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The occurring temperature increase in crop production areas worldwide is generating conditions of heat stress that negatively affect crop productivity. Tomato (Solanum lycopersicum), amajor vegetable crop, is highly susceptible to elevated temperatures. Under such conditions, fruit set is dramatically reduced, leading to significant yield losses. Solanum pimpinellifolium, a wild species closely related to the cultivated tomato, was shown to have beneficial attributes under various abiotic stress growth conditions. We have utilized a new population of backcross inbred lines originated from a cross between S. pimpinellifolium and S. lycopersicum, in order to evaluate its potential as a new genetic resource for improvement of reproductive performance of cultivated tomato under heat stress conditions. This population was screened for various heat stress-related traits, under controlled heat stress and non-stress conditions. Our results show that significant variation exists for all the heat stress related traits that were examined and point at individual lines with better reproductive performance under heat stress conditions that share a common introgression from the wild S. pimpinellifolium parent, suggesting several candidate genes as potential drivers of thermotolerance. Thus, our results place this population as a valuable new resource for the discovery of heat stress related genetic loci for the future development of heat stress tolerant tomato cultivars. [ABSTRACT FROM AUTHOR]

Sweet cherry producers annually confront climatic challenges such as spring frost and fruit cracking. This vulnerability arises primarily from spring frost during bloom or cracking at critical maturity stages during persistent rainfall. With changing climate patterns, innovative strategies are essential to mitigate these adversities. Foliar applications of melatonin (MT) at 0, 0.01, 0.05 and 0.1 mM were tested on the ‘Prime Giant’ and ‘Sweetheart’ cultivars over four different production cycles (2020–2023) to evaluate the effect on frost resilience on flower buds and fruit cracking reduction. MT-treated flower buds showed reduced malondialdehyde content and increased fruit set in most seasons, reducing their vulnerability to extreme weather events. In addition, MT consistently decreased sweet cherry cracking incidence across all studied seasons, indicating a strong effect between the fruit ripening stage and susceptibility to fruit cracking, which was cultivar dependent. Quality parameters at harvest, including fruit firmness, and colour at harvest, were either delayed or unaffected in MT-treated fruits compared with controls. However, other ripening parameters were stimulated by pre-harvest MT applications in several growing cycles, such as total soluble solids, which slightly reduced total acidity in MT-treated fruits. In summary, pre-harvest MT treatments can be a promising strategy for climate change adaptation and stress mitigation, potentially increasing sweet cherry production under extreme weather conditions.

The occurring temperature increase in crop production areas worldwide is generating conditions of heat stress that negatively affect crop productivity. Tomato (Solanum lycopersicum), a major vegetable crop, is highly susceptible to elevated temperatures. Under such conditions, fruit set is dramatically reduced, leading to significant yield losses. Solanum pimpinellifolium, a wild species closely related to the cultivated tomato, was shown to have beneficial attributes under various abiotic stress growth conditions. We have utilized a new population of backcross inbred lines originated from a cross between S. pimpinellifolium and S. lycopersicum, in order to evaluate its potential as a new genetic resource for improvement of reproductive performance of cultivated tomato under heat stress conditions. This population was screened for various heat stress-related traits, under controlled heat stress and non-stress conditions. Our results show that significant variation exists for all the heat stress related traits that were examined and point at individual lines with better reproductive performance under heat stress conditions that share a common introgression from the wild S. pimpinellifolium parent, suggesting several candidate genes as potential drivers of thermotolerance. Thus, our results place this population as a valuable new resource for the discovery of heat stress related genetic loci for the future development of heat stress tolerant tomato cultivars.

