首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 78 毫秒
1.
Summary

This study addresses vegetative growth and the uptake of nutrients and their accumulation in the vegetative and reproductive tissues of pepino (Solanum muricatum Ait.). The study was conducted in soilless plastic house conditions, with a planting density equivalent to 25.000 plants ha–1 during two seasons (1997–98 and 1998–99). The plants were sampled, fractionated into leaves, stems, fruits and roots, then dried and weighed and the macronutrient content was analysed every 30.d for 300.d after transplanting. The yield obtained was 2.kg of fruit per plant, which is 30% of the total dry weight. The relative growth rate (RGR) ranged from 0.0028 to 0.0451.d–1. The highest N, K, Ca and Mg concentrations were recorded in the leaves, and the highest P concentration in the roots. The nutrient accumulation of this yield was 10.64, 1.12, 16.06, 10.0 and 1.58.g of N, P, K, Ca and Mg per plant respectively. The highest accumulation of all nutrients was found in the leaves. The nutrient with the highest specificuptake rate was K, which ranged from 0.0037 to 0.0838.g g–1 d–1.  相似文献   

2.
Three parsley cultivars (plain-leafed, curly-leafed and turnip-rooted) were grown under conditions of 35–40% and 45–60% water deficit in order to evaluate the effect of this form of stress on plant growth, essential oil yield and composition. Plant growth (foliage and root weight, leaf number) was significantly reduced by water stress, even at 30–45% deficit. Water stress increased the yield of essential oil (on a fresh weight basis) from the leaves of plain-leafed and curly-leafed, but not turnip-rooted, parsley. However, on a m2 basis foliage oil yield increased significantly only in curly-leafed parsley. Water stress also caused changes in the relative contribution of certain aroma constituents of the essential oils (principally 1,3,8-p-menthatriene, myristicin, terpinolene + p-cymenene), but these changes varied between cultivars. The oil yield of roots was low and water deficit stress had relatively little effect on the root oil composition. It is concluded that because the biomass of plants subjected to water deficit is reduced, it is possible to increase the plant density of plain-leafed or curly-leafed parsley, thereby further increasing the yield of oil per m2. However, the application of water deficit stress to parsley essential oil production must also take into account likely changes in oil composition, which in turn relate to the cultivar.  相似文献   

3.
Summary

The influence of growing season on some physiological and biochemical variates related to fruit yield and quality was investigated in melon (Cucumis melo L.) plants cultivated in nutrient film technique in a greenhouse located at Pisa, Central Italy, from mid-March to mid-June, or from mid-July to mid-September. Compared with spring, the plants grown in summer exhibited faster growth and development, but produced fewer fruits of larger size and poorer quality due to reduced sucrose content. Growing season did not affect total leaf area, but dry-matter production and partitioning to the fruits was significantly lower in summer than in spring. Summer fruit ripened within 30–35 d after anthesis, about 14 d fewer than in spring. Higher average temperature was presumably responsible for earlier fruit maturation in summer, as in both seasons all melons were harvested after 450–500 degree-days (base temperature of 12°C) from anthesis. Fruit swelling did not account for the reduction of sucrose content in summer-grown fruits, which instead was due to shortage of photoassimilate supply and inadequate sucrose synthesis, as suggested by the rate of leaf gas exchange and the activity of sucrose phosphate synthase in the fruit flesh, as determined during the final stages of fruit development. Lower solar radiation was presumably responsible for the reduced leaf carbon assimilation in summer, as growing season did not affect leaf turgor, stomatal conductance, mineral status and chlorophyll content.  相似文献   

