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1.
Summary

We have evaluated the influence of four different peach rootstocks (Prunus pumila,‘GF 655/2’ ,‘Missour’ and ‘GF 677’ as a standard) planted in medium-heavy to heavy soil on phenological events (flowering and harvest date), growth, yield, fruit quality and mortality of peach (P. persica L.) scions of cv. ‘Redhaven’. At the end of flowering, there were no significant differences between the different rootstocks in the years 1999, 2000, 2003 and 2004. In 2001, trees grafted on P. pumila reached the end of flowering 2 d before trees grafted on the other rootstocks. ‘Redhaven’ fruits ripened on the same day on trees grafted on the different rootstocks. The differences were only between years. The results showed that significantly less vigorous trees, according to their trunk cross-sectional area (TCSA) and canopy volume, with the lowest yield, were observed on P. pumila rootstock. The rootstock P. pumila had a significant negative influence on fruit dimensions and mortality was 50%. Trees grafted on ‘GF 655/2’ rootstock produced significantly lower yields than those grafted on ‘GF 677’ or ‘Missour’ rootstocks. Only the ‘GF 655/2’ rootstock had root suckers. Trees grafted on ‘GF 677’ rootstock were significantly more vigorous than on the other rootstocks, and produced the highest yield with good fruit quality. The final canopy volumes of peach trees grafted on the different rootstocks were very different. The most vigorous trees were those grafted on ‘GF 677’ rootstock, where the final tree volume was 12.8 m3. Trees grafted on P. pumila and ‘GF 655/2’ had significantly lower TCSA values than on the other rootstocks.  相似文献   

2.
Summary

An evaluation of five rootstocks for pepper (Capsicum annuum L.) was carried out over a 3-year period on three farms in Campania (Italy). Pepper is very susceptible to soil-borne pathogens, especially Phytophthora capsici, Verticillium dahliae and Meloidogyne spp. (root-knot nematode). The lack of resistant hybrids and of crop rotation, and the longterm survival of propagules of the pathogen, have increased the risk of damage that so far has been controlled by pre-planting soil treatment with methyl bromide. The use of pepper grafted onto rootstocks resistant to the main soil-borne pathogens is not undertaken commercially in Italy because the available rootstocks are unsatisfactory. P. capsici, V. dahliae, Fusarium oxysporum, F. solani and M. incognita have been detected on farms where the new rootstocks were tested. Trials were performed on the same sites for 2 or 3 years in order to provide favourable conditions for parasites. Two rootstocks, ‘Graffito’ and ‘Gc 1002’, were found to be resistant to P. capsici. In the presence of an early, high population density of M. incognita, ‘Graffito’ showed good tolerance, while ‘Gc 1002’ was susceptible to the root-knot nematode. In addition, both rootstocks showed good compatibility with the different scions tested and did not decrease vegetative growth, fruit yield or the size of the scions. In contrast, in the presence of V. dahliae, F. oxysporum and F. solani, none of the rootstocks tested was sufficiently resistant to vascular or crown and root rot damage.  相似文献   

3.
Summary

Six wild species of Eriobotrya were evaluated as rootstocks for domesticated loquat. Twelve-month-old seedlings of Oak leaf loquat (an Oak Leaf loquat ‘Zaozhong No. 6’ hybrid) and wild Fragrant loquat (E. fragrans Champ) had higher root-to-shoot fresh weight (FW) ratios than other wild species. When the domesticated loquat, ‘Zaozhong No. 6’, was grafted onto seedlings of six different wild loquat species, differences in compatibility were observed. Graft compatibility was lower for all combinations compared to ‘Zaozhong No. 6’ grafted onto domesticated loquat seedlings. When wild Henry loquat was used as a rootstock, delayed incompatibility was observed. Differences in soluble sugar contents (SSC) between scion and rootstock were observed, and there was a significant negative correlation between graft compatibility and the difference in SSC values. The influence of the rootstock on anatomical changes at the graft union were observed using a scanning electron microscope (SEM). Wild rootstocks also influenced scion growth, fruit bearing, and fruit quality. Graft combinations which used wild Fragrant loquat as the rootstock had increased cold tolerance and improved scion growth. Wild Fragrant loquat therefore appears to have value as a rootstock for domesticated loquat.  相似文献   

