Effect of hydrogen cyanamide,mineral oil and thidiazuron in combination with tip pruning on bud break,shoot growth and yield in ‘Bourjasotte Noire’, ‘Col de Damme Noire’ and ‘Noire de Caromb’ figs

Commercial fig production is relatively new to the Mediterranean-type climate Western Cape Province of South Africa. A lack of lateral branch development impedes tree structure development and therefore adequate yields of quality fruit. The chemical rest breaking agents, Lift^® (thidiazuron 3 g L⁻¹) at 6%, Dormex^® (hydrogen cyanamide, 520 g L⁻¹) at 4%, mineral oil at 4% and a combination of mineral oil and Dormex^® at 2% each were evaluated in a split plot design in combination with tip-pruning vs. no-pruning to overcome apical dominance and increase complexity (Experiment 1). During the 2008/2009 season, an additional investigation was conducted to evaluate the use of thidiazuron and hydrogen cyanamide for harvest scheduling (Experiment 2). Dormex^® at 3% and Lift^® at 6%, were applied to dormant trees on 30 June 2008, 3 August 2008, 15 August 2008 or 30 August 2008. In general, Lift^® can be used to increase the number of buds breaking in ‘Bourjasotte Noire’ and ‘Col de Damme Noire’, while tip pruning decreased bud break with a resultant increase in shoot length. Dormex^® and oil combined decreased bud break in these two cultivars but was effective on ‘Noire de Caromb’. Where bud break was increased the resultant N + 1 shoot length was decreased. RBAs increased the number of fruit in both the breba and main crop of ‘Noire de Caromb’, but decreased fruit size of the breba crop. Our data are not conclusive as to what the reason for low lateral bud break might be but leans towards strong AD in seasons with 400 Utah CU or more, but might include some delayed foliation response in seasons with less than 200 Utah CH.     

Growth characteristic and sink strength of fruit at different CO2 concentrations in a Japanese and a Dutch tomato cultivar

The aim of the present study was to elucidate how fruit growth was limited by the source and sink capacities in a Japanese (‘Momotaro York’) and a Dutch (‘Dundee’) tomato cultivar. The two cultivars were grown hydroponically with a high-wire system in greenhouses for 25 weeks, and the growth characteristics and sink strength of fruit were determined. Fruits were pruned to four (4F) or one (1F) per truss. The latter were used to determine potential fruit growth, an indicator of fruit sink strength. Growth was also determined under normal (LC) and enriched (HC, 700 μmol mol⁻¹) CO₂ concentrations to examine the effect of source enhancement on fruit production. In both cultivars under normal CO₂, the growth rate of fruit pruned to 4F per truss was lower than that in 1F, indicating that maximum potential fruit growth was not achieved. Under HC conditions, fruit growth rate of ‘Dundee’ achieved in 4F trusses was lower than that in 1F. In ‘Momotaro York’ in HC, fruit growth in 4F trusses was close to potential. This implies that fruit growth was source-limited irrespective of CO₂ concentrations in ‘Dundee’ cultivar while fruit growth in ‘Momotaro York’ under normal and enriched CO₂ conditions was limited by source and sink strengths, respectively. Adjustments of cultural practices including increasing fruit number per truss and/or genetic approaches to enhancing fruit sink strength by breeding may improve fruit yields of Japanese cultivars under high source/sink conditions.     

Floral analysis cannot be considered as an alternative to the foliar diagnosis in the olive

Correlations between macro and micronutrient concentration of olive leaves and those obtained in floral buds at five development stages, were studied in order to evaluate the utility of floral analysis for the diagnosis of the nutritional status of olive orchards. Olive leaves from ‘Arbequina’, ‘Frantoio’, ‘Hojiblanca’, ‘Bella de España’ and ‘Picual’ cultivars were taken during July of 2002 and 2003. Samples of floral buds were collected at five development stages: closed bud (E), petal fall (G), G + 15 days, G + 30 days and pit hardening (H). Results showed a lack of signification of the correlation coefficients between leaf and floral analysis for N, P, K, Ca, Mg, B, Zn, Mn, Fe, Cu and Na in both years of the experiment. The few significant correlations obtained were not repeated in both years. Therefore, the results indicate that floral bud mineral analyses cannot substitute the foliar diagnosis to establish the nutritional status of the olive orchards.     

