Molecular characterization and genetic diversity of Prunus rootstocks

Twenty microsatellite primer pairs, previously developed in peach, were used to characterize and to explore genetic relationships among 44 clones, representing three groups of rootstocks defined as: (1) Peach-based rootstocks (Prunus dulcis × P. persica, P. persica × P. davidiana); (2) Myrobalan-Marianna plums (P. cerasifera and interspecific hybrids having P. cerasifera as a parent); and (3) Slow growing plums (P. insititia, P. domestica, and P. domestica × P. spinosa). Eighteen SSR markers, from the 20 initially used, were able to amplify polymorphic products for the Peach-based rootstocks and 13 common markers gave also polymorphism for the Myrobalan-Marianna and Slow growing plums groups. The Dice coefficient of similarity was calculated between all pairs of accessions and their genetic similarity represented by a principal coordinate analysis. The genetic diversity detected among the 44 clones studied divided them in three groups, which are in agreement with their current taxonomic classification and their morphological characteristics. A set of three microsatellites (BPPCT001, CPPCT022 and UDP98-407) can distinguish between all the clones analyzed. The analysis within groups reveal another two sets of three SSR to distinguish between the clones from the Peach based rootstocks and the Myrobalan-Marianna plums, respectively, and only a single SSR is needed to distinguish within the clones from the Slow growing plums group. These results demonstrate the high potential of the SSR analysis for peach rootstock identification and studies of diversity in Prunus species.     

Evaluation of rootstocks for the Cyprus local lemon variety ‘Lapithkiotiki’

The effect of various rootstocks on yield, yield efficiency, tree size and fruit quality of the local lemon variety ‘Lapithkiotiki’ (Citrus limon (L.) Burm. F.) was studied under Cyprus conditions. Total cumulative yield over 13 years of production was the highest on rough lemon (C. jambhiri Lush) followed by that on Volkameriana (C. volkameriana Ten. & Pasq.), Yuma Ponderosa lemon (C. limon (L.) Burm. F.), sour orange (C. aurantium L.), Citrus macrophylla Wester, Morton citrange (C. sinensis cv. Washington navel × Poncirus trifoliata (L.) Raf.), Yuma citrange, Rangpur lime (C. limonia Obs.), Palestine sweet lime (C. limettioides Tan.), C-32 citrange and Citremon 1449 (C. limon × P. trifoliata), although no statistically significant differences were found between sour orange, the commercial rootstock used in Cyprus, and the other above mentioned rootstocks. Next in order as regards to total cumulative yield was Cleopatra mandarin (C. reticulata Blanko.) followed by Carrizo citrange, with statistically significant differences compared with sour orange. Trees on Citrumelo CPB-4475 (C. paradisi Macf. × P. trifoliata) and C-35 citrange died 3–4 years after grafting. Canopy volume was the lowest for trees on Cleopatra mandarin and Carrizo citrange. Yield efficiency A, expressed as total cumulative yield per trunk cross-sectional area, was the highest on C. macrophylla and lowest on Carrizo citrange. Rootstock significantly affected fruit size and weight, rind thickness, juice content, brix, total acids and brix:acid ratio. The results of the present study reveal that the most promising rootstocks that may replace sour orange for the local lemon variety ‘Lapithkiotiki’ under Cyprus conditions are Volkameriana, Yuma Ponderosa lemon, C. macrophylla and Citremon 1449.     

Influence of different vigour cherry rootstocks on leaves and shoots mineral composition

In this study, the field performance of Adara, CAB 6P, Gisela 5, MaxMa 14, Saint Lucie GF 64 (SL 64), Saint Lucie GF 405 (SL 405), and Tabel-Edabriz rootstocks, grafted with two sweet cherry cultivars (‘Stark Hardy Giant’ and ‘Van’, Prunus avium L.), were compared after 7 years of planting on a calcareous clay-loam soil. The leaf and shoot mineral elements analysed were N, P, K, Ca, Mg, Fe, Mn, Zn, Na and Cu. In the case of both cultivars, tree vigour and cumulative yield were highest on Adara, whereas yield efficiency was greater on Gisela 5. All rootstocks induced low leaf Fe concentrations, although visual chlorosis symptoms were not observed. In both cultivars, significant positive correlations between Mn shoot and leaf concentration were found. Significant positive correlations were also found between yield efficiency and shoot mineral concentration, with the exception of Mg and Zn, which showed no correlation, and K with negative correlation. In ‘Van’ cultivar, Adara rootstock followed by CAP 6P and Gisela 5 showed the most balanced nutritional values. On the other hand, SL 64 had leaf mineral element concentrations below the optimum, probably due to the bad adaptation to heavy soil conditions.     