4.
Summary

The effects of environmental conditions, planting date and crown size on the timing, intensity and duration of cropping in the strawberry Fragaria × ananassa cv. Elsanta were investigated. Temperature was positively correlated with the rate of progress to fruiting whereas crown size had no effect. The first fruit reached harvest maturity after an estimated 891 day-degrees had elapsed above a base temperature of 2.9°C for waiting bed plants and 831 day-degrees above a base temperature of 2.4°C for cold stored plants. Temperature was negatively correlated with total yield, berry number and average berry weight for both waiting bed and cold stored plants of different crown sizes. Yield, berry number and average berry weight were positively correlated with crown size. The effect of temperature on the yield components appeared to be due to its effect on vegetative growth of the plants: canopy development was more limited at warmer temperatures. These results can be used to generate models to predict the effect of growth environment on cropping in strawberry.  相似文献   

5.
Summary

The effects of three planting dates and three plant densities, covering most of the planting dates and densities used in the Netherlands, on yield determining factors of Brussels sprouts (Brassica olerácea var. gemmifera), were studied in field experiments during three seasons. Planting dates were between the end of April and early July. Plant density ranged between 2.7 and 4.4 plants per m2. Planting late in the season initially resulted in more leaves being formed, a higher Leaf Area Index and a longer stem. During crop growth this trend was reversed to a lower number of leaves formed, and in two of the three years a lower LAI and stem length when planting was delayed. The effect of plant density on these characteristics was generally either less pronounced than that of planting date or was absent. There was no, or only limited, interaction between the effects of planting date and plant density on these characteristics. The initial rate of dry-matter accumulation after planting was higher after planting late in the season, but the final amount of standing dry matter was reduced by the late planting. Plant density did not influence the final amount of standing dry matter. There was no interaction between the effects of planting date and plant density on dry-matter accumulation. Planting date and plant density hardly influenced the radiation use efficiency. Overall radiation use efficiency was 2.2 g MJ–1. The time of bud initiation expressed as numbers of days after planting was advanced by delayed planting, but was not influenced by plant density. Planting late in the season decreased the number of buds per plant and in one of the three years also reduced the weight per bud. A decrease in the number of buds per plant due to increased plant density was more than compensated for by the increase in number of plants per hectare. The final number of buds as a percentage of the final number of leaves, was either not, or not consistently, influenced by treatment. Bud dry-matter concentration at final harvest decreased when planting was delayed, but was not influenced by plant density. There was no interaction between the effects of planting date and plant density on bud dry-matter concentration. The dry-matter harvest index of 30–45% was not greatly affected by treatments. To aim for high yields, planting should be as early as field conditions allow.  相似文献   

6.
Two experiments were carried out during two successive seasons to investigate the response of Dracocephalum moldavica L. (dragonhead) to various plant densities and compost applications. Compost levels had a promoting influence on most of vegetative growth parameters and accelerated essential oil accumulation and chemical constituents including total carbohydrate and photosynthetic pigments content. Similarly, wider plant spacing showed the greatest effect on growth components and chemical constituents. Generally, the maximum rate of compost (39.6 t/ha) combined with wider distance between plants (40 cm) had a favorable effect on most of growth characters. The same treatment gave the highest mean value for essential oil yield during the first season while the same compost rate combined with the medium distance (30 cm) gave the highest value during the second season. The main constituent of the essential oil was linalool followed by geranial. On the other hand, compost levels combined with different distances had a pronounced effect on the various essential oil constituents. It can be decisived that there is no significant difference between wider distance (40 cm) and medium one (30 cm); so, it can be recommended to apply the maximum level of compost (39.6 t/ha) combined with medium distance.  相似文献   