Comparison of two 6-benzyladenine formulations and carbaryl for post-bloom thinning of apples

Three trials assessed the effects of two 6-benzyladenine (BA) formulations, CyLex^® and Accel^®, and carbaryl/thiram (C/T) combination sprays as secondary or post-bloom thinners of ‘Fuji’, ‘Delicious’ and ‘Golden Delicious’ apples. Ethephon was applied as a primary thinner at full bloom (FB) on ‘Fuji’ and ‘Delicious’, while NAA was used on ‘Golden Delicious’. CyLex and Accel were applied at different rates at 20 days after full bloom (dAFB) while C/T was applied as a tank mix either once, twice or three times at seven day intervals from 18 dAFB on ‘Fuji’. The ‘Delicious’ and ‘Golden Delicious’ were treated with either Accel or C/T. In ‘Fuji’, all CyLex treatments achieved target crop load levels and resulted in increased fruit weights, but neither Accel nor C/T achieved thinning or fruit weight targets. In ‘Delicious’ Accel showed no thinning effect, while C/T thinned slightly. Accel had no thinning effect on ‘Golden Delicious’. Accel caused development of pygmy fruit in both ‘Fuji’ and ‘Delicious’. All C/T, CyLex and Accel treatments increased fruit soluble solids in ‘Fuji’, while the CyLex and Accel treatments also increased fruit firmness over ethephon alone. Although not achieving target levels of thinning, C/T was more effective than Accel, however neither Accel or C/T improved fruit size. It is concluded that Accel is an ineffective thinner of ‘Fuji’, ‘Delicious’ and ‘Golden Delicious’, while CyLex is an effective and consistent thinner of the difficult to thin cultivar ‘Fuji’.     

An Experiment in Pruning Cox’s Orange Pippin Apple Trees in Alternate Years

Five pruning treatments were compared on Cox’s Orange Pippin on M.II rootstock, viz.

1. Open-centre tree, established-spur pruned

2. Open-centre tree, renewal-pruned

3. Delayed open-centre tree, established-spur pruned

4. Delayed open-centre tree, renewal-pruned

5. Regulated-pruned tree.

At 15 years, secondary pruning treatments were begun and carried on for a further 7-year period, the trees being pruned by the same methods but either annually or in alternate years. Differences in growth and cropping between trees pruned to open-centre and delayed open-centre shapes were small, but open-centre trees cropped more heavily than did delayed open-centre trees when renewal-pruned, probably on account of their greater branch spread. The method used in pruning the laterals had an effect upon cropping during the first 10 years. At the end of the trial there was no effect of either primary or secondary treatments upon trunk girth, neither was there a significant difference in girth increment between the secondary treatments. Almost the same amount of wood was removed from trees pruned in alternate years as from those pruned annually, but a greater proportion of old to new wood was removed from trees pruned in alternate years. Pruning in alternate years increased the cropping of established-spur pruned trees but not with regulated or renewal-pruned trees. There was no consistently adverse effect upon fruit size but, when a year of heavy setting followed a winter when the trees were left unpruned, fruit size was reduced and early fruit thinning would have been necessary to lessen the proportion of fruit in the two smallest size grades. With this variety fruit colour was unaffected by pruning in alternate years.     

The effects of hydrogen cyanamide on budburst and fruit maturity of ‘Thompson Seedless’ grapevine

Summary

The effect of hydrogen cyanamide (H₂CN₂) on budburst and fruit maturity of `Thompson Seedless' grapes was examined. Nine year old vines of cv. Thompson Seedless grafted on R.110 rootstock and supported on overhead tendone trellis (parral), were treated with either 2% or 4% of H₂CN₂, 53 and 67 d before expected budbreak and compared with unsprayed vines. The earliest treatment with 4% H₂CN₂ enhanced budbreak and advanced fruit maturity by 17 d. However, the same concentration applied 53 d before natural budbreak advanced the date of maturity by only 4 d. All the treatments increased significantly the percentage of budburst compared with the control. H

² CN₂ had no significant effect on yield, but a positive effect on fruit quality. A higher index of maturity was obtained by the treatment: 4% H₂CN₂, 67 d before budbreak. All the treatments of H₂CN₂ induced more uniform budburst compared with the control. The best uniformity was obtained by the earliest spray using the higher concentration (4%).     

