共查询到20条相似文献，搜索用时 843 毫秒
1.
R.A. Webb 《Scientia Horticulturae》1976,4(3):247-254
Examination of black currant data relating berry weight, seed number and position on the raceme indicates that there is an upper limit of berry weight (potential weight) for each position on the raceme. This limit may be a genetic character of the cultivar.A suitable combination of seed number and rate of development is necessary to reach potential berry weight and berries may be sub-maximal from deficiency in either or both factors arising from different causes.Berries seem to develop within a range of potential sizes so that differences in numbers of berries do not affect the mean size.Crop yields can be related to 5 variable components affecting fruit number and to 2 affecting fruit size, apart from the possible genetic limit. Of these components 5 operate in the pre-fruiting year ending with the termination of flower initiation, and 2 affect performance in the fruiting year.Partitioning the shortfall in numbers and size to the variable components can direct attention to deficiencies in particular phases of development causing reduced yields. 相似文献
2.
The canopy of a mature ‘Kerman’ pistachio (Pistacia vera L.) tree is composed of two types of shoots: short-shoots composed entirely of preformed nodes, and long-shoots composed of both preformed and neoformed nodes. Since the production of these two types of shoots is known to be related to rootstock and rootstock influences yield of pistachio the relationship of these two types of shoots to yield was investigated during two cropping years. Individual short-shoots produced significantly less yield and had fewer fruit clusters per shoot compared with long-shoots, but collectively produced 55–60% of the total yield. Long-shoots positively affected yield components in one year, but had no effect in the other year. Whether the differences in the one year were due to canopy position and light interception or differences in the carbohydrate allocation within the two types of shoots could not be determined from the current data. Long-shoots initiated more inflorescence buds, although inflorescence bud formation was restricted to the preformed growth and only the 3–4 earliest neoformed nodes. However, when expressed as a percentage, long-shoots retained a lower percentage of initiated inflorescence buds, compared with short-shoots. Regardless of shoot type, less than half of the retained inflorescence buds produced mature fruit clusters. Thus, inflorescence bud retention, a previously hypothesized mechanism of pistachio alternate bearing, may not be the primary limiting factor to yield in pistachio. 相似文献
3.
Hilary Hughes 《The Journal of Horticultural Science and Biotechnology》2013,88(3):253-262
In experiments over the period 1962–64 in southern England the effects of runner size, planting time and in-row spacing were compared with regard to the yield of one-year strawberry plants. Planting time had the greatest effect. Early planting markedly increased yield, though runner size interacted with it. In August, runner size had no effect, very small runners yielding as well as large ones but, from September planting, large runners outyielded smaller runners. Plots with spacing of six inches in the row outyielded those with spacing of twelve inches.The experimental treatments did not have a marked effect on the yield of large berries in 1962, but in 1963, when growth was less vigorous, treatment effects were similar to those on overall yield. The yield of very early, ripe fruit was greatest from the September-planted runners. Plant spacing had no effect on time of ripening.The difference in growth and crop between the two years was probably related to the soil and to air-temperature differences each autumn after planting.In the second season of each trial, plant spacing was doubled, by removal of alternate plants. The original planting treatments had few significant effects on the yield from the spaced, two-year old plants. From both one-and two-year-old plants Cambridge Favourite outyielded Cambridge Rival, but the latter gave more early ripe fruit and less waste fruit. 相似文献
4.
Two shading experiments on the sultana are described, a preliminary one in which shades of different intensities were used during October and November, and a main experiment in which shades reducing light intensity by about 70% were applied for different lengths of time between October and January.In the season of shading, bunch weight was reduced because of smaller, and possibly fewer, berries by shades of greatest intensity in the first experiment. In the second, shades in position later than 8th December reduced berry size, and yield was depressed when shading lasted for at least six weeks.In the season following shading, fruitfulness and consequently yields were severely depressed where light intensities had been reduced by about 70% for at least four weeks between early November and mid-December. The only other yield component affected was sugar concentration of the berries which was increased where fresh yield was depressed, but not enough to prevent depression of dried yield also.It is concluded that light intensity is an important factor for fruit bud formation in the sultana; reduction of light is inhibitory, but only during the period of inflorescence initiation. 相似文献
5.
