| Xinjiang wild apple is an important stress-resistant breeding resource of Malus,it has high ornamental value and is an excellent tree species for landscape greening.In this study,18 Xinjiang wild apple clones were selected from 600 Xinjiang wild apple plants in 2010,and their morphological indicators,physiological indicators and were analyzed and evaluated,molecular identification based on SSR molecular marker technology;Analysis and evaluate of fruit quality of 7 soild clones;Contrast with midget crabapple,comprehensive evaluation of cold resistance of 8 clones by electrical conductivity method,electrical impedance map method and growth restoration method.The main results are as follows:1、There were significant differences among 18 Xinjiang wild apple clones in tree height,ground diameter,east and west crown width,south and north crown width,sub-branch height,diseases and insect pests,branch angle,leaf area,aspect ratio and specific leaf weight.The variation coefficients of morphological indicators ranged from2.19% to 15.91%.Among them,the variation coefficient of south and north crown width(15.91%)was the largest,and the variation coefficient of leaf area(2.19%)was the smallest.There was a significant positive correlation between the tree height and ground diameter of the clones,the correlation coefficient was 0.942.2、There were significant differences in chlorophyll b,total chlorophyll content,carotenoids,anthocyanin,soluble sugar,soluble protein,L*,a*,b* among 18 Xinjiang wild apple clones,but no significant difference in chlorophyll a.The variation coefficients of physiological indicators ranged from 2.04% to 13.58%.Among them,the variation coefficients of chlorophyll b(13.58%)were the largest and that of L* was the smallest(2.04%).There was a significant positive correlation between the color parameter a* and anthocyanin content of the clones,the correlation coefficient was 0.820.3、A total of 62 bands were amplified by 13 pairs of SSR primers.The number of bands amplified by each pair of primers ranged from 3 to 6.The average number of bands amplified by each pair of primers was 4.77.The percentage of polymorphic loci per pair of primers was 100%.The PIC value of polymorphic information content of each pair of primers ranged from 0.512 to 0.879.18 Xinjiang wild apple clones were classified into four groups at genetic distance of 0.566.The first category is M-1,M-14,M-13,M-16,M-3,M-4,M-6 7 clones;the second category is M-15 1 clone;the third category is M-2,M-5,M-9,M-11,M-12 5 clones;the fourth category is M-7,M-17,M-18,M-8,M-10 5clones.Based on the results of SSR amplification,DNA fingerprints and two-dimensional codes of 18 wild apple clones were constructed.4、There were significant differences in soluble solids,single fruit quality,acidity,transverse length,vertical length and fruit shape index among 7 Xinjiang wild apple clones.The variation coefficients of fruit quality indicators ranged from 3.73% to 11.14%,among which the variation coefficients of fruit acidity(11.14%)were the largest and the variation coefficients of fruit transverse length(3.73%)were the smallest.The average single fruit quality of clone M-15 reached 84.00 g,which was significantly higher than that of other 6clones,indicating that it had specificity in single fruit quality.The soluble solids content and acidity of clone M-9 were 15.66% and 0.79% respectively,which were significantly higher than those of other 6 clones,reflecting its specificity in soluble solids content and acidity.There was a very significant positive correlation between transverse length and vertical length of the clones,the correlation coefficient was 0.977;There was a very significant positive correlation between single fruit quality and transverse length of the clones,the correlation coefficient was 0.973;There was a very significant positive correlation between single fruit quality and vertical length of the clones,the correlation coefficient was 0.949.5、According to the semi-lethal temperature of the clones and the germination rate under different low temperature treatments,the cold resistance of the clones was evaluated comprehensively.The results showed that the cold resistance of clone M-15 was the strongest,followed by M-11.The cold resistance of midget crabapple was lower than that of any clone of Xinjiang wild apple.There were significant differences in cold resistance among clones in December,but no significant differences among clones in March(except midget crabapple).Semi-lethal temperatures fitted by electrical conductivity method and electrical impedance map method in December and March were significantly correlated.Semi-lethal temperature fitted by electrical conductivity method and electrical impedance map method and germination rate showed significant or extremely significant negative correlation in December and March.The results of these three methods are basically the same,indicating that these three methods can comprehensively evaluate the cold resistance of clones. |
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