桃(Prunus persica(L.) Batsch.)品种核心种质的构建与评价

为构建桃品种核心种质,通过对56份桃（Prunus persica（L.） Batsch.）初级核心种质的形态农艺性状数据（MOR）和SSR等位基因数据的分析,研究了不同聚类取样方法和完全随机取样方法下9种取样比例的遗传多样性指数、保留比例及各频率段等位基因的丢失比例。结果表明：聚类取样的方法优于完全随机取样,并以在80%的取样比例下MOR结合SSR数据聚类取样的效果最好,利用此方案构建的桃品种核心种质共包括45份材料,该核心种质的基因遗传多样性指数最高,保留了初级核心种质100%的形态农艺性状和96.6%的SSR等位基因,在出现频率低于0.05的等位基因中共丢失了2个等位变异,保留了出现频率在0.05-0.10的所有等位基因;利用6个数量性状对所构建的核心种质的代表性检测表明所构建的核心种质很好地代表558份桃原始种质的遗传变异。

Effects of Weak Light on the Ultrastructural Variations of Phloem Tissues in Source Leaves of Three-Year-Old Nectarine Trees(Prunus persica L.var. nectarina Ait.)

Leaves from three_year_old solar greenhouse nectarine trees ( Prunus persica L. var. nectarina Ait. “Zao Hong Yan”) were used as materials in this study. It was the first time that the ultrastructural characteristics of phloem tissues of source leaves were observed and compared in normal and weak light intensities using the transmission electron microscopy. Results showed that the average diameters of companion cells (CC) and sieve elements (SE) of all kinds of veins were bigger in normal than that in weak light intensity, indicating that light could influence the cell development and growth. Dense cytoplasm with abundant mitochondria, endoplasmic reticulums, multivesicular bodies, vesicles and plastids were observed in normal light intensity. On the contrary, CC with small vacuolar structures and few mitochondrias, endoplasmic reticulums were shown in weak light. Misalignment of grana thylakoid margins of nectarine leaves also was seen in weak light. The sieve pores of SEs were obstructed in weak light. Chloroplasts with numerous starch grains and few mitochondrias were noticed in the mesophyll cell (MES) surrounding the bundle sheath in weak light. The storage of starch grains appeared to result from an unbalance between photosynthate production and export of photosynthates. This observation provided a strong support to the point that most leaves export the most of assimilates in the light time. Plasmodesmal densities between SE/CC, CC/PP (phloem parenchyma cell), PP/PP and PP/BSC (bundle_sheath cell) decreased in weak light. Plasmodesmata were observed between CC/SE (NS) (nacreous_walled sieve element), PP/BSC in branch veins in normal light intensity, but not in weak light. Thus apoplasmic pathway may be the main mode of transport of assimilates in weak light, however symplasmic pathway may be the main mode of transport of assimilates in normal light intensity. These results demonstrated that the solar greenhouse nectarine trees could be adapted to the weak light via the ultrastructure variation of phloem tissues of the source leaves.

Study on SSR Markers Linked to Flesh Color around the Stone of Prunus persica(L.) Batsch

[Objective] This study aimed to select SSR molecular markers linked to flesh color around the stone of Prunus persica （L.） Batsch. [Method] P. persica （L.） Batsch varieties Chongyanghong and Yanhong were used as parents to construct F1 orthogonal group. A total of 138 FI individuals were selected as experimental materi- als for construction of color around the stone gene pool （B1） and non-color around the stone gene pool （B2） by using bulked segregant analysis （BSA） method, molec- ular markers linked to the flesh color around the stone of P. persica （L.） Batsch were selected with SSR molecular marker technology. [Result] After selection with 256 pairs of SSR primers, three pairs of molecular markers linked to the gene con- trolling flesh color around the stone of P. persica （L.） Batsch were selected （UDP96- 003, ch04g09 and UDP97-402）. In addition, genetic distances between the three molecular markers and the gene controlling flesh color around the stone of P. persi- ca （L.） Batsch were calculated, which were 16.7, 10.1 and 17.0 cM, respectively. [Conclusion] This study laid the foundation for further selection of co-dominant molecular markers with closer genetic distance.