4.
Summary

The vegetative and reproductive performance of ‘Coscia’ pear (Pyrus communis L.) growing on seven rootstocks [OHF 69, OHF 97, OHF 513 and BP 1 (P. communis), clonal seedling (Davis AxB) of P. betulifolia, and quince BA 29 and EMA (Cydonia oblonga)] were compared over an 8-year period. The trial was conducted at the Experimental Orchard Farm Station in northern Israel, on a well-drained soil with pH 7.5. Trees were planted in December 1998 at a distance of 4.0 m 2.0 m, and trained with a central axis. The most vigorous trees were on P. betulifolia seedling, followed by BP 1 and the three OHF rootstocks (69, 97, 513). All the above rootstocks demonstrated greater vigour than quince BA 29 or EMA. The reason for this effect, at least in part, appeared to be the excellent water status (high midday stem water potential values) of trees on P. betulifolia in comparison with the other rootstocks. The highest cumulative yields per tree were harvested from trees on P. betulifolia and BP 1, followed by the three OHF rootstocks (69, 97, 513). However, the highest cumulative yield of large fruit (> 60 mm) was obtained from trees on P. betulifolia, followed by the OHF series and BP 1. The two quince rootstocks had the lowest cumulative yield, and the lowest yield of large fruit. A positive correlation was found between the vigour of the tree, as affected by the rootstock, and both total yield and 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 the weak scion cultivar is the first requirement for establishing an orchard. Fruit quality at harvest and during cold storage were examined for fruit from three rootstocks only. The highest soluble solids content values at harvest were obtained in fruit grown on quince EMA, compared to values for BP 1 and P. betulifolia fruit.  相似文献   

5.
Summary

Melon (Cucumis melo L.) ‘Arava’ was grafted onto 22 experimental Cucurbita rootstocks including intra- or interspecific hybrids to examine scion-rootstock compatibility and to correlate plant performance under greenhouse and field conditions. The commercial Cucurbita ‘TZ-148’ rootstock and non-grafted plants were used as controls. Numbers of leaves, stem length and plant fresh weights were recorded three weeks after planting. Vegetative growth of the grafted plants varied markedly, indicating differences in compatibility between the scion and rootstocks. A positive correlation was found between number of leaves, stem length and fresh weight of melon plants. No significant advantage in vegetative growth was found in melons grafted onto intra- or interspecific hybrid rootstocks. Stem diameter and number of vascular bundles of the rootstock did not correlate with scion plant fresh weight. Twelve selected rootstocks out of the 22 tested were grown in the field during the spring and autumn, to determine if there is an association between the plant performance in the greenhouse and fruit yield under field conditions. Positive and significant correlations were found between greenhouse growth parameters and fruit yield under field conditions. It is suggested that testing grafted melons under greenhouse conditions could be a useful tool for preliminary testing of scion-rootstock compatibility.  相似文献   

6.
Summary

`Huangjin' peaches (Prunus persica Batsch) were harvested at commercial harvest time (commercial) and 20 d before (early) or after (later) commercial harvest. Fruit from each harvest were stored at three temperature regimes (0, 5 and 10°C) at 95% r.h. After four weeks of storage at 0 or 5°C, early harvested fruit developed more leatheriness but less mealiness and later harvested fruit did not develop leatheriness but developed more mealiness comparedwith fruit from commercial harvest. Overall, fruit stored at 5°C developed more mealiness but less leatheriness than fruitat 0°C for the same period of storage. When stored at 10°C for two weeks, after which fruit were senescent, fruit did not develop any leatheriness or mealiness regardless of harvest times. Fruit with leatheriness were firmer (>30 N) thanjuicy or mealy fruit (<10 N) after the same period of cold storage and 4 d at 20°C. Mealy fruit were as soft as juicy fruit. 1-Aminocyclopropane-1-carboxylate oxidase (ACO) activity, 1-aminocyclopropane-1-carboxylic acid (ACC) content, and polygalacturonase (PG) and galactosidase (GAL) activities were lower, and insoluble pectin content was higher in leathery fruit than that in juicy or mealy fruit. ACO, PG and GAL activity, ACC, and insoluble pectin content were similar between mealy and juicy fruit.  相似文献   

