Study On Seedling Growth Characteristics Of Onion In Open Field Winter Sowing Tray Seedling In Northern Xinjiang

In recent years due to the flourishing market economy,people’s living quality has been improving and the demand for high quality vegetables has been increasing.Therefore,in order to determine the suitable sowing date and density range of hill-hole planting for efficient and low-cost seedling raising of onion in winter in Northern Xinjiang.In this experiment,the first-generation hybrid onion variety Baixue was used as the experimental material,a two-factor block experiment scheme was adopted,and 4 sowing dates were determined(October 22,October 28,November 3,November 9),three hill-drop density(4 capsules/hole,6capsules/hole,9 capsules/hole),to study the effects on the agronomic characters,physiological and biochemical indexes and photosynthetic gas exchange parameters of onion seedlings.The main conclusions are as follows:(1)The effect of suitable density and suitable sowing period on plant growth and trait morphology is crucial.The highest number of green leaves,the highest dry and fresh weight per plant,and the highest strongest seedling index were 9.02,2.07 g,17.84 g,0.07,and 0.12,respectively,on November 9(A4)and at a hole sowing density of 6 capsules/hole(B2).(2)Suitable sowing periods and planting densities help to promote the growth and development of onion seedlings and increase the content of protective enzymes and osmoregulatory substances in the leaves.At a hole sowing density of 9 capsules/hole(B3),leaf POD,SOD,CAT activity and MDA content and cytosol concentration were the highest at 343.80μg/g/min,500.20 U/g/h,13.25 U/g/min and 12.28μmol/g,respectively;on November 9,leaf soluble protein content was higher at 5.92 mg/g.(3)The construction of a reasonable population structure can effectively regulate the relationship between individual crops and the population.At November 9(A4),leaf Pn and Tr values were larger,8.54μmol/m~2/s and 22.65 mmol/m~2/s,and at a burrowing density of 4 capsules/hole(B1),Gs and Ci values were larger,1.47 mol/m~2/s and 361.49μmol/mol.(4)In conclusion,the seedlings were synthesized by correlation and factor analysis to compare agronomic traits,physiological&biochemical indicators&photosynthetic gas exchange parameters.The results showed that the time range for winter sowing of onion seedlings in cavity trays in the Northern Territory was about November 9,and the optimal density of cavity sowing was 6 capsules/hole.