Abstract Background Cassava (Manihot esculenta Crantz) is staple food and major source of calories for over 500 million people in sub-Saharan Africa. The crop is also a source of income for smallholder farmers, and has increasing potential for industrial utilization. However, breeding efforts to match the increasing demand of cassava are impeded by its inability to flower, delayed or unsynchronized flowering, low proportion of female flowers and high fruit abortions. To overcome these sexual reproductive bottlenecks, this study investigated the effectiveness of using red lights to extend the photoperiod (RLE), as a gateway to enhancing flowering and fruit set under field conditions. Materials and methods Panels of cassava genotypes, with non- or late and early flowering response, 10 in each case, were subjected to RLE from dusk to dawn. RLE was further evaluated at low (LL), medium (ML) and high (HL) red light intensities, at ~ ≤ 0.5; 1.0 and 1.5PFD (Photon Flux Density) in µmol m−2 s−1 respectively. Additionally, the effect of a cytokinin and anti-ethylene as plant growth regulators (PGR) and pruning under RLE treatment were examined. Results RLE stimulated earlier flower initiation in all genotypes, by up to 2 months in the late-flowering genotypes. Height and number of nodes at first branching, particularly in the late-flowering genotypes were also reduced, by over 50%. Number and proportion of pistillate flowers more than doubled, while number of fruits and seeds also increased. Number of branching levels during the crop season also increased by about three. Earlier flowering in many genotypes was most elicited at LL to ML intensities. Additive effects on flower numbers were detected between RLE, PGR and pruning applications. PGR and pruning treatments further increased number and proportion of pistillate flowers and fruits. Plants subjected to PGR and pruning, developed bisexual flowers and exhibited feminization of staminate flowers. Pruning at first branching resulted in higher pistillate flower induction than at second branching. Conclusions These results indicate that RLE improves flowering in cassava, and its effectiveness is enhanced when PGR and pruning are applied. Thus, deployment of these technologies in breeding programs could significantly enhance cassava hybridizations and thus cassava breeding efficiency and impact.

Background: Cassava (Manihot esculenta Crantz) is staple food and major source of calories for over 500 million people in sub-Saharan Africa. The crop is also a source of income for smallholder farmers, and has increasing potential for industrial utilization. However, breeding efforts to match the increasing demand of cassava are impeded by its inability to flower, delayed or unsynchronized flowering, low proportion of female flowers and high fruit abortions. To overcome these sexual reproductive bottlenecks, this study investigated the effectiveness of using red lights to extend the photoperiod (RLE), as a gateway to enhancing flowering and fruit set under field conditions. Materials and methods: Panels of cassava genotypes, with non- or late and early flowering response, 10 in each case, were subjected to RLE from dusk to dawn. RLE was further evaluated at low (LL), medium (ML) and high (HL) red light intensities, at ~ ≤ 0.5; 1.0 and 1.5PFD (Photon Flux Density) in µmol m−2 s−1 respectively. Additionally, the effect of a cytokinin and anti-ethylene as plant growth regulators (PGR) and pruning under RLE treatment were examined. Results: RLE stimulated earlier flower initiation in all genotypes, by up to 2 months in the late-flowering genotypes. Height and number of nodes at first branching, particularly in the late-flowering genotypes were also reduced, by over 50%. Number and proportion of pistillate flowers more than doubled, while number of fruits and seeds also increased. Number of branching levels during the crop season also increased by about three. Earlier flowering in many genotypes was most elicited at LL to ML intensities. Additive effects on flower numbers were detected between RLE, PGR and pruning applications. PGR and pruning treatments further increased number and proportion of pistillate flowers and fruits. Plants subjected to PGR and pruning, developed bisexual flowers and exhibited feminization of staminate flowers. Pruning at first branching resulted in higher pistillate flower induction than at second branching. Conclusions: These results indicate that RLE improves flowering in cassava, and its effectiveness is enhanced when PGR and pruning are applied. Thus, deployment of these technologies in breeding programs could significantly enhance cassava hybridizations and thus cassava breeding efficiency and impact. [ABSTRACT FROM AUTHOR]

