Molecular cloning,identification,and chromosomal localization of two MADS box genes in peach(Prunus persica)

MADS box proteins play an important role in floral development. To find genes involved in the floral transition of Prunus species, cDNAs for two MADS box genes, PpMADS1 and PpMADSIO, were cloned using degenerate primers and 5＇- and T-RACE based on the sequence database of P. persiea and P. duleis. The full length of PpMADS1 cDNA is 1,071 bp containing an open reading frame （ORF） of 717 bp and coding for a polypeptide of 238 amino acid residues. The full length of PpMADSIO cDNA is 937 bp containing an ORF of 633 bp and coding for a polypeptide of 210 amino acid residues. Sequence comparison revealed that PpMADS1 and PpMADSIO were highly homologous to genes API and PI in Arabidopsis, respectively. Phylogenetic analysis indicated that PpMADS1 belongs to the euAP1 clade of class A, and PpMADSIO is a member of GLO/PI clade of class B. RT-PCR analysis showed that PpMADS1 was expressed in sepal, petal, carpel, and fruit, which was slightly different from the expression pattern ofAPl; PpMADS10 was expressed in petal and stamen, which shared the same expression pattern as PI. Using selective mapping strategy, PpMADSI was assigned onto the Binl：50 on the G1 linkage group between the markers MCO44 and TSA2, and PpMADSIO onto the Bin1：73 on the same linkage group between the markers Lap- 1 and FGA8. Our results provided the basis for further dissection of the two MADS box gene function.

Accumulated chilling hours during endodormancy impact blooming and fruit shape development in peach(Prunus persica L.)

Winter chill is essential for the growth and development of deciduous species. To understand the relationship between accumulated chilling hours during endodormancy and blooming and fruit shape development, we controlled chilling hours and investigated their effects on blooming date and fruit shape of peaches. The results showed that the number of days to full bloom date and the heat requirement for blooming were negatively correlated with accumulated chilling hours. Accumulated chilling hours were significantly negatively correlated with fruit shape index and fruit tip lengths, suggesting that the number of chilling hours affect the fruit shape development. Fewer accumulated chilling hours may be the major reason for longer fruit shape and protruding fruit tips. In conclusion, our results indicate specifically that decreased winter chilling hours can delay the bloom date and may lead to aberrant fruit shape development in peaches. Our study provides preliminary insights into the response of temperate fruit species to global climate change.

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.

Characterization and Expression of Ammonium Transporter in Peach (Prunus persica) and Regulation Analysis in Response to External Ammonium Supply

As the preferred nitrogen(N)source,ammonium(NH_(4)^(+))contributes to plant growth and development and fruit quality.In plants,NH 4+uptake is facilitated by a family of NH_(4)^(+) transporters(AMT).However,the molecular mechanisms and functional characteristics of the AMT genes in peach have not been mentioned yet.In this present study,excess NH_(4)^(+) stress severely hindered shoot growth and root elongation,accompanied with reduced mineral accumulation,decreased leaf chlorophyll concentration,and stunned photosynthetic performance.In addition,we identified 14 putative AMT genes in peach(PpeAMT).Expression analysis showed that PpeAMT genes were differently expressed in peach leaves,stems and roots,and were distinctly regulated by external NH_(4)^(+) supplies.Putative cis-elements involved in abiotic stress adaption,Ca^(2+) response,light and circadian rhythms regulation,and seed development were observed in the promoters of the PpeAMT family genes.Phosphorylation analysis of residues within the C-terminal of PpeAMT proteins revealed many conserved phosphorylation residues in both the AMT1 and AMT2 subfamily members,which could potentially play roles in controlling the NH 4+transport activities.This study provides gene resources to study the biological function of AMT proteins in peach,and reveals molecular basis for NH_(4)^(+) uptake and N nutrition mechanisms of fruit trees.

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.

