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1.
The citriculture in Brazil, as well as in other important regions in the world, is based on very few mandarin cultivars. This fact leads to a short harvest period and higher prices for off-season fruit. The ‘Okitsu’ Satsuma (Citrus unshiu Marc.) is among the earliest ripening mandarin cultivars, and it is considered to be tolerant to citrus canker (Xanthomonas citri subsp. citri Schaad et al.) and to citrus variegated chlorosis (Xylella fastidiosa Wells et al.). Despite having regular fruit quality under hot climate conditions, the early fruit maturation and absence of seeds of ‘Okitsu’ fruits are well suited for the local market in the summer (December through March), when the availability of citrus fruits for fresh consumption is limited. Yet, only a few studies have been conducted in Brazil on rootstocks for ‘Okitsu’. Consequently, a field trial was carried out in Bebedouro, São Paulo State, to evaluate the horticultural performance of ‘Okitsu’ Satsuma mandarin budded onto 12 rootstocks: the citrandarin ‘Changsha’ mandarin (Citrus reticulata Blanco) × Poncirus trifoliata ‘English Small’; the hybrid Rangpur lime (Citrus limonia Osbeck) × ‘Swingle’ citrumelo (P. trifoliata (L.) Raf. × Citrus paradisi Macfad.); the trifoliates (P. trifoliata (L.) Raf.) ‘Rubidoux’, ‘FCAV’ and ‘Flying Dragon’ (P. trifoliata var. monstrosa); the mandarins ‘Sun Chu Sha Kat’ (C. reticulata Blanco) and ‘Sunki’ (Citrus sunki (Hayata) Hort. ex. Tanaka); the Rangpur limes (C. limonia Osbeck) ‘Cravo Limeira’ and ‘Cravo FCAV’; ‘Carrizo’ citrange (Citrus sinensis × P. trifoliata), ‘Swingle’ citrumelo (P. trifoliata × C. paradisi), and ‘Orlando’ tangelo (C. paradisi × Citrus tangerina cv. ‘Dancy’). The experimental grove was planted in 2001, using a 6 m × 3 m spacing, in a randomized block design. No supplementary irrigation was applied. Fruit yield, canopy volume, and fruit quality were assessed for each rootstock. A cluster multivariate analysis identified three different rootstock pairs with similar effects on plant growth, yield and fruit quality of ‘Okitsu’ mandarin. The ‘Flying Dragon’ trifoliate had a unique effect over the ‘Okitsu’ trees performance, inducing lower canopy volume and higher yield efficiency and fruit quality, and might be suitable for high-density plantings. The ‘Cravo Limeira’ and ‘Cravo FCAV’ Rangpur limes induced early-ripening of fruits, with low fruit quality. ‘Sun Chu Sha Kat’ and ‘Sunki’ mandarins and the ‘Orlando’ tangelo conferred lower yield efficiency and less content of soluble solids for the latter rootstock.  相似文献   

2.
‘Swingle’ citrumelo [Citrus paradisi MacFaden × Poncirus trifoliata (L.) Raf.] has been extensively used as a rootstock in several citrus growing regions of the World, including Southern Brazil where ‘Rangpur’ lime (Citrus limonia Osbeck) is still the predominant variety despite being affected by several important pathogens. In this case, ‘Swingle’ citrumelo is used to produce nursery trees to establish new orchards or to be inarched in adult and healthy groves in order to change the rootstock. We report herein a system to produce trees on ‘Swingle’ citrumelo more rapidly by budding onto non-rooted cuttings, as well as assessing potential to rapidly multiply ‘Swingle’ through rooting of non-budded cuttings. Therefore, two potential products are described: budded trees and rooted rootstock cuttings. ‘Valencia’ sweet orange [Citrus sinensis (L.) Osbeck] was budded at different heights on cuttings derived from eight-month old rootstocks. Grafted and additional non-budded cuttings were then treated with indole-3-butyric acid (500 mg L−1) or left untreated before rooting. Three types of cuttings were evaluated: softwood, semi-hardwood and hardwood. The use of nursery trees derived from pre-budded hardwood cuttings of ‘Swingle’ citrumelo is an alternative grafting method on this cultivar. Softwood cuttings with one leaf pair were considered the most adequate material for rapid multiplication of ‘Swingle’ citrumelo by cutting. This could be particularly useful for inarching production or conventional budding after transplant of cutting-derived rootstocks.  相似文献   