High Correlation coefficients have been found in the application of the formula: to data for a large number of strawberries from nine cultivars. Of the terms in the equation (Total no. of achenes — C) was found to be different in different cultivars and to be related to the position of the berry on the inflorescence, but there was no constant relationship between the achene numbers in the different ranks of berry. Whether the numbers of achenes per berry can be altered by environmental or cultural treatments was not resolved. F, a term having the dimensions of weight per area, represents weight per unit area of berry surface and seems to be constant amongst plants of a cultivar subject to uniform treatment, but differs between cultivars and treatments.The number of achenes per cm2 of surface on ripe berries is a measure of berry development in the fruiting season and may be affected by environmental and managerial factors and by internal competition between fruits and leaves on the same plant.The interactions of these factors on berry size enable two stages to be recognised at which size is determined, namely during flower formation, when achene numbers and possibly F are fixed, and during fruit development after pollination when the term for spatial distribution of achenes is settled.It is suggested that an examination of the effects of different treatments on each of the size components might enable a distinction to be drawn between the influence on yield of genetic characteristics on the one hand and intrinsically variable characteristics subject to external influence on the other hand, thus clarifying the type of research and/or development needed to enable growers to achieve maximum yields. 相似文献
6.
Light-Modulated Temperature Control and the Response of Greenhouse Tomatoes to Different CO2 Regimes
A light-modulated greenhouse controller that varied the air temperature with incoming solar radiation was used in an experiment to compare the response of Craigella, Eurocross B and J172 tomatoes from first anthesis to the end of fruit harvesting to light-modulated and steady day-time air temperature regimes at CO2 concentrations of 600 and 1200 volumes per million.The yield of marketable fruit obtained from the light-modulated temperature regime was on average 26% higher after 6 weeks of picking and 9% higher after 22 weeks of picking than that from the steady temperature treatment. An increase in CO2 concentration from 600 to 1200 vpm resulted in overall increases of 15% and 8% in the early and final yields of ripe marketable fruit respectively. Tomatoes grown under a light-modulated temperature regime reached the half-harvest date on average 5 days ahead of those grown in a steady temperature regime. The difference in earliness of cropping resulting from CO2 enrichment to 1200 instead of 600 vpm was 3 days. J172 was the most successful cultivar judged by marketable yield and estimated gross monetary returns. 相似文献
7.
R.A. Webb 《The Journal of Horticultural Science and Biotechnology》2013,88(2):199-204
Examination of berries taken from a commercial holding and from an Experimental Station has shown that it is possible to attribute to each position on the strig a maximum berry weight under the conditions of cultivation. From this can be calculated the shortfall of the crop below its potential best.Further examination of the data has enabled the shortfall to be partitioned between ‘run-off’ and two factors affecting berry size, the number of seeds in the berry and the weight per seed.In the two cases examined yields were less than half the best possible in the situation, but the sites differed as to the cause of this. On the commercial holding the major loss was due to poor berry development, whereas on the Experimental Station where irrigation had reduced loss of this type inadequate pollination was the main cause of reduced berry size. ‘Run-off’ accounted for one quarter of the crop in each case.It is also suggested that, as with strawberries, crop potential is fully established before flower emereence. 相似文献
8.
R. A. Webb B. A. White R. Ellis 《The Journal of Horticultural Science and Biotechnology》2013,88(1):99-110
The crops harvested from maiden plants of Redgauntlet, Cambridge Vigour and Cambridge Favourite, rooted at intervals from April to November, have been examined in detail. Total crop decreased with later rooting dates, but average berry weight increased. This is attributed to the initiation of potentially larger receptacles on the flowers, to a higher proportion of primary flowers and to better berry development on the later-rooted plants. Usually the heavier total yield of early-rooted runners was due to the production of greater numbers of smaller berries, which adversely affected the profitability of the crop.The actual yield of the plants examined was only one half to two-thirds of the possible yield had all the flowers initiated produced full-sized berries. The shortfall has been examined and attributed to a serious failure of some flowers to produce berries of any sort, coupled with poor berry development resulting in the formation of fruits that were only two-thirds to four-fifths of their possible size. Fields for study are indicated that offer the prospect of substantial increases in yields. 相似文献
9.
D. W. Way 《The Journal of Horticultural Science and Biotechnology》2013,88(2):167-174
The growth and cropping of two virus-infected strawberry varieties was compared with that of clones the virus content of which had been reduced by heat therapy.The heat-treated clones of both Cambridge Favourite and Early Cambridge were considerably more vigorous, bearing more crowns than their untreated counterparts. In the first year after planting, both clones of each variety produced similar total yields, but the heat-treated clones produced a higher percentage of large fruit. Plants of the heat-treated clone of Cambridge Favourite flowered and ripened their fruit later than plants of the untreated clone in the second year, but gave a greater yield. However, the two clones of Early Cambridge gave similar yields, the increased potential of the heat-treated clone provided by a greater number of crowns being offset by reduced inflorescence formation.In order to establish whether reduction of vigour would lessen the tendency of some heat-treated clones to form barren crowns, spring planting was compared with autumn planting. Spring planting, which reduced plant size and yield of both varieties in the first season but had less effect on size and none on yield in the second season, failed to check partial barrenness in the heat-treated clone of Early Cambridge.At the end of the first growing season the heat-treated clones of both varieties showed a greater incidence of Verticillium wilt than the untreated clones but this difference was not maintained in the second year. 相似文献
10.