Performance of ‘Coscia’ pear (Pyrus communis) on nine rootstocks in the north of Israel

The vegetative and reproductive performances of ‘Coscia’ pear (Pyrus communis L.) grown on nine rootstocks [OHF 69, OHF 97, OHF 217, OHF 333, OHF 513 and BP 1 (P. communis), clonal seedling (Davis AxB) of Pyrus betulifolia and quince BA 29 and EMA (Cydonia oblonga)] were compared during a 9-year period. The trial was conducted at the Experimental Station ‘Avnei Eitan’ in northern Israel (elevation 400 m above sea level, a.s.l.), on a well-drained soil with pH 7.1. Trees were planted in December 1998, spaced at 4.0 m × 2.0 m and trained with a central axis. The most vigorous trees were on P. betulifolia seedlings, followed by the four OHF rootstock (69, 97, 333, 513) and BP 1 (with no significant difference between them). All the above rootstocks demonstrated greater vigor than OHF 217 and quince BA 29 or EMA. The highest cumulative yields per tree were harvested from trees on the four OHF rootstocks (69, 97, 333, 513) and P. betulifolia followed by the BP 1. The two quince rootstocks, as well as OHF 217, had the lowest cumulative yield and the lowest yield of large fruit. A positive correlation was found between the vigor of the tree, as affected by the rootstock, and both the total yield and the fruit size. We conclude that in a warm climate, yield efficiency is not the only parameter that should be taken into account, and building a strong tree for a weak cultivar is the first requirement for establishing an orchard.     

Growth and its partitioning in Prunus rootstocks in response to root zone temperature

Rootstocks for stone fruit varieties differentially influence tree physiology and one possible explanation for these differences is that varieties vary in their response to root zone temperature (RZT). To examine the effects of RZT, two trials using actively growing plants of five different Prunus rootstocks with chill requirements between 100 and 1100 h were undertaken. Plants were grown at RZTs of 5, 13 and 19 °C for 6 weeks after which total dry matter accumulation and its partitioning amongst roots, stems and leaves was determined. In general, the magnitude of total dry matter and its component parts positively correlated with RZT and significant differences were found among varieties in the magnitude of total dry matter accumulation. Individual varieties ranked differently at the three RZTs with respect to total dry matter: in general, the same ranking was also seen in the ranking of each growth component. RZT significantly influenced partitioning causing differences in leaf, stem and root mass ratios. These differences were greatest at low RZTs and became less as RZT increased. Several patterns of partitioning were found. Firstly, the low chill varieties (Okinawa and Flordagold) were little affected by RZT with similar partitioning occurring at each RZT. Secondly, the higher chill varieties, Green Leaf Nemaguard (GL), Golden Queen (GQ) and Fay Elberta (FE), reacted more strongly to RZT and were particularly affected by the lowest RZT. For these varieties, the root mass ratio rose and stem mass ratio fell as RZT increased. However, with respect to leaf mass ratio, two different trends were found: the leaf mass ratio for FE and GQ positively correlated with RZT whilst the relationship for GL was negative. These findings suggest that the response to RZT is related to a variety's chill requirement; offer an explanation for differences in performance of rootstock–scion combinations at different locations; and will aid the development of more accurate tree performance models by taking RZT into account.     