Chronic anthropogenic disturbances and climate change have been recognized as drivers of biological reorganization across human‐modified tropical landscapes, also negatively affecting the reproductive output of some plant species. Here, we investigated to what extent these drivers affect the reproductive output of Cenostigma microphyllum, a disturbance‐adapted tree species endemic to the Caatinga dry forest. The production of flowers/inflorescence, fruits and seeds was estimated for 105 plants (≥3 cm diameter at soil height) across 11 forest stands (20 × 50 m each), covering gradients of chronic disturbances (e.g. goat and livestock herbivory; wood extraction; and removal of non‐timber forest products) and aridity at the Catimbau National Park. We documented that when the drivers were analysed in isolation, the fruit‐set was positively associated with increased wood extraction, and the fruit‐set and total number of seeds/plots were reduced under increasing aridity. We also verified a complex interaction between wood extraction and aridity emerged. In forest stands, the combination of high levels of aridity and wood extraction leads to a decrease in the fruit‐set and total number of seeds/plots. Conversely, the fruit‐set and total number of seeds/plots increased in stands exposed to lower aridity but high levels of wood extraction. Our results suggest that chronic disturbances and aridity affect plant fitness in a complex way including both negative and positive effects on attributes related to plant reproductive performance, which could result in both proliferation and population decline in the same landscape. Although C. microphyllum benefits from anthropogenic disturbances and is considered a disturbance‐adapted species, it apparently does not benefit from increases in aridity, which is an expected future scenario for the Caatinga dry forest. [ABSTRACT FROM AUTHOR]

Snake fruit blooms every three months, but only one to two of the flowering seasons result in fruit production. Failure of fruit-set causes the fruit harvest seasonally. Therefore, the aim of this research was to increase off-season production by preventing the failure of fruit-set with various exogenous auxin spray. The research was conducted in the snake fruit orchard at Bebandem Sub-District, Karangasem Regency, Bali Province, Indonesia, from February to November 2019. The experiment was designed as a nested factorial with a randomized block design. The treatment consisted of three types of auxin with a specific concentration for each, IAA at 0, 25, 50 and 75 ppm, IBA at 0, 50, 100 and 150 ppm, and NAA at 0, 50, 100 and 150 ppm. The IAA, IBA, and NAA were sprayed on the flowers and leaves 3 times in March, April, and May. The results showed the highest percentage of fruit-set, fruit weight per tree, and weight per fruit obtained with IAA treatment were 59.80 %, 2,612.91 g, and 91.06 g, respectively. These results were not statistically different to those of the IBA and NAA. Furthermore, the IAA concentration of 25, 50, and 75 ppm produced a significantly higher percentage of fruit-set compared with the control. The increased fruit-set in the IAA, IBA and NAA treatments resulted in better yield than the control. The novelty of this result is that spraying snake fruit with IAA, IBA and NAA can prevent the failure of the fruit-set. Therefore, IAA, IBA, and NAA are recommended to be applied to increase off-season fruit production of snake fruit. [ABSTRACT FROM AUTHOR]

Background and aimsAdaptive explanations for variation in sex allocation centre on variation in resource status and variation in the mating environment. The latter can occur when dichogamy causes siring opportunity to vary across the flowering season. In this study, it is hypothesized that the widespread tendency towards declining fruit-set from first to last flowers on plants can similarly lead to a varying mating environment by causing a temporal shift in the quality (not quantity) of siring opportunities.MethodsA numerical model was developed to examine the effects of declining fruit-set on the expected male versus female reproductive success (functional gender) of first and last flowers on plants, and of early- and late-flowering plants. Within- and among-plant temporal variation in pollen production, ovule production and fruit-set in 70 Brassica rapa plants was then characterized to determine if trends in male and female investment mirror expected trends in functional gender.Key resultsUnder a wide range of model conditions, functional femaleness decreased sharply in the last flowers on plants, and increased from early- to late-flowering plants in the population. In B. rapa, pollen production decreased more rapidly than ovule production from first to last flowers, leading to a within-plant increase in phenotypic femaleness. Among plants, ovule production decreased from early- to late-flowering plants, causing a temporal decrease in phenotypic femaleness.ConclusionsThe numerical model confirmed that declining fruit-set can drive temporal variation in functional gender, especially among plants. The discrepancy between observed trends in phenotypic gender in B. rapa and expected functional gender predicted by the numerical model does not rule out the possibility that male reproductive success decreases with later flowering onset. If so, plants may experience selection for early flowering through male fitness.