Molecular Identification and Cultivar Fingerprints of Prunus persica (L.) Batsch Germplasms

[Objective] The aim was to study the molecular identification and cultivar fingerprints of Prunus persica (L.) Batsch germplasms.[Method] Sixty peach genotypes,representing China common local cultivars and European samples were screened by microsatellites (simple sequence repeats,SSRs) and Inter-Simple Sequence Repeat (ISSR) markers.[Result] 26 reproducible bands were amplified by Nine SSR primers,and 24 of which were polymorphic; 236 bands were amplified by 30 ISSR primers,and 113 of which were polymorphic.31 genotypes were discriminated with 1-3 distinct polymorphic bands generated from the primers ISSR and SSR.Seven cultivar-specific ISSR fragments and two SSR unique alleles obtained from this study were available to be converted into Sequence Characterized Amplified Region (SCAR) markers.The genetic similarity coefficient (GS) estimated from these molecular data averaged were 0.939 (ranged from 0.856 to 0.983) for ISSR and 0.646 (ranged from 0.240 to 1.000) for SSR,respectively.The combined grouping association indicated that most local Chinese peach cultivars and exotic accessions were clustered together.This could be related to the mode of introduction and maintenance of the peach cultivars involving limited foundation germplasm,exchange of cultivars between plantations,and periodic development of new recombinant cultivars following sexual reproduction.[Conclusion] The results obtained in this work would help to improve the conservation,molecular identification and management of peach germplasm in breeding.

Effects of nitrogen content on growth and hydraulic characteristics of peach(Prunus persica L.) seedlings under different soil moisture conditions

A pot experiment was conducted to investigate the effects of nitrogen content [Nl （no fertilizer）, N2 （0.15 g.kg-l）, and N3 （0.3 g.kg 1）] on the growth and the hydraulic characteristics of peach seedlings under different soil moisture conditions （Wl, W2 and W3, in which the soil water content was 45% to 55%, 60% to 70%, and 75% to 80% of the field water capacity, respectively） by using a specialized high pressure flow meter with a root chamber and a coupling, which was connected to plant organs. Leaf area and leaf hydraulic conductivity （KL） increased significantly in the seedlings because of increased soil moisture and N content. KL increased with leaf area. A linear correlation was documented between KL and leaf area. KL was higher in the morning and began to decline sharply after 16：00, at which KL declined after an initial increase. Soil moisture and N content enhanced shoot （Ks） and root （Kr） hydraulic conductivities, thereby improving the low soil moisture condition to a large extent. Ks and Kr of the seedlings were reduced by 32% and 27% respectively in N~, and by 14.7% and 9.4%, respectively in N2, and both in Wb compared with the control treatment. N3 had no significant effect on Ks and Kr under similar conditions. Linear negative correlations were observed between Kr and the excised root diameter as well as between Ks and the shoot stem diameter. The shoot-to-root ratio increased with in- crease in N content. The shoot-to-root ratio in N3 was increased by 14.37%, compared with N1 in W1 as well as by 12% and 4.39% in Wz and W3, respectively. Knowledge of the effects of soil moisture and N fertilizer on hydraulic characteristics and growth is important. Our results provide basic guidelines for the implementation of water-saving irrigation and fertilization management of nursery stock.

Novel in silico EST-SSR markers and bioinformatic approaches to detect genetic variation among peach(Prunus persica L.)germplasm

Because there are thousands of peach cultivars,cultivar classification is a critical step before starting a breeding project.Various molecular markers such as simple sequence repeats(SSRs)can be used.In this study,67 polymorphic primers produced 302 bands.Higher values for SI index(1.903)suggested higher genetic variability in the genotype under investigation.Mean values for observed alleles(Na),expected heterozygosity(He),effective alleles(Ne),Nei’s information index(h),and polymorphic information content(PIC)were 4.5,0.83,5.45,0.83,and 0.81,respectively.The dendrogram constructed based on Jaccard’s similarity coefficients outlined four distinct clusters in the entire germplasm.In addition,an analysis of molecular variance(AMOVA)showed that70.68%of the total variation was due to within-population variation,while 29.32%was due to variation among populations.According to this research,all primers were successfully used for the peach accessions.The EST-SSR markers should be useful in peach breeding programs and other research.

