Morphology and anatomy of the burl disorder of mango (Mangifera indica L.) in India

Summary

Burl, typically manifest as a swelling of the trunk and lower branches, is a relatively unknown disorder of mango (Mangifera indica L.). We studied the incidence of the disorder in trees of each of three mango cultivars in India, and its effect on fruit yields over 2 years. Information was also collected on the relationship between the growth of the burl and the age of the trees, together with details of the anatomy of the affected tissues. ‘Langra’ had the highest incidence of the disorder (80.3% of 24 studied trees affected) and the largest burl (31.8 cm diameter), followed by ‘Chausa’ (17.5%; 16.4 cm), then ‘Gulab Jaman’(7.5%; 4.0 cm). Burl significantly reduced fruit yields in ‘Langra’ (121 kg tree^–1 in affected trees vs. 162 kg tree^–1 in normal trees), but not in ‘Chausa’ (110 vs. 129 kg tree^–1) or ‘Gulab Jaman’ (100 vs. 98 kg tree^–1). The sizes of the burls increased as the ages of the trees increased from 15 to 55 years, especially in ‘Langra’ and ‘Chausa’. No pathogens or insects were found to be associated with the affected tissues. The woody tissues in the burl lacked orientation and were not specifically aligned in a transverse, radial, or tangential direction. Further studies are warranted to determine the cause of this disorder and how it can affect fruit yields.     

Thinning ‘Red Fuji’ apples with ethephon or NAA

Summary

A series of trials in Tasmania examined the thinning effects of ethephon and NAA on ‘Red Fuji’ apple. In the ethephon trials, concentrations from 25 to 600 ppm were applied at full bloom (FB) or 14 days after full bloom (AFB) to trees on either seedling or M.M.106 rootstocks. The NAA trial involved spraying concentrations of 5, 10 or 15 ppm at FB or 14 days AFB to trees on seedling rootstocks. Ethephon thinning of ‘Red Fuji’ was similar at FB and 14 days AFB. The dependence of fruit thinning on ethephon concentration was described by fitting non-linear response curves. These relationships were stronger and less variable for M.M.106 than seedling trees. Ethephon proved a satisfactory thinner for trees on both rootstocks. At the high spray volume used, the preferred concentrations at both FB and 14 days AFB would be 25 or 50 ppm for seedling and 100 or 200 ppm for M.M.106 rootstocks. NAA under-thinned at 5 ppm and over-thinned at 10 and 15 ppm at both FB and 14 days AFB. No firm recommendation can be given for NAA as a thinner of ‘Fuji’ at this stage.     

Effect of stage of ripening and ethephon treatment on color content of paprika pepper

In order to determine the proper time to harvest paprika pepper (Capsicum annuum L.) fruits to obtain maximum extractable color, two maturity indexes were evaluated. Most consistent results were obtained when fully shriveled fruits were harvested.Foliar applications of ethephon (50, 100, 200 and 500 ppm) were made on two cultivars, ‘Paprika-505’ and ‘Paprika-D.Z.’. Total extractable color and capsanthin content were determined using fully shriveled pericarp tissue. Some flower and leaf abscission was caused by treating plants with 500 ppm ethephon and leaves of plants treated with 200 or 500 ppm ethephon turned yellow. Ethephon stimulated ripening and increased the total extractable color and capsanthin levels of paprika fruits. ‘Paprika-505’ contained more total extractable color and capsanthin than ‘Paprika-D.Z.’ as a result of ethephon treatment.     

Effects of ethephon and 2,4,5-T on fruit size,rind pigments and alternate bearing of ‘Imperial’ mandarin

Ethephon and 2,4,5-T were used on ‘Imperial’ mandarin to study their effects on fruit thinning, fruit size, rind pigments and alternate bearing.Ethephon at 250 p.p.m. produced the largest and heaviest fruits. Pigment levels were not affected by 2,4,5-T, but ethephon increased carotenoids and reduced chlorophyll a and b levels. The effectiveness of a colouring agent seems to be related to its ability to reduce both levels of chlorophyll a and b provided that carotenoid levels do not decrease.Treated trees exhibited less tendency towards alternate bearing than control trees. Ethephon had a greater thinning-effect than 2,4,5-T. It also evened cropping for 2 successive years. One spray of ethephon in an “on” year would be effective in reversing and leveling cropping of ‘Imperial’ mandarin for at least 4 years under Mildura conditions.     