7.
Summary

The establishment of the optimum plant population has been shown to be one of the most crucial determinants of the marketable yield of bulbous crops. This study was conducted to determine the best plant arrangements for maximum yields and maximum bulb quality in rainfed garlic (Allium sativum L.) grown under Mediterranean conditions. The effects of row width and plant spacing on the yield and quality of the two cvs. Morado de Pedroneras and Germidour, were investigated on Córdoba, Spain, in Vertisol Chromoxerert soil. In 1987–1988, a wet growing season, higher yields and higher bulb quality were obtained than in 1988–1989; cv. Germidour yielded more per unit of land area of higher quality bulbs during both seasons. Narrow row width and/or narrow plant spacing resulted in higher values of dry matter, LAI, LAD, CGR and yield, whereas wide row spacing and/or wide plant spacing resulted in higher ware-sized bulb yield. LAD was closely related to yield (r2 = 0.96**) and total dry matter (r2 = 0.90**). Mean leaf surface was affected by plant density and climatic conditions and showed a high positive relationship (r2 = 0.90**) with the percentage of Extra grade of bulbs (>50 mm). As a result of this study, a row width of 45–60 cm with plant spacing of 12–16 cm is recommended for cv. Germidour and 45 × 16 cm for cv. Morado, to maximize the proportion of high-quality yield under Mediterranean rainfed cropping systems.  相似文献   

8.
《Scientia Horticulturae》2005,105(2):177-195
Zucchini plants (Cucurbita pepo L.) were grown in closed soilless systems to analyze the effects of two of the most promising and used irrigation systems (drip and subirrigation) and two cropping seasons (spring-summer and summer-fall) in terms of substrate EC, growth, yield, fruit quality (dry matter, carbohydrates, protein, Vitamin C, nitrates and mineral composition), total nutrient uptake, mineral solution composition and water use efficiency (WUE). Plants grown with subirrigation had a high electrical conductivity in the upper and lower layers of the pots in both growing seasons, especially in the spring-summer season. In the spring-summer season, zucchini yield (total and marketable) was 18% lower with the subirrigation than with the drip-irrigation system, but the fruit quality was higher (dry matter, glucose and fructose concentrations), while no significant difference of total and marketable yield were recorded between irrigation systems during summer-fall season. In both growing seasons, and after 76 days of solution recycling, the variation of nutrients (N, P, K, Mg and Na) in the solution composition at the end of the experiment was lower with the subirrigation than with the drip-irrigation systems. Compared with the spring-summer season, plants grown in the summer-fall season exhibited a 35 and 33% lower total and marketable yield, respectively, but offer several benefits: earlier production (10 days), and higher fruit quality (higher concentration of glucose, fructose, sucrose, starch, P, K, and Mg), and water use efficiency. To produce 1 kg of marketable fruits 29 L of nutrient solution were necessary in the summer-fall season and 42 L in the spring-summer season. From an environmental point of view, growing zucchini during the summer-fall season represents an important practice to improve WUE especially in areas where water conservation is a concern.  相似文献   

9.
Summary

The essential oil yields and expression of related characters were compared for seven cultivar genotypes of menthol mint Mentha arvensis using two methods of planting in the winter rabi – summer season (October to July) in a sub-tropical agroclimatic environment. The crops of all the cultivars were planted in the field by (1) sowing of suckers on 2 January and (2) transplanting germinated pieces of sucker at different times between 17 March to 14 April. Staggering of transplanting time up to 7 April did not affect oil yields and the related plant growth properties of mint crops. The oil yields of the crops planted on 14 April were lower by about 30%. In the early sucker planted crops, the oil yields were about 30% higher than those obtained from the transplanted crops of 17 March to 7 April and about double that obtained from crops transplanted on 14 April. The oil yields from the crops of the superior genotype Kosi were equal to or higher than the corresponding means of all genotypes under both planting methods. The oil yield from the crops of Kosi genotype obtained by sucker sowing method was estimated as 333 kg ha–1. The corresponding average yield from the crops of this genotype obtained by transplanting of germinated suckers between 17 March and 7 April was about 293 kg ha–1 and that from the crop transplanted on 14 April was 218 kg ha–1. With the Kosi genotype, the latter two types of transplanted mint crops gave oil yields lower only by about 12% and 33% compared with the long-duration sucker-sown crop. It is concluded that a crop of mustard (brassica), Bengalgram (chickpea) or wheat sown between October and November and harvested between early March to middle of April could be taken before cropping of the Kosi genotype of M. arvensis by plantlet transplanting. These results demonstrate the potential of the following rotation of crops in the sub-tropical environments: from June/July/August to October/November (kharif cropping season), rice, maize, sorghum or pigeonpea; from November/December to February/March, mustard and Bengalgram or from November/December to April (rabi cropping season), wheat; from March/April to June/July (zaid cropping season), transplanted menthol mint.  相似文献   