Growth,yield and fruit quality of ‘Van’ and ‘Stark Hardy Giant’ sweet cherry cultivars as influenced by grafting on different rootstocks

The influence of Adara, CAB 6P, Gisela 5, MaxMa 14, Saint Lucie GF 64 (SL 64), Saint Lucie GF 405 (SL 405), and Tabel rootstocks onto vegetative growth, yield and fruit quality of ‘Van’ and ‘Stark Hardy Giant’ (SHG) sweet cherry cultivars was studied during 10 years after grafting. The experiment was performed in the Ebro Valley (Zaragoza, Spain), on a heavy and calcareous soil. Significant differences in some of these parameters such as vigour, yield, fruit size, soluble solids content (SSC), titratable acidity (TA), skin colour and fruit firmness were examined among rootstocks. In general, the highest vigour, annual and cumulative yield were induced by Adara rootstock, whereas Gisela 5 induced the lowest when grafted with both cultivars. The highest yield efficiency was induced by Gisela 5 due to its low trunk cross-sectional area (TCSA), together with Adara, CAB 6P and Tabel for ‘SHG’ cultivar. Regarding fruit quality, Adara, CAB 6P and MaxMa 14 showed, in general, the highest fruit weight and the more attractive skin colour for both sweet cherry cultivars. Furthermore, the high yield shown by Adara did not significantly affect its fruit size. Cherries of trees grafted on Adara also showed high firmness, which implies a better resistance to post-harvest damage. CAB 6P showed a tendency to induce higher TA. Despite the higher firmness of fruits on Gisela 5 and its tendency to induce higher SSC and ripening index, the smaller size fruits together with the less attractive skin colour resulted in a non-interesting rootstock in terms of fruit quality for our growing conditions. Interesting correlations were found among quality parameters, such as the positive correlation showed by SSC with fruit weight and TA. The work demonstrates that the scion–rootstock combination influences some important sweet cherry attributes such as vigour, yield, fruit size, acidity, skin colour and firmness.     

Leaf development,net assimilation and leaf nitrogen concentrations of five Prunus rootstocks in response to root temperature

Rootstocks differentially influence tree physiology and these differences may be due to varying responses to root zone temperature (RZT). To determine if this is the case, the physiology, leaf development and nitrogen relationships of five different Prunus rootstocks with chill requirements between 100 and 1100 h were examined during and after growth at RZTs of 5, 12 and 19 °C for 6 weeks. RZT correlated positively with leaf numbers, expansion rates and final leaf area, and significant differences existed among the rootstocks in the magnitude of these parameters at different RZTs. In particular, leaf expansion and area were less affected at low RZT in the low chill varieties. Net assimilation (A_n), leaf nitrogen (N%) and photosynthetic nitrogen use efficiency (A_n/N) also correlated positively with RZT: again, there were differences in the magnitude of these parameters among the rootstocks. No associations amongst A_n, N% or A_n/N could be found for the rootstocks; hence, they all differed in their physiological responses to RZT. Low RZT alone was sufficient to reduce A_n and decreased both leaf area and photosynthetic activity. Leaf expansion was related to N%, as the varieties with the lowest N% also had the lowest expansion rates. Infrared thermography of the cv. Golden Queen showed a negative correlation between RZT and leaf temperature with leaves of plants at the lowest RZT being 2 °C warmer than ambient whilst those at the highest RZT were 2 °C cooler than ambient. These differences were due to transpiration, as transpiration for the variety used decreased with reducing RZT. Transpiration from the other rootstock varieties was lowest at the 5 °C RZT but, depending on variety, at 12 °C was either higher, lower or the same as that from plants whose roots were at 19 °C. Together, the results of this study explain some of the rootstock-induced changes in tree growth and suggest the need to incorporate seasonal changes in RZT into development models for peaches.     

Growth,yield and fruit quality of ‘Marisol’ clementine grown on four rootstocks in Egypt

To evaluate the most appropriate rootstocks for mandarin production in Egypt, vegetative growth, yield and fruit quality of ‘Marisol’ clementine (as newly introduced cultivar in Egypt) grafted on Sour orange (the common rootstock), Cleopatra mandarin, Carrizo citrange and ‘Swingle’ citrumelo were evaluated under the Egyptian conditions during 2004/2005 and 2005/2006 seasons. Trees were grown in a private farm at ‘Wady El-Mullak’ region, Ismailia Governorate (Latitude, 30°36′ N; longitude, 32°14′ E; Altitude, 10 m above sea level).     

