Genetic Diversity Of Common Apricot And Siberian Apricot In North China

China is one of primary origins of cultivation apricot centres of the world. Siberianapricot (Prunus sibirica L.) and common apricot (Prunus armeniaca L.) is widely distributedin north China, and played an important role in north China for soil and water conservationand economic development. The bitter kernel of Siberian apricot producted have higheconomic value, but the spring frozen injury, low yield and lack of improved varietiesseriously restricting the development of apricot industry. The wild apricot in the Ili Valleywas one origin center of cultivation apricot, and performed a special role on the origin anddomestication of apricot. Study on the genetic diversity of common apricot and Siberianapricot in Northern China have important significance in breeding, resources protection anddomestication origin analysis.On the basis of germplasm resources investigation, this study mainly using ISSR andSRAP and SSR molecular marker technology to focus on the genetic diversity of21Siberianapricot populations in China,14wild apricot population in the Ili Valley and main cultivationapricot varieties in north China. The genetic relationship and genetic structure of Siberianapricot, wild apricot and cultivation apricot from different ecological groups were analyzed,and discussed the origin and domestication of apricot. The main results were as follows:1. The entire population of Siberian apricot in China has a relatively high level of geneticdiversity, with populations HR and MY showing very high diversity. A low level ofinter-population genetic differentiation and a high level of intra-population geneticdifferentiation was found (ISSR=74.99%, SRAP=76.16%, SSR=83.35%), which issupported by a moderate level of gene flow (ISSR=74.99%, SRAP=76.16%, SSR=83.35%),and largely attributable to the cross-pollination and self-incompatibility reproductive system.In addition, the gene exchange among Siberian apricot natural groups and cultivation groups,and a set of other apricot plants under the overlapping habitats was an important cause of thecurrent population genetic differentiation2. The21populations can be divided into two main groups including including107accessions and147accessions. A Mantel test revealed a significant positive correlationbetween genetic and geographic distance matrices. Geographical differences and geneticexchange is the main cause of the Siberian apricot subgroup differentiated. Construction of a core germplasm repository is the most effective conservation strategy for Siberian apricot, andthe populations HR, MY, and ZY should implement of an in situ conservation.3. The wild apricots in the Ili Valley still maintained a relatively high level of diversity,with populations Tu showing very high diversity. a low level of genetic differentiation amongpopulations, and genetic variation mainly resided within populations (ISSR=82.28%, SRAP=76.42%, SSR=91.51%), which was identified with the moderate gene flow value (ISSR=1.8295，SRAP=1.3680，SSR=2.3735). The relatively high intraspecific genetic diversity andlow inter-population genetic differentiation was largely attributed to long-distance dispersal ofpollen, continuous distribution of populations and the self-incompatible breeding system.4.14wild apricot populations can be divided into predominantly HuoCheng samples insubgroup G1, predominantly GongLiu and YiNing samples in subgroup G2andpredominantly XinYuan samples in subgroup G3. The samples in same subgroup have similargenetic structure, and there is significant correlation between genetic distance and geographicdistance. The resources of wild apricot in Ili valley should be given priority to an in situconservation, and complement with ex situ conservation. Population Tu, Guo and Ye shouldbe prioritized for set up a nature reserve.5. A relatively high level of genetic diversity was maintained at cultivation apricots inNorth China, the Chinese and Central Asian cultivars exhibited a high level of geneticdiversity, and the European and Iran-Caucasian cultivars exhibited a low level of geneticdiversity. The European and North American cultivars have similar genetic backgrounds andare more distantly related to the Chinese and Central Asian cultivars. The Iran-Caucasiancultivars were similar to the Sinkiang cultivars in China. Chinese and Central Asian cultivarshave some partly similar genetic backgrounds. The kernel-using apricot cultivars were similarto Siberia apricot, probably is a natural hybrid or introgression type between P. armeniaca L.and P. sibirica L.6. Central Asian cultivars were the closest with the wild apricot in Ili valley, and mostsimilar in genetic structure. Iran-Transcaucasia ecological group and European ecologicalgroup has some genetic background belong to wild apricot germplasm. Chinese cultivarswere close relatives with wild apricot and Siberia apricot, and have fewer geneticbackgrounds belong to Europe cultivars and plumcot.