Genetic Diversity And Cross Compatibility Of Elite Genotypes In Camellia Oleifera

Camellia oleifera is a unique woody oil plant in South China.It is known as one of world's "four major woody oil plants" with Elaeis guineensis,Olea europaea,and Cocos nucifera.Studying genetic diversity and hybridization compatibility among the excellent genotypes can provide references for parent selection and pollination tree configuration of C.oleifera.The study adopted SSR molecular marker technology to study the genetic diversity among 135 genotypes of common Camellia oleifera and determine their genetic relationship.The genetic diversity of 10 Camellia oleifera genotypes from Fujian Province were also studied in combination with variations in phenotypic traits such as their fruits,leavesand oil content.The results can provide references for crossbreeding and selection,of parents.From the 10 Camellia oleifera genotypes,five pairs of excellent Camellia genotypes were selected for double crosses to provide basis for subsequent allocation of pollination trees.The main findings are as follows:1.10 pairs of SSR primers were used to amplify 135 elite genotypes by PCR.A total of 92 bands were amplified by 10 pairs of primers,92 bands were polymorphic,and the percentage of polymorphic bands was 100%.The PIC values of single primer combinations varied from 0.153 to 0.344 with an average value of 0.272;the band information index of the primer combinations varied from 0.197 to 0.545 and the average value was 0.403;the label discrimination of the primer combinations varied by 1.970-5.452,the average value was 3.677;the change range of the labeling index was 1.527-3.441,the average value was 2.491,the similarity coefficient of 135 genotypes was 0.21-0.87,and the averagevaluewas 0.66,indicating the inheritance between these excellent Camellia genotypes with a large variation.The excellent Camellia genotypes can be divided into five groups at 0.424.Among them,11 varieties of the Changlin line were accurately divided into one group,which verifies the accuracy of the SSR molecular marker in this experiment.2.Based on the analysis of the phenotypic traits of 10 excellent genotypes of C.oleifera,it was found that there was a certain degree of variation in different traits.The coefficient of variation of each trait in different parents ranged from 8.68%to 37.74%,with an average coefficient of variation of 21.57%.The coefficient of variation of fruit shape index was smallest while the coefficient of variation of dry fruit weight was largest.The variation among different parents was abundant means that the potential of hybrid offspring was relatively large.Through the cluster analysis of these coefficients of variations,the 10 excellent genotypes were divided into 4 categories.Using 10 pairs of primers to carry outSSR molecular markers analysis on 10 parent samples,a total of 53 bands were detected including 53 polymorphic bands which occupied 100%.The average of bands amplified by each pair of primers is 5.3.The PIC value of a single primer varies by 0.313-0.450 with an average value of 0.371.The band information index of the primer combination varies by 0.400-0.700 with an average value of 0.532.The band resolution of the primer combination changed from 1.400 to 4.800 with the average value of 2.720.The primer combination index was 0.900-3.400,and the average value was 1.912.The genetic similarity coefficients of the 10 elite clones ranged from 0.1212 to 0.7917 with a range of 0.6705 and an average of 0.524.These results shows that genetic differences exist among the 10 Camellia superior genotypes.3.The diallel crossing(5x5)double-strand hybrids were used in the 5 elite clones(min 43,min46,min50,min54,min60)planted in Fujian Province,and the fruit setting rate was calculated after pollination,The combination with the highest fruit setting rate was min60×min46,fruit setting rate was 0.790,The combination min43×min46 had the lowest rate of fruit setting rate,it is 0.200,and the average fruit setting rate was 57%.Min43 and min60 can be used as the main cultivars,while min50 and min54 can be configured as pollinators.