Effect of pruning and plant spacing on the growth of cherry rootstocks and their influence on stem water potential of sweet cherry trees

Summary

The aims of this work are to describe the effects of pruning and planting density on growth and water relations of ungrafted and grafted sweet cherry trees. A trial with cherry rootstocks ‘Prunus avium’, ‘CAB 11E’, ‘Maxma 14’, ‘Gisela 5’ and ‘Edabriz’ was begun in 1997. Pruning severities were applied to the rootstocks (0, 30, 60 and 90% of the vegetative growth was removed corresponding to P1, P2, P3 and P4 treatments, respectively) after planting to two plant spacings (S1 = 0.25 × 1.0 m and S2= 0.45 × 1.5 m). Canopy, root growth and leaf water potential (ψ_leaf) were quantified throughout the growing season. Pruning significantly affected root length and root weight of the rootstocks. Uncut plants (P1) showed a heavier and expanded root biomass (231 g and 108 m) than the intensively pruned plants (P4) (187 g and 75 m). The greater root biomass was obtained with the spacing/pruning combination, S1/P1 (285 g), and the smaller with S1/P4 (180 g) and S2/P4 (176 g). ψ_leaf varied significantly between the rootstocks and plant spacing but not with pruning. ‘Maxma 14’ and ‘P. avium’ attained the lowest values of midday ψ_leaf, –2.28 and –2.04 MPa, but the highest values of predawn ψ_leaf, –0.29 and –0.25 MPa, respectively. Generally, with high density (S1), the rootstocks exhibited lower predawn and midday ψ_leaf. In 1998, cultivars ‘Burlat’, ‘Summit’ and ‘Van’ were grafted onto rootstocks and a trial was installed in 1999. Predawn and midday stem water potential (ψ_stem) on cherry trees, measured in 2002, were affected significantly by the rootstock/genotype combination. Cultivars grafted on ‘P. avium’ and ‘Maxma 14’ showed the less negative midday ψ_stem, –1.36 and –1.42 MPa respectively, so these rootstock genotypes perhaps induced a higher drought resistance to the scion. Recorded data show that the scion-rootstock interaction with regard to production performance under water deficits may be an important consideration in cherry tree planting strategies.     

四倍体甜樱桃矮化砧木新品种‘矮杰’

甜樱桃四倍体矮化砧木‘矮杰’（原代号LBS）是从‘吉塞拉6’（Prunus cerasus × P. canescens）六倍体的实生后代中选育出,与绝大多数甜樱桃品种嫁接亲和性良好,嫁接口光滑,无大小脚现象,平均嫁接成活率87.3%。以其为砧木嫁接的甜樱桃‘萨米脱’定植翌年始花,4年丰产,比乔化砧嫁接树早丰产3 ~ 5年。以‘矮杰’为砧木的‘萨米脱’甜樱桃定植后4年,其分枝数量、树高、干周和冠径均大于‘吉塞拉6’砧的‘萨米脱’,平均株产高24.3%。     

The role of Pre-harvest Aminoethoxyvinylglycine (AVG) Treatments on Total Phenolics,Antioxidant Capacity and Fruit Quality Attributes of Sweet Cherry Cultivars

The present study was conducted to investigate the effects of pre-harvest aminoethoxyvinylglycine (AVG) treatments on fruit quality parameters and bioactive compounds of sweet cherry fruits (Prunus avium L. cvs. ’0900 Ziraat’, ‘Regina’ and ’Sweetheart’). Whole trees were sprayed once with an aqueous solution containing AVG (0, 100 and 200?mg L^?1) three weeks before the anticipated commercial harvest. Measurements were performed a week before anticipated harvest date, at anticipated harvest date and a week after anticipated harvest date. AVG treatments significantly maintained flesh firmness of all three sweet cherry cultivars. Harvest was delayed at least for a week through the keeping of flesh firmness with AVG treatments. The treatments slowed down the red skin color development in all three cultivars. The measurements performed over fruits collected at different ripening stages revealed that AVG resulted in decreased total phenolics and total anthocyanin and ultimately decreased antioxidant capacity in sweet cherry fruits. AVG treatments also decreased soluble solids content and increased titratable acidity of the fruits. This study revealed that pre-harvest AVG treatments were more effective in delaying sweet cherry fruit softening. The main advantage is to maintain the firmness of late-harvested fruit by retaining fruit quality attributes of sweet cherry fruit.     