Effects of growth-regulating chemicals on two cultivars of Mid-Century Hybrid lily

The effects on growth and flowering of Mid-Century Hybrid lilies ‘Enchantment’ and ‘Joan Evans’ of soil drench applications of ancymidol at 0, 5, 10 and 15 ppm have been compared with those produced by drenches of chlormequat chloride, chlorphonium chloride and ethephon at 25 000, 1000 and 1000 ppm, respectively.Ancymidol inhibited stem growth more effectively than a 5000-fold greater quantity of chlormequat chloride. Chlorphonium chloride had little dwarfing effect, and ethephon, although producing height reductions similar to those obtained with 5 ppm ancymidol, delayed flowering slightly in both cultivars (significantly in ‘Enchantment’), and adversely affected overall plant appearance.Ancymidol reduced the lateral spread of foliage, increased the proportion of the total stem length bearing dead leaves, did not significantly delay flowering in either cultivar and appeared to favour the initiation and survival of secondary flowers in ‘Enchantment’.     

Potential of ethephon,NAA, NAD and urea for thinning pistachio fruitlets

Alternate bearing, the occurrence of high yield ‘on’ year followed by low yield ‘off’ year, is striking in pistachio (Pistacia vera L.). Floral buds of pistachio are formed a year before bloom, but abscise during the years with heavy crop (‘on’ year). Abscission of floral buds is due to competition between growing seeds on 1-year-old shoots and developing buds on current season growth. We studied the effects of chemical fruit thinning on alternate bearing and nut characteristics in a commercial orchard of ‘Owhadi’ pistachio cultivar during 2003–2004 in Rafsanjan, Iran. In both years, ethephon (100 and 200 mg l⁻¹), naphthaleneacetic acid (NAA) (125 and 250 mg l⁻¹) and urea (2.5 and 5%) were applied to the branch units of each individual ‘on’-year trees. The results showed that ethephon at both concentrations significantly increased fruit thinning and floral bud retention for the subsequent year. Other treatments also increased fruit thinning and floral bud retention but were inferior to ethephon.     

Effects of foliar application of boron on mango

Foliar application of boric acid, at varying concentrations, to mango cultivar ‘Langra’ significantly influenced the growth, flowering, fruiting and fruit quality. Highest values for most of the characteristics were obtained in the treatment where 0.8% boric acid was used.     

Ethephon as a fruit thinning agent for ‘Murcott’ mandarins

Ethephon (2-chloroethylphosphonic acid) was tested as a fruit thinning agent in an experiment on the mandarin cultivar ‘Murcott’.Ethephon was effective at 150 and 300 mg l^?1, but 300 mg l^?1 gave the higher yield and larger fruit sizes over a 2-year period, following a single spray application during natural fruit fall in November. The thinning percentage was also higher when ethephon was applied to trees with a heavy crop density than when applied to trees with a light crop density.     

Preharvest applications of ethephon reduce superficial scald of ‘Fuji’ and ‘Granny Smith’ apples in storage

In 1989 and 1990, preharvest applications of 2-chloroethyl phosphonic acid (ethephon) at dosages from 50–400 mg 1’1 were applied to ‘Fuji’ and ‘Granny Smith’ apples. In 1989, the greatest reduction in scald after storage on both ‘Fuji’ and ‘Granny Smith’, relative to the untreated control resulted from applying 400 mg 1^?1 ethephon five weeks before harvest and was 45% and 55% of controls, respectively. On ‘Granny Smith’ 400 mg 1^? was also effective when applied three weeks before harvest. In 1990, preharvest applications of ethephon at either 200 or 400 mg 1^?1 reduced scald in both cultivars relative to the controls. Ethephon applied six weeks before harvest had no dosage effect on scald reduction after storage. There was no consistent effect on fruit maturity at harvest from any treatment in either year, and no effect on quality of fruit out of storage.     