7.
Micropropagated plantlets of OH x F 51 and GF 677, respectively pear (Pyrus communis L.) and peach (Prunus persica x Prunus amygdalus) clonal rootstocks were inoculated during an early weaning stage of acclimatization with Glomus sp. Both rootstocks were well colonized, although the infection of OH x F 51 spread more slowly. At the end of initial vegetative growth, mycorrhizal plants of both rootstocks showed a three-fold increase in shoot length over control plants. Mycorrhizal plants also had longer internode and greater fresh mass. The root/shoot ratio was especially altered by arbuscular mycorrhizal inoculation in OH x F 51 plants, which showed a greater increase in shoot rather than in root biomass. The growth-promoting ability of endomycorrhizal fungus persisted throughout the experimental period: Glomus sp. induced a greater development of both rootstocks in the second growing year, after overwintering. Colonization of micropropagated plants by arbuscular mycorrhizal fungus appears to alter the carbohydrate status in stems and roots. Mycorrhizal plants always had a higher content of total soluble sugar, although there were no differences in soluble carbohydrate concentration between inoculated and uninoculated plants. Starch accumulation was found only in mycorrhizal plants of the peach rootstock.  相似文献   

8.
Summary

High-throughput amplified fragment length polymorphism (AFLP) analysis, employing a two-dye automated DNA sequencer, was used to genotype accessions of four important Prunus spp. fruit crops in China, fruiting-mei (P. mume), apricot (P. armeniaca), plum (P. salicina, and P. ussuriensis) and peach (P. persica). Nine primer pairs generated a total of 2,089 AFLP bands, of which 94.4% were polymorphic. Levels of polymorphism and the genetic relationships among the crops were studied.The fixation index (Fst) of the four different fruit trees ranged from 0.53 – 0.82, and the average genetic diversity (AGD) in these species ranged from 3.2% to 12.8%. These four stone fruit species could be clustered into four clear groups on a phylogenetic tree based on bootstrap analysis. Phylogenetically, fruiting-mei was shown to be closest to apricot and most distant from peach.  相似文献   

9.
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   

10.
Summary

Growth, yield, and leaf nutrient concentrations were measured in ‘Hass’ avocado (Persea americana Mill.) trees grown on one of ten clonally-propagated rootstocks (‘Borchard’, ‘D9’, ‘Duke 7’, G1033, G755A, G755B, G755C, ‘Thomas’, ‘Topa Topa’, or ‘Toro Canyon’) over a 10-year period in southern California. After 10 years, trees on ‘Borchard’ were larger than trees on all other rootstocks. Trees on all rootstocks displayed an alternate-bearing pattern, typical of avocado. Alternate-bearing was most pronounced in trees grafted onto ‘Topa Topa’ and ‘Toro Canyon’. Rootstocks in the G755 series had the lowest alternate-bearing index, but also had the lowest yields.Trees on ‘Duke 7’ and ‘Borchard’ had the highest cumulative yields, and trees on G755A, G755B, and G755C had the lowest yields. Differences in yield were due to differences in the number of fruit per tree, not individual fruit weight. When yield was evaluated in terms of canopy efficiency (kg fruit m–3), no rootstock outperformed ‘Duke 7’, the industry standard rootstock. Leaf concentrations of all nutrients examined (N, P, K, Ca, Mg, S, Zn, Cl, Mn, B, Fe, and Cu) were within, or close to the recommended ranges. P, Ca, and S were higher, and Fe was lower in high-yielding years in all rootstocks.  相似文献   

11.
Summary

Grafting is a suitable method to control soil-borne diseases in melon (Cucumis melo L.) crops. To date, several Cucurbita species and their inter-specific hybrids have been tested as rootstocks. However, graft-scion incompatibility and lower fruit quality have prevented their commercial use. The wild accession ‘Pat 81’ ssp. agrestis of C. melo is highly resistant to Monosporascus cannonballus Pollack et Uecker root rot, and develops a root system that is more suitable to withstand infested soils than that of cultivated melon. The potential of ‘Pat 81’ as a rootstock for melons (e.g., ‘Piel de Sapo’ type, C. melo ssp. melo) compared with the popular rootstock ‘RS 841’ (Cucurbita maxima Cucurbita moschata) has been evaluated here. The response of grafted plants to Monosporascus root rot disease, and rootstock effects on plant performance and fruit quality have been investigated using both classical methods and modern technologies (e.g., root image analysis and real-time PCR). The results indicate that, during infection, the root system of ‘Pat 81’ adapts to the needs of the aerial part of the ‘Piel de Sapo’ scion, displays a high level of resistance to M. cannonballus (similar to ‘RS 841’), and provides the plant with more healthy roots, with a higher root/vine biomass ratio compared with non-grafted ‘Piel de Sapo’. In addition, ‘Pat 81’ rootstock retains its favourable root structure (i.e., larger total length and root area) to withstand soil stress. In healthy soils, ‘Pat 81’ rootstocks had less effect on fruit quality than ‘RS 841’, leading to a lower percentage of non-marketable products. The high resistance of ‘Pat 81’, and its reduced effect on fruit quality, point to it as a good rootstock for the grafting of melons to resist M. Cannonballus infested soils.  相似文献   

