| Grape belongs to Vitis vinifera L.,who is one of the five major fruits in China and plays an important role in the fresh fruits market.In recent years,due to the continuous improvement of agricultural cultivation techniques and facilities,Sichuan & Chongqing region has been rapidly developed into a new viticultural production region of grape,where was once not the most suitable place for grapes cultivation.For the problem of lacking of sunshine and high air humidity,there is no means economically and effectively to improve the facility cultivation conditions currently.Because the limitation of climatic factors,the white grape varieties,who have low requirements for sunshine and annual accumulated temperature,is widely promoted in Sichuan & Chongqing region.The hybrid white grapes cross between European and American are widely loved by growers,because of their certain ability of humidity resistance.Therefore,this research aimed at the ‘Shine Muscat' grape,which is popular in the fruit market and has a high price current now.And another two hybrid white grapes cross between European and American: ‘Shuijing',‘White Banana' were selected as comparison in the study.This experiment compared the basic quality about appearance and intrinsic flavor of the grape fruits.The aroma components and contents of their three were determined by GC-MS(Gas Chromatography-Mass Spectrometer).By the means of comparison of the quality and main aroma components,we analyzed the aroma characteristics and genetic provenances of the three varieties.It will provide a scientific basis for improving three white grape verities cultivation techniques and product processing.On the other hand,it also laid a theoretical foundation for breeding work.In this research,we also selected 8 Sampling places in Sichuan & Chongqing region,all of these Sampling places have similar cultivation techniques.The study compared the basic quality of the grape fruits in different Sampling places,and analyzed the main aroma components of them.Then contrast the relative expression of genes related to the biosynthetic of monoterpenoid,the experiment based on the gene,which is at the molecular level.The main experiment results are as follows:(1)In the comparison of the basic appearance and intrinsic flavor quality of ‘Shine Muscat' with another two white varieties fruits,we found that the quality of ‘Shine Muscat' is much better than the other two grapes,and there are significant differences between them in multiple indicators.Among all the soluble sugars,sucrose is a characteristic of the hybrid vitis crossed between European and American,although the content of sucrose is very low.In our present study,the characteristics of hybrid in ‘Shine Muscat' was higher than that in ‘Shuijing',while the lowest was ‘White Banana'.The characteristic is known by comparing the content of sucrose.(2)There were significant differences in the aroma components between ‘Shine Muscat' with the other two grapes.The results showed that there are 36,33 aroma substances has been determined in ‘Shuijing' and ‘White Banana' grape respectively.They are divided into 7 categories,including alcohols,aldehydes,ketones,esters,alkanes and a small amount of other compounds.The esters accounting for a large proportion among all the aroma compound,which has the highest content.Methyl anthranilate is a characteristic aroma of the American variety,who has “Foxy-smelling”,and it only determined in ‘Shuijing'.This result shows that ‘Shuijing' is highly heterozygous in Europe and American,while the other two grapes varieties have been diluted for generations.‘Shine Muscat' contains only 5 kinds of aroma substances: alcohols,aldehydes,esters and alkanes,29 kinds of aroma substances in total.It's the main aroma components belongs to alcohols,especially several kinds of monoterpene alcohols,as well as Myrcene,1,3,6-Octatriene,3,7-dimethyl-and Limonene.(3)The aroma components of the eight Sampling places in ‘Shine Muscat' grapes have certain differences,but all of them take monoterpenoid as the main aroma substance.We found that grapes in Xichang has the richest aroma components,Yongchuan and Nan7 an also have more kinds of aroma components,but Yubei was the least.DXS3?GPPS and LIS are the key genes in the early,middle and late terpenoids metabolic pathway,respectively.In the terpenoids metabolic pathway,this research show that DXS3 has a regulatory effect on the monoterpenoid content in the early stage,while GPPS in the middle stage plays a minor role,and LIS has a greater influence on the synthesis of Linalol in the late stage.(4)The correlation analysis between the flavor quality of ‘Shine Muscat' grape and the main climatic factors of each sampling place by GRA(Grey relational analysis).The correlation between the flavor quality and the climatic factors are the highest in the following indices: color index and temperature,Vitamin C and precipitation,Total soluble solid and precipitation,Titrable acidity and temperature.Total sugar,fructose and glucose are mainly restricted by rainfall,sucrose is greatly affected by the illumination duration.Oxalate acid and malate acid are mainly affected by the illumination duration.Tatrate acid and citrate acid are more sensitive to moisture(humidity).The kinds of aroma substances(including monoterpenoid substances)is limited by moisture,especially rainfall from June to September.(5)Xichang exactly has a small climate zone,which is very suitable for cultivating of ‘Shine Muscat' grape.Take a comprehensive comparison of the fruit quality of ‘Shine Muscat' grape between Xichang and other regions in Sichuan & Chongqing region,the grape in Xichang has the highest Vitamin C content,the lowest organic acid content,and a well ratio of sugar to acid(37.95).The aroma components categories of this region is the richest,including alcohols,aldehydes,esters,alkanes,and others,6 kinds of aroma substances in total.This region has a very suitable climate for ‘Shine Muscat' grape's cultivating,which is good for enhancing the development of the grape industry,the climate include high altitude?sufficient illumination duration and suitable temperature.In addition,the harvesting period of ‘Shine Muscat' grape in Yubei is really late,the quality of the fruit is relatively poor,and the aroma is relatively monotonous.It is recommended to product high-quality wine to improve its economic efficiency. |
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