Flavonol and phenolic acid composition of sweet cherries (cv. Lapins) produced on six different vegetative rootstocks

The effect of rootstock (‘MaxMa 14’, ‘Weiroot 13’, ‘PiKu 1’, ‘Weiroot 158’, ‘Gisela 5’ and ‘F12/1’) on phenolic acid and flavonol content of “Lapins” sweet cherry was investigated. Phenolic acids and flavonols were isolated from sweet cherries and analyzed by using reversed phase high-performance liquid chromatography (RP-HPLC). The major phenolic acids in sweet cherries were neochlorogenic acid (18–50 mg kg⁻¹), chlorogenic acid (19–62 mg kg⁻¹) and p-coumaric acid derivatives (15–125 mg kg⁻¹). The amount of flavonol quercetin-3-rutinoside (8–37 mg kg⁻¹) was significant as well. There are significant variations in the phenolic compound content among sweet cherry fruits grown on trees grafted on different vegetative rootstocks. The significantly higher chlorogenic acid, neochlorogenic acid, p-coumaric derivative and quercetin-3-rutinoside contents were found in sweet cherry fruits grown on trees grafted on ‘Weiroot 13’ and ‘PiKu 1’ rootstocks. Sweet cherries produced on trees grafted on other rootstocks had significantly lower phenolic compound content.     

S-genotyping of 25 sweet cherry (Prunus avium L.) cultivars from the Czech Republic

Sweet cherry (Prunus avium L.) is a self-incompatible species. Determination of the S-genotypes of cherry cultivars is crucial for breeding and to select appropriate cultivars for cross-fertilisation and fruit set. In this study, we characterised the S-genotypes of 25 sweet cherry cultivars, some of which had being bred at the Research and Breeding Institute of Pomology (RBIP), Holovousy, Czech Republic, and others were European cultivars in the RBIP collection. S-genotyping was carried out by polymerase chain reaction using consensus primers for the S-RNase and SFB genes, and capillary electrophoresis. Nine different known S-haplotypes (S₁, S₂, S₃, S₄, S₅, S₆, S₉, S₁₃, and S₁₆) were identified and the cultivars were assigned to 12 incompatibility groups. One local cultivar, ‘Pta?ka z Plzně’, originated from a wild forest seedling and used as a pollinator, was assigned to Group 0 of universal donors. The pedigree of some cultivars was confirmed by their S-genotype. This study represents the ?rst comprehensive S-genotype screening of sweet cherry genetic resources in the Czech Republic and will be useful for the design of crossing programmes and orchard management of these sweet cherry cultivars.     

Influence of Melatonin Treatments on Fruit Quality and Storage Life of Sweet Cherry cv. ‘Sweetheart’

The study was carried out to determine the effect of melatonin on quality and postharvest life of sweet cherries (Prunus avium L.) cv. ‘Sweetheart’ during storage. The fruits were dipped at different concentrations of melatonin (0, 250, 500 and 1000?µmol l^?1 for 10?min) and distilled water as control. The changes of sweet cherries were assessed at 7?day intervals by evaluating the following quality parameters: firmness, soluble solids content, titratable acidity, respiration rate, color values (L* and chroma), ascorbic acid content, total anthocyanin content, total phenolic content, and antioxidant activity. The results showed that increasing the dose to 1000?µmol l^?1 melatonin had a remarkable effect on maintaining the quality of sweet cherry. 1000?µmol l^?1 and 500?µmol l^?1 melatonin treatments significantly inhibited the decrease in firmness, ascorbic acid, total phenols, total anthocyanin, antioxidant content and reduced color changes and respiration rate. However, the total soluble solids content and titratable acidity of the fruit were not influenced by melatonin applications. These findings indicate that melatonin treatment may be effective in maintaining quality and bioactive compounds of sweet cherry fruit.