不同方法测定桃树抗寒性关系研究

以生产中抗寒性表现较强、中等、较弱的3个桃品种为试材,应用电解质渗透法(EL)和电阻抗图谱法(EIS)研究了不同时期枝条抗寒性和未经冷冻处理枝条EIS参数的变化,并对未经冷冻处理枝条EIS参数、冷冻处理枝条EIS参数测定的半致死温度与EL测定的半致死温度的关系进行了统计分析。结果表明:未经冷冻处理3个桃品种的胞外电阻率(r_e)和胞内电阻率(r_i)均随着外界温度的降低而升高,随着外界温度的升高而降低;弛豫时间(τ)与r_(e)、r_(i)变化趋势相反;通过对4个电阻抗参数与EL测定的半致死温度统计分析得出,EIS(r_(i))是最佳参数,其相关系数为-0.828,通径系数为-7.385,线性回归方程为y=-4.063 9x+4.333 8,R^(2)=0.686。EL和EIS参数法测定3个桃品种的抗寒性与生产上抗寒性强弱表现一致;通过对2种方法统计分析得出,EL与EIS 4个参数法测定抗寒性均呈极显著正相关,其中弛豫时间法相关系数、通径系数和决定系数均最高,因此,弛豫时间是预测冷冻处理桃树枝条抗寒性的适宜参数。

氨基酸水溶肥促进桃苗生长

氨基酸水溶肥是具有营养效果好、无污染等优点的新型绿色肥料。以桃(Prunus persica L.)苗为材料,通过盆栽试验探究施用不同稀释倍数(600、900、1200、1500倍)的氨基酸水溶肥对桃苗生长的影响,以期筛选出效果最佳的喷施浓度。结果表明,施用氨基酸水溶肥增加了桃苗各部位的生物量,其根、茎、叶及地上部分生物量在稀释倍数为1500倍时最高,较对照分别增加了54.83%、51.28%、35.73%和42.12%;施用氨基酸水溶肥提高了桃苗光合色素含量,当稀释倍数为1500倍时,桃苗的光合色素含量最大;施用氨基酸水溶肥提高了桃苗的抗氧化酶活性,但降低了桃苗的可溶性蛋白质含量。因此,稀释1500倍的氨基酸水溶肥为促进桃苗生长的最佳喷施浓度。

丛枝菌根真菌对桃幼苗生长及硒富集的影响

采用盆栽试验,研究了摩西球囊霉(Glomus mosseae)、脆无梗囊霉(Acaulospora delicata)、隐类球囊霉(Paraglomus occultum)和幼套球囊霉(Glomus etunicatum)4种丛枝菌根真菌对桃[Prunus persica(L.)Batsch]幼苗生长及硒富集特性的影响。结果表明,施用脆无梗囊霉增加了桃幼苗的生物量,促进了桃幼苗的生长,使桃幼苗的根系和地上部分生物量分别比未施用增加了11.28%和9.18%,也在一定程度上提高了光合色素含量、过氧化酶活性及过氧化氢酶活性。施用摩西球囊霉、隐类球囊霉和幼套球囊霉3种丛枝菌根真菌降低了桃幼苗的生物量、光合色素含量及抗氧化酶活性或对其没有显著影响。施用脆无梗囊霉也在一定程度上增加了桃幼苗的总硒含量及有机硒含量,其中地上部分的总硒含量和有机硒含量分别较未施用增加了8.01%和9.34%。施用摩西球嚢霉、隐类球囊霉和幼套球囊霉降低了桃幼苗的总硒含量及有机硒含量或对其没有显著影响。

Identification and expression analysis of chlorogenic acid biosynthesis key gene PpHCT in peach