不同化学物质打破葡萄、桃休眠的研究

以保护地栽培的葡萄、桃为试材,对氰氨类、细胞分裂素、赤霉酸和KNO3打破休眠的效果进行了研究。结果表明,1.5%单氰氨、11%石灰氮可明显促使葡萄提前萌芽,提早着色9-10d;50mg/LGA3和100mg/L6-BA对打破休眠基本无效。TDZ与单氰氨混用提高萌芽率的效果最好。在2个葡萄品种上,均没有观察到单氰氨或石灰氮处理对果穗或果实品质性状的不良影响。在华光油桃上,没有观察到化学物质对提早开花或成熟有明显的作用。对葡萄和桃上应用化学物质打破休眠的有关问题进行了讨论。     

6-Benzylamino purine stimulates in vitro shoot organogenesis in Eucalyptus erythronema, E. stricklandii and their interspecific hybrids

In vitro bud and shoot organogenesis was investigated for the ornamental plants Eucalyptus erythronema var. erythronema, E. stricklandii and their interspecific hybrids cv. ‘Urrbrae Gem’ and ‘Hybrid 2.5’ by using 0.0, 0.1, 0.25, 0.5 or 1.0 μM BAP on apex and leaf explants. Callus developed on all explants and increased with all concentrations of BAP without significant differences between BAP concentrations. Buds formed on apex and leaf explants of E. erythronema and E. cv. ‘Urrbrae Gem’ especially with 1.0 μM BAP, but these buds rarely developed into shoots. Bud clusters formed on E. erythronema and E. cv. ‘Urrbrae Gem’ apex and leaf explants whereas E. stricklandii and ‘Hybrid 2.5’ produced fewer, individual buds on the explant. Shoots regenerated from apex explants of all genotypes with all levels of BAP, whereas few shoots of any genotype regenerated from leaf explants regardless of the number of buds formed. Shoots from apex explants could be multiplied successfully. Light microscopy showed meristems developed within the callus, and at the callus and bud surfaces. However, few shoots developed considering the level of bud and meristem formation. This report is the first for successful shoot organogenesis and multiplication in an ornamental eucalypt.     

Effect of Pruning and Partial Disbudding on the Cropping of Comice and Beurré Hardy Pears

The effects of three intensities of pruning on fruit set, fruit bud development, cropping and vigour of intensively grown Cornice and Beurré Hardy pears were compared over a three-year period. Severe pruning, in which extension shoots were cut back to fruit buds on the two-year-old wood, greatly increased the set of fruits per 100 flower clusters and reduced vigour, in comparison with a renewal type of pruning. Severe pruning of Comice caused a relative reduction in the number of fruit buds in subsequent years, so the improvement in fruit set did not lead to an increase in crop per tree, but with Beurré Hardy fruit bud formation was unaffected and the crop per tree was increased by hard pruning. There was an improvement in yield in relation to tree size with both varieties. Pruning to fruit buds provides a means of increasing yields per acre by ‘containing’ pear trees at close spacings without reducing the yield per tree.

Partial disbudding just before blossoming increased fruit set but not enough to offset the reduction in number of fruit buds. Supplementary pollination did not improve the yields of Comice and increased the crop of Hardy in one year only.     

设施“晚红”葡萄栽培果树破眠剂应用试验

在温室大棚栽培"晚红"葡萄的生产中,升温前1周,应用含50%单氰胺的果树破眠剂2号喷布葡萄冬芽芽眼。结果表明:应用果树破眠剂2号20倍液催芽,催芽效果好于石灰氮,萌芽期比涂抹石灰氮提前7d,花期提前6d,萌芽率提高16.2%,坐果率提高9.1%,可在生产中代替石灰氮应用。     

Long-term effects of managed grass competition and two pruning methods on growth and yield of peach trees