Effects of pruning intensity on the biochemical status of shoot buds in three mango (Mangifera indica L.) cultivars planted at high density

Summary

Mango (Mangifera indica L.) trees grown at high density show a decline in flowering and fruiting after good fruiting years as a result of various factors. Annual pruning can restore production and productivity in such trees. Chlorophyll, total sugars (TS), total phenolics (TP), and proline contents as well as polyphenol oxidase (PPO) activities, were measured in the 2005–2006 and 2006–2007 seasons in shoot buds with a few leaves in three mango cultivars (‘Amrapali’, ‘Mallika’, and ‘Dashehari’). Trees were grown at high density in an orchard and the aforesaid parameters were measured 1 month after different degrees of pruning (Stage I) and after subsequent fruit bud differentiation (FBD; Stage II). Severely-pruned mango trees had the highest contents of chlorophyll a, while chlorophyll b and total chlorophyll contents were found to be highest in moderately-pruned trees. Lightly-pruned trees had the highest contents of reducing sugars (RS), whereas TS contents were highest in severely-pruned trees. The contents of RS and TS increased in shoot buds during the FBD stage. A moderate intensity of pruning significantly increased TP contents, while the lowest TP contents were recorded in non-pruned trees. ‘Off’-year shoots had higher TP contents than ‘on’-year shoots. Irrespective of pruning intensity, shoot buds of ‘Mallika’ trees had the highest PPO activities, with lower levels in ‘Amrapali’ and ‘Dashehari’ shoot buds. PPO activities were reduced at the FBD stage in ‘on’-year shoots. Severely-pruned trees had the highest PPO activities, while the lowest PPO activities were recorded in lightly-pruned trees. Shoot bud proline contents were found to be highest in non-pruned trees, and decreased with increasing pruning intensity. Thus moderate pruning can be adopted in high density orchards to obtain sustainable production with improved maintenance of canopy architecture.     

Relations between the concentration of diffusable and extractable gibberellin-like substances and the alternate-bearing behaviour in apple as affected by chemical fruit thinning

The levels of diffusable and extractable gibberellin-like substances (GA_s) of apple fruits were investigated in the alternate-bearing ‘King of the Pippins’ and the regularly fruiting ‘Golden Delicious’, using the barley endosperm bioassay. During 1977 and 1978 there were marked differences between the two cultivars in both the chronological appearance and the absolute amounts of diffusable GA_s. The application of fruit-thinning chemicals (carbaryl, ethephon, NAAm) to ‘King of the Pippins’ suppressed the early increase of GA_s in diffusates, which normally occurs during the second week after full bloom. The following year, the thinned trees exhibited heavy flower- and fruit-set, while the untreated control trees showed a very poor bloom. The later appearance of the GA peak in diffusates from fruits of ‘Golden Delicious’ (5 weeks after full bloom), was not accompanied by a similar inhibitory effect on subsequent flowering.In contrast to their effect on the levels of diffusable GA_s, the thinning-treatments caused no real change in the amount of extractable GA_s, which was very similar in fruits from both cultivars.     

秋季叶施尿素及乙烯利对枣树贮藏氮素的影响

枣树(Zizyphus jujuba Mill.)秋季叶施尿素、乙烯利及尿素十乙烯利均可促进叶片及落性枝的氮素向树体回流,增加树体贮藏氮素水平,尤以尿素 200ppm乙烯利的效果最佳;尿素及乙烯利处理均增加了次年枣吊长度、平均单果重及枣果还原糖含量;尿素处理还显著增加了叶片及新梢含氮量,座果数,但降低了枣果蔗糖含量。枣树秋冬季地上部与根系具有同等重要的贮藏氮素作用;蛋白态氮是主要贮藏形态,为非蛋白态氮的2—3倍。     

Manipulating Regular Bearing in ‘Golden Delicious’/M9 Apple Trees using GA4+7 and Ethephon

Control of regular cropping in apple is considered critical for fruit growers to ensure their economical sustainability. Irregular flowering can be mitigated by plant growth regulators thanks to their promotion or inhibition effects. In this study, responses of GA₄₊₇ and ethephon on alternate bearing in ‘Golden Delicious’/M9 were examined. GA₄₊₇ and ethephon were applied on the same trees during three consecutive years (2010–12). Flowering, yield, shoot growth, and also some fruit quality parameters were assessed. GA₄₊₇ appeared to be more effectual to regulate alternate bearing. The alternate bearing index calculated with yield in successive years was high in control (0.91), moderate in ethephon (0.71), and low in GA₄₊₇ treated trees (0.41). Modified alternate bearing index, based on cluster number, indicated moderate intensity in GA₄₊₇ (0.53) and high intensity in the others. Although GA₄₊₇ reduced crop density at about 50%, there was little variation in yield per tree and crop efficiency due to increasing of fruit size. GA₄₊₇ did not increase shot length after establishment of equilibrium between vegetative and generative growth in 2012. Ethephon slightly reduced vegetative growth and relatively increased fruit size due to the decrease of fruit set.     

