Hand and Machine Pollination of Kiwifruit

ABSTRACT

Two artificial pollination field trials were carried out in Central Chile (32°S. Lat.) during the 1999-2000 season with ‘Hay-ward’ kiwifruit plants (Actinidia deliciosa (Chev.) Liang et Ferguson). The treatments for both trials used pollen collected from ‘Matua’ and included: flower to flower hand pollination; hand pollination using a velvet pad attached to a handle; and mechanical pollination using a portable pollen (1:1, pollen: licopodium) dusting machine; and a control treatment without artificial pollination. Trial 1 did not include bee hives as did Trial 2. In Trial 2, half of the selected shoots in each plant were isolated from bee pollination by means of a light fabric bag. A block design with 5 replications of one plant each was used in Trial 1, while in Trial 2 a fully random split plot (with and without isolation) with 5 replications was used. In both trials, flower to flower and pad pollination increased fruit set, fruit size, seeds and fertilized locules per fruit. Mechanical pollination also increased these variables but to a lesser degree. In the split plot design carried out in the Trial 2, even though there was an interaction between isolation and pollination treatment, the supplementary bee pollination tended to increase fruit size, seeds and fertilized locules per fruit.     

Floral biology,pollination ecology and seed production of the ornamental plant Salvia splendens Sello

Summary

In this paper, the floral biology and pollination ecology of Salvia splendens are described. All flower characteristics (red corolla, large tubular flowers with abundant but dilute nectar) indicate that S. splendens is adapted to hummingbird pollination. Honeybees, however, were also found to be good pollinators of this plant. Apis mellifera was equally effective in pollinating S. splendens as hand pollination and open pollination, resulting in a 300% increase in seed set compared with bagged control plants. The much smaller stingless bee Tetragonisca angustula was not an effective pollinator of these flowers since during visitation its body failed to touch the stigma. Although pollination seemed not to be the only limiting factor in seed production, external pollinators enhance seed production in S. splendens, and Apis mellifera is an effective, commercially available pollination agent of this economically important ornamental plant.     

Crop failure in gooseberry due to poor pollination

Some commercial plantations of gooseberry (Ribes uva-crispa L. cultivar ‘Careless’) recently carried poor crops of small fruit with few seeds. The flowers appeared normal and there was an effective pollination period of at least 11 days. Hand pollination resulted in a good set of normal fruits. Few pollinating insects were recorded on a typical affected site, but on trouble-free sites insects, particularly honey bees, were plentiful and effective in transferring pollen. On trouble-free sites, excluding pollinating insects by caging bushes resulted in a typical crop failure, but caging had little effect on the problem site. Introducing honey-bee colonies to the affected site increased fruit set and seed number by comparison with caged bushes.     

The importance of male red mason bee (Osmia rufa L.) and male bufftailed bumblebee (Bombus terrestris L.) pollination in blackcurrant (Ribes nigrum L.)

Summary

Male wild bees visit flowers to feed and, despite their lack of specialised organs for carrying pollen, simultaneously pollinate them. We analysed the pollinating efficiency of the males of two bee species for blackcurrant (Ribes nigrum L.): red mason bee (Osmia rufa L.) and bufftailed bumblebee (Bombus terrestris terrestris L.). Both bee species are commercial pollinators and many males are produced during their rearing. Gauze sleeves were used to isolate the inflorescences and to keep the males inside (one per sleeve). In each experimental group, there were six shoots with four neighbouring inflorescences (n = 24). The sleeves were also used to prevent other bees from reaching the flowers, and to allow self-pollination. Non-isolated flowers were pollinated by free-range bees. The effect of male bee pollination was similar to that of free-range bee pollination. The percentages of flowers that developed into fruit were as follows: male bufftailed bumblebee pollination, 79.5%; free-range bee pollination, 71.1%; male red mason bee pollination, 65.1%; and self-pollination, 46.4%; while the mean numbers of fruit per raceme were 5.0, 4.4, 3.6, and 2.4, respectively. The number of non-pollinated flowers per raceme (ranging from 1.3 – 2.8) exhibited an inverse relationship to these numbers of fruit. Our observations showed that male wild bees can pollinate blackcurrant flowers successfully, and could potentially be useful in other crops.     