In the new introducing almond areas, it is necessary to test the more promising almond cultivar and rootstock combinations able to guarantee the best agronomic performances according to the specific pedoclimatic conditions. With this aim, two almond trials have been established in an experimental farm located in the Latium region (Italy). The first trial (A) focused on the phenological, and agronomical influences induced by the clonal rootstock ‘GF677’ on the grafted cultivars ‘Tuono’, ‘Supernova’ and ‘Genco’, in comparison to those induced by peach seedling rootstocks, in order to identify the best grafting combination for developing “high density” plantings in this new growing area. The second trial (B) tested the phenological and agronomical influences induced by three different clonal rootstocks (‘GF677’, ‘Rootpac® 20’ and ‘Rootpac® R’), on the Spanish cultivar ‘Guara’ to identify suitable dwarfing rootstocks for “super high density” plantings in the same environment. Flowering and ripening calendars of the trial A highlighted as the medium-late flowering cultivars ‘Genco’, ‘Supernova’ and ‘Tuono’ could be subject to moderate risk of cold damages. The clonal rootstock ‘GF677’ seems to anticipate flowering and vegetative bud break by a few days in ‘Tuono’ when compared to the same cultivar grafted on peach seedling rootstocks. Furthermore, the yield per plant was always higher in plants grafted on ‘GF677’. The observations carried out in trial B highlighted as the flowering of cultivar ‘Guara’ were affected by the rootstock, with ‘Rootpac® 20’, which postponed its full bloom of about one week when compared to other rootstocks, whereas ‘GF677’ imposed more vigor to the cultivar than ‘Rootpac® 20’ and ‘Rootpac® R’.

The American persimmon (Diospyros virginiana) is a slow-growing, moderately sized tree fruit native to the forests of Kentucky. This tree fruit is in the early stages of commercial production with many cultivars selected from the wild. Small orchards of commercially available cultivars are planted in Kentucky. Persimmons are normally dioecious, and female trees require cross-pollination to produce fruit. There are two races of persimmon: the tetraploid (60-chromosome) race is centered in the southern Appalachian region, while the hexaploid (90-chromosome) race generally occupies a range north and west of the tetraploid range. These ranges overlap in Kentucky. Because the ranges overlap, cross-pollination may cause sexual incompatibility, resulting in pollination without fertilization, and therefore seedless fruits of poor quality. The objective of this study was to assess the ploidy level of commercially available American persimmon cultivars and native Kentucky persimmon populations. Leaf samples were collected from 45 cultivars and advanced selections, as well as 45 trees from native populations in Bullitt, Barren, and Franklin Counties. Flow cytometer analysis showed that only four of the selected cultivars were from the tetraploid race: Ennis Seedless, Weeping, Sugar Bear, and SFES; the remaining cultivars were from the hexaploid race. Both hexaploid and tetraploid American persimmon trees were identified in the populations sampled in the Bullitt County locations, but only tetraploid races were found in Franklin and Barren Counties. Because pollen from native trees could result in seedless fruit formation of poor quality when native seedlings are used as pollinizers in commercial production of American persimmon, ploidy level of seedlings needs to be considered. [ABSTRACT FROM AUTHOR]

Two plant growth regulators: β-NOA (50 and 80 ppm) and GA (200 and 250 ppm) were applied to emasculated flowers at anthesis to set parthenocarpic fruit, while in the control treatment fruit set was achieved by natural pollination. The application of β-NOA found ineffective in setting parthenocarpic guava. No significant differences were observed in the length and diameter of fruit between parthenocarpic and naturally pollinated seeded fruit at different days after anthesis. The mean fruit weight, TSS and ascorbic acid content of parthenocarpic fruit were similar to that of seeded fruit. Significant higher amount of total polyphenol was detected in the seeded fruit than the parthenocarpic fruit. Although 200 ppm GA showed comparatively better response to fruit growth, TSS and ascorbic acid content than 250 ppm GA but not in a statistical level.