Apricot (Prunus armeniaca L.) fruit quality attributes and phytochemicals under different crop load

Three apricot (Prunus armeniaca L.) cultivars were subjected to different degrees of fruit thinning during pit hardening. At harvest fruit quality characteristics were assessed, along with phytochemicals’ concentration, such as carbohydrates, phenolic compounds and organic acids. Antioxidant capacity of the pulp was estimated by diphenyl picryl hydrazyl and ferric reducing antioxidant power assays. Thinning improved fruit weight in two of the three cultivars with a subsequent decrease in fruit firmness, without significant effect on total soluble solid content and titratable acidity. The skin color was not influenced by thinning, but carbohydrate concentration and sweetness index increased. Total phenol concentration increased with thinning, without any similar increase of the major individual phenolic compounds detected (neo-chlorogenic acid, chlorogenic acid, rutin, catechin, epicatechin, ferulic acid, p-coumaric acid and caffeic acid). The antioxidant capacity of the pulp was not influenced by thinning. In overall, thinning enhanced the pomological traits of apricot fruits as well as their phytochemical content.     

Cross-transferable polymorphic SSR loci in Prunus species

This work reports the transferability and polymorphism of previously reported SSRs in 10 Prunus species. The availability of a large number of SSRs in the genus Prunus makes marker choice random, while preventing comparison of results in fingerprinting studies. The availability of SSR markers, polymorphic in a wide sample of Prunus species, would facilitate marker choice, while allowing the comparison of results. In this work, microsatellite markers useful for analyzing 10 different Prunus species (P. persica, P. dulcis, P. armeniaca, P. domestica, P. insititia, P. salicina, P. cerasifera, P. avium, P. cersus and P. mahaleb) were searched through screening SSRs previously reported to be conserved and/or polymorphic in more than one Prunus species. A selected group of 13 SSRs, transferable to the 10 species, was analyzed in terms of their usefulness for analyzing these species. The amplification range, polymorphism and variability detected by these loci are reported. The information provided will be useful for Prunus genetic studies as well as conservation and management of Prunus germplasm resources.     

多胺在果实生长发育中的作用研究进展

多胺是广泛存在于植物体内的具有生物学活性的低分子量脂肪族含氮碱。它在植物的胚胎发育、花和果实的发育等生长发育过程具有重要的调控作用,同时在延缓植物衰老和抗逆境等方面也具有重要意义。近几年的研究表明多胺代谢同植物开花坐果、果实发育甚至果实品质特性密切相关。概述了多胺对果实坐果,膨大与衰老等果实发育生理过程的影响,并对多胺在果实逆境发育中的作用进行了探讨,对多胺在果实发育过程中可能的调控作用机理以及外源多胺在植物开花坐果上的应用潜力进行了讨论,并展望了多胺作用分子机理的研究前景。     

杏制汁适应性评价指标的探讨

以凯特×新世纪、巴旦×凯特杂交组合的F1代群体111个株系及凯特、金太阳、山农凯新1号、山农凯新2号等9个杏品种果实为试材,探讨了制汁用杏相关性状的分布特点及其评价标准。结果表明:(1)同一杏品种(株系)单果质量不同,出汁率亦有较大差异;(2)在本试验测定的性状中,单果质量和维生素C含量的分布频率接近正态分布,出汁率的分布频率呈偏态分布,而可溶性固形物含量的分布频率呈离散分布;(3)根据各个制汁相关性状的分布特点,初步提出了制汁用杏的评价标准,其中一级标准为单果质量≥50g、出汁率≥64.5%、可溶性固形物≥12%、单宁含量<0.91mg/g、维生素C含量≥0.09mg/g、糖酸比为3.33～3.98且可溶性糖含量为7.09%～7.88%,特级标准为:单果质量≥70g、出汁率≥67%、可溶性固形物≥15%、单宁含量<0.91mg/g、维生素C含量≥0.12mg/g、糖酸比为4.15～4.80且可溶性糖含量为8.12%～11.11%。     

Effects of cadmium and copper on pollen germination and fruit set in pea (Pisum sativum L.)