12.
Summary

Simple Sequence Repeat (SSR) and Sequence-Related Amplified Polymorphism (SRAP) molecular marker systems were used to analyse four commercially important pistachio rootstocks: two species of Pistacia atlantica (cv. ‘Standard Atlantica’), P. integerrima (cv. ‘Pioneer Gold’) and two interspecific hybrids of the same, ‘Pioneer Gold II’ (‘PGII’) and ‘University of California at Berkeley 1’ (‘UCB-1’). A total of 35 putative alleles were detected by 12 SSR primer pairs with an average of 2.9 alleles per locus. The number of putative alleles ranged from 2 to 5 in the pistachio rootstocks tested. The number of bands produced by the SRAP protocol was highly variable, ranging from 11 to 38, with an average of 25.2 per primer combination. Eight primer combinations resulted in 104 (51%) polymorphic markers in these samples. SSR and SRAP markers successfully identified all pistachio rootstocks tested from their unique fingerprints. Both SSR and SRAP molecular markers confirmed that the observed variation in ‘UCB-1’ rootstock is genetic.Thus, there will always be variation among ‘UCB-1’ hybrid seedling progeny due to the segregation of alleles when propagated by seed.We also found evidence of contaminating pollen other than from P. integerrima in some hybrid ‘UCB-1’ rootstock progeny produced by closed pollination. Only alleles from the cultivar ‘Standard Atlantica’ were observed in abnormal ‘UCB-1’ rootstock in the nursery. We found that the poor performance of the scion cv. ‘Kerman’ on ‘UCB-1’ rootstock was not due to ‘UCB-1' rootstocks displaying abnormal behaviour in the nursery. We have successfully developed two efficient marker systems for genome analyses in pistachio, which can be used for identification and management in pistachio rootstock production.  相似文献   

13.
《Scientia Horticulturae》2005,107(1):36-42
In clayey and calcareous soils without a stable irrigation and fertilization system, the type of rootstock can particularly affect both the vegetative and productive properties of ‘Suncrest’ peach (Prunus persica L. Batsch) plants, and the qualitative and nutritional attributes of their fruit. The GF677 rootstock (P. persica × Prunus amygdalus) promoted the highest vegetative development, followed by Julior (Prunus insistitia). The ‘Suncrest’ on Ishtara [(Prunus cerasifera × P. persica) × (P. cerasifera × Prunus salicina)] and Barrier1 (P. persica × Prunus davidiana) had lower, but similar, plant vigour, but the latter rootstock differed in its higher production of pruned wood. The lowest adaptability to these cultivation conditions was observed for ‘Suncrest’ grafted onto Citation (P. persica × P. salicina), which showed the lowest plant development and production. For the plant yield, the ‘Suncrest’ grafted onto GF677, Julior, Ishtara, and Barrier1 were all similar. The fruit yield and both the canopy volume and pruned wood of ‘Suncrest’ grafted onto Ishtara showed a particular relationship, giving the best indices of yield efficiency and plant physiological equilibrium. Moreover, the same rootstock promoted the largest fruit size, while the smallest fruit were found on GF677 rootstock. The fruit from the Citation ‘Suncrest’ ripened 3 days early, while those from Barrier1 had a late fruit ripening. Firmness, soluble solids and the soluble solids to total acidity ratio were only affected slightly by the different rootstocks, while the total acidity of the fruit varied significantly according to rootstock; the fruit from ‘Suncrest’ grafted onto Barrier1, Julior, and Citation had the highest total acidities. The rootstock effects on the nutritional attributes of the fruit were relevant. The ‘Suncrest’ on Julior and GF677, followed by Ishtara, produced fruit with the greatest antioxidant activities and total phenolic contents. The ‘Suncrest’ on Citation and, especially, Barrier1 had reduced nutritional values of the fruit. The variations in antioxidant activities and total phenolic contents showed a positive correlation.  相似文献   

