Population Genetic Structure in Apricot (Prunus armeniaca L.) Cultivars Revealed by Fluorescent-AFLP Markers in Southern Xinjiang,China

Population-wide genetic structure was studied using fluorescent-AFLP markers on 85 apricot （Prunus armeniaca L.） cultivars collected from Kuche, Kashi, Hetian in the Tarim Basin, southern Xinjiang Uygur Autonomous Region of China. The purpose of this study was to determine the genetic structure and genotypic diversity among the different eco-geographical populations. Based on the results from this study, 8 pairs of fluorescent-AFLP primers showed clear electrophoregram and high polymorphism amongst the 64 pairs of EcoR Ⅰ/Mse Ⅰ （Mse Ⅰ - a FAM fluorescent marked primer） primers screened. There was a significant polymorphic difference for the same primer pair in different populations and for the same population with different primer pairs. The percentage of polymorphic loci （P） at species level was higher than Kuche, Hetian, Kashi population levels, respectively. The Nei＇s gene diversity index （H） and Shannon＇s information index （I） at species level were higher than those of Kuche, Hetian, and Kashi at population level, respectively. H and I of Kuche population were the highest amongst the three populations. Apricot population genetic diversity was found mainly within the population, Genetic differentiation coefficient between populations （GST） was 0.0882. Gene flow Nm between the populations was 5.1689. Population genetic identity was between 0.9772-0.9811 and genetic distance was between 0.0191-0.0232. These results further indicated that the similarity between populations was higher and the genetic distance between populations was smaller. The UPGMA cluster analysis indicates that the geographical populations at Kuche, Kashi, Hetian were relatively independent Mendelian populations. Concurrently, there was also partial gene exchange between the populations. All the evidences indicated that the genetic diversity in Kuche population was the highest, suggesting that it could be a transition population from wild apricot to cultivated apricot. There were abundant genetic diversities in apricot cultivar populations in southern Xinjiang, China, which provide promising germplasm for further breeding and theoretical basis for biodiversity conservation and utilization for apricot population in this area.

Seed germination and seedling development of Prunus armeniaca under different burial depths in soil

A semi-greenhouse study was conducted to understand the effects of soil burial depth on seed germination and seedling development. The seeds of wild apricot （Prunus armeniaca） were buried at the soil depths of 0-cm, 4-cm, 8-cm, and 12-cm, respectively, to simulate the seed hoarding behavior of rodents in the field. The results revealed that the rates of seed germination and established seedlings from buried seeds were both the highest in 4-cm burial depth group, and then decreased with increasing soil depth. The number of rotten seeds increased in deeper burial depth. It is unfavourable for seed germination at 0-cm burial depth （i.e., seeds were laid on soil surface）. There was insignificant effect of burial depth on growth of established seedlings. The results from this study indicated that proper burial depth in soil would be helpful for the seed germination and seedling growth. The seedlings derived from buried seeds at shallower depth （4 cm） in this research have advantage in their early development.

Identification of Hybrids between Prunus salicina and Prunus armeniaca by RAPD and SSR

[ Objective] This study aimed to investigate the genetic variation between hybrids and their parents, and to find a rapid identification method. [ Method ] The progenies between Prunus armeniaca （ apricot ） Katy and Prunus salicina （plum） Moriteni were analyzed by means of RAPD and SSR molecular markers. [ Result] We found the differences in the electrophoresis bands between progenies and their parents, indicating that hybrid seedlings obtained in this study were real. [ Conclusion ] The combination of the above methods is effective and fast to identify the hybrids, and can shorten the breeding period.

Study on the Daily Change of Photosynthetic Rate for Prunus domestica × armeniacain Different Seasons

[Objective] The aim of this study was to explore the daily change of photosyntheticratefor Prunus domestica ×armeniacain different growing seasons. The study can provide theoretical basis for arid area high yield and quality cultivation.[Method] The photosynthetic physiological properties of leaves of different types of Prunus domestica × armeniaca were measured by the Li-6400 portable photosynthesis system indifferent seasons. By this method could analysis of photosyntheticcharacteristicsfor different types of Prunus domestica×armeniaca in different seasons.[Result] Daily change of photosyntheticrate（Pn） for Prunus domestica×armeniaca in differentseasons showed a ＂double-peak＂ curve. The peak values were at 10：00 and16：00. The Pn of ‘Fengweihuanghou＇, ‘Konglongdan＇, ‘Weihou＇, ‘Weiwang＇ and‘Weidi＇ reached the maximum in July, theywere 13.75, 14.76, 12.96, 13.3, and 11.9μmol/（m^2·s）, respectively. The Pn of Prunus domestica×armeniaca reached minimumin August, they were 9.78, 10.71, 12.02, 10.43 μmol/（m^2·s）. The Pn overall average of ‘Konglongdan＇ was highest,it reached 12.65 μmol/（m^2·s）.The Pn overall average of ‘Weiwang＇ was lowest, it reached 11.31μmol/（m^2·s）. There were extremely significant positive correlation between the Pn and Gs（P0.01）. [Conclusion] Daily change of photosyntheticrate for Prunus domestica ×armeniaca in differentseasons showed a ＂double-peak＂ curve, showing significant phenomenon of ＂midday depression＂.The photosynthesis intensity of Prunus domestica ×armeniaca was strongest in July, and the photosynthesis intensity was weakest in August. ‘Konglongdan＇showed the strongest photosynthesis capacity, ‘Weihou＇ and ‘Weiwang＇, followed.There were highest correlation between the Pn and stoma conductance（Gs）.