3.
Faced with new challenges, such as emerging diseases, shortening of orchard longevity, and larger social and environmental demands from consumers, practices such as rootstock diversification, irrigation and high density plantings have become relevant for the Brazilian citrus industry. This research had the objective to evaluate the performance of irrigated and non-irrigated ‘Tahiti’ lime trees grafted on 12 rootstocks and one interstock. Plots were distributed following a randomized block design, with four replicates and one plant per plot. Rootstocks influenced plant vigor, especially ‘Flying Dragon’ trifoliate, which reduced tree height by approximately 47% compared to the ‘Rangpur’ lime. Trees that were budded on more vigorous rootstocks showed higher yield when grown without irrigation than with irrigation. The ‘1646’ citradia and ‘Morton’ citrange rootstocks performed particularly well. On the other hand, the plants on less vigorous rootstocks showed better performance in terms of yield under irrigation than the same combinations without irrigation, especially those grafted on the tetraploid ‘Carrizo’ and ‘Troyer’ citranges, ‘Swingle’ citrumelo, ‘Davis A’ trifoliate and ‘Flying Dragon’ trifoliate. Plants budded on the ‘1708’ citradia had high yields under irrigated and non-irrigated conditions. The effect of interstock on plant vigor was dependent of rootstock. Interstocked plants on ‘Davis A’ trifoliate were higher than those without interstock. On the other hand, interstocked plants on Catania 2 ‘Volkamer’ lemon were less vigorous than those without interstock.  相似文献   

4.
Agrobacterium-mediated genetic transformation of a tetraploid “tetrazyg” citrus rootstock selection ‘Orange #16’ [Nova mandarin (Citrus reticulata Blanco) + Hirado Buntan pummelo (Citrus grandis L. Osbeck)] × [Cleopatra mandarin (C. reticulata Blanco) + Argentine trifoliate orange (Poncirus trifoliata (L.) Raf.)] was performed. Juvenile epicotyl segments were transformed with a construct containing a bifunctional egfp–nptII fusion gene under the control of an enhanced double CaMV 35S promoter. Our protocol resulted in a reasonable transformation efficiency of 18%. Stable integration of the transgene was confirmed by visual observation of EGFP expression, PCR and Southern blot hybridization. The purpose of this work was to investigate the amenability of novel citrus rootstock germplasm being developed for improved tree size control, soil adaptation, and disease resistance, to existing transformation technologies. Seed trees of such transgenic tetraploids also have potential as trap plants containing potent insecticidal transgenes, due to their inedible fruit and inherent crossing barriers with conventional commercial diploid scion cultivars, and could be planted around producing citrus groves.  相似文献   

5.
Vegetative growth, yield, and fruit quality of ‘Fallglo’ and ‘Sunburst’ mandarins on ‘Rangpur’ lime, ‘Swingle’ citrumelo, ‘Orlando’ tangelo, and ‘Cleopatra’ mandarin were evaluated under subtropical climate of Northern São Paulo State, Brazil, from 2000 through 2006 harvest seasons. ‘Fallglo’ mandarin trees had the highest cumulative yield on ‘Rangpur’ lime, and the smallest on ‘Swingle’ citrumelo and ‘Orlando’ tangelo. Plants of this cultivar had the highest yield efficiency on ‘Rangpur’ lime, and the lowest on ‘Orlando’ tangelo. ‘Sunburst’ mandarin trees began to bear fruits later than ‘Fallglo’ mandarin trees, with no differences in yield induced by the rootstocks. ‘Cleopatra’ mandarin induced the most vigorous growth in ‘Fallglo’ mandarin as compared to plants on ‘Swingle’ citrumelo. On the other hand, the largest trees of ‘Sunburst’ mandarin were registered on ‘Orlando’ tangelo, and the smallest on ‘Rangpur’ lime. ‘Sunburst’ mandarin had higher alternate bearing than ‘Fallglo’ regardless the rootstock. Fruit weight and juice content were not affected by the rootstock. These two mandarin scion cultivars may be considered adequate alternatives to produce good fruit quality for the fresh fruit market. ‘Cleopatra’ mandarin and ‘Rangpur lime are suitable rootstocks for ‘Fallglo’ mandarin, whereas all rootstocks evaluated are adequate for ‘Sunburst’ mandarin.  相似文献   