Shikimic acid/quinic acid hydroxy cinnamyl transferase(HCT)is one of the key enzymes in the phenylpropanoid pathway.However,the role of the HCT gene in chlorogenic acid(CGA)biosynthesis in peach fruit remains unclear.For this,we identified the accumulation pattern of CGA in four peach cultivars,cloned and characterized 11 PpHCT gene members,and further analyzed the expression patterns of these PpHCT genes during fruit development.The contents of CGAs in the four peach cultivars all exhibited a trend of increasing and then decreasing during the fruit growth and development.Moreover,the contents of CGAs in the peel and flesh were tissue-specific.Gene structure analysis indicated that the PpHCT genes were highly conserved,containing two exons and one intron.The protein structure analysis demonstrated that the PpHCT proteins contained two conserved motifs(HXXXD,DFGWG)and a transferase domain(PF02458),which belonged to the BAHD acyltransferase family.The cis-acting element analysis suggested that the promoters of PpHCT genes contained many light-related,hormone-related,stress-related,tissue-specific,and circadian-related elements,and they could participate in a variety of biological processes.Phylogenetic analysis showed that the HCT proteins of peach were closely related to the HCT proteins of plum and had a close evolutionary relationship.The qRT-PCR analysis indicated that the expression levels of PpHCT1 and PpHCT2 showed an opposite trend to the accumulation of CGA,whereas the expression levels of PpHCT4,PpHCT5,PpHCT7,PpHCT8,and PpHCT11 demonstrated the same trend as CGA accumulation.It was worth noting that only PpHCT4 and PpHCT5 were highly expressed in the two high-CGA cultivars but showed low levels of expression in the two low-CGA cultivars.Therefore,it was hypothesized that these two genes might be key genes to the synthesis of CGA in peach fruit.Those findings provide a theoretical basis for further study on the biological functions of the HCT gene and help to reveal the molecular mechanism of CGA.

中国桃主要品种资源及其野生近缘种的分子身份证构建

【目的】以国家果树种质郑州葡萄、桃圃保存的237份中国桃地方品种、育成品种及其野生近缘种为试材,进行种质分子身份证构建工作,并对构建方法进行探讨。【方法】采用筛选后的SSR标记对品种进行区分,然后根据引物对不同品种扩增条带分子量的大小进行编码、组合。【结果】从80对引物中筛选出来自桃8条染色体上的16对SSR引物,在供试种质间共检测出等位基因203个,每对引物平均检测到等位基因数为12.7个。根据等位基因既位于地方品种、育成品种,又位于近缘野生种的选择方法,筛选出123对等位基因并赋值后可用于构建种质的分子身份证。【结论】在237份种质中有202份具有的可辨分子身份证编码,继续对不同引物组合对种质的筛选效率进行分析,筛选出8对核心引物使176份种质具有可辨的分子身份证,平均每对引物区分种质达22.1份,即在保证每对引物区分效率较高的基础上,兼顾了总的区分数量。最后,为使区分品种简便化,依据引物的多样性指数先后选择引物组合,达到用最少的引物组合区分不同品种的目的。

桃炭疽病病原鉴定及木醋液防治研究

炭疽病是湖北省桃[Prunus persica(L.)Batsch]产区一种重要的桃树病害。为有效控制该病的危害,试验采用分子生物学技术对湖北省桃园炭疽病的病原进行了分子鉴定,并在实验室内测定了不同浓度的木醋液对炭疽病病原菌的抑菌效果。结果表明,木醋液稀释300倍后对炭疽病病原菌的抑菌效果仍在70%以上;同时田间试验结果表明,木醋液能较好地控制炭疽病危害,在桃园绿色防控上具有广阔的应用前景。

湖北地方红肉桃种质资源收集、评价及利用

红肉桃[Prunus persica(L.)Batsch.]是湖北省的地方特色桃品种,其果实成熟时果肉呈紫红色或鲜红色,风味浓甜,质地脆爽,离核,在桃果肉颜色的更新选育上具有重要作用。从湖北红肉桃的特征特性、资源收集及评价、遗传育种、果肉颜色、红色素开发利用等几个方面进行了综述,并结合作者的研究工作情况对红肉桃育种利用及遗传倾向进行了讨论,分析了湖北红肉桃育种利用中存在的问题及难点。