     

Ergebnisse der Leistungsprüfungen der Süßkirschensorte ‚Stella‘ auf Gisela- und Weiroot-Unterlagen in Bulgarien

Zusammenfassung Die Leistungsprüfungen wurden im Zeitraum 1997 bis 2003 mit den Unterlagen Gisela 4 und 5, den Klonnummern 195/20 und 497/8 aus der Gisela-Serie sowie Weiroot 10, 13, 53, 72 und 158 durchgeführt. Dabei dienten Sämlinge von P1 (bulgarische Selektion aus Prunus mahaleb) als Kontrolle. Alle Unterlagen waren mit der Sorte Stella veredelt und im Dezember 1996 in der Versuchsanlage der Agraruniversität in Plovdiv, Bulgarien, im Abstand von 6 m×4,5 m gepflanzt worden. Dabei erfolgte ein Pflanzschnitt. Nach Abschluss der natürlichen Kronenentwicklung wurde jedes Jahr ein Winterschnitt vorgenommen. Der Boden wurde durch mechanische Bearbeitung offen gehalten und nach dem 4. Standjahr wurden die Baumstreifen mit Herbiziden behandelt. Die Wasserversorgung erfolgte durch eine dem natürlichen Gefälle folgende Überflutung, allerdings nicht immer zum optimalen Zeitpunkt, da keine eigene Wasserquelle zur Verfügung stand.Basierend auf den Ergebnissen bis zum Anfang des 7. Standjahres können die untersuchten Unterlagen in zwei Gruppen differenziert werden: starkwüchsig—Weiroot 10, P1 und Weiroot 13; mittelstarkwachsend bis schwachwüchsig—Gi 497/8, Gisela 4, Weiroot 53, Weiroot 158, Gi 195/20, Weiroot 72 und Gisela 5. Letztere zeichnete sich durch besondere Schwachwüchsigkeit aus. Die meisten Wurzelschosser bildeten Gisela 4, Weiroot 10 und Weiroot 13. Weiroot 53, Weiroot 72 und Weiroot 158 entwickelten deutlich weniger und P1, Gisela 5, Gi 195/20 sowie Gi 497/8 keine Wurzelschosser. Den frühesten Blühbeginn induzierte Gisela 4. Die anderen Unterlagen führten, in Abhängigkeit von den Temperaturbedingungen des jeweiligen Jahres, zu einer Verspätung der Blüte: P1 und Weiroot 10 um 1–2 Tage; Gi 497/8, Weiroot 13 und Weiroot 158 um 2–4 Tage; Weiroot 72 um 2–7 Tage; Gi 195/20 um 3–6 Tage; Weiroot 53 um 3–8 Tage und Gisela 5 um 3–10 Tage. Die Reifezeit der Früchte war bei den Bäumen auf Gisela 5 im Vergleich zu den anderen Varianten um 2–3 Tage verspätet. Gisela 5, Weiroot 72 und Gisela 4 induzierten bei der aufveredelten Sorte die höchsten Ertragsleistungen, P1 die geringsten. Bei den Bäumen auf Gisela 5 war die Fruchtgröße geringer als bei den anderen Unterlagen. Bäume auf Gisela 5 brauchen intensive Pflege. Nur wenn alle Produktionsfaktoren und kulturtechnischen Maßnahmen optimiert werden, kann das hohe Ertragspotenzial dieser Unterlage ausgeschöpft werden.     