This study was conducted to assess the Elaeidobius kamerunicus (EK) population density among the biparental dura × pisifera hybrids’ palms on deep peat-soil. Twenty-four hybrids derived from 10 genetic sources were used. Variance analysis showed that the EK population density varies between different oil palm hybrids, with a more noticeable variation of a low population mean in the male weevil across the hybrids. The highest weevil population mean/spikelet was attained on the third day of anthesis. The maximum monthly population of EK/spikelet (12.81 ± 0.23) and population density of EK (1846.49 ± 60.69) were recorded in January. Accordingly, 41.67% of the hybrids recorded an EK population density greater than the trial means of 973.68 weevils. Hybrid ECPHP550 had the highest mean of EK/spikelet (10.25 ± 0.11) and the highest population density of EK/palm (1241.39 ± 73.74). The parental mean population was 963.24 weevils and parent Deli-Banting × AVROS recorded the highest EK population density (1173.01). The overall results showed a notable disparity in the EK population among the biparental hybrids. Parental Deli-Banting × AVROS and hybrid ECPHP550 could be more useful to optimize the weevil population for pollination improvements in palm plantations. However, we suggest that volatile production should be included as a desirable trait in oil palm selective breeding.

Pollination of wild plants and agricultural crops is a vitally important ecosystem service. Many landscape and environmental factors influence the pollination success of crops, including distance from natural habitat, wind speed, and solar radiation. Although there is a general consensus that increasing distance from forest decreases pollination success, few studies have examined the influence of specific environmental factors. In this study, we examined which environmental factors influence the pollination success of blackberries (Rubus glaucus). We measured the number of fruitlets per berry, a proxy for pollination success, as well as the weight and sweetness of each berry. Our results indicate that number of fruitlets is positively correlated with wind speed, but number of unripe red berries per bush is negatively correlated with wind speed. In addition, sweetness increased with increasing numbers of red berries per bush but was lower when flowers and berries were present, though this result should be considered with caution due to methodological limitations. Our findings suggest that a little studied environmental factor, wind, has a large impact on the number of fruitlets in blackberries. Although our findings should be confirmed in other locations to draw broader conclusions, they suggest that producers should consider the effect of wind on blackberry yield to optimize blackberry production.

Naturally, Salak Gula Pasir (Salacca zalacca var. Gula Pasir) is flowering every three months or four times a year, but only one or two flowering seasons that the flowers can develop into fruit. The condition causes Salak Gula Pasir is available in the market in a short period (only 2-3 months) i.e. at the time of harvest (on-season) from December to February. This seasonal nature of Salak Gula Pasir occurs because Salak Gula Pasir is planted on dry land where irrigation depends only on rainfall, and drought occurs when water is shortage so that the plant internal water content is low that causes a high failure development rate of flower to become fruit (fruit-set failure). This study was aimed to overcome the fruit-set failure by providing drip irrigation. Two treatments (with drip irrigation and without drip irrigation/control) with sixteen replicates were tested at Salak Gula Pasir production centre (at Sibetan village, Bebandem District, of Karangasem Regency, Bali) at two harvest seasons, i.e. Gadu (July) and Sela II (October). The results showed that the plant provided with drip irrigation significantly yielded fruit-set percentage higher that that without drip irrigation, both in Gadu and Sela II seasons. The percentages of fruit-set in Gadu and Sela II seasons provided with drip irrigation were 75.30% and 93.13%, respectively, while those without drip irrigation were only 59.94% and 61.67%, respectively. The increase of fruit-set observed for drip irrigation treatment associated with the increase of leaf chlorophyll content, relative water content (RWC) of leaves, and leaf N, P, and K contents. The increase of fruit-set led to higher number of fruits and fruit weight per plant under drip irrigation than that without drip irrigation. Based on the results of this study, drip irrigation can be applied to produce Salak Gula Pasir planted out of season on dry land.