The influence of tree training and plant density on growth,yield components and yield of Arabica coffee cv. Ruiru 11

Assessment of tree growth and yield components of Coffea arabica L. cv. Ruiru 11, as influenced by tree training on single or two-stem systems at densities between 1600-4800 trees per ha during the first production cycle was carried out at Ruiru, Kenya over three years. Trees trained on the two-stem system tended to be taller than those on singlestems. Although the results were not clear, trees at low plant densities had thicker stems irrespective of the training system. The total number of primary branches was significantly higher on trees trained on the two-stem system. However, bearing primaries and productive wood were higher on the single-stem system during the first year of production. The number of bearing primaries and productive wood increased in subsequent production years on the two-stem system. Training trees on the two-stem system significantly depressed yields in the first production year by 245 to 842%, irrespective of plant density. Yields of clean coffee increased significantly with tree density irrespective of the tree training method. Yields over the production period increased by 33, 45,27 and 9% with increases in planting densities from 1600 to 2400, 2400 to 3200, 3200 to 4000 and 4000 to 4800 trees per ha, respectively. However, yields increased at a decreasing rate at densities above 3200 trees per ha. The proportions of the large grade ‘A’ sized coffee beans were not significantly affected by the treatments. It was concluded that it is possible to raise two stems during the first production cycle of ‘Ruiru 11’, although this might not be economical. Single stems would be preferred and a high plant density of between 3200-4000 trees per ha would be optimum during the first coffee production cycle.     

Effect of Leaf Number and Area on the Fruit Growth of Regular and Biennial Bearing Mango (Mangifera indica L.) Grown Under North Indian Conditions

Abstract

The optimum leaf number required for normal fruit growth in the regular bearing mango cultivar ‘Amrapali’ and the biennial bearing cultivars ‘Chausa’, ‘Dashehari’ and ‘Langra’ were studied by isolating individual fruits with known numbers of supporting leaves by shoot girdling at the time of fruit set. There were significant differences in the leaf area (249.01-1817.10 cm2), fresh weight (7.0-77.0 g) and dry weight (3.7-50.0 g) of leaves on shoots having 30, 20, 10 and 5 leaves as compared with control in different cultivars. In both types of cultivars, there was a progressive reduction in fruit size in terms of total fruit, pulp, peel, and seed weight with decreasing numbers of supporting leaves, however, a minimum reduction (2.4%) in fruit growth in ‘Amrapali’ was noticed with 30 supporting leaves. A nonsignificant difference in photosynthetic rate with varying number of leaves was found but its efficiency in leaves was higher in ‘Amrapali’ as compared with biennial bearing cultivars. Starch accumulation in the leaves was reduced by shoot girdling. The stomatal resistance of the leaves of girdled shoots was comparable with that of leaves on control shoots. In all the cultivars except ‘Amrapali’ it was observed that 30 leaves, the maximum retained on a shoot, could not support the growth of a single fruit to normal size. The data on rate of photosynthesis in different pool size of leaves and fruit growth in girdled and nongirdled shoots clearly show that fruit development depends not only on the current assimilates but also to a great extent on reserves. A 14CO2 feeding experiment showed a higher rate of carbon fixation in the leaves of girdled shoots than in the control shoots, but the translocation of 14C assimilated to the developing fruits on the girdled and control shoots was comparable. The results also indicated that developing fruits are major sinks for current photosynthates as more than 60 percent of the 14C exported from the treated leaf was found in the fruit in all instances.     