Determination of self-incompatible genotypes in 21 cultivated sweet cherry cultivars in Greece and implications for orchard cultivation

Summary

Sweet cherry is self-incompatible due to having a gametophytic self-incompatibility system. S alleles in the style and pollen determine possible crossing relationships. Knowledge of the S allele constitution of cultivars is important for sweet cherry growers and breeders. Recently, molecular methods have been developed to distinguish between S alleles in sweet cherry.The S allele genotypes of 21 sweet cherry cultivars widely grown in Greece, including 19 not previously genotyped, were determined based on their S-RNase gene sequences using PCR analysis. Eight different S alleles in ten combinations were distinguished and two new S-genotypes (S₁S₁₃ and S₄S₃₀) were documented. Four alleles, S₁, S₃, S₄, and S₉ were widespread and together were responsible for 85% of the S-haplotypes. Therefore many of the cultivar combinations were semi-compatible. In Greece, semi-compatibility was shown to correlate with low yields. However, the cultivar ‘Hybrid Tragana Edessis x Unknown’ (S₃S₁₃) and the cultivar ‘Kapsiotika’ (S₂S₅) carry rare S-haplotypes and are therefore fully cross-compatible with most of the cultivars analysed.     

Study on Fruitset and Pollen-Compatibility Status in Sweet Cherry (Prunus avuim L.) Cultivars

Prunus avium L. is one of the most important temperate zone fruits in the world. Most of the cherry cultivars always have difficulties of fertilization and fruit set due to self-incompatibility, so they need suitable and compatible pollinizers for commercial fruit production. In this experiment, pollination compatibility of cherry cultivars of ‘Napoleon’, ‘Burlat’, ‘Zhan’, and ‘Lambert’ was studied as both pollen recipients and donors. To determine the compatibility or incompatibility of pollinizers, percent of fruit set was calculated. This research was carried out as a factorial experiment in a randomized complete block design. The final average fruit set in studied cultivars was different under self or cross-pollination. The results showed that ‘Napoleon’, ‘Zhan’ and ‘Lambert’ cultivars are the suitable pollinizers for ‘Burlat’. Also, ‘Burlat’ is a cultivar which produced many fruits under self-pollination. Therefore, ‘Burlat’ can be used as monoculture for orchard establishment. Results showed that cultivar ‘Napoleon’ was cross-incompatible with ‘Lambert’. ‘Zhan’, ‘Napoleon’ and ‘Lambert’ cultivars are founded self-incompatible and require cross-pollinations to obtain fruits.

     

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.     

Cultivars Resulting From Cherry Breeding in Germany

In Germany the sweet and sour cherry breeding is concentrated at the Julius Kühn-Institut in Dresden-Pillnitz. The main breeding goals are directed on sweet cherries for fresh market and sour cherries for processing. The selection of new cultivars is focused on fruit quality, high and stable fruit set and tolerance to biotic and abiotic stress. In result of the breeding activities in sweet cherry four new cultivars, ‘Narana’, ‘Areko’, ‘Swing’, ‘Habunt’, were selected. ‘Narana’ is an early ripening cultivar with good fruit characteristics. ‘Areko’ ripens in the middle of the cherry season some days before cultivar ‘Kordia’ and has large, firm fruits. The both cultivars ‘Swing’ and ‘Habunt’ are self-compatible and more recommended for the use in house gardening. In sour cherry breeding four new cultivars, ‘Coralin’, ‘Spinell’, ‘Jachim’, ‘Boas’, were selected. The cultivar ‘Coralin’ shows good characteristics for processing and mechanical harvest and is tolerant to fungus diseases on leaves. With the large and tasty fruits, the cultivar ‘Spinell’ is mainly suitable for fresh consumption. The both other cultivars ‘Jachim’ and ‘Boas’ have a pillar growth habit.     