Ground cover competition and tree training strongly affect development of newly planted peach trees and eventual productivity of peach orchards. This experiment characterized the long-term interactive effects of three levels of competition and two pruning criteria on yield, fruit size, and marketable yield efficiency. Trees of two cultivars (’Jersey Dawn’, JD, and ‘Redskin’, RS, on Lovell) of peach (Prunuspersica (L.) Batsch) were planted in an orchard in 1993 and grown for 14 years in a vegetation free area (VFA) width of 0.6 or 2.4 m. A separate group of trees that were in the 2.4 m VFA had grass seeded beneath them in 1998 to obtain 0 m VFA. All trees were pruned to maintain canopy size with wide-angled scaffold limbs and intense pruning (IP) or upright branch form with reduced pruning (RP). In general, RS had greater yield than JD and yield was greatest in the 2.4 m VFA with RP and least in the 0.6 m VFA with IP. Cumulative marketable (≥6.35 cm) and average annual total yield of both cultivars was similar for RP trees in 0 m VFA and IP trees in 2.4 m VFA's although more of the fruit were in the largest size class (>6.98 cm) in the IP trees. Reduced pruning increased crop load. Fruit weight decreased with increased crop load more in RS than JD and this response was similar for all VFA's within each cultivar. Grass competition tended to reduce both the number and weight of fruit per tree but the average weight of individual marketable fruit was reduced only in the 0.6 m VFA of RS. Tree size was reduced by grass competition and pruning times measured from 1995 to 2000 were less in RP than IP. Consequently, marketable yield efficiency of marketable fruit (grams fruit ≥6.35 cm/cm² trunk cross-sectional area, TCSA) measured from 2004 to 2007 was generally greater in trees with RP than IP and in the 0.6 than the 0 and 2.4 m VFA. The results indicate that persistent competition will reduce total annual yield per tree but with reduced pruning the concomitant increased crop load can help maintain marketable yield.     

冬季修剪对石榴观花赏果的影响

采用冬季粗放修剪、细致修剪和不修剪3种处理,对翌年石榴挂花量、挂果量的影响进行试验研究。结果表明:采用冬季粗放修剪,可提高挂花量;采用冬季细致修剪,可提高挂果量。建议在攀西地区园林绿化中,以观花为主的石榴,宜采用冬季粗放修剪,提高观花效果;以观果为主的石榴,宜采用冬季细致修剪,提高赏果效果。     

Chilling response of ‘Granny Smith’ apple lateral buds inhibited by distal shoot tissues

Apple (Malus×domestica Borkh.) shoots were decapitated before or after chilling and then forced to budburst to determine the influence of distal inhibition (paradormancy) on the chilling response of lateral buds. Shoots were chilled and forced with the presence or absence of an inhibitory distal disbudded shoot piece. Endogenous cytokinins were determined from distal and proximal segments of shoots segmented before and after chilling and/or forcing. The isolation of lateral buds from distal inhibition by decapitation before chilling resulted in a dramatic increase in growth rate. This increase is greater than that observed in terminal buds during the normal development of acrotony on intact shoots. Distal shoot tissues appear to inhibit the chilling response of lateral buds. On intact shoots cytokinin increased more in the distal shoot tissues, but in decapitated shoots cytokinin increased more in the proximal shoot tissues. Increased cytokinin in the proximal stem segment following decapitation is possibly associated with an increased lateral bud growth rate.     

Breaking the rest of apple buds by narrow-distillation-range oil and dinitro-o-cresol

The effect of various combinations of dinitro-o-cresol (DNOC) and narrow-distillation-range mineral oil (NRO) was tested during 4 consecutive years on breaking bud-rest and on fruiting of ‘Golden Delicious’ apple trees under mild winter conditions. Breaking of lateral leaf buds was directly correlated with oil concentration between 2.4 and 8.8%, while DNOC did not increase bud break at concentrations over 0.12% in the rest-breaking spray. Lower phytotoxicity of NRO compared with winter oil allowed safe use of higher concentrations of the former.Increased lateral leaf bud-break resulted in formation of more spurs and thus increased the yield in subsequent years. These higher yields were not accompanied by reductions in mean fruit weight or in trunk diameter, suggesting an increase in overall bearing potential of the tree by the best rest-breaking treatments.     

The fruit pitting disorder—A physiological anomaly in mango (Mangifera indica L.) due to deficiency of calcium and boron

A new disorder known as fruit pitting has been observed in some Indian mango orchards during the recent years. In this disorder, there is a development of some sunken pits on fruit peel, which distract consumers. Based on preliminary observations, it was observed that deficiency of nutrients could be the cause, and hence systematic studies were conducted in five indigenous cultivars such as ‘Alphonso’, ‘Amrapali’, ‘Dashehari’, ‘Mallika’ and ‘Neelum’, and five exotic mango cultivars such as ‘Edward’, ‘Irwin’, ‘Rosari’, ‘Sensation’ and ‘Tommy Atkins’ with the aim to observe the fruit pitting incidence and degree, and to investigate its probable causes. Our studies indicated that nearly 13% of the mango fruit was affected by fruit pitting with variable degree and magnitude. All indigenous cultivars had higher incidence of fruit pitting than exotic cultivars. ‘Dashehari’ had the maximum incidence of fruit pitting (30.3%), followed by ‘Amrapali’ (28.6%), and ‘Rosari’ the least (3.4%). Our studies indicated that the incidence of fruit pitting in mangoes was nearly 13% with a significant variability among the cultivars (Table 1). Although the concentrations of most of the major nutrients such as N, P, K, Mg, and minor nutrients such as Cu, Mn, Fe, Zn, did not differ significantly. However, the pitted fruit had lower Ca (1.53%) and B (22 mg kg⁻¹) concentrations than normal fruit (2.47% and 38 mg kg⁻¹, respectively), indicating that deficiency of Ca and B probably is the cause for fruit pitting in mangoes.     