桃分子连锁图的构建与分析

以‘大久保’与‘兴津油桃’杂交的F2 代 10 9株群体为试材 ,采用AFLP、RAPD、SSR分子标记进行遗传分析。筛选扩增稳定、多态性丰富的 36对AFLP引物、 3对SSR引物、 2对RAPD引物进行群体分离分析 ,获得分离标记 136个 ,卡方检验 2 7个标记偏离孟德尔分离比例。应用Mapmaker分析软件将符合孟德尔遗传分离比例的标记构建了包含 11个连锁群的连锁图谱 ,每个连锁群包含 3～ 2 1个标记 ,平均为 8 73个标记。该图谱覆盖基因组 10 6 1 8cM ,11个连锁群的平均长度为 96 5cM ,标记间平均图距为11 0cM ,与果实毛 /油桃 (G/g)、白 /黄肉 (Y/y)连锁的RAPD标记、非酸 /酸 (D/d)性状连锁的AFLP标记分别定位在第 3、 7、 9连锁群上。

桃园秋冬季生草栽培适宜草种的筛选与评价

南方果园大多集中在丘陵山区地带,土壤较为瘠薄,有机质含量较为低下。试验选择大麦草（Hordeum vulgare L.）、黑麦草（Lolium perenne L.）、毛叶苕子（Vicia villosa Roth.）等3个草种8个品种为研究对象,在桃[Prunus persica（L.）Batsch]园开展间作试验,对几个草种的耐旱性、耐寒性、封行期、观青期等特性进行了调查,测定了高度、盖度、重量等生物学指标。结果表明,冷季型草种大麦草综合性状较好,其抗寒性、抗旱性较强,第二年春季温度回升后生长快,行间封行早,刈割后再生能力较强,耐土壤贫瘠能力最强;并且大麦草生长期与桃园的冬闲期重叠时间最长,可达2~3个月,观青期长,可较好地改变桃园冬季落叶后的季相。因此,确定大麦草作为桃园秋冬季间作的适宜草种,这为湖北省乃至南方地区的桃园生草栽培技术应用提供了依据。

外源赤霉素对桃的成花效应及其作用机制

【目的】揭示赤霉素对桃成花的影响及其可能的作用机制。【方法】在桃花诱导期叶面喷施100mg·L-1GA3,运用解剖学、免疫组织化学及半定量RT-PCR方法,研究‘八月脆’桃花芽分化过程中顶端分生组织赤霉素的原位分布及成花关键基因表达变化。【结果】‘八月脆’桃在7月10日前处于成花诱导期(北京);成花诱导期叶面喷施100mg·L-1GA3显著抑制了桃花诱导及进一步的正常分化,处理后成花率仅为11.67%;顶端分生组织中GA1的分布随花芽分化进程而变化,6月13日-7月25日,花芽中GA1主要分布在芽基部的维管组织中,顶端分生组织中没有检测到信号。GA3处理后,GA1的分布在6月13日-7月3日与正常花芽相同,在7月13日顶端分生组织中检测到了GA1信号,且芽基部维管组织中的GA1信号增强,但至7月25日顶端分生组织和芽基部维管组织中的GA1信号明显减弱;GA3处理后,芽中PpLEAFY及MADS6基因仅在10月10日低量表达,其它时期几乎检测不到。【结论】在北京,‘八月脆’桃成花诱导期在7月10日之前;成花诱导期100mg·L-1GA3处理能显著抑制花诱导和进一步正常分化;赤霉素家族中GA1类在桃成花过程中起抑制作用,并且具有一定的时期性;GA3处理抑制了成花关键基因PpLEAFY及MADS6的正常表达。

桃树子房发育初期蔗糖含量及其相关酶活性的变化

【目的】研究桃树子房发育初期(从现蕾到花萎)蔗糖含量比率及蔗糖代谢相关酶比活力的变化规律。【方法】以‘京玉’和‘久保’两个桃品种为试材,研究桃树子房发育初期子房、韧皮部、叶片与花瓣中蔗糖、淀粉含量及蔗糖代谢关键酶——酸性转化酶(AI)、中性转化酶(NI)、蔗糖磷酸合酶(SPS)和蔗糖合酶(SS)比活力的变化。【结果】两品种各部位中蔗糖积累规律较为相似,韧皮部蔗糖含量比率明显高于其它部位;总可溶性糖在韧皮部中的积累量除盛花期(第10D)低于花瓣中含量,其余时期均较其它部位高,但总体呈下降趋势。子房发育初期子房和叶片中淀粉含量不断升高,韧皮部中则呈下降趋势,花瓣中含量先降低后升高。AI、NI比活力变化对糖的积累作用不明显,SS合成方向、SPS比活力变化与蔗糖的积累量变化一致,SS分解方向比活力变化对两品种桃树糖的积累和转化作用较为突出。【结论】韧皮部是桃树子房发育初期碳水化合物主要的代谢"源",子房发育初期蔗糖代谢相关酶时空性表达受到某些相关因子的调控。