6.
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.  相似文献   

7.
Somatic hybridization is a biotechnology tool that can be used in citrus breeding programs to produce somatic hybrids with the complete genetic combination of both parents. The goal of this work was to test the reaction of citrus somatic hybrids that may be useful as rootstocks to trunk and root infections caused by Phytophthora nicotianae van Breda de Haan (P. parasitica Dastur) and to citrus tristeza virus (CTV). The somatic hybrids evaluated were ‘Caipira’ sweet orange (Citrus sinensis L. Osbeck) + ‘Rangpur’ lime (C. limonia Osbeck), ‘Caipira’ sweet orange + ‘Cleopatra’ mandarin (C. reshni hort. ex Tanaka), ‘Caipira’ sweet orange + ‘Volkamer’ lemon (C. volkameriana V. Ten. & Pasq.), ‘Caipira’ sweet orange + rough lemon (C. jambhiri Lush.), ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, ‘Cleopatra’ mandarin + sour orange (C. aurantium L.), ‘Rangpur’ lime + ‘Sunki’ mandarin (C. sunki (Hayata) hort. ex Tanaka), ‘Ruby Blood’ sweet orange (C. sinensis L. Osbeck) + ‘Volkamer’ lemon, ‘Rohde Red’ sweet orange (C. sinensis L. Osbeck) + ‘Volkamer’ lemon, and ‘Valencia’ sweet orange + Fortunella obovata hort. ex Tanaka. For P. nicotianae trunk and root infection assays, plants of the somatic hybrids, obtained from 9-month semi-hardwood cuttings, were evaluated and compared with diploid citrus rootstock cultivars after mycelia inoculation in the trunk or spore infestation in the substrate, respectively. ‘Cleopatra’ mandarin + sour orange, ‘Rangpur’ lime + ‘Sunki’ mandarin, ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, ‘Ruby Blood’ sweet orange + ‘Volkamer’ lemon, ‘Rohde Red’ sweet orange + ‘Volkamer’ lemon, and ‘Caipira’ sweet orange + ‘Volkamer’ lemon had less trunk rot occurrence, whereas the somatic hybrids ‘Cleopatra’ mandarin + ‘Volkamer’ lemon, ‘Cleopatra’ mandarin + sour orange, ‘Caipira’ sweet orange + ‘Volkamer’ lemon, and ‘Caipira’ sweet orange + ‘Rangpur’ lime were tolerant to root rot. For CTV assays, plants of the somatic hybrids along with tolerant and intolerant rootstocks were budded with a mild strain CTV-infected or healthy ‘Valencia’ sweet orange budwood. Differences in average scion shoot length indicated that the hybrids ‘Cleopatra’ mandarin + sour orange and ‘Valencia’ sweet orange + Fortunella obovata were intolerant to CTV.  相似文献   