In this work, pea (Pisum sativum) plants exposed to increasing cadmium and copper concentrations were tested for heavy metals accumulation in flowers and for ‘in vivo’ pollen germination. Based on the Cd and Cu accumulation amounts in the flowers, an evaluation of the same metals effects on ‘in vitro’ pollen germination was achieved. Moreover, the effects of both metals on fruits number and weight and on seed set and yield at individual plant level were examined. While cadmium concentrations did not affect ‘in vivo’ pollen germination, only higher copper concentrations rendered a significant reduction. This is in contrast with the clear negative effect on pollen germination in vitro and might be explained by the different dynamic and bioavailability of both metals. A clear effect of Cd and Cu was observed on two important yield components ie, fruit weight and seed set. Although results obtained herein cannot give a clear cut relationship between the effect of Ca and Cu on reproductive development and its consequences on yields, they represent emerging results on the potential consequences of metals contamination on reproductive development in plants.     

热带地区苦瓜品种引进试验

为筛选适合三亚等热带地区种植的优良苦瓜品种,引进8个不同的苦瓜品种进行出苗率、田间生长、始花期、果实性状、果实品质及小区产量等比较。试验结果表明,翠秀、F2259 2个品种出苗率高,前期长势强,产量高,果实大小适中,品质好,果实颜色及条瘤等外观符合当地种植习惯,推荐在三亚地区种植。     

Susceptibility of grapevine rootstocks to Cylindrocarpon liriodendri and C. macrodidymum

The susceptibility of the grapevine rootstocks most commonly used in Spain to Cylindrocarpon liriodendri and C. macrodidymum was evaluated. Rooted cuttings of rootstocks 110-R, 1103-P, 140-R, 161-49C, 196-17C, Fercal and SO4 were inoculated by dipping their roots in conidial suspensions (5 × 10⁵ conidia mL⁻¹) of both pathogens and placed in a greenhouse. One month later, each plant was drench inoculated with 20 mL of the corresponding spore solution to guarantee root infection. After four months of incubation, root disease severity index (RSDI) and dry weights of shoot and root were recorded for each plant. RSDI was the best variable to show the effect of the inoculation with C. liriodendi and C. macrodidymum. According to this, all rootstocks inoculated were affected by the disease in some degree, being the rootstock 110-R the most susceptible to both pathogens.     

Interaction of photoperiod and temperature in the control of growth and dormancy of Prunus species

Growth and dormancy induction of seedlings or micropropagated plants of three Prunus species were studied under controlled environment conditions. All the species tested, P. cerasus L. and P. insititia L. (two cultivars each), and P. avium L. were insensitive to photoperiod at high temperature and maintained continuous growth in both 10 and 24-h photoperiods at 21 °C. At lower temperatures, however, growth was controlled by the interaction of photoperiod and temperature, the species and cultivars varying somewhat in their responses. At 9 °C growth cessation was induced regardless of day-length conditions in the plum rootstocks ‘St. Julien A’ and ‘Weito’ as well as in the sour cherry rootstock ‘Weiroot’, whereas in the sour cherry rootstock ‘Gisela 5’ growth cessation took place in short day (SD) only. At intermediate temperatures (12 and 15 °C) growth cessation occurred in SD only in both sour cherry cultivars. In P. avium seedlings on the other hand, growth cessation in SD was only induced at 9 °C, continuous but reduced growth taking place also in SD at all higher temperatures. Growth rates increased progressively with increasing temperature under long day (LD) conditions in all species, and this was associated with increased internode length in LD compared with SD conditions. Production of new leaves was unaffected by photoperiod at high temperature, but was higher in LD than in SD at lower temperatures. After growth cessation at low temperature the plants developed winter buds and became dormant also in LD conditions. These results demonstrate that, like several species of the Pomoidae subfamily of the Rosaceae, these Prunus species are insensitive to short photoperiods at relatively high temperatures. However, the photoperiodic response of the Prunus species is highly temperature dependent, and the transition temperatures for shifts in the photoperiodic response mode vary among the species.     