Promoting branching in young trees of apple cv. Red Delicious using growth regulators

Summary

In two trials in the Huon Valley of Tasmania, a mixture of GA₄₊₇ and B A (Cytolin^®) was applied to one year old spur-bearing and non-spur-bearing apple trees cv. Red Delicious at concentrations of 0, 100, 200, 300, 400 and 500 ppm in an effort to increase branching. No effects were evident on the non spur-bearing trees, and therefore Cytolin cannot be recommended. Spur-bearing trees had quantifiable responses to Cytolin, with a higher branching percentage, and reduced branch and leader length. Average branch angle was significantly increased using 100 ppm Cytolin, thereafter decreasing with higher Cytolin concentrations. Present evidence concludes that Cytolin should be used at 100 ppm on spur-bearing ‘Red Delicious’ to promote branches of adequate length, wider angles and sufficiently above the grafting union.     

International society for horticultural science calendar of events 1979

A study was made to induce flowering in an “off-year” in the strictly irregularly-bearing mango cultivar ‘Langra’. Cycocel 3000 mg/l on ringed shoots produced the largest number of flower panicles (62.3%), whereas the control recorded the lowest number (8%). MH-1500 mg/l with ringing reduced the length of the shoot, increased the diameter of the shoots, and greatly reduced the vegetative growth. All the treatments produced quite good percentages of flower buds in comparison to the control, and enhanced the flowering-time. With CEPA 400 mg/l the flowering-time was enhanced by 16 days.     

Production variability in apple crops

The problem of year-to-year variation in English apple crops was studied for the cultivar ‘Cox's Orange Pippin’ by analyzing data collected from similarly-managed commercial blocks of trees. In the period 1971–1975 yields, in each block of trees, moved in the same direction each successive year. In low-average yield years the variation in yield tended to be as extensive as in high-average yield years. Over the period studied, no relationships between climatic factors during the blossoming-period and subsequent yield could be determined. The most important factor linked with low-average yield was found to be above-normal temperatures in the pre-blossom stage.It was postulated that in order for a tree to carry a crop to its full potential, a decisive vernal temperature impulse is needed. If this dormancy break does not occur, because of above-normal temperatures, a full crop cannot be carried, even though subsequent weather conditions are optimum. Yield failures are attributed to some hormonal or other physiological imbalance occurring due to the lack of the normal decisive vernal dormancy break.It was shown that the alternate-year bearing pattern evident in apple crops in the United Kingdom, The Netherlands and Belgium between the years 1971 and 1975 could be explained by this hypothesis.     

梨幼树到结果初期春施15N–尿素的利用及其在土壤的残留与损失

2014—2016年,以‘黄冠’梨为材料,采用15N示踪技术研究了从幼树期到结果初期梨树对春季施用氮素的吸收利用及土壤残留与损失情况。研究结果表明,幼树期(2014—2015年)梨树生长以中心干和粗根等树体骨干结构建立为主,生长量相对较小;进入结果初期(2016年)后树体生长表现为树体骨干结构建立为主,枝梢等营养器官生长与产量形成并存,生长量大幅增加。整个试验期间,树体贮藏器官的标记氮素吸收量较大,其中幼树期中心干吸收量最大,结果初期粗根吸收量最大。0~100 cm土层标记氮素残留量随土层深度和施用年限增加逐渐降低,其中,施用标记氮素后第1年(2014年),土壤标记氮素残留量较高,残留率达63.61%,梨幼树对标记氮素利用率仅为3.25%。随后两年(2015—2016年)土壤残留量较低,树体对标记氮素利用率仅为0.51%和0.80%。试验结束时,幼树期到结果初期梨树对标记氮素的累计利用率为4.57%,土壤标记氮素残留量为20.34%,损失率达75.07%。     

Screening of chemicals to regulate yield of Citrus sinensis

Antimetabolites, gibberellic acid, growth retardants, abscission chemicals and white oil, alone or in combination, have been used in a series of trials to regulate the alternate bearing of ‘Valencia’ orange trees after they had been screened on ‘Navel’ orange trees.Although most of the chemicals reduced yields of ‘Navel’ orange trees, none reduced the “on”-year crop of ‘Valencia’ orange trees to a level that would increase “off”-year crop enough to even their bearing.This appears to be due to the physiological differences between the two cultivars, to the effect of the different time of fruit removal and to the different patterns of bearing of ‘Valencia’ orange trees.