8.
Asiatic citrus canker (ACC), caused by Xanthomonas axonopodis Starr & Garces pv. citri (Hasse) Vauterin et al., and citrus variegated chlorosis (CVC), caused by Xylella fastidiosa Wells et al., are considered the main diseases affecting sweet orange scion varieties in Brazil. Among commercial varieties, mandarins and tangerines are recognized as tolerant to these pathogens. We report herein the production of ‘Hamlin’ sweet orange (Citrus sinensis L. Osbeck) + ‘Montenegrina’ mandarin (Citrus deliciosa Ten.) allotetraploid somatic hybrid plants by protoplast fusion with improved disease tolerance that could be used as a donor of resistance genes in interploid hybridisation. Somatic hybridisation was confirmed by leaf morphology, flow cytometry and RAPD analyses. The somatic hybrid was propagated by grafting and cultivated in a screenhouse for tolerance assays. For X. axonopodis pv. citri assays, buds were collected from both ‘Hamlin’ sweet orange and the somatic hybrid and grafted onto ‘Cleopatra’ mandarin (Citrus reshni hort. ex Tanaka). As a negative control, buds from ‘Mexerica Tardia’ mandarin (C. deliciosa) were collected and grafted onto ‘Cleopatra’ mandarin. Two-month old plants with at least one young vegetative flush were individually spray-inoculated with a 106 CFU mL−1X. axonopodis pv. citri suspension and incubated in a growth chamber, at 27 °C, under 16-h photoperiod. The somatic hybrid showed a statistically significant reduction in susceptibility to ACC 30 days after inoculation. Compared to ‘Hamlin’ sweet orange, disease severity was reduced by 70%, with similar tolerance to that of the mandarin negative control. For X. fastidiosa assays, buds were collected from the somatic hybrid and its parental plants and grafted onto ‘Rangpur’ lime (Citrus limonia Osbeck). The developed plants were needle-inoculated with a X. fastidiosa suspension (8.7 × 1010 CFU mL−1) into the new growth flush stem. Bacterial population was quantified both at 4 (at the inoculation point) and 8 months (50 cm above the inoculation point) after inoculation. The first evaluation detected X. fastidiosa in 63% of ‘Hamlin’ sweet orange and ‘Hamlin’ + ‘Montenegrina’ mandarin samples. In the second evaluation, X. fastidiosa was detected in 47.4% of ‘Hamlin’ sweet orange and 10.5% of ‘Hamlin’ + ‘Montenegrina’ somatic hybrid samples, suggesting that bacterial movement was restricted in the somatic hybrid. X. fastidiosa was not detected in both evaluations in samples collected from leaves of ‘Montenegrina’ mandarin. These results indicate that the ‘Hamlin’ sweet orange + ‘Montenegrina’ mandarin somatic hybrid has potential for improved disease tolerance that should enhance its value regarding future use in citrus breeding programs.  相似文献   

9.
This study was conducted to assess the genetic basis and develop a regression model for a QTL trait, fruit setting of a full sib population of 164 hybrids obtained between ‘Clementine’ mandarin (Citrus reticulata Blanco ‘Clementine) and ‘Orlando’ tangelo’ (Citrus paradisi Macf. ‘Duncan’ × C. reticulata Blanco ‘Dancy’). Fruit setting of a 164 full sib population field-planted in 2007 was evaluated by visual counting of fruits in 2008, 2009, and 2010. We estimated linkage groups and effects of QTLs by using MapQTL5. Based on interval mapping, seven linkage groups of the maternal and eight linkage groups of the paternal maps harboured QTLs of the fruits setting, covering a total 300 of 1744 cM Citrus map. Only three segments were associated with all three-year data (one in ‘Clementine’ and two in ‘Orlando’ map) spanning 60 cM of 1744 cM of Citrus linkage map. Twenty-seven (17%) and 13 (8%) hybrids consistently produced less than 5 fruits and the highest number of fruits (≥50) in their 2nd, 3rd, and 4th ages. Based on BACKWARD elimination procedure of PROC REG option nested in SAS program, regression models constructed for 2008, 2009, and 2010s fruit setting explained 35, 81, and 38% of the total phenotypic variation (R2) observed in the 164 full-sib hybrids, respectively (P ≤ 0.05). This study indicated that early fruit setting was a complex trait affected by many QTLs and the regression model developed in this study might be used to predict performances of hybrids with similar genetic background.  相似文献   

10.
Pink or red-fleshed fruit mutations are commonly found in grapefruit, sweet orange, and occasionally in lemon, which combine novel appearance with fine eating quality. In order to identify the major coloured pigments, high performance liquid chromatography (HPLC) with ultraviolet detection was applied for the separation and characterization of carotenoids from five pink or red-fleshed citrus cultivars. As a result, both lycopene and β-carotene with similar HPLC profiles were detected in the five citrus cultivars, ‘Fengdu’ red-fleshed pomelo (Citrus grandis (L.) Osbeck), ‘Guanxi’ sweet pomelo red mutant, ‘Hirado Buntan’ pomelo, ‘Cara Cara Navel’ orange (C. sinensis (L.) Osbeck) and ‘Star Ruby’ grapefruit (C. paradisi Macf.). ‘Star Ruby’ contained the highest lycopene and β-carotene content in its flesh. However, although the significant correlation between the concentrations of lycopene and β-carotene was detected with a coefficient of 0.9692 (P < 0.01), ratios of lycopene/β-carotene were different among the cultivars. Post-harvest biosynthesis verified that the flesh itself synthesized carotenoids rather than acquiring them via transport from other tissues. In addition, a product feedback regulation mechanism might be involved in the process of carotenoid biosynthesis.  相似文献   