早熟甜樱桃新品种‘福玲’

‘福玲’是从‘红灯’甜樱桃实生后代中选育出的早熟、大果新品种。果实肾形,果皮紫红色,平均单果质量10.4 g,可溶性固形物含量18.6%,可食率94.2%,果肉硬脆,味甜,品质好,果实发育期42 d,在烟台地区5月25日左右果实成熟,比‘红灯’早熟5 d,早实丰产,盛果期产量12 t ? hm-2,适宜在早中熟甜樱桃产区栽培。     

早熟甜樱桃新品种‘泰山蜜脆’

 ‘泰山蜜脆’是从乌克兰引进的樱桃品种‘抉择’自然授粉的杂种胚培苗中选出的新品种。果实心形,平均单果质量7.8 g,最大10.2 g。果实底色黄色,果面着红色;果肉浅黄色,肉质硬脆,肥厚多汁,可溶性固形物含量20.6%,比对照品种‘红灯’高2 ~ 3百分点,甜酸适口,品质极佳。在山东泰安地区5月中下旬果实成熟,果实发育期40 ~ 45 d,比‘红灯’晚熟3 ~ 5 d。     

Detection of genetic diversity among populations of sweet cherry (Prunus avium L.) by AFLPs

Summary

The high degree of polymorphism of AFLPs provides an efficient system for identification and genome analysis of sweet cherry (Prunus avium) cultivars and selections. The cultivars of sweet cherry have usually been characterized by assessment of phenotypic and pomological traits. AFLP markers were employed to identify 38 sweet cherry accessions and estimate the genetic diversity among this material. Ten of 18 tested primer combinations were informative with up to 80 bands per primer combination. Seven to 33% of the amplfied bands were polymorphic depending upon primer combination. Allcultivars and selections tested could be clearly identified. The objective of this work was to demonstrate the usefulness of molecular markers in revealing the genetic diversity among different sweet cherry genotypes.     

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.     

Adventitious shoot regeneration and Agrobacterium tumefaciens-mediated transformation of leaf explants of sweet cherry (Prunus avium L.)

Sweet cherry (Prunus avium L.) remains recalcitrant for genetic transformation due to the lack of efficient plant regeneration systems via organogenesis or somatic embryogenesis. In this study, in vitro shoot cultures were derived from a single mature embryo (open pollinated) of ‘Selah’ sweet cherry. Leaf explants were cultured on Woody Plant Medium supplemented with different plant growth regulators to induce shoot regeneration. The optimal regeneration at a frequency of 32.5% and an average of 1.1 shoots per explant occurred on the medium containing 4.54 µM thidiazuron (TDZ) and 2.95 µM indole-3-butyric acid (IBA). Transient transformation showed an efficient delivery of the β-glucuronidase (GUS) reporter gene (gusA) using Agrobacterium tumefaciens strain EHA105. Under the optimal gene delivery conditions, stable transformations were conducted using pGA643 and pBI-VcFT containing a blueberry FLOWERING LOCUS T (VcFT). A total of 500 leaf explants, 250 for each construct, were used for transformation. After 10-week selection, three leaf explants transformed with the pGA643 produced four kanamycin-resistant shoots, in which stable integration and expression of the nptII were confirmed by Southern blot and RT-PCR analysis, respectively. This study demonstrated that it was possible to produce stable transgenic sweet cherry using Agrobacterium tumefaciens-mediated transformation of leaf explants.     

Assessment of genetic relationships among 29 introduced and 49 local sweet cherry accessions in Turkey using AFLP and SSR markers

Summary

The characterisation of sweet cherry (Prunus avium L.) genetic resources in Turkey may help to increase their use in breeding programmes worldwide, as Turkey is the centre of origin of sweet cherry. Amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers were therefore used to analyse genetic diversity among a total of 78 local and introduced sweet cherry cultivars. Four AFLP primer combinations, and six SSR primer pairs for sweet cherry were used for genetic diversity analysis. A genetic similarity matrix was calculated using the combined data from AFLP and SSR analyses with simple matching coefficient. Genetic similarities among the sweet cherry genotypes studied were higher than 42%. No two accessions had an identical AFLP and SSR marker profile, indicating that all 78 genotypes were unique. An UPGMA dendrogram, based on the similarity matrix, revealed 18 separate Groups at or above the 70% similarity level. While some Groups consisted of both introduced and local genotypes, other Groups had only local genotypes. This result suggests that there was broad genetic diversity among the local Turkish sweet cherry genotypes, which was not present in the introduced sweet cherry accessions. The genetic variation present in local Turkish sweet cherry genotypes may be useful for future breeding programmes. We found that the use of both SSR and AFLP marker systems was effective for distinguishing between genetically-close sweet cherry genotypes. These marker systems can be used to complement pomological and morphological markers during the characterisation and identification of sweet cherry genotypes.     