Simple Sequence Repeat Analysis of Genetic Diversity in Primary Core Collection of Peach(Prunus persica)

In this study, the genetic diversity of 51 cultivars in the primary core collection of peach （Prunus persica （L.） Batsch） was evaluated by using simple sequence repeats （SSRs）. The phylogenetic relationships and the evolutionary history among different cultivars were determined on the basis of SSR data. Twenty-two polymorphic SSR primer pairs were selected, and a total of 111 alleles were identified in the 51 cultivars, with an average of 5 alleles per locus. According to traditional Chinese classification of peach cultivars, the 51 cultivars in the peach primary core collection belong to six variety groups. The SSR analysis revealed that the levels of the genetic diversity within each variety group were ranked as Sweet peach 〉 Crisp peach 〉 Flat peach 〉 Nectarine 〉 Honey Peach 〉 Yellow fleshed peach. The genetic diversity among the Chinese cultivars was higher than that among the introduced cultivars. Cluster analysis by the unweighted pair group method with arithmetic averaging （UPGMA） placed the 51 cultivars into five linkage clusters. Cultivar members from the same variety group were distributed in different UPGMA clusters and some members from different variety groups were placed under the same cluster. Different variety groups could not be differentiated in accordance with SSR markers. The SSR analysis revealed rich genetic diversity in the peach primary core collection, representative of genetic resources of peach.

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.

The Potential Efficacy of Glycyrrhizic Acid and Its Nanostructure Against Brown Rot of Peach fruits

Production of peaches(Prunus persica(L.)Batsch)for both local market and export is increasing each year in Egypt.Brown rot disease,caused by Monilinia laxa and Monilinia fructigena,is considered one of the most important postharvest rots affecting peaches in Egypt and economic losses are increasing.Antifungal activity of glycyrrhizic acid nanoparticles(GA-NPs)and glycyrrhizic acid(GA)at 0.2 and 0.4 mmol/L was investigated as a control for both these brown rot pathogens on peach fruits in both in vitro and in vivo studies.In the in vitro studies,GA-NPs were the most effective as shown by the ability to decrease linear growth of both brown rot pathogens in potato dextrose agar(PDA)amended with 0.4 mmol/L GA-NPs.Micrographs of M.fructigena exposed to 0.4 mmol/LGA showed mycelial deformations,nodule formation,detachment of the cell wall,shrinkage and inhomogeneous cytoplasmic materials with large vacuoles.Mycelium of M.laxa exposed to 0.4 mmol/LGA-NPs resulted in thinner and distorted hyphae,nodule formation,cell wall thinning,and swellings.The GANPs and GA treatments improved fruit quality by maintaining firmness and total soluble solids(TSS).GA-NPs were more effective in decreasing decay incidence than their bulk material.The 0.4 mmol/L GA-NPs completely inhibited the disease on naturally infected peach fruits for both seasons of 2018 and 2019.Furthermore,0.4 mmol/L GA-NPs reduced the disease incidence in inoculated fruits by 95(M.laxa)and 88%(M.fructigena)in 2018 season and 96(M.laxa)and 85%(M.fructigena)in 2019 season.In conclusion,GA-NPs could enhance the resistance of peaches against brown rot caused by M.laxa and M.fructigena.

Relationships Between the Distribution of Relative Canopy Light Intensity and the Peach Yield and Quality

The aim of the present experiment was to study the relationship between the distribution of relative light intensity in canopy and yield and quality of Wanmi peach. The optimum relative canopy light intensity was judged to be 36.3% for high quality peaches, when canopy volumes of Wanmi peach trees with a relative light intensity 〈 30% accounted for 7.7 and 47.9% of the total canopy volume in June and September, respectively. The canopy volume with a relative light intensity 〉 80% was 27.7 and 3.1% of the total canopy volume in June and September, respectively. Peach canopies were divided into 0.5 m × 0.5 m × 0.5 m cubes, with the relative light intensity being measured at different positions of the canopy during the growing season. Yield and fruit quality were also measured at these positions at harvest. The results showed that the relative light intensity decreased gradually from outside to inside and from top to bottom of the tree canopy. Fruit were mainly distributed in the upper and middle portions of the canopy, 1.5-3.0 m above ground. Regression results showed that single fruit weight and soluble solid content were positively related to relative light intensity.

