Preliminary Evaluation And Screening Of Hybrid Seedlings Of Malus Sieversii

The Malus sieversii alias Sevis apple belongs to the Tertiary remnant plant and is only distributed in parts of Xinjiang,China.It has excellent traits such as cold resistance,drought tolerance,and resistance to diseases and insects,but the gametophyte has self-incompatibility.In order to screen out the Malus sieversii hybrid progeny with"super-parent"traits.In this experiment,Malus sieversiis were used as the female parent,and the same genus of the genus of the sea bream and the ruby sea bream were used as the male parent to carry out sexual crosses,obtain hybrid progeny seedlings,and establish different hybrid combination progeny groups,for different combinations and combinations of inner progeny.Variation evaluation of seedling morphology and physiological indexes.The SSR molecular marker technique was used to construct the fingerprints of the hybrid progeny.The basic characteristics of the nine selected red leaf seedlings were compared and analyzed.The main findings are as follows:1.The growth traits among the three different hybrid combinations and combinations including seedling height,ground diameter,lateral branches and leaf traits were compared and analyzed,and the overall variation in the combination was higher than that between the combinations.Among them,the three indicators of seedling height,ground diameter and side branch length reached extremely significant differences in all three combinations.Among the different hybrid combinations,the coefficient of variation of 9 phenotypic traits ranged from 1.65%to 74.81%.The smallest variation indicator is the number of blade serrations,with an average of only 7.17%.The maximum variation of the length of the lateral branches between the combinations reached 55.93%,indicating that the genetic variation of the hybrid progeny was extremely rich.2.Physiological indicators including chromaticity parameters between three different hybrid combinations and combinations（L*、a*、b*）、Photosynthetic parameters（Pn、GS、Ci、Tr、WUE）、pigment content（Ch1a、Ch1b、Car、Cy）、and chlorophyll fluorescence（Fo、Fm、ETR、PQ、NPQ、Fv/Fm）and comparative analysis of organic matter content,Section indicators include soluble protein,fluorescence parameters in each of the compositions were highly significant difference.The coefficient of variation of 20physiological traits ranged from 0.21%to 172.110%,and the average coefficient of variation of intercellular CO₂ concentration was the smallest,only 5.06%.The overall performance is that the variation within each combination is higher than the variation between the combinations,and although there are differences between the combinations,it is not significant.Correlation analysis of physiological indexes of seedlings showed that Pn was significantly positively correlated with WUE and Gs,and the correlation coefficients were0.569**and 0.845**,respectively.The correlation coefficient between Gs and Ci was0.523**;Fo and Fm were extremely Significant positive correlation was significantly negatively correlated with PSII（Fv/Fm）.The correlation coefficients were 0.701**and-0.467**.NPQ was significantly negatively correlated with ETR and PSII（Fv/Fm）,and the correlation coefficients were-0.520**、-0.485**;leaves Ch1a and Ch1b showed a significant positive correlation,and Car was significantly positively correlated with correlation coefficients of 0.680**and 0.974**respectively.3.Using SSR-PCR method,the SSR fingerprints were constructed by using 11 pairs of high-efficiency primers and 3 different hybrid combinations.The genomic polymorphism analysis showed that the genetic consistency of each combination ranged from 0.7179 to0.8333.The Shannon’s index is between 0.8621 and 1.0190,and the genetic diversity is expressed as M-10 combination>M-11 combination>M-12 combination.The relationship between M-10 combination and M-12 combination is the closest,reaching 0.1824.The polymorphisms of 25 hybrid progeny seedlings were further analyzed.The average effective allele number was 3.0418,and 11 random primers amplified 41 bands.The total number of polymorphic loci reached 96.90%,and the inheritance between the clones.The distance is between 0.0732 and 0.5219 and the average genetic distance is 0.234.The average Shannon’s information index was 1.167,and the average Nei’s gene diversity index was 0.654,indicating that the hybrid offspring have rich genetic diversity.The matrix results of SSR markers were correlated with the maternal growth index distance matrix and the physiological index distance matrix.The correlation coefficients were 0.032 and 0.019,respectively,which did not reach significant correlation.28morphological and physiological traits were clustered separately.11 pairs of primers were individually matrixed.In the 308 two-two matrix analysis,the correlation between the primer No.7 and the net photosynthetic rate Pn was the highest,reaching 0.408**.Then,11 pairs of SSR primers were clustered with a single index.Only the net photosynthetic rate Pn and the water use efficiency WUE were significantly correlated,and the correlations were 0.438**and 0.333**,respectively.4.The phenotypic traits,chroma,photosynthesis parameters,chlorophyll fluorescence,pigment and leaf organic matter content of 9 hybrid leaves were significantly different,but the spectral curves of different progenies were similar,and it was easy to distinguish the wavelength frequencies of individual plants.Between 700 and 800 Hz.Through the principal component analysis,the phenotypes and physiological characteristics of 9 red leaves were combined and ranked,and 4 progeny plants with strong comprehensive advantages were selected for later promotion and application,which were 5,15,9 and 25respectively.