Rootstock effect on budburst of ‘Premier’ low-chill peach cultivar

To determine the effect of rootstock with different chilling requirements on the bud break of the low-chill ‘Premier’ peach cultivar (150 CH), the trees grafted on ‘Newbelle’ (150 CH) and ‘O’Henry’ (750 CH) seedling rootstocks were forced in a glasshouse after being subjected to 100, 200 and 300 CU chilling. The percentage of flower bud burst was slightly higher on ‘Newbelle’ than on ‘O’Henry’, although the difference was not significant. There was little leaf bud burst with 100 CU chilling on both rootstocks. With 200 and 300 CU chilling, the percentage of leaf bud burst and the total leaf number per tree was higher on the ‘Newbelle’ than on the ‘O’Henry’ rootstocks.     

晚熟柑橘新品种‘华晚无籽沙糖橘’

 采用芽变选种的方法,从‘无籽沙糖橘’选育出晚熟柑橘新品种--‘华晚无籽沙糖橘’。果略小,单果质量45.0 g 左右,单果平均种子数2.0 粒以内,达到柑橘无籽的标准。果实扁圆形,皮橙黄色,薄而脆;果肉橙红色,味清甜,可溶性固形物含量14.43%,肉质爽脆化渣,品质优。早结实,丰产稳性好,发梢能力强,3 月中下旬开花,1 月下旬至2 月上旬果实成熟。     

Effect of distance from early flowering pollinizers ‘Maypole’ and ‘Dolgo’ on ‘Fiji’ fruit set

An apple orchard consisting of a single cultivar under the condition of natural pollination must have suitable pollinizers such as Crab apples to ensure stable fruit production. We selected ‘Maypole’ and ‘Dolgo’ as pollinizers for the cultivar ‘Fuji’, and investigated the rate of fruit and seeds in ‘Fuji’ fruits produced by pollen of the pollinizers. We developed a method for tracing pollen flow based on the leaf color of progeny and S-RNase allele of ‘Maypole’, and on Simple Sequence Repeat (SSR) analyses of ‘Maypole’ and ‘Dolgo’. These were powerful tools for determining the distance insects (mainly Osmia cornifrons) carry pollen from the pollinizers to ‘Fuji’. Although the fruit set of ‘Fuji’ apples was not reduced with increasing distance between ‘Fuji’ apple trees and pollinizers (probably due to pollen flow from other commercial cultivars planted outside the area), the rate of ‘Fuji’ apple fruit produced by the pollen of the pollinizers decreased with increasing distance. The rate of fruit produced by the pollinizers was 84% and 77% when ‘Fuji’ was 2.5 m from ‘Maypole’ and ‘Dolgo’, respectively, and 71% and 64% when ‘Fuji’ was 5 m from ‘Maypole’ and ‘Dolgo’, respectively, but was reduced to 47% and 39% when ‘Fuji’ was 10 m from ‘Maypole’ and ‘Dolgo’, respectively. However, the spacing could cause reduced fruit size, and require extra fruit thinning for producing large fruits. It could also cause reduction of the yield for increasing the planting area of pollinizers. We recommend that pollinizers should be planted not more than 10 m from ‘Fuji’.     

柑橘新品种‘粤农晚橘’

 柑橘新品种‘粤农晚橘’是从‘砂糖橘’芽变枝条中选育而成。生长健壮,果实扁球形, 单果质量39.9 g,果皮橙黄或橙色,果肉细嫩,多汁,甜酸可口,风味浓,果汁含可溶性固形物16.0% ~ 16.89%,总酸0.606% ~ 0.89%,总糖12.2% ~ 13.92%,维生素C 163 mg · L^-1,果实可食率70%,无核, 品质优良。成熟期比‘砂糖橘’晚2.5 ~ 3 个月。适宜在广东省‘砂糖橘’适栽区种植。