Phenological,morphological and functional indicators of genetic variability and their implication in the sexual reproductive system of Olea europaea L. (Oleaceae)

The floral biology of ‘Koroneiki’, ‘Kalamata’ and ‘Mastoidis’ was studied for three consecutive years to elucidate the potential physiological and genetic controls of inflorescence architecture and phenology and to identify potential genotype-distinguishing characters that could be employed for morphological cultivar discrimination. The first open flowers were mainly observed at position I for ‘Koroneiki’ (83%) while they were mainly located at position II for ‘Mastoidis’ (40%) and ‘Kalamata’ (63%). The last open flowers were principally located at the apical position for ‘Koroneiki’ (46%) and ‘Kalamata’ (68%) and at position II for ‘Mastoidis’ (75%). Most of the first open flowers were perfect for ‘Koroneiki’ (89%) and ‘Mastoidis’ (97%) while lower percentages were observed in the last open flowers (67% and 80%, respectively). Higher percentages of perfect flowers were observed in ‘Mastoidis’ compared to ‘Koroneiki’ in both cases. The average flowering shoots of ‘Kalamata’ produced significantly more flowers (1523/m) compared to ‘Koroneiki’ (1139/m) and ‘Mastoidis’ (1044/m). The half of the flowers in ‘Mastoidis’ were located at position I while the 38% was located at position II and only the 12% at the apex. By contrast, approximately the 80% of flowers in ‘Koroneiki’ and ‘Kalamata’ panicles was equally distributed at positions I and II, while the 18% and 19%, respectively, was located at the apex. A marked relationship was also observed between flower position in the panicle and flower gender.     

The S-RNase-based gametophytic self-incompatibility system in Prunus exhibits distinct genetic and molecular features

Most Prunus fruit tree species exhibit a homomorphic gametophytic self-incompatibility (GSI) system, in which specificity of self/nonself-recognition is controlled by products encoded within the S locus. In the pollination event, a self-incompatibility (SI) reaction is triggered when the same “S allele” specificity is expressed in both the pollen and pistil. During the last two decades, much progress has been made in our understanding of the molecular basis of the gametophytic self-incompatibility system in Prunus. Identification of the pistil S and pollen S determinants led to the development of PCR-based S genotyping and marker-assisted selection for self-compatible (SC) individuals. Molecular and genetic analyses of Prunus SC S haplotypes and polyploid sour cherry (Prunus cerasus) reveal the possible existence of a distinct SI/SC recognition mechanism in the S-RNase-based GSI system of Prunus. This review summarizes the current molecular knowledge of the S-RNase-based GSI system in Prunus with reference to data collected for S-RNase-based GSI in other plants and its potential usefulness in SC breeding.     

Flowering and fruiting in ‘Patterson’ apricot (Prunus armeniaca) in response to postharvest application of gibberellic acid

In July or August of 1988 and 1989 which was approximately 2 or 6 weeks, respectively, after fruit harvest, cultivar ‘Patterson’ apricot (Prunus armeniaca) trees were sprayed with a single spray of either 10, 50 or 100 p.p.m. gibberellic acid (gibberellin A₃, GA). GA sprays of 100 p.p.m. applied in early July reduced flower number per centimeter of limb length in the year following treatment. Flower number per centimeter of limb circumference was reduced by sprays of 50 and 100 p.p.m. GA applied in July. Fruit set was not affected by GA sprays. The yield and fruit number of hand thinned trees was equivalent to that found on trees treated with 50 and 100 p.p.m. GA sprays in July. Individual fruit weight (size) was increased by GA sprays of 50 and 100 p.p.m. in July compared to hand thinned trees. Fruit maturity was advanced when yields were reduced by GA sprays. In July, GA sprays of 10 p.p.m. resulted in increased individual fruit weight without reduced total yields per tree compared to non-thinned control trees. Results showed that the use of GA sprays the year before flowering (July) decreased flower numbers, eliminating the need for chemical or hand fruit thinning of ‘Patterson’ apricot.     

不同厚皮甜瓜品种基质栽培研究

为筛选适合东南沿海地区有机基质栽培的厚皮甜瓜品种,引进5个甜瓜品种,研究其基质栽培的生育期、植株长势、净光合速率、产量和品质。结果表明,5个厚皮甜瓜品种在基质栽培条件下生长良好,果实发育期46～63d,净光合速率19.4～23.3μmol/m2·s,667m2产量1396.8～1922.4kg,品质佳,适合在东南沿海地区种植。