Effects of Temperature and Several Chemicals on Metabolic Changes During Dormancy Release in NJ72 Nectarine

Poor, delayed and ununiform budbreak is a major problem for peaches in greenhouse. To clarify the mechanism of breaking bud dormancy in nectarines, the effect of temperature and three dormancy-breaking agents on metabolic changes during dormancy release in two-year old NJ72 nectarine (Prunus persica L. Batch) was investigated. The result showed temperature and chemicals affected the budbreak and the metabolism of NJ72 nectarine during dormancy. Endogeneous peroxide content in buds increased soon after low temperature treatment. Meanwhile, catalase activity was also shown to increase significantly at low temperature treatment, coincided with increase of the activity of peroxidase and superoxide dismutase. The rate of respiration in flower buds increased at low temperature during dormancy. The rate of the pentose phosphate pathway increased, while the rate of the Embden-Meyerhof pathway decreased and the rate of tricarboxlic acid cycle changed little. Glucose 6-phosphate dehydrogenase activity increased at low temperature during dormancy. At the same time we found an accumulation of peroxide after treatment with dormancy-breaking chemicals. In flower buds treated with dormancy-breaking agents, thiourea, KNO3 and NH4NO3, catalase activity was inhibited soon after treatment, whereas peroxidase activity increased, and the changes of superoxide dismutase remained little. In this study, it was found that the rates of respiration in flower buds increased by chemicals sprays during dormancy. The activity of glucose 6-phosphate dehydrogenase, the key enzyme in the pentose phosphate pathway (PPP), increased by spraying with dormancy-breaking agents, concomitantly with the activation of the pentose phosphate pathway.

Effects of Nitric Oxide and Exogenous Ethylene Treatments on Ethylene Biosynthesis in Feicheng Peach

The effects of nitric oxide （NO） and exogenous ethylene on ethylene biosynthesis in harvested Feicheng peaches were studied. The antagonistic actions between NO and exogenous ethylene was also investigated. The Feicheng peaches were fumigated with 10μL L^-1 NO, 1 000 μL L^-1 ethylene, or 10 μL L^-1 NO plus 1 000 μL L^-1 ethylene for 3 h. The results suggested that application of exogenous ethylene promoted the biosynthesis of endogenous ethylene in peach fruit. The treatment with NO remarkably inhibited the biosynthesis of ethylene by significantly reducing the activities of ACC synthase （ACS） and ACC oxidase （ACO）. Ethylene biosynthesis in the fruits treated with both NO and exogenous ethylene was lower than that in fruits treated with exogenous ethylene alone but higher than that in fruits treated with NO alone, suggesting that there were antagonistic actions between NO and exogenous ethylene. NO could inhibit the biosynthesis of ethylene and the catalysis of exogenous ethylene during ethylene biosynthesis in peach fruits.

Effect and Functional Mechanism of the Action of Exogenous Gibberellin on Flowering of Peach