授粉技术和单株留瓜数对鄂丝瓜1号制种效果的影响

以鄂丝瓜1号的父、母本为试材,以父本当天上午开放的雄花为花粉来源,研究了授粉时间、花粉供给量和单株留瓜数对种子产量和质量的影响。试验结果表明,母本雌花开放的当天上午和开花前1 d上午均可作为鄂丝瓜1号制种的适宜授粉时间;以1朵雄花为3朵雌花进行授粉为鄂丝瓜1号制种的首选花粉供给量;鄂丝瓜1号制种中,1株母本可以留5~6个种瓜。     

The Effect of Summer Nitrogen Applications on The Quality of Apple Blossom

A summer application of nitrogen was used to induce the production of “ strong ” flowers for comparison with the " normal ” flowers produced on trees of Worcester Pearmain given only a spring application of nitrogen.

The flowers were given various pollination treatments to provide material for an assessment of flower quality. These included the following : auto and alio self-pollination and cross-pollination with diploid apple or pear at anthesis, cross-pollinations and self-pollinations at additional daily intervals subsequent to anthesis.

The stigmas of strong flowers remained receptive for a longer period than those of normal flowers.

After cross-pollination with a diploid apple, fertilization took place in 6-7 days. After self-pollination a typical incompatibility reaction was apparent. Pear pollen tubes showed an intermediate response.

Egg sacs in strong flowers continued to enlarge after those of corresponding normal flowers had ceased to grow. The fertilized ovules and embryo sacs of strong flowers showed a more rapid acceleration in growth rate than those of normal flowers.

Cell division in unfertilized ovules also continued for a longer period in strong flowers and appeared to be correlated with the behaviour of the egg sac.

Ovule longevity provided the most striking difference between the two flower types. The ovules of strong flowers remained capable of fertilization for almost twice as long as those of normal flowers.

Abnormalities of several types were seen in ovules. The most common was the production of secondary egg sacs, a feature of strong flowers which had been self-pollinated. Three types of secondary sac, micropylar, lateral and chalazal are described and illustrated.

The effects of rate of pollen tube growth, ovule longevity and the period of stigma receptivity in limiting the effective pollination period, are discussed. It is suggested that some variations in fruit set may be due to differences in flower quality. The use of summer or early autumn nitrogen is advocated as a method of improving blossom quality in certain varieties.     

The Pollinating Efficiency of Honey-Bee Visits to Apple Flowers

Bees scrabbling for pollen set a greater percentage of the flowers they visit than bees collecting nectar.

The pollinating efficiency of visits is much greater to self-compatible than to self-incompatible varieties; on the latter the efficiency decreases as distance from the source of compatible pollen increases.

Calculations indicate that one colony of honey-bees probably provides enough foragers to pollinate sufficient flowers to give an economic set in an acre of apple orchard.     

Gametophytic self-incompatibility causes seedlessness in ‘Kagzi Kalan’ lemon (Citrus limon)

The present study aimed to study the flower and pollen structure, pollen viability, in vitro pollen germination of ‘Kagzi Kalan’ lemon (Citrus limon (L.) Osbeck), and in vivo pollen tube growth in self- and cross pollination to understand the mechanism of seedlessness. The results revealed that Kagzi Kalan had tetra-colporate spherical shaped pollen of uniform size. The results of Acetocarmine and FDA test and in vitro germination indicated normal pollen viability and germinability in Kagzi Kalan. In vivo pollen tube growth showed > 50% pollen germination on stigma in all treatments though a greater number of pollen tubes at the mid style, base of the style, and near the ovule was found in cross pollination. Contrary to this, despite optimum pollen germination (53.51–70.37%) in self-pollination treatments, none of the pollen tubes reached the base of the style due to abnormal growth of pollen tubes, viz. curvatures, inhibition of pollen tube growth, and callose deposition. The inhibition of pollen tubes at the mid style under self-pollination treatments, and production of seeded fruits under cross pollination treatments, indicate the presence of self-incompatibility and the site of inhibition of pollen tubes. Thus, gametophytic self-incompatibility (SI) caused seedlessness in Kagzi Kalan by blocking fertilization in the ovary.     

Pollinator selection in kiwifruit (Actinidia deliciosa)

SUMMARY

Pollinator performance was evaluated in kiwifruit to select pollinators for cv. Hayward adapted to the cultural conditions of southern Europe. Flowering time was determined in forty male seedlings. From, these, nine were selected for having a flowering period overlapping with ‘Hayward’. In these nine males, as well as in the commercial pollinators‘Matua’ and Tomuri’, the production of pollen was studied over two years, investigating pollen quantity through flower density and pollen production per flower. Likewise, in vitro pollen viability and its in vitro germination were recorded to study pollen quality. Finally, in vivo pollen performance was studied through fruit set and fruit characteristics in controlled hand pollinations. Two males have been selected with a flowering period coincident with ‘Hayward’, which produce more than twice as much germinable pollen than commercial pollinators. Whilst there were no significant differences in pollen quality or in fruit production, clear differences existed for pollen quantity in terms of both flower density and pollen production per flower. As pollen quantity, together with flowering time, can be easily evaluated at an early stage, this is encouraging for future selection ofkiwifruit pollinators.     

