Studies On Identification Of Tolerances About Pulling Force Of Fruit Stalk,Fruit Compression And Correlated Grading Standard For Grape Germplasm Resources

The pulling force of fruit stalk and fruit compression toleracne for 600 accessions from 4 populations in Zhengzhou National Grape Germplasm Repository were evaluated with a digital tension machine and according to the specific range of concrete numerical value,the pulling force of fruit stalk and fruit compression toleracne were classified into different grades.The major conclusions were as follows:1.Developmental changes of pulling force of fruit stalk and fruit compression tolerance were analyzed from 30 d after flowering to ripening on ‘Cardinal',‘ Red Baradeau',‘Mills',‘Pinot Gris',‘Hupei No.2',and ‘Jingkejing' 6 grape varieties.The results showed that during the ripening of fruit,the pulling force of fruit stalk and fruit compression tolerance of 6 grape varieties showed a decreasing trend and became stable finally.The change trend of the pulling force and fruit compression tolerance of 6 grape varieties was a significant positive correlation with each other.Besides,the trend of soluble solid content was a significant negative correlation with pulling force and fruit compression tolerance.The stability period of fruit stalk pulling force and fruit compression tolerance,the content of soluble solids and the accumulation rate of soluble solids varied with the genetic characteristics and developmental stages in different varieties.2.The pulling force of fruit stalk and fruit compression tolerance of 600 accessions were evaluated with a digital tension machine and according to the specific range of numerical values,the pulling force of fruit stalk and fruit compression toleracne were classified into different grades,which provided some reference for the identification and evaluation of grape germplasm resources.According to the international and national standards of fruit separation difficulty,the pulling force(P)was distributed into weak(P?3 N),medium(3 N<P?6 N)and strong(P>6 N)3 classes and fruit compression tolerance(T)was distributed into weak(T?12 N),medium(12 N<P?23 N)and strong(P>23 N)3 classes respectively as well as.3.According to different grade standards,15 grape varieties exhibiting the strongest pulling force of fruit stalk were ‘Red Globe',‘MuDanhong',‘Mathias Aromatic',‘Scarlet royal',‘Victory',‘Elisabeth grape',‘Lival',‘Autumn royal',‘Sweet Scarlet(2014)',‘Boulgal',‘Jintian hong',‘Afuali',‘Red Baradeau',‘Wanhei bao' and ‘spring buds'.21 grape varieties exhibiting the strongest fruit compression tolerance were ‘Jingxiu',‘spring buds',‘Autumn royal',‘Afuali',‘Sweet Scarlet(2014)',‘Waltham Cross',‘Manicure Finger',‘Kaiotome',‘Scarlet royal',‘Midnight beauty',‘Red globe of Xiaji',‘Flame tokay',‘Greaca',‘Warser',‘Skendberg',‘Centenial',‘Purple damasous',‘Rosario Bianco',‘Siva grape',‘Hunan unnaming' and ‘Pride'.7 grape varieties exhibiting strongest tolerance which pulling force and compression tolerance were strong,were ‘Red globe of Xiaji',‘Autumn royal',‘Sweet Scarlet(2014)',‘spring buds',‘Afuali' and ‘Hunan unnaming'.All the above germpasms are Eurasian population except the ‘Pride' that belongs to V.labrusca,which can provide some references for grape breeding.4.The relationship between pulling force of fruit stalk and fruit compression tolerance in 600 grape germplasm was compared.The results showed that there was a significant positive correlation between the pulling force of fruit stalk and fruit compression tolerance in different grape germplasm.Generally speaking,the stronger the pulling force of fruit stalk,the stronger the fruit compression tolerance.In Eurasian population,interspecific hybrid,East Asian population and North American population,the pulling force of fruit stalk and fruit compression tolerance of different germplasm also showed the same correlation.