10.
ABSTRACT

Composts can have beneficial effects on strawberry production and these benefits can be dependent on the type of compost used. Four commercial composts were evaluated: cow manure, spent mushroom, yard trimmings, and vermicompost. The nutrient composition, abundance of fungi and bacteria, and microbial activity were determined. Five field trials assessed effects on plant growth, root development, soil microbial activity, nutrient availability, and yield during one growing season. Manure and mushroom compost significantly increased soil electrical conductivity levels to 9.9 ± 1.7 dS/m and 7.3 ± 0.8 dS/m, respectively. Manure, yard trimmings, and mushroom composts shifted soil pH toward optimal levels for up to 7 months. Mushroom compost had the greatest effect on soil nitrate, which was up to 32 mg/kg of soil higher than non-amended soil. Significant effects on yield were more likely to occur where environmental conditions and management practices were less than optimal or compost was not routinely added. Several factors important to plant production were significantly affected by compost: soil salinity, plant establishment, soil nitrate, production curves, soil microbial activity, and soil pH.  相似文献   

11.
Summary

Growth, évapotranspiration, water relations and yield components of clementine trees (Citrus clementine, Hort ex Tan) subjected to differential drip-irrigation treatments were investigated during two seasons (1990–1992), Irrigation treatments were applied in a factorial design of two or four emitters per tree and four amounts of water (50,80,110 and 140% of tree évapotranspiration measured by a large weighing lysimeter located in the same plot), Seasonal water use in the lysimeter was 290 and 397 mm per year for 1990 and 1991, respectively, and the corresponding crop coefficient values were 0, 25 and 0, 31, Soil evaporation during selected periods of 1991 ranged from about 50% of évapotranspira tion in months with frequent rainfall to 8-30% in rainless months, The number of emitters per tree did not significantly affect soil matric tension, tree water status or tree growth, nor flowering, fruit-set or yield, Irrigation amount, however, significantly affected all these variates, Irrigation with 50% ET was insufficient in both seasons, producing high water stress and reducing tree growth, Yield was also reduced by a reduction in fruit number per tree, Optimum growth of the trees was obtained with irrigation at 110% ET which did not differ from that at 140%.  相似文献   

12.
Summary

The effects of temperature on growth, development and yield of tomato (Lycopersicon esculentum) are reviewed with special emphasis on cultivar differences. The focus is on sub-optimal temperatures, above the level where chilling injury occurs. Temperature has a large effect on all aspects of development. Leaf and truss initiation rates decrease linearly with decreasing temperature. Although these rates may be different for different cultivars their response to temperature is the same. Young plants grown at sub-optimal temperatures produce thicker leaves, so they intercept less light and therefore have a lower relative growth rate. There was no interaction between temperature and cultivar for relative growth rate and related traits. In a crop producing fruits, this aspect is less important as most of the light is intercepted anyway. At sub-optimal temperatures, fruit set is reduced as a result of poorer pollen quality. The period between anthesis and ripening of the fruit increases and, as the growth rate of the fruit at a certain developmental stage is independent of temperature, fruits become larger at sub-optimal temperature. Higher temperature leads to an increase in early yield, at the cost of vegetative growth, but may also cause a delay in later trusses. Total yield over a whole season might be equal at lower temperatures, but higher tomato prices early in the season do not make it economically profitable to reduce the temperature in the greenhouse. Short-term effects might thus be different from long-term effects. In the literature, the link between yield and whole plant growth is often missing, limiting the possibilities of studying the underlying processes that contribute to changes in yield. Breeding for cultivars with equal production at lower temperatures is hampered by the limited variation for temperature response in cultivated tomato. Therefore breeders have to look for other sources of variation, as in related wild Lycopersicon species.  相似文献   

13.
Two phases of a factorial NPK field experiment with strawberry are described and discussed. The object of the experiment was to study the effect of NPK fertilizers on soil fertility, leaf nutrient status, crop yield, and the relationships of these.