This study was conducted to assess the effect of gibberellin and its possible mechanism of action on peach flower formation. At flower induction, 100 mg L^-1 of gibberellic acid 3 （GA3） was sprayed on the leaves of peach [Prunus persica （L.） Batsch.] cv. Bayuecui. Using anatomy, immunohistochemistry, and semi-quantitation, the in situ distribution of GAs and the expression of the key genes involved in peach flower formation in the apical meristem were studied during flowering differentiation. The results showed that induction of flowering in the Bayuecui peach occurred prior to 10 July in Beijing, China. Flower induction and further differentiation of the peach flower organs were significantly inhibited by leaf-spraying of GA3 at a concentration of 100 mg L^-1 during the induction stage. The flowering rate was only 11.67% after treatment. The distribution of GA1 in the apical meristem varied during the process of flower bud differentiation. From 13 June to 25 July, the GA1 signal from control plants was detected mainly in the vascular bundles at the base of the flower buds. No GA1 signal was detected in the apical meristem. After treatment with GA3, the distribution was similar to that of the control from 13 June to 3 July. On 13 July, a GA1 signal was detected in the apical meristem accompanied by an increase in the GA1 signal in the vascular bundles at the base of the flower buds. The GA1 signal weakened significantly in both the vascular bundles and the apical meristem on 25 July. The expression of the genes PpLEAFY and MADS6 in flower buds could be detected only on 10 October in the GA3-treated plants. The critical period for flower induction of Bayuecui peach in Beijing was in early July, during which time, leaf-spraying with 100 mg L-1 GA3 could effectively inhibit flower induction and further differentiation of the flower buds. GA1 in the gibberellin family was the suppressor for flower induction in peach. Its action was affected by the stage of flower bud differentiation. Expression of the key genes PpLEAFY and MADS6 involved in flower formation was inhibited by GA3 treatment.

7个桃品种在河西沙地栽培抗寒性比较

以河西沙地栽培的7个桃(Prunus persica)品种为试材,采用电导法测定低温处理对桃1年生枝条细胞伤害率,拟合Logistic方程计算低温半致死温度,与田间冻害指数调查比对,明确7个桃品种抗寒力的大小。结果表明:1)7个桃品种细胞伤害率随处理温度的降低不断上升,呈“S”型增长,但不同品种间上升速率不同。2)不同品种低温半致死温度LT50为-29.2~-24.9℃,由低到高依次为:‘夏甜’‘中华寿桃’‘中油金铭’‘春蜜’‘雨花露’‘瑞光27号’和‘中桃5号’。3)不同桃品种田间冻害指数为15.0%~45.0%,由低到高依次为:‘夏甜’‘中华寿桃’‘中油金铭’‘春蜜’‘雨花露’‘中桃5号’和‘瑞光27号’,冻害指数与低温半致死温度呈正相关,相关系数0.923。研究认为:7个桃品种在河西沙地栽培抗寒性强弱为:‘夏甜’‘中华寿桃’‘中油金铭’‘春蜜’‘雨花露’‘瑞光27号’‘中桃5号’。

桃基因密码子使用模式及其偏好性分析

为深入研究桃密码子使用特征,本研究基于桃(Prunus persica)基因组26873个注释基因编码序列的GC含量特征、有效密码子数(ENC)和同义密码子相对使用频率(RSCU)等参数的计算,统计分析了桃基因组密码子的偏好性及其密码子使用模式。分析结果表明桃密码子使用具有偏好性,61个密码子中存在4个密码子TCA,ACA,GCA,GAA为桃最优密码子,它们均以A结尾。进一步统计桃与其它9种近缘蔷薇科植物的密码子使用频率,发现近缘种属的密码子使用规律具有一定相似性。研究同时发现桃基因组tRNA基因拷贝数与氨基酸及特定密码子的出现频率呈正相关。这些结果揭示了桃基因组密码子的使用模式,为相关密码子使用机制研究及基因工程改良提供了重要的参考。

皮球桃黄肉芽变的ISSR和SRAP分子标记鉴定

本研究采用ISSR和SRAP两种分子标记方法对皮球桃(Prunus persica)及其黄肉芽变进行分子鉴定,从DNA水平揭示两者的遗传差异。结果显示,39条ISSR引物共扩增出176个位点,多态性比率为9.7%,遗传系数为0.95;224对SRAP引物组合共扩增出444个位点,多态性比率为5.0%,遗传系数为0.97,表明两者的亲缘关系非常相近,遗传背景基本一致。经过反复筛选与多轮PCR鉴定,引物UBC827、UBC848、组合Me4-Em1在皮球桃与黄肉突变体的基因组中稳定扩增出差异条带,说明两者在DNA分子水平确实存在较小程度的差异,遗传物质发生了微小的变异,证明该黄肉突变体桃的确为皮球桃的芽变。