Study on the Flowering Biological Characteristics of Prunus domestica × armeniaca

[Objective] The aims of this study were to understand the flowering biological characteristics of Prunus domestica ×armeniaca and analyze its differences with other apricot varieties and plum varieties. [Method] Taking three varieties of Prunus domestica ×armeniaca as the research object, the phenophase of blooming,morphology characteristics of floral organs and development characteristics of floral organs were observed, pollen amount, pollen viability and stigma receptivity were measured. [Result] The results showed that three varieties of Prunus domestica×armeniaca were in blossom in early April, the florescence were relatively late for 8-12 d comparing with the varieties of apricot, the florescence were relatively similar to the P. domestica L. Morphology characteristics of floral organs of three varieties of Prunus domestica×armeniaca had few differences, were relatively similar to two varieties of plum, and they all had high percent of middle-style and long-style flower.The pollen amount of three varieties of Prunus domestica ×armeniaca had a little differences comparing with two varieties of plum, but were lower than three varieties of apricot. There were some differences in pollen viability, the germination percentage of pollen of ‘Konglongdan＇ was relatively high, was 51.6%; The pollen amount of ‘Fengweihuanghou＇ was relatively high, was 880.8 per anther; ‘Weidi＇ had fewer pollen amount, and the pollen viability was just 2.1%; Three varieties of Prunus domestica ×armeniaca all had strong stigma receptivity on the bloom day, and the stigma receptivity continued exist until the day that 5 days after blooming. [Conclusion] The florescence of three varieties of Prunus domestica ×armeniaca were relatively concentrated, and the rate of pistil abortion was lowest, the variation intensity of stigma receptivity and sustainable time of three varieties of Prunus domestica×armeniaca almost had a little differences comparing with a variety of plum, but slightly more than three varieties of apricot.

Comparison of Photosynthetic Characteristics among Different Prunus domestica × armeniaca Cultivars

[Objective] This study aimed to investigate the photosynthetic characteristics of different Prunus domestica × armeniaca cultivars, thereby providing some theoretical basis for high-yield and high-quality cultivation of P. domestica × armeniaca. [Method] Total three cultivars（Konglongdan, Fengwei Huanghou and Weiwang）of P. domestica × armeniaca were selected as the test materials, and their leafphotosynthetic parameters were measured with Li-6400 portable photosynthesis system.The light response curve and CO_2 response curve were drawn. [Result] There were significant differences in photosynthetic rate among the three cultivars of P. domestica × armeniaca（P〈0.01）. The photosynthetic rate of Konglongdan [14.76 μmol/（m^2·s）]was highest. When the light intensity reached 1 800 μmol/（m^2·s）, the maximum net photosynthetic rate of Konglongdan was up to 27.27 μmol/（m^2·s）, and its apparent quantum yield reached the peak. Konglongdan showed lower light compensation point [43.069 μmol/（m^2·s）] and higher light saturation point [697.684 μmol/（m^2·s）].Weiwang showed the lowest CO2 compensation point（68.264 μmol/mol） and the highest carboxylic efficiency [0.072 μmol/（m^2·s）]. [Conclusion] Konglongdan showed the highest light utilization efficiency and photosynthetic potential, and it had the strongest utilization ability for weak light. The utilization ability of Weiwang for lowconcentration CO2 was strongest, followed by those of Fengwei Huanghou and Konglongdan.

杏NBS基因家族鉴定及其对果实抗病性的影响

【目的】探讨杏果实发育过程中NBS基因家族的表达规律,为果实抗病机制研究提供理论指导。【方法】运用生物信息学方法进行NBS基因家族鉴定与转录组分析。【结果】在串枝红杏基因组中共鉴定到155个NBS抗病基因,主要分为CNL型(126个)和NL型(29个),45%的基因主要分布在1号与2号染色体上,顺式作用元件较多且大多属于激素调控元件,发现1个杏特有的基序CNBS-1。NBS基因在不同品种发育过程中的基因表达模式类似,但在表达量上存在较大差异。8个NBS基因在串枝红果实发育的4个时期表达量均显著高于同时期大白杏,表明这些基因可能与串枝红果实抗病性高于大白杏有关。【结论】获得8个NBS差异表达基因,主要与抗致病疫霉病原与霜霉病原有关,为杏果实抗病育种提供理论指导。

不同浓度水杨酸处理对杏李恐龙蛋采后贮藏品质的影响

以杏李恐龙蛋(Prunus domestica×armeniaca konglongdan)为试验材料,研究了不同浓度水杨酸处理对其采后生理和贮藏品质的影响。结果表明,与对照相比,不同浓度水杨酸处理均能抑制恐龙蛋果实的乙烯释放速率,降低果实的呼吸强度,保持果实较高的硬度,降低果实失重率和腐烂率,此外,水杨酸处理可维持果实较高的可溶性固形物含量,同时显著提高果实的抗氧化酶活性。水杨酸处理能增强采后恐龙蛋果实的耐贮性和维持较高的贮藏品质,尤其以0.1 mmol/L水杨酸处理的保鲜效果最佳,可作为提高恐龙蛋果实采后耐贮性、延长其保鲜期的适宜处理条件。