Evidence for a major role of honeybees (Apis mellifera) rather than wind during avocado (Persea americana Mill.) pollination

Summary

The purpose of this study was to determine the relative importance of honeybee (Apis mellifera) activity and wind in the pollination of avocado (Persea americana Mill.) trees. Data on the pollination rates of five cultivars of avocado, honeybee densities, ambient temperatures, and wind velocities were recorded in an orchard in Israel on 61 d over a period of 7 years. The effect of wind velocity on avocado-flower pollen under laboratory conditions was also studied. Rates of pollination showed highly positive correlations with honeybee density, whereas no correlations were observed with wind velocity. Under laboratory conditions, no effect of wind velocities equivalent to those measured in the field was observed on avocado-flower pollen. Our results agree with earlier work in which wind contributed only slightly to avocado yield. Hence, we conclude that contrasting data which show the effectiveness of wind pollination in avocado are not relevant to most avocado-growing regions, including Israel and California. It is, therefore, strongly recommended that avocado growers continue using honeybees for pollination.     

Pollen germination as affected by pollen age in cherimoya

Cherimoya (Annona cherimola (Mill.)) is a subtropical fruit tree, which is cultivated in a good range of subtropical regions. In most of these areas the crop relies on hand pollination. However, following this practice, erratic fruit set is often produced, which could be related to problems in pollen handling. Indeed, very little is known of the time that the pollen remains viable and on which is the best stage to collect the anthers or pollen from the flower. The aim of this work is to evaluate pollen germinability prior and after anther dehiscence and also how the age of pollen affects pollen vigor, understood as speed of germination. Pollen samples at different times following anther dehiscence were germinated in vitro and in vivo. Pollen up to 90 min following dehiscence performed as well as freshly dehisced pollen. However, the pollen taken 120 min following dehiscence, showed a clear reduction in vigor and germinated much slower in vivo. To overcome this short pollen germinability, pollen was taken from anthers 30 and 5 h prior to natural anther dehiscence and compared with pollen taken at anther dehiscence and 20 h later. However, a reduction in germination rate was obtained in pollen taken prior to anther dehiscence. The narrow stage at which pollen can be collected together to its ephemeral germinability explains erratic results obtained following hand pollination in this crop and these results provide the clues for an adequate pollen handling.     

Effective pollination period in durian (Durio zibethinus Murr.) and the factors regulating it

The effective pollination period (EPP) of durian was determined by both delayed and bud pollination, during which reproductive factors affecting the EPP, e.g., stigma receptivity, pollen tube growth in the style, and ovule longevity were studied histologically. This study was conducted in three distinct locations in Thailand, namely, the Chantaburi Horticultural Research Center and two private orchards in Chantaburi and Trat provinces. Results from artificial pollination revealed that at anthesis, the durian flower is receptive and has a high fruit set ratio. A mean fruit set of 50% was obtained at anthesis in the private orchard in Chantaburi province. However, the EPP of durian was found to be very short, lasting for only one night; the fruit set from pollination on the morning after anthesis ranged from 0% to 3.4%. No fruit set occurred following pollination 24 or more hours after anthesis. When compared with the flowers of other fruit species, the durian flower has a unique feature in that it blooms overnight; the following morning, there is abscission of all parts of the flower, except the gynoecium. Thus, EPP appears to be synchronized with flower longevity. On the other hand, the durian flower was receptive several hours before anthesis. The results of chemical tests, including the hydrogen peroxide test and Perex-Test^®, for the evaluation of stigma receptivity appeared to be in agreement with the EPP. However, fluorescent microscopy revealed that pollen could germinate even in the stigmas pollinated 48 h after anthesis, but the number of pollen tubes at the top of the style rapidly decreased from 34.6 (at anthesis) to 0.5 (48 h after anthesis). A correlation test demonstrated a higher correlation coefficient between the fruit set and the number of pollen than that between the fruit set and the result of Perex-Test^®. This indicated that pollen tube penetration or elongation in the style was inhibited, probably due to the deterioration of nutritional support from the pistil to the pollen tubes; this can be a limiting factor of the EPP in durian.     