桃TCP转录因子家族的鉴定与分析

TCP基因家族是含有bHLH基序的植物特有转录因子,广泛参与植物的多种生物过程。为了解桃(Prunus persica)中TCP家族的成员和特征,本研究基于其全基因组组装及注释数据,首次在桃基因组中对TCP基因进行了系统鉴定,并进行了染色体定位、蛋白特征、基因结构、进化关系、启动子区域顺式元件分析。结果显示:桃基因组中共有20个TCP家族成员,在7条染色体上均有分布,其推导蛋白的长度、分子量和等电点差异较大。大部分TCP基因不含有内含子,基因结构较为简单。桃TCP基因家族含有植物TCP家族的所有类别,每一类别均含有保守的且能明显区别于其他类别的特征。TCP基因家族的启动子区域含大量光应答、激素响应等顺式作用元件,与该基因家族功能的多样性一致。本研究初步探索了桃基因组中TCP基因家族的特征,为后期该基因家族在桃中的功能验证提供了理论支撑。

Different Expression Analysis in Fruit Softening and Ethylene Biosynthetic Pathways in Peaches of Different Flesh Textures

The aim of our study was to assess differences in the expression of genes involved in fruit softening and ethylene biosynthetic pathways under different temperature storage conditions. Different peach cultivars of ‘Xiacui' and ‘Yumyeong', which are stonyhard, ‘Yinhualu', which is softmelting, ‘Hujing Milu', which is hard-melting, and ‘Baby Gold 6', which is non-melting at 80% ripening, were collected as test materials. The results showed that only slight ethylene production was detected after harvesting of ‘Yumyeong' and ‘Xiacui' under either a room temperature(25 °C) or low temperature(4 °C). The fruit firmness of stonyhard cultivars was retained at a high level under room temperature over time, whereas a low temperature induced ‘Yumyeong' fruit to soften. Quantitative real-time PCR results indicated that the PpACS1 gene was highly expressed in soft-melting, hard-melting and non-melting cultivars; however, expression was extremely low in stonyhard peaches. PpACS2 or PpACS3, however,was not detected in all five cultivars. Interestingly, cold treatment significantly decreased firmness along with endo-PG expression obviously upregulated in ‘Yumyeong', but not in ‘Xiacui' peaches. In conclusion, this study revealed that fruit softening of peaches with different flesh textures was closely related to ethylene biosynthesis during the storage period, which was controlled via regulating relevant gene expression levels under different storage temperatures.

YIELD AND FRUIT QUALITY OF ALMOND,PEACH AND PLUM UNDER REGULATED DEFICIT IRRIGATION

The effects of regulated deficit irrigation(RDI)on the performance of almond cv.Tuono,peach cv.JH-Hall and plum cv.Stanley were assessed on the Saiss Plain(NW,Morocco)over three consecutive growing seasons(2011–2013).Irrigation treatments consisted of a control,irrigation applied to fully satisfy crop water requirements(100%ETC),and two RDI treatments,irrigation applied to 75%ETC(RDI-75)and 50%ETC(RDI-50).These three treatments were applied during fruitgrowth slowdown periods corresponding to Stages II and III in almond and Stage II in peach and plum.Yield and fruit quality traits were determined.The effect of RDI differed between species.Yield and fruit size were reduced significantly only in peach under RDI-50.Fruit quality improved in this species in the first year of the experiment,with an increase of sugar/acid ratio and polyphenol content.Plum quality also improved but the effects were significant only in the second and third years.Similar results were recorded in almond kernel,but their epidermal grooves were deeper under RDI-50,and this may have affected their commercial value.It is concluded that water can be saved during the fruitgrowth slowdown period by up to 25%in peach and 50%in almond and plum with improvements in fruit quality without affecting total yield.