Treatments had significant effects on soil pH and soil exchangeable-K at all depths sampled, and on 0·5 N acetic acid-soluble P at 0-6 in. and 6-12 in. depths only.

Nitrogenous fertilizer had no significant effect on crop yield or fruit grade; phosphatic fertilizer had a small but significant effect on crop yield in the first season only; potassic fertilizer was effective mainly in the later stages of the experiment when it enhanced crop yield.

Nitrogenous fertilizer increased leaf-N significantly in all seasons; phosphatic fertilizer increased leaf-P in one season only; potassic fertilizer increased leaf-K in all seasons.

Leaf-K, soil exchangeable-K, soil potassium potential (AR°e) and crop yield were significantly related with each other. When individual plot values for leaf-K and exchangeable-K were correlated with crop yield, 90% of the yield variance was due to factors other than potassium.  相似文献   

14.
Different fertilizers may affect soil enzymatic activity and soil fertility dynamics. These effects were investigated in a field experiment with cucumber (Cucumis sativus L.) and the relationship with yield and soil nutrient availability was assessed. Soil enzymatic activity, measured as phosphatase, catalase, invertase and urease activities, decreased in the early growth stages of cucumber, but increased in the late ones, when plant were supplied with partially decomposed horse manure. Chemical N fertilizer inhibited soil enzymatic activity but P and K fertilizers enhanced it. Activity of different soil enzymes was positively correlated with soil NH4+–N and available P concentration, but negatively correlated with leaf N and P concentration. Cucumber yield was also positively correlated with the soil enzymatic activity. Our results demonstrate that soil enzymatic activity acted as a useful indicator of soil fertility dynamics.  相似文献   

15.
ABSTRACT

Monthly above-ground destructive sampling and partitioning of the plant into distinct component parts for growth and nutrient element (N, P, K, Ca, Mg, Na, B, Cu, Zn, Fe and Mn) analyses were used to compare elemental compositions in two red raspberry (Rubus idaeus L.) cultivars (‘Willamette’ and ‘Haida’) grown in a uniformly managed field plot. Quantitative measurements showed that the two cultivars had different growth patterns. ‘Haida’ yielded greater fresh berry weight and dry matter content than ‘Willamette’ on a per floricane basis, but, because of fewer ‘Haida’ than ‘Willamette’ floricanes in the plot after standard commercial pruning practices, fresh berry yield was similar for both cultivars on a unit area basis. ‘Haida’ berries ripened slightly earlier than ‘Willamette’. Stem, lateral and leaf growth differed between the two cultivars. Although only whole above-ground accumulation (kg ha-1) of one (Ca) of the ten elements measured was different in the two cultivars, the amounts and patterns of all nutrients in the various plant components of floricanes and primocanes differed in significant ways. In some cases, element concentrations in a specific plant component differed between cultivars while dry matter accumulation differed in the opposite way resulting in the same total accumulation in the cane involved. In other cases, there was greater accumulation in one cane type (primocane vs. floricane) than the other such that there was similar accumulation of that element in the whole plant. For Ca, accumulation in primocanes was greater for ‘Willamette’ than ‘Haida’ whereas there was no difference of accumulation in floricanes which resulted in greater accumulation of Ca in the whole above-ground plant in ‘Willamette’. Maximum accumulation of the elements in floricanes occurred generally earlier in the growing season (July to September) than in primocanes (September to October), and these maxima were frequently at different times for the two cultivars, making comparisons of nutrient compositions in the two cultivars complex. Detailed sampling periodically over the growing season in combination with element analysis of these raspberry plant components as done in this study provided a better basis for comparing nutrients in raspberry cultivars than examining element concentrations of a specific plant component (e.g., leaves) sampled once during the growing season because patterns of nutrients over time in the cultivars differed.  相似文献   