11.
Sting nematode (Belonolaimus longicaudatus Rau) has become a primary factor limiting citrus production in localized regions of the central Florida sandridge citrus production area, making the development of resistant rootstocks a new breeding objective. In efforts to develop a replacement rootstock for the widely adapted sour orange, our focus has been on somatic hybridization of selected mandarin + pummelo combinations [Grosser, J.W., Gmitter, Jr., F.G., 1990. Protoplast fusion and citrus improvement. Plant Breed. Rev. 8, 339–374; Ananthakrishnan, G., Calovic, M., Serrano, P., Grosser, J.W., 2006. Production of additional allotetraploid somatic hybrids combining mandarins and sweet oranges with pre-selected pummelos as potential candidates to replace sour orange rootstock. In Vitro Cell. Dev.: Plant 42, 367–371], since sour orange is probably an introgression hybrid of mandarin and pummelo as suggested by molecular marker analyses [Nicolosi, E., Deng, Z.N., Gentile, A., La Malfa, S., Tribulato, E., 2000. Citrus phylogeny and genetic origin of important species as investigated by molecular markers. Theor. Appl. Genet. 100, 1155–1166; Gulsen, O., Roose, M.L., 2001. Lemons: diversity and relationships with selected Citrus genotypes as measured with nuclear genome markers. J. Am. Soc. Hort. Sci. 126, 309–317]. Somatic hybrid plants were produced from four new mandarin (C. reticulata Blanco) + pummelo (C. grandis L. Osbeck) parental combinations by fusing embryogenic suspension culture-derived protoplasts isolated from selected mandarins with leaf protoplasts of pummelo seedlings previously selected for tolerance/resistance to the sting nematode (B. longicaudatus Rau) as follows: Amblycarpa mandarin + ‘Liang Ping Yau’ (seedling) pummelo seedling SN7; Amblycarpa mandarin + ‘Hirado Buntan Pink’ (HBP) pummelo seedling SN3; Murcott tangor + pummelo seedling SN3; and Shekwasha mandarin + pummelo seedling SN3. Somatic hybridization was verified by ploidy analysis (via flow cytometry) and RAPD analyses. Mandarin parents were selected for wide soil-adaptation and ability to produce friable embryogenic callus lines. Pummelo seedlings used as leaf parents were identified from a previous screen of large seed populations (200 each) from four pummelos for resistance to sting nematode as follows: ‘Hirado Buntan Pink‘; ‘Red Shaddock‘; ‘Large Pink Pummelo’ and a seedling pummelo of ‘Liang Ping Yau‘. Ten resistant/tolerant pummelo seedlings were selected from the 800 pummelo seeds planted in the screen for further study. The four new somatic hybrids have been propagated to evaluate their horticultural performance and resistance to the sting nematode. These potential somatic hybrid rootstocks should also have potential to control tree size due to polyploidy.  相似文献   

12.
Asiatic citrus canker caused by Xanthomonas citri subsp. citri (Xcc) is one of the most detrimental diseases affecting citrus production. ‘Meiwa’ kumquat (Fortunella crassifolia) and ‘Newhall’ navel orange (Citrus sinensis) are two genotypes with contrasting Xcc resistance. In the current study, efforts were made to perform pairwise comparison between them in terms of structural difference and biochemical response to Xcc attack. Pinprick inoculation demonstrated that ‘Meiwa’ had lower disease incidence rate and smaller lesion size, concurrent with significantly less bacterial number at the inoculation sites relative to ‘Newhall’. Microscopic observation demonstrated that stomatal density and size of ‘Meiwa’ were significantly smaller than ‘Newhall’. Stomatal apertures of ‘Meiwa’ were smaller than ‘Newhall’ measured at 2 h after their leaves were immersed in Xcc suspension, consistent with the bacteria number in the internal tissues counted at 4 d. Epicuticular wax content of ‘Meiwa’ was significantly higher than that of ‘Newhall’, while no difference in palisade and spongy tissue was observed between them. Enzymatic activity assay showed that after Xcc inoculation, ‘Meiwa’ exhibited significantly higher activities of catalase (CAT), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) in comparison with ‘Newhall’ at most of the sampling time points. Our data showed that the two genotypes with contrasting Xcc resistance exhibited clear difference in the structure and physiological response, which may provide information to facilitate our understanding of Xcc resistance.  相似文献   