14.
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15.
Summary

Inorganic nutrient concentrations in leaves, xylem sap and fruit from ‘Hort16A’ kiwifruit (Actinidia chinensis Planch. var. chinensis) vines grafted onto eight inter-specific rootstocks [A. deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson var. deliciosa; A. eriantha Benth.; A. hemsleyana×eriantha; A. macrosperma C.F. Liang; A. chrysantha Merr.; A. kolomikta (Maxim. et Rupr.) Maxim.; A. kolomikta (Maxim. et Rupr.) Maxim.; and A. polygama (Sieb. et Zucc.) Maxim.] were measured over three seasons. The nutrients analysed were phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn) and boron (B). The objectives of these studies were to identify rootstocks which induced relatively high or low levels of nutrients in the scion cultivar, and to correlate the nutrient concentrations of the fruits with the incidence of storage disorders. The use of inter-specific clonal rootstocks had a substantial effect on the accumulation and concentration of inorganic nutrients in the fruit, leaves and stem sap of ‘Hort16A’ kiwifruit vines, but few consistent relationships were observed between fruit nutrient concentrations and the incidence of storage disorders. Vines on A. hemsleyana×eriantha accumulated high levels of P in their fruits, leaves and xylem sap, and high levels of Ca and Mg in their leaves and xylem sap. Vines on A. macrosperma accumulated high levels of K in their fruits and leaves. In general, vines on rootstocks with low vigour (i.e. A. polygama; A. kolomikta) accumulated relatively low levels of nutrients. The incidence of physiological pitting, a mineral-related storage disorder, was higher in fruit with lower Mg concentrations. While rootstock-induced differences in the vigour of vines had an important role in determining nutrient concentrations in fruits and leaves, some rootstocks clearly had a stronger inherent ability to absorb nutrients from the soil than others, independent of their effect on vine vigour.  相似文献   

16.
以5种砧木分别嫁接‘瑞都红玉’和‘瑞都香玉’葡萄为试验材料,以接穗自根苗为对照,比较不同砧穗组合的树体生长特性、品质特性和内源激素动态变化规律,为葡萄适宜砧穗组合的筛选提供理论基础和参考依据。结果表明（1）以SO4、5BB和110R为砧木的接穗品种生长量大于以3309M和1103P为砧木的,但是110R小脚现象严重。（2）以SO4和5BB为砧木提高了‘瑞都香玉’的果实成熟度,5种砧木均显著提高了‘瑞都红玉’的可滴定酸含量,降低了固酸比,提高了‘瑞都红玉’的口感酸甜平衡性。（3）新梢生长期和转色期是促生长类激素分泌的高峰期,以110R和SO4为砧木的组合叶片和新梢中激素含量水平较高,以5BB为砧木的组合新梢中含量较高,且其叶片和新梢的ZR/GA3在新梢生长期处于高水平。‘瑞都红玉’/SO4在新梢生长期的ABA含量最低,与其长势强相吻合。以SO4为砧木的组合ABA含量从转色期到果实成熟期不升反降,有利于新梢的二次生长。110R、SO4和5BB组合的ZR/GA3在新梢生长期和转色期高于3309M和1103P组合,ABA/ZR + IAA + GA3低于3309M和1103P组合。研究结果表明,冬葡萄和河岸葡萄的后代SO4和5BB砧木的嫁接亲和力强,其接穗在新梢生长期和转色期促生长类激素水平相对高,嫁接植株生长旺盛,果实品质优良。  相似文献   

17.
Summary

The compound benzo-(1, 2, 3)-thiodiazole-7-carbothioic acid S-methyl ester (BTH) effectively induces a systemic acquired resistance (SAR) response in plants and increases plant resistance to disease. To learn how BTH may affect post-harvest quality and disease resistance in peach, (Prunus persica L. cv. ‘Jiubao’) peach fruit were treated with 200 mg l–1 BTH for 5 min immediately after harvest, then incubated for 60 h at 20°C, 85–95% RH. Sixty h after treatment, fruit were inoculated with spore suspensions of Penicillium expansum at 1.2 104 CFU ml–1. The incidence of disease and lesion areas on peach fruit were significantly reduced by BTH-treatment (P < 0.05). In addition, chitinase and -1,3-glucanase activities in peach fruit were significantly enhanced by BTH-treatment (P < 0.05). Moreover, the total levels of phenolic compounds and chlorogenic acid, and the lignin content of BTH-treated fruit were significant higher than in control fruit (P < 0.05). The effects of BTH on fruit quality were also analysed. Soluble solids content, soluble pectin, titratable acidity and ascorbic acid levels in peach fruit were not significantly affected by treatment with BTH. Our results suggest that the application of BTH may control post-harvest diseases in peach fruit during commercial production.  相似文献   

