A Study On The Cold Resistance Of Six Elite Lines Of Shushanggan Apricot In Yili Area

Objective:The cold resistance of fruit trees refers to its ability to resist the low temperature of freezing in winter,which will directly affect the expansion of fruit trees in low temperature areas.The low temperature in the Yili area severely restricts the development of Shushanggan apricot?Armeniaca sp?.It is a very rare fruit,which can be consumed directly or processed products.It was first discovered in the Yili area,and they were introduced and domesticated in the Ili region in the 1980s and began to be widely planted in the 1990s.It has a very high economic return.At present,Yili is also the most important growing area.However,due to the local introduction of chaos,the quality between different varieties is uneven.Moreover,the cold damage occurs severely,which limits the output of apricots to some extent.Therefore,this work will evaluate the cold resistance of 6 elite lines and explain their cold resistance.This will provide the foundation for selecting and nurturing new cultivars,which provided a basis for the screening and genetic breeding of improved varieties.Method:6 elite lines have been screened at the Agricultural 14th Academy of Agricultural Sciences.One-year-old dormant shoots were collected as the materials for measuring relative conductivity,semi-lethal temperatures(LT₅₀)and physiological indexes.These materials were processed at 4°C,-15°C,-20°C,-25°C,-30°C,-35°C for 6 hours and measured free proline,Malondialdehyde,soluble protein,SOD and CAT,respectively.Logistic curve and membership function values were calculated to analyze the cold resistance of 6 elite lines.Result:With the decrease of temperature,the relative conductivity,MDA content,soluble protein content,proline content and SOD activity of the six lines increased gradually.Soluble sugars increased first and then decreased.CAT activity decreased first and then increased,finally decreased again.Because the relative conductivity and the cold resistance are negatively correlated,so we can calculate the correlation between the six indicators and the cold resistance based on the correlation between the six indicators and the relative conductivity.The content of MDA was negatively correlated with the cold resistance of plants,and the other five indicators were positively correlated.The semi-lethal temperature of each line was S3?-18.08??>S5?-15.15??>S6?-14.29??>S4?-13.95??>S2?-12.02??>S1?-9.40??.Semi-lethal temperature analysis showed that S3 was the most cold-tolerant.However,membership function of the seven indicators indicated that the cold resistance of 6 elite lines was S6?Mj=0.5366?>S3?Mj=0.0.5098?>S1?Mj=0.0.4823?>S5?Mj=0.4662?>S2?Mj=0.4552?>S4?Mj=0.4482?.S6had the strongest cold resistance,while S4 had the most weak cold resistance.