK104,JK105,JK106 from Jiangxi;Jufeng,champion,TC,082,0914,New Century from Shandong;Mill from Canada;Precoce from Italy.The second group included Herkolim,Thielim from the Netherlands,Jingzilu No.2 from Beijing and Pacific 2000 from New Zealand.The third group included JK103 and JK107 from Jiangxi.The fourth group had only one germplasm,Jersey Knight from USA.The fifth group included Jinglvlu No.1 and 097 from Shandong.The results showed that there was no significant correlation between the genetic diversity of asparagus germplasm and its origin.All the asparagus germplasm had a very close genetic relationship.