13.
Somatic hybridization provides an alternative for transferring mitochondria-encoded cytoplasmic male sterility (CMS). Herein, symmetric protoplast electrofusion was conducted between embryogenic callus protoplasts of Citrus unshiu Marc. cv. Guoqing No. 1 (G1), a CMS cultivar, and mesophyll-derived protoplasts of seedy ‘Page’ tangelo [C. reticulata Blanco × (C. reticulata Blanco × C. paradisi Macf.)] or ‘Nova’ tangelo [C. reticulata Blanco × (C. reticulata Blanco × C. paradisi Macf.)], to transfer CMS trait. Flow cytometry analysis showed that 14 plants recovered from G1 + ‘Page’ tangelo that displayed typical morphological character of ‘Page’ were diploid, and 6 plants regenerated from G1 + ‘Nova’ tangelo were tetraploid. Genetic compositions of regenerated plants from the two fusions were determined by SSR, CAPS and chloroplast-SSR analysis. Cybrid nature of diploids from G1 + ‘Page’ tangelo with nuclear DNA from ‘Page’, mitochondrial DNA (mtDNA) from the G1 and chloroplast DNA (cpDNA) derived from either parent was confirmed. Tetraploid plants from G1 + ‘Nova’ tangelo were identified as somatic hybrids with random cpDNA inheritance. The regenerated cybrid and hybrid plants hold great potential for Citrus seedless breeding at diploid or triploid levels.  相似文献   

14.
We propose the utilization of eggplant (Solanum melongena L.) interspecific hybrids derived from crosses with closely related species as an approach for developing new improved rootstocks for eggplant. Here we investigate rootstock effects on fruit yield, apparent quality and proximate and mineral composition of S. melongena ‘Black Beauty’ (BB) scions grafted on interspecific hybrid rootstocks developed from crosses of S. melongena with Solanum incanum L. (SI × SM) and Solanum aethiopicum L. (SM × SA). The results are compared with non-grafted (BB control) and self-grafted (BB/BB) controls and with S. melongena ‘Black Beauty’ scions grafted onto Solanum torvum Sw. (STO) and Solanum macrocarpon L. (SMA) rootstocks. All treatments were grown in a soil naturally infested with root-knot nematodes (mostly Meloidogyne incognita (Kofoid and White) Chitwood). SI × SM and SM × SA interspecific hybrids had high germination (≥90%) and total graft success (100%). Contrary to what occurred with all other treatments, no plants from scions grafted onto these hybrid rootstocks died during the experiment. In particular, the SI × SM hybrid rootstock conferred the highest vigour to the scion, which resulted in the highest values for fruit earliness and early and total yield. Little difference was observed among treatments for apparent fruit quality traits, except for a greater fruit calyx length and prickliness of fruit grafted onto SMA rootstocks. A similar result was obtained for fruit composition where phenolics content was higher in fruit from plants grafted onto SMA rootstocks. Grafting eggplant onto interspecific eggplant hybrids, especially on the SI × SM hybrid, has proved advantageous for eggplant production, as the high vigour and good compatibility of the rootstock with scion results in improved early and total yield without negative effects on apparent fruit quality or composition. Interspecific hybrids represent an alternative to the commonly used STO rootstock, which is a wild species with irregular germination.  相似文献   