Determining the S-genotypes of several sweet cherry cultivars based on PCR-RFLP analysis

Summary

Based on the cDNA sequences encoding sweet cherry self-incompatibility associated ribonucleases (S-RNases), a PCR-based S-allele typing system for sweet cherry cultivars has been recently developed. Using this technique, we determined S-genotypes of the three newly released Japanese cvs Kouka-Nishiki, Beni-Sayaka and Beni-Shuho and one British cv Merton Glory that was classified as a Universal Donor, which is able to be used as a pollen donor for all cultivars in pollen incompatibility groups I to XIII. Furthermore, we also determined the partial sequences of the S-RNase genes of ‘Rainier’ (S¹S⁴)‘ and ‘Sato-Nishiki (S³S⁶)’,which leads to the development of a more reliable S-allele identification method of PCR-RFLP for sweet cherry cultivars. Total DNA isolated from leaves of the four cultivars along with those from ten cultivars with known S-genotypes were PCR amplified with two sets of primers that were designed from DNA sequences encoding the signal peptide (Pru-T2) and two conserved domains (Pru-C2 and Pru-C4R) of sweet cherry S-RNases. By comparing the size of PCR products on agarose gel, the 5-genotypes of ‘Kouka-Nishiki’, ‘Beni-Sayaka’, ‘Beni-Shuho’ and ‘Merton Glory’ were suggested to be S¹S³, S¹S⁶, S⁴S⁶, and S⁴S⁶, respectively. Two of these three S-genotypes (S¹S⁶ and S⁴S⁶) were found for the first time. DNA sequencing of PCR products from S-alleles of ‘Rainier’ and ‘Sato-Nishiki’ revealed that Ban II, Nru I, Apa LI and Ava I sites, respectively, were unique in the S¹-, S³-, S⁴- and S⁶- sequences flanked by Pru-T2 and Pru-C4R primers. RFLP analysis of the PCR products using these enzymes confirmed that S¹-, S³-, S⁴- and S⁶-alleles of the four cultivars contained the respective restriction enzyme recognition sites.     

Induction of lateral branches in tree fruit nursery stock with propyl 3-t-butylphenoxy acetate (MB 25, 105) and Promalin (GA4+7 + 6-benzyladenine)

Sprays with 250–2000 mg l^?1 propyl 3-t-butylphenoxy acetate (MB 25,105) and 250 and 500 mg l^?1 GA₄₊₇ + 6-benzyladenine (Promalin) were applied to scion growth of first nursery trees of ‘Bartlett’ pear (Pyrus communis L.), ‘Bing’ cherry (Prunus avium L.) and ‘Oregon Spur II Delicious’ apple (Malus domestica Borkh.) to stimulate lateral branching in the nursery. Most treatments significantly increased branching compared to untreated controls. Combination sprays of the two chemicals were usually better than either used alone. Chemical treatment usually produced greater branching and wider branch angles than mechanical heading. Both chemical and mechanical treatments reduced tree height and caliper, but the decrease was not always statistically significant.     

5种樱桃砧木光合特性的初步研究

 以马哈利、大青叶、本溪山樱、吉塞拉5号及考特5种樱桃砧木为试材, 通过气体交换等方法研究了它们的光合特性。结果表明, 马哈利对低浓度CO2及高光强利用能力均强, 光合能力最大; 考特对弱光利用能力显著强于马哈利和吉塞拉5号, 但其光合能力最弱; 5种樱桃砧木新梢中下部、中部、中上部叶面积占新梢总叶面积比率及相应3部分光合产物占总光合产物比率均明显高于基部和顶部所占比率,中下部及中部叶片较大且发育良好, 是整个新梢叶片光合生产力的主要贡献者。