18.
The possibility of applying grafting to improve fruit quality has been scarcely investigated. Different shoot tomato (Solanum lycopersicum) genotypes were grafted onto distinctly-different tomato rootstocks and the effect of the rootstock on two important fruit quality parameters, soluble solids content (SSC) and titratable acidity (TA), was studied under both non-saline and saline conditions. Increased SSC and TA in fruits from grafted plants grown under saline conditions were observed on different grafting combinations. One of these rootstocks (cv. Radja) was able to induce increases in both fruit yield and fruit quality traits of the scion. When recombinant inbred lines (RILs) from the crossing of the cultivated tomato and wild tomato (Solanum cheesmaniae) were tested as rootstocks, using the commercial hybrid ‘Boludo’ as scion, the rootstock also improved SSC and TA when grafted plants were grown under non-saline conditions. On the whole, these results show the effectiveness of grafting with respect to upgrading of fruit quality in tomato, which is of great importance as grafting is a rapid and efficient alternative to achieve this goal.  相似文献   

19.
Summary

To breed fruitful triploid tomatoes, diploid (2x) and tetraploid (4x) plants were regenerated from hypocotyl explants, using two pairs of near-isogenic lines differing respectively for the parthenocarpic fruit and parthenocarpic fruit-2 mutations. From 626 regenerated shoots, 53 were tetraploid. In the 4x plants, the mean number of fruits was lower than in the 2x class for all the genotypes, but in the two parthenocarpic lines it was higher than in the respective wild-types at the same ploidy level. Compared with 2x, the mean weight of 4x fruits was lower in wild-type and higher in parthenocarpic lines. Out of four cross combinations between tetraploid and diploid plants (within two parthenocarpic and two corresponding wild-type lines), only two yielded seeds (the parthenocarpic fruit line and its near-isogenic wild-type). Triploids were vegetatively propagated and evaluated in a field trial. Whereas wild-type triploids were completely sterile, the 3x parthenocarpic fruit plants had a fruit set that was not statistically different from that observed in 2x individuals. Mean fruit weight in 3x parthenocarpic plants was also higher than in 2x and comparable with 4x plants. Yield estimates in such triploids were not statistically different from those recorded in diploids, both wild-type and parthenocarpic. Triploid fruits had a soluble solids value higher than 2x fruits. The total seedlessness and the increased dry-matter content appeared traits peculiar to triploid parthenocarpic fruits. Therefore, triploids may deserve interest in breeding fresh market and processing tomatoes, providing that their commercial multiplication is ensured by micropropagation.  相似文献   

20.
Summary

The influence of three rootstocks, Carrizo citrange (Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf.), Cleopatra mandarin (Citrus reshni Hort. ex Tanaka) and sour orange (Citrus aurantium L.) on the incidence and severity of rind breakdown in ‘Navelate’ sweet oranges was studied over seven years in four orchards. The proportion of affected fruit was greater in trees on Carrizo citrange (60% on an average) followed by Cleopatra mandarin (38%) and then on sour orange (9%). There were also significant differences in the severity of the disorder among rootstocks; more than 35% and 20% of fruit from trees on Carrizo citrange and Cleopatra mandarin, respectively, were rejected for commercialization, whereas only 4% of fruit on sour orange was rejected. Cryo-scanning electron microscopy (SEM) of fruit peduncles showed that average diameter of xylem vessel elements of peduncles of fruits on Carrizo citrange rootstock were 6% and 17% larger than those on Cleopatra mandarin and sour orange, respectively. Defoliation of fruit-bearing branches reduced water loss from fruit, maintained fruit peel water potential at a higher value than that of fruit on undefoliated branches and reduced the proportion and severity of affected fruit. It is concluded that fruit-tree water relationships are related to rind breakdown in ‘Navelate’ oranges and low fruit water content might be responsible for the disorder.  相似文献   

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