15.
The responses to root zone salinity (0, 25 and 50 mM NaCl) by 40 citrus rootstock genotypes introduced from the People's Republic of China, measured as shoot chloride (Cl−) and sodium (Na+) ion accumulation, growth and dry matter accumulation, were investigated under glasshouse conditions. Two experiments, one using aerated nutrient solutions and the other irrigated sand cultures, were conducted with plants grown from rooted cuttings taken from representative trees of different mandarin (Citrus reticulata Blanco and C. erythrosa Hort. ex Tan.), yuzu (C. junos Sieb. ex Tan.), Ichang papeda (C. ichangensis Swing.), sour orange (C. aurantium L.) and trifoliate orange (Poncirus trifoliata (L.) Raf.) genotypes. Two standard genotypes, viz. Rangpur lime (Citrus x limonia Osbeck.) and William's trifoliate orange were included in the experiments as reference controls.  相似文献   

16.
Eighty-six triploid Citrus plants were recovered from interploid crosses between a natural tetraploid selection of the tangerine ‘Dancy’ (Citrus reticulata Blanco, cultigroup ‘Tangerine’), used as the pollen parent, and two seedy selections of diploid mandarins (C. reticulata Blanco) as well as one clementine (Citrus clementina Hort. ex Tan.): ‘Fortune’ mandarin, ‘Wilking’ mandarin and ‘Monreal’ clementine. Flow cytometric analysis was used for screening the triploid plantlets and the ISSR-PCR technique was used to characterize the obtained triploids through a double approach, confirming the hybrid nature of the offspring and allowing the analysis of the genetic pool obtained. Selection among triploid genotypes generated from elite seedy parents will give us a better chance to obtain superior mandarin cultivars characterized by true seedlessness.  相似文献   

17.
Characteristics and oleocellosis sensitivity of citrus fruits   总被引：1，自引：0，他引：1  
The effects of variety, growth phase, and water loss on development of oleocellosis, and relationships between chromatism and Vis/NIR spectra were studied in ‘EarlyGold’ sweet orange (Citrus sinensis Osbeck), ‘Fukumoto’ navel (Citrus sinensis Osbeck), and ‘Cara Cara’ navel (Citrus sinensis Osbeck) oranges. The varieties showed significant differences in the rate (RO) and degree (DO) of oleocellosis development. The sensitivity of varieties (from most to least sensitive) was ‘EarlyGold’ > ‘Fukumoto’ > ‘Cara Cara.’ Growth phase and water loss had a significant influence on fruit sensitivity to oleocellosis. The order of sensitivity to oleocellosis was dependent on harvest time (i.e., at normal period > at delayed period > at uncolored period), and RO and DO decreased significantly with water loss. The RO and DO models for fruit water loss were established as y = 0.75 − 3.94x − 271.33x2 (R2 = 0.77) and y = 1.70 − 7.29x − 1025.83x2 (R2 = 0.583). The sensitivity of ‘EarlyGold’ to oleocellosis was significantly correlated with dL and dC of fruit chromatism. At the same time, there were significant differences at 480–575 nm, 650–720 nm, and 925–965 nm between varieties with low and high sensitivity to oleocellosis, and ‘EarlyGolds’ with a low RO and DO had a higher reflectance than those with a high RO and DO.  相似文献   

18.
Sweet orange (Citrus sinensis L. Osb.) ‘Hamlin’ is a canker (Xanthomonas axonopodis pv. citri: Xac) susceptible citrus genotype grown commercially worldwide. Canker causes severe economic losses and restricts the marketability of crop for export. Little is known about the role of oxidative stress in canker development. In the present investigation, sweet orange ‘Hamlin’ leaves were artificially inoculated with Xac to determine the impact of Xac infection on hydrogen peroxide (H2O2) metabolism. Characteristic symptoms following artificial inoculation were water soaking of the infiltrated zone between 2 and 8 days after inoculation (dai); raised epidermis accompanying tiny yellow colored bacterial colonies at 8 dai; and yellowing and necrosis of the infected zone by 12–16 dai. In planta Xac population increased 1000 fold by 14 dai from an initial population of 7.3 × 106 cfu cm−2 (0 dai). Peak concentrations of H2O2 were observed at 24 h and between 8 and 10 dai and coincided with higher activity of total superoxide dismutase (SOD). Lower levels of H2O2 in infected leaves were maintained by Xac induced higher activities of catalase (CAT), ascorbate peroxidase (APOD), and guaiacol peroxidase (POD). It appears Xac altered H2O2 metabolism in C. sinensis L. Osb. ‘Hamlin’ to enhance survival and growth.  相似文献   