11.
In direct seeded tomato density experiments with constant rectangularity of 1.0 carried out at Preston and Simcoe Research Stations, Ontario, Canada in 1971, the effect of increasing plant density from 4.2 to 62.1 plants/m2 was to increase total plant weight, total fruit weight and ripe fruit weight per unit area. The proportion of ripe fruit to total fruit increased with increased density, and ripe fruit yields from a single harvest of up to 14 kg/m2 were obtained.Using the reciprocal yield-density equation
(when W is the mean weight per plant (or plant part) at density , A and B are constants, and density is the only variable) to analyse the experiments, showed that both the A and B constants were influenced by cultivar while the A constant was influenced more by fertilizer application than was the B constant. In general the effect of increased fertilizer was to increase the yield potential (
) for total plant weight and total fruit weight, but this effect was not so marked for ripe fruit weight. 相似文献
12.
R.A. Webb 《Scientia Horticulturae》1976,5(2):119-126
The potential and actual yields per bush evaluated in 14 black currant cultivars were shown to result from the interaction of 8 yield components. Of these, 4 developed in the pre-fruiting year and 4 in the fruiting year.By relating berry size to position on the raceme and to seed content, potential yields were calculated, and the shortfall in actual yield partitioned between 3 causes of loss: missing berries, insufficient seeds and poor berry development.It is suggested that the upper limit of berry size for each position on the raceme is determined genetically.From comparisons of plant performance it was concluded that yield differences are related more to a potential created in the pre-fruiting year than to differences arising during the fruiting-year. 相似文献
13.
K.J. Fisher 《Scientia Horticulturae》1977,7(1):37-42
There were 6 treatments in each of 2 series covering the range from 1–6 fruit trusses per plant. The terminal growing-points were removed 2 leaves above the last inflorescence of each treatment in the “limited-stem” series, and 2 leaves above inflorescence 6 with inflorescences removed as necessary in the “full-stem” series.The yield of trusses 2–5 in the “full-stem” and of truss 2 in the “limited-stem” series was reduced by the presence of subsequent trusses. Similar trends were apparent with trusses 3–5 of the “limited-stem” series. It was suggested that the reduction in yield was due to competition between trusses for assimilates resulting in smaller and/or fewer fruit per truss.Data is presented to suggest that the net assimilation rate in the tomato plant can be reduced due to lack of fruit load and that fruit yield can be limited simultaneously by lack of both source and sink strength. 相似文献
14.
【目的】为从枇杷果实中提取高质量的RNA,【方法】以枇杷果实为材料,对6种总RNA提取方法进行分析和比较。【结果】结果表明,在裂解前先用70%丙酮和80%乙醇分别对枇杷果皮和果肉进行预处理,再结合CTAB-LiCl法,得到的总RNA质量较好,OD260/OD280在1.8～2.2,OD260/OD230超过2.0,得率分别为幼果果皮56.78μg.g-1,幼果果肉40.62μg.g-1,成熟果果皮40.86μg.g-1,成熟果果肉9.24μg.g-1;并根据其他植物的八氢番茄红素合成酶基因(PSY)保守区设计引物,用以上方法提取的RNA为模板进行RT-PCR,得到453 bp的基因片段,其推导的氨基酸序列与其他植物的同源性高达95%,推测该片段为PSY基因。【结论】先用70%丙酮和80%乙醇分别对枇杷果皮和果肉进行预处理,再结合CTAB-LiCl法,得到的RNA质量好,可用于后续的分子生物学研究。 相似文献
15.
J. B. Duggan 《The Journal of Horticultural Science and Biotechnology》2013,88(3):189-191
Methods of establishing tomato seedlings in nutrient-film technique were compared, namely, by the use of rockwool cubes, compressed peat blocks (Jiffy 7), bitumenized paper pots filled with a loam-based compost, lattice plastic pots filled with expanded clay granules, and bare-rooted seedlings. The effects of these methods were mainly confined to the earlier stages of growth, development and fruit yield. Plant height, plant dry weight, date of anthesis, flower bud number, fruit number and the rate of picking during the first two months of cropping were affected. There was little effect on percentage fruit set or on the date of the start of picking, and only a small effect on mean fruit weight. After one month of cropping the greatest yields were obtained from plants established in loam-based compost, ccmpressed peat blocks and in clay granules; reduced yields resulted from the use of bare-rooted seedlings and rockwool cubes. After two months’ cropping the method of establishment had no effect on yield. 相似文献
16.