16.
Summary

Alternate bearing is a serious problem in many apple varieties. In fact, each year, apple trees have to be thinned in order to ensure a correct and constant balance between the reproductive and vegetative tendencies of the plant. In organic fruit growing, there is no alternative to the expensive and time-consuming process of hand-thinning. Under these conditions, the use of natural bio-stimulants which enhance the efficiency of nutrient uptake, plant fitness to different pedoclimatic conditions, and plant tolerance to stress, offers new opportunities to reduce the negative effects of alternate bearing. The aim of this work was to evaluate the effects of Actiwave®, a metabolic enhancer derived from the alga, Ascophillum nodosum, on ‘Fuji’ apple trees affected by experimentally-imposed alternate bearing. The experiments were carried in open field conditions over four consecutive years. Although the effect of Actiwave® was erratic from year-to-year, the compound generally reduced those problems linked to alternate bearing. Actiwave® had its most significant effect on alternate bearing plants that were also affected by nutrient deprivation due to the absence of fertilisation. In these trees,Actiwave® decreased the oscillations in yield between “on” and “off” years and increased the average fruit weight on plants affected by too-high a crop load. Treated trees also showed higher leaf chlorophyll contents (increased by 12%), with a consequent increase in the rates of photosynthesis and respiration. On the other hand, under standard conditions, in well-fertilised balanced plants, Actiwave® did not have any significant effect. This evidence corroborates the hypothesis that Actiwave® may be a useful tool to reduce alternate bearing in organic and low-input farming.  相似文献   

17.
A field experiment was conducted in Southern Italy to investigate the effect of different nitrogen (N) rates (0, 100 or 300 kg ha−1) on the number of branchings and leaves per plant, plant height, yield of above-ground fresh biomass, total leaf area, dry weight, leaf-to-stem ratio, leaf essential oil content and the essential oil quality at commercial harvest (full bloom) of the three cultivars of basil (Ocimum basilicum L.): (i) “Mostruoso mammouth” (MM); (ii) “Genovese profumatissimo” (GP); (iii) “Napoletano a foglia di lattuga” (NFL). Nitrogen fertilization up to 300 kg ha−1 increased yield of above-ground and leaf fresh biomass, leaf essential oil yield, but it did not affect leaf-to-stem ratio, plant height and the number of branchings per plant. The increase in essential oil yield induced by N fertilization depended on an increase in both leaf essential oil concentration and leaf biomass. The increase in LAI with increasing N fertilization was due to an increase in leaf number per plant rather than in individual leaf expansion. The cultivar GP was different in morphology from MM and NFL, since it had greater leaf number and plant height, but lower leaf-to-stem ratio and LAI. The physiological efficiency of N use (PE) in producing above-ground biomass was not related to N application whereas PE in producing essential oil (PE-oil) tended to increase with increasing levels of N applied. With regard to the effect of the cultivar, GP was less efficient in N use for oil production than MM and NFL since PE-oil of GP was lower while leaf N and PE-biomass were higher than the other cultivars. NFL was the richest in methyl chavicol but the lowest in linalool, whereas MM and GP contained linalool and eugenol.  相似文献   

18.
Summary

Four cultivars of each of three cucurbit species were used to examine the effects of pollen-load (i.e., the number of pollen grains deposited on the stigma of pistillate flowers) on fruit-set, seed-set, and germinability (i.e., germination percentage and germination rate) in four greenhouse experiments. Increasing pollen-load increased the number of fruit per plant in the four melon cultivars over two growing seasons, and in two non-parthenocarpic cucumbers, but had no effect on all four squash cultivars. In most cases, increasing pollen-load increased the number of fully-developed seeds, decreased the percentage of empty seeds, and tended to decrease mean seed weights. On average, melons produced 2.2 fruits per plant in the Winter, and only 0.9 fruits per plant in the Autumn. In contrast, melons produced 275 fully-developed seeds per fruit in the Autumn, but only 57 seeds in the Winter. Mean melon seed weight was higher in Autumn, and the sum of all seed yield component effects resulted a significantly higher seed yield per plant in the Autumn. Germinability of melon seeds from the Autumn season, and of squash seeds from the Winter season, were not significantly affected by pollen-load treatment. These data are contrary to the theory that microgametophyte competition has a positive effect on the vigour of the progeny. The lower germinability of melon seeds obtained by passive pollination (i.e., self-pollination in covered flowers) may be due to the fact that pollination without insect or human interference yielded only a few seeds per fruit, and, under such circumstances, there may be a survival advantage for slow and distributed germination.  相似文献   