19.
In addition to managing soil-borne diseases in muskmelon (Cucumis melo L.) production, grafting with resistant rootstocks may impact fruit quality. The ethylene antagonist 1-methylcyclopropene (1-MCP) has been shown to extend shelf life of fresh muskmelon fruit. Postharvest characteristics of 1-MCP-treated melon fruit as affected by grafting, however, have not been well examined. This study was conducted to explore the influence of grafting with different rootstocks on ripening and quality attributes of 1-MCP-treated muskmelon fruit during postharvest storage. Grafted ‘Athena’ muskmelon with two commercial squash interspecific hybrid rootstocks including ‘Strong Tosa’ and ‘Tetsukabuto’ as well as non-grafted and self-grafted ‘Athena’ were grown in replicated field plots at the University of Florida Plant Science Research and Education Unit (Citra, FL, USA) during April–June 2010. Half-slip fruit from two harvests were treated with 1.0 μL L−1 1-MCP (18 h, 20 °C) and analyzed during storage at 13 °C. For fruit from the 27 May harvest, whole fruit and mesocarp firmness, titratable acidity, soluble solids, and ascorbic acid content were measured, while production of ethylene and CO2 was determined on fruit from the 29 June harvest. Grafting did not show a significant impact on fruit yield but affected the fruit shelf life significantly. Fruit from non-grafted ‘Athena’ and ‘Athena’ grafted onto ‘Strong Tosa’ demonstrated a shelf life of 31 d for the first harvest and 22 d for the second harvest. Shelf life of fruit from self-grafted ‘Athena’ and ‘Athena’ grafted onto ‘Tetsukabuto’ declined by 6 d and 3 d for the first and second harvest, respectively. Whole fruit firmness decreased by approximately 15.5% on average from 13 to 31 d except day 19 as a result of grafting, but to a lesser extent with ‘Strong Tosa’ rootstock. Mesocarp firmness of grafted melon was reduced by about 30.2% at days 13 and 19 compared to non-grafted ‘Athena’ fruit. In contrast, titratable acidity, soluble solid content, and ascorbic acid concentration were less affected by grafting. All the measurements except for ethylene and CO2 production declined during storage regardless of the grafting treatment. Compared with ‘Strong Tosa’ rootstock, ‘Tetsukabuto’ resulted in a more rapid ripening under 1-MCP application, as reflected by earlier increase in ethylene production and higher respiratory rate. The study demonstrates that grafting effects on postharvest ripening and quality of ‘Athena’ muskmelon can vary markedly with rootstocks used.  相似文献   

20.
Worldwide, gibberellic acid (GA3) is used routinely to increase fruit number and size of seedless mandarins. The efficacy of seven combinations of GA3 concentrations and application times to maximize total yield and yield of commercially valuable fruit (diameter 57.2–76.2 mm) of ‘Nules’ Clementine mandarin (Citrus reticulata Blanco) was determined in a commercial orchard. GA3 applied during the period of intense flower abscission failed to reduce the total number of abscised flowers in both the light off- and heavy on-bloom years. No GA3 treatment reduced fruit abscission when trees were setting the low yield off-crop. However, all trees receiving GA3 in the high yield on-crop year had fewer abscised fruit than untreated control trees (P = 0.0188) and GA3 applied 10 days after 75% petal fall and in July increased the number of fruit retained on tagged branches >20% compared to control trees (P = 0.0005). Maximum air temperature was not related to flower or fruit abscission. In the off-crop year (548 fruit per untreated control tree), it was necessary to apply 15 or 25 mg L−1 GA3 at 60% bloom, 90% bloom, 75% petal fall and 10 days after 75% petal fall to significantly increase the number of fruit per tree and yield of commercially valuable fruit (kilograms and number per tree) (P < 0.0001) above that of control trees, with no reduction in total kilograms per tree. In the following on-crop year, it was better not to apply GA3: no treatment increased total yield or fruit size and five of seven GA3 treatments tested reduced total yield as kilograms and number of fruit per tree (P = 0.0003). The results provide strong evidence that GA3 efficacy is crop load-dependent and dictate that crop load should be considered when using GA3 to increase fruit set or fruit size of mandarins.  相似文献   

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