Study On Genetic Diversity Of Chinese Common Apricot (Prunus Armeniaca) Germplasm And Origin Of Purple Apricot (Prunus Dasycarpa)

Apricot (Prunus armeniaca) is a deciduous fruit tree crop in the temperate zones, originating from Central and Western Asia mountains. China is one of primary center of apricot domestication in the world, owning very abundant germplasm resources of apricot. In order to properly assess genetic diversity and evolution process of Chinese apricot, morphological and genetic diversity about three eco-geographical apricot groups native to China were performed in the study. Furthermore, based on the hypothesis of origin of purple apricot (Prunus dasycarpa), distance crosses between common apricot and myrobalan were conducted to survey the origin of purple apricot in the view of fertilization biology and molecular phylogenetics. The main results are as follows:1) Frequency distribution of several biological characters and agronomic traits of 520 Chinese apricot genotypes in three eco-geographical groups (North China, Central Asia, Dzhungar-Zailij) were analyzed in the study. In general, self-incompatibility was a common character for the three eco-geographical groups with averages less than 2.0% and percentages of self-incompatible cultivars more than 90%. Therefore, a few self-compatible germplasms were found, too.2) Higher sterile flower rate of 40% was observed in all eco-geographical groups with a higher coefficient of variance 50%. For a certain cultivar or form, the trait was relatively stable in different years.3) Glabrous-fruited cultivars were only observed in the Central Asian eco-geographical group with a higher percentage of 76.6%. In other two groups, the cultivars or forms were all identified as roughskin-fruit.4) The largest fruit size (with an average of 51.4 g) was a predominate trait in the North China group with the comparison of those of the Central Asian group (23.2 g) and the Dzhungar-Zailij group (8.2 g).5) In the three groups assayed, the rate of freestone-fruited cultivars or forms was remarkably higher than those of clingstone. The frequencies of freestone were different among groups with the highest frequency of 94.6% in the Dzhungar-Zailij group and the lowest frequency of 58.8% in the North China group.6) The highest value of the total soluble solid was measured in the Central Asia group (18.5%).The total soluble solid was greatly affected by environmental factors indicating it was an classical quantitative trait. For cultivars from the North China, the values measured from Shandong (13.1%) and Xinjiang...