Pollination requirements of eight cultivars of black currant (Ribes nigrum L.)

Summary

Fruit 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.     

毛茛铁线莲开花结实生物学特性研究

定点观察毛茛铁线莲的开花物候、开花动态、单花的功能形态特征、花粉活性、访花昆虫的种类及频率,利用去雄、套袋、人工授粉对毛莨铁线莲结实生物学特性进行观察与调查.结果表明:(1)毛茛铁线莲10～11月开花,单花花期为14～18 d.(2)在散粉当天,花粉活性及柱头可授性均最高,随开花时间的延长,柱头可授性及花粉活力逐渐降低.(3)自然结实率、自花结实率和异花结实率差异显著,其中异花结实率最高.     

Improving Pollination of Early Strawberry Crops

ABSTRACT

Our work on strawberry pollination started in 1996 because die top cultivar grown in France is ‘Gariguette’ and growers get good prices widi this cultivar very early in the season (March-April) as the quality of the product is well recognized. Crop management aimed at earliness (early covering, covering with a layer of non-woven fabric or under greenhouse polyethylene film, heating, etc.) induces the plant to flower under conditions unfavorable for pollination such as short days with low irradiation levels and temperatures around 8-10°C which hinder pollen formation. Such conditions often lead later on to problems in strawberry development and shape (large areas with unfertilized ovules, furrows, etc.). This is especially true for primary flowers, which should provide the largest strawberries. A preliminary study was first conducted to assess whether pollination was, indeed, a limiting factor for strawberry production in early crops and whether female reproductive structures also have played a role as well. When this work was completed and pollination was demonstrated as the main limiting factor for strawberry development from the first batch of flowers, the authors studied the different pollen vectors and quantified their action to determine their incidence in terms of production under “limiting” early cropping conditions.     

Effects of temporal floral resource availability and non-crop habitats on broad bean pollination

Landscape Ecology - Flowering plants can enhance wild insect populations and their pollination services to crops in agricultural landscapes, especially when they flower before the focal crop....     

Identification and characterisation of incompatibility factors in Hamelia patens Jacq. (Rubiaceae)

Summary

Hamelia patens Jacq., commonly called firebush, is a fast-growing, semi-woody, evergreen, perennial shrub in the family Rubiaceae. It is native to central southern Florida, USA and is cultivated on a wider scale as an ornamental plant in home gardens of India. From previous analyses, it was found that sexual reproduction in H. patens was limited due to self-incompatibility and was overcome by intraspecific pollination between morphologically different accessions. Diffusion plate assays, spectrophotometric analysis, and in vitro bioassays were conducted to measure RNase activity among stigma proteins. After compatible cross-pollination, the RNase activity was less than during incompatible pollination. RNase activity was present in extracts as well as leachates of the stigma. Diffusion plate assays and spectrophotometric assays were used to measure the RNase activity. In vitro assays revealed that RNase activity was essential for the inhibition of pollen tube growth. Our study confirmed that RNase-based gametophytic self-incompatibility operates in H. patens.     

4种授粉方法对切花百合不同杂交组合结籽量的影响

 以11种优质切花百合为试材, 对两种发育时期的花采用常规柱头授粉、0.1%BA处理后授粉、花粉培养液(蔗糖100 g·L ^{- 1} +H₃BO₃ 20 mg·L ^{- 1} +CaCl₂ 10 mg·L ^{- 1} ) 处理后授粉、3%食盐水处理后授粉等方法, 比较了不同授粉方法对杂交结籽的影响。结果表明: 百合亲本组合、花发育时期对杂交结籽有很大影响; 花粉培养液处理对杂交结籽普遍有促进作用, 克服了1个亚洲百合杂交系内组合的杂交不亲和; 食盐水和BA处理的作用不稳定, 在有的亲本组合中表现为促进杂交结籽, 在有的组合中表现为抑制作用。     

库车小白杏授粉生物学特性观察初报

对新疆库车小白杏的授粉生物学特性进行研究表明：（1）库车小白杏完全花比例为39.35%,不同果枝类型的完全花比例大小为中果枝﹥花束状果枝﹥短果枝﹥长果枝。（2）自花授粉试验表明,库车小白杏为自花不实类型,自然授粉结实率为5.85%。（3）疏花和液体授混合花粉可以明显提高库车小白杏坐果率,疏花50%和70%是自然授粉结实率的1.31倍和1.71倍;液体授混合花粉是自然授粉结实率的1.91倍。     

Fruit Size in Black Currant and the Assessment of Crop Potential

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.