19.
ABSTRACT

Sucker production of important clones belonging to different ploidy levels and genomic groups were assessed in three different planting seasons at Kerala Agricultural University, Thrissur, India. The study revealed that morphological characters such as plant height, collar girth, and total number of leaves recorded very strong, significant, and positive correlation with sucker production characters but negative correlation was observed with average leaf production interval and bunch weight. The number of dead suckers was found to be positively correlated with plant height, collar girth, “D” leaf area, bunch weight, and average leaf production interval. In a cluster analysis, six banana varieties that were planted in different three seasons (18 entries) and their pooled data (6 entries) were grouped into four distinct clusters each. In factor/principle component analysis, the first three major factors/principle components amounted to a total of 85.9% of the variability. The communality values of the factor analysis revealed that collar girth was the major relative contributory trait for deciding the sucker yield and production in banana.

Abbreviations: EVS: Early vegetative stage; AVS: Active vegetative stage; FBI: Flower bud initiation; FBD: Flower bud differentiation; PCA: Principle component analysis; FA: Factor analysis  相似文献   

20.
Summary

Apogee® sprays were applied to mature ‘Bartlett’ pear (Pyrus communis L.) trees as single or multiple sprays during the growing seasons of 1999 to 2003 at concentrations of 420 g ha–1 (125 mg –1) or 840 g ha–1 (250 mg–1): both reduced vegetative shoot growth. Two sprays of 840 g ha–1 applied 3–3.5 weeks apart were most effective and reduced shoot growth by approximately 40%. An application made 2 d after fall bloom was ineffective and led to more vegetative shoot growth. Single sprays of Apogee® made within 9–28 d after full bloom (DAFB) were equally effective in reducing vegetative shoot growth. Bourse shoot growth was reduced 43% by 3 April, 2001 (8 DAFB) treatment of 840 g ha–1 when bourse and vegetative shoots ranged from 2.5 to 7.5 cm in length. Subsequent single applications of 840 g ha–1 Apogee® (on April 12 or 23, 2001) did not reduce bourse shoot growth significantly. Vegetative shoot growth was also reduced by 12% (9 d after treatment) and by 38% (approximately one month after treatment) by 840 g ha–1 Apogee® applied on 3 April, 2001, (8 DAFB). In 2002, bourse shoot growth was controlled most effectively by split applications (840 + 420 g ha–1 or 840 2 g ha–1, 9 April and 24 May) and by 840 g ha–1 Apogee®, applied at 2.5 to 7.5 cm shoot growth (9 April). These split applications, as well as girdling, decreased shoot strikes in 2002, the year after treatment. Split applications of 840 g ha–1 Apogee® made in April to early May were most effective in controlling both vegetative and bourse shoot growth in most years, although single applications of Apogee® were effective in some years. Subsequent flushes of shoots tended to be controlled by split applications with the second application timed to the emergence of new shoots. Apogee® was not consistently effective in reducing the incidence of Type I or Type V secondary flowers in these trials. Single or multiple sprays of Apogee® had no measurable or consistent effect on return bloom, fruit size or shape, firmness, percentage soluble solids, or yield per tree over the period of these experiments. Apogee® appears to have promise as a shoot growth control agent in ‘Bartlett’ pear growing in California, USA, without deleterious effects.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号