沼液配施化肥对太湖地区水蜜桃品质及土壤氮素累积的影响

将沼液农田回用是有机废弃物资源化与循环利用的重要途径。以7年生蜜露桃树为供试材料,通过连续2年牛粪沼液和水葫芦沼液的果园田间施用试验,研究等氮量条件下不同比例沼液与化肥配施对水蜜桃果实大小、单重、产量和果实品质及土壤矿质氮积累状况的影响。结果表明,1)水葫芦沼液、牛粪沼液和化肥配施可提高水蜜桃的产量与品质,在水葫芦沼液25%配施比例、牛粪沼液50%配施比例下产量及果实的可溶性固形物、糖分含量分别为最高,水葫芦及牛粪沼液中的水分含量是影响桃树产量和品质的关键因子,其适宜用量为200kg/(plant.a);2)各施肥处理土壤NH4+含量随土壤深度增加呈递减趋势;沼液比例过高(75%和100%)会导致土壤硝酸盐在表层和近地下水层的累积,比例低下则硝酸盐累积不明显;习惯施肥(过量施肥)和低比例沼液(相应的高化肥比例)处理硝酸盐主要累积于犁底层之上;3)连续2年在沼液灌溉条件下,25%的水葫芦沼液、50%的牛粪沼液配施比例处理其近地下水层土壤硝酸盐含量均低于15 mg/kg,处于安全可控范围,但在该地区(高地下水水位)进行长期沼液灌溉尚需进一步观测和评价。

桃树冠层相对光照分布与果实产量品质关系的研究

【目的】研究桃树开心形树冠内相对光照强度与果实品质的关系。【方法】以5年生晚蜜为试材,以树干为中心,用竹竿将树冠分成不同层次、方位的50cm×50cm×50cm的立方体,在生长时期测量不同部位相对光照强度,成熟期测量不同部位果实产量和品质。【结果】桃树开心形树冠内相对光照强度随树冠由外到内、由上到下逐渐递减;在第一次叶幕形成和最终叶幕形成的两个不同时期,不同相对光照强度的树冠体积占整个树冠体积的比例差异显著,小于30%的分别占7.71%、47.91%,大于80%的分别占27.7%、3.13%;果实主要集中分布在树冠上、中部1.5～3.0m。回归方程解析得出果实单果重和可溶性固形物含量与相对光照强度均呈显著相关性。【结论】相对光照强度是影响果实单果重和可溶性固形物的主要因素,生产优质桃果实的最低相对光照强度为36.31%,生产中应注意合理进行夏季修剪,调节枝叶数量和空间分布,降低相对光照强度小于36.31%的树冠空间体积。

长枝修剪对桃树生长和果实品质的影响

通过2009-2011年连续3年对桃树[Prunus persica（L.）Batsch.]品种金山早红（P.persica cv.Jinshanzaohong）、极早518（P.persica cv.Jizao 518）、锦绣（P.persica cv.Jinxiu）、1-21（P.persica cv.1-21）进行长枝修剪方式试验,对树体生长、结果枝比例、果实品质等进行了调查与测定,同时比较了差异显著性。结果表明,与传统修剪方式相比,长枝修剪后4个桃树品种的总结果枝量和总坐果数均明显增加,徒长性结果枝和长果枝数量大幅度上升,中果枝和短果枝数量略有减少,但未达到显著差异水平;其中金山早红、极早518、锦绣的整株坐果数可提高13%~43%;长果枝的坐果数显著提高,中果枝与短果枝的坐果数整体增加。在产量上,长枝修剪方式促进了单株产量和单果重的增加;而在果实品质方面,可溶性固形物和可滴定酸含量却略有降低。