樱桃番茄主要农艺性状与产量的相关及通径分析 总被引：4，自引：4，他引：0
对9个樱桃番茄品种的8个农艺性状进行了相关和通径分析.相关分析结果表明,单株产量与每穗结果数呈极显著正相关,相关系数为0.5967.回归分析和通径分析结果表明,每穗结果数和单果重对单林产量形成的直接作用最大,单株穗数对产量的间接作用大;这三个性状是影响单株产量的主要因素,可作为樱桃番茄丰产育种的主要选择性状. 相似文献
17.
不同生育期弱光胁迫对番茄生长及产量的影响 总被引：1，自引：0，他引：1
于番茄的开花期、果实膨大期和果实绿熟期进行持续5周的50%自然光强的弱光处理。试验结果表明:果实绿熟期的弱光胁迫对植株干物重、各器官的物质分配率和果重影响程度最小,果实膨大期的弱光胁迫使番茄果重显著降低,而开花期弱光胁迫使坐果率和单果重显著下降,导致产量显著降低。因此,番茄对弱光的敏感程度依次为开花期>果实膨大期>果实绿熟期。 相似文献
18.
Z. Koltowski S. Pluta B. Jablonski K. Szklanowska 《The Journal of Horticultural Science and Biotechnology》2013,88(4):472-474
SummaryFruit set and yield of the following cultivars of black currant (Ribes nigrum L.): `Ben Alder', `Ben Lomond', `Ben Nevis', `Ben Tirran', `Ceres', `Ojebyn', `Titania' and `Triton' were investigated in 1994±1996. Percentage fruit set, size of berries and yield of all investigated cultivars were higher when much foraging activity of pollinating insects was observed. The bushes on open-pollinated plots set more fruit (50-200%), had bigger fruits (10±20%) and gave higher yields (60±300%) than plants isolated from insects. All eight cultivars, including `Titania', had lower fruit set when pollinated with their own pollen under nets than when subjected to free pollination in open plots. 相似文献
19.
S. Gu S. D. Jacobs B. S. Mccarthy H. L. Gohil 《The Journal of Horticultural Science and Biotechnology》2013,88(4):287-292
SummaryIn warmer regions, winegrapes ripen their fruit during the hottest portion of the growing season, producing wines of high pH, low acidity, less intense colour, and a less complex flavour. Experiments were conducted in a commercial vineyard of ‘Cabernet Sauvignon’ at Fresno, CA, USA in 2009, and in 2010, to determine if vines could be forced to enhance fruit quality. Forcing was conducted by hedging growing shoots to six nodes and removing summer laterals, leaves, and primary clusters between 14 – 70 d after anthesis in late-May, June, and July. Vines grown under conventional practices were used as controls. Forcing in June shifted fruit ripening from the hot (July and August) to the cool (October through early-November) portion of the growing season, a period with more hours at lower, more favourable temperatures. Fruit from the forced crop had smaller berries, a lower pH, higher acidity, and higher contents of anthocyanins, tannins, and total phenolics, compared with non-forced fruit. The yield and vigour of forced vines were comparable to, or slightly lower than, control vines. The best forcing treatment consisted of hedging growing shoots to six nodes and removing summer laterals, leaves, and primary clusters. Our study demonstrates the potential of forcing to address the detrimental effects of high temperatures on fruit quality in warmer regions of winegrape production. 相似文献
20.
Analysis of data relating to berries of 9 cultivars grown under different conditions indicates that the weight of ripe berries can be accounted for by the general equation where C is a numerical adjustment probably due to the non-spherical shape of berries, and F is the weight in g per unit area of tissue which forms the berry, and both may be characteristic of each cultivar under normal conditions.The number of achenes on perfect berries, equal to the number of ovules initiated on the flowers, is closely related to the position of the flower on the inflorescence. Expressing Rank value on the scale 1 : : : for Rank 1 : Rank 2 : Rank 3 : Rank 4, a general equation can be applied to all cultivars, although K and D may vary between cultivars and to a less extent within a cultivar. If these size factors are in fact basically genetic, a grower may have little scope for influencing berry size except during berry development in the fruiting-season. 相似文献