Aims Floral traits in animal-pollinated plants are proposed to be selected by the behavior of pollinators, which create differential fitness. However, fitness estimation is not trivial and there is no agreed or universal measure of fitness. In plants, fitness can be measured in various ways, including the number of fruits or seeds, probability of survival, or growth rate. Methods Because each fitness measure can be associated with different pollinator behavior, estimating pollinator-mediated selection on floral traits can differ among various fitness measures. We used the annual Mediterranean plant, Linum pubescens, as a model to assess the relative role of various fitness measures in estimating pollinatormediated selection on floral traits. We compared four maternal fitness measures and estimated their relative advantage in assessing natural selection on floral traits of L. pubescens. To identify whether each trait is under pollinator-mediated selection, we used mediational analysis. Important Findings We found that each floral trait was under natural selection assessed by a different fitness measure. The color combination of floral tube throat and stamen color was under selection when using seed mass as a fitness measure, and floral diameter was under positive directional selection when the number of seeds or number of fruits was used as a fitness measure. Selection on floral color was not mediated by pollinators' visitation rates, while flower diameter showed partial pollinator-mediated selection. We conclude that using several fitness measures gives an insight into the mechanisms underlying phenotypic selection on a floral trait, and facilitates the understanding of pollinator-mediated selection. [ABSTRACT FROM AUTHOR]

Aims: Competitiveness in modern viticulture requires that vineyard management techniques used for crop regulation, besides being economically viable, would assure stable grape composition improvement across variability of genotypes and seasons. Pre-flowering basal leaf removal has previously been shown as an effective tool in controlling yield primarily through a reduced fruit-set. This study aims to evaluate the impact of early leaf removal on the differential growth of the various berry organs (skin, flesh and seeds) as well as the constancy of such effects across season variability and their impact on final grape composition. Methods and results: Pre-bloom defoliation (D) of the first six basal leaves on main shoots was applied to the field-grown Barbera cultivar (Vitis vinifera L.) from 2006 to 2008 and compared with non-defoliated (ND) controls. Over a three-year period, defoliation induced a 34% average reduction in berry number as compared to ND, which led to a notable decrease in fruit-set (-7.6 %), cluster mass (-34%) and yield per shoot (-30%). The berry mass showed a significant relationship with the year factor, as berry size in D shoots was larger, similar and smaller than ND in 2006, 2007 and 2008, respectively. In both treatments, skin mass was closely correlated with berry mass and, within each season and berry mass category, D had relative skin mass values higher than ND. Although the effects were milder in 2007, D induced a significant increase in soluble solids, anthocyanins and phenolics, whereas total acidity was unaffected. Conclusion: These results indicate that, regardless of final berry size, a pre-flowering defoliation favors skin development, which results in higher relative skin mass than ND vines. This effect appears to predominate over variations due to specific weather and cultural conditions along the season and leads to a marked improvement in final grape composition. Significance and impact of study: Repeatability of results implies a strong physiological regulation of this technique and encourages extension of its use in areas where the occurrence of high cropping and large clusters with a high degree of compactness does exist. In a global warming scenario, it is also relevant that the yield decrease and the improvement in overall grape composition are not obtained at the expense of a further reduction in berry acidity.

The main problem of snake fruit production in Indonesia is high fluctuation of fruit production between different harvesting seasons, due to fruit-set failure in some parts of the year. The objective of this research was to find out the relationship between IAA and sugar content of leaves and flowers in relations to the failure of fruit-set in three flowering seasons of snake fruit (April, July, and October). The study was conducted at the production center of snake fruit in Bali (Karangasem Regency) by using Completely Randomized Design. The results showed that fruit-set in April, July and October was 54.16, 47.00 and 70.10%, respectively. Low fruit-set was found associated with low IAA content both in leaves and flowers. The lowest percentage of fruit-set found in July (47.00%) was related to the lowest IAA content in the leaves (10.06 ng g-1) and flowers (20.60 ng g-1). However, the highest percentage of fruit-set in October (70.10%) was correlated to the highest IAA content in the leaves (29.67 ng g-1) and flowers (52.56 ng g-1). Low fruit-set was also closely related to the low content of sugar in the leaves. The lowest percentage of fruit-set in July was caused by the lowest total sugar (24.54%) and reducing sugar (6.56%) content in the leaves, whereas the highest percentage of fruit-set on October related to high total sugar (30.58%) and reducing sugar (12.22%) content in the leaves. It can be concluded that failure of fruit-set in snake fruit was associated with low IAA and sugar content in leaves and flowers. [ABSTRACT FROM AUTHOR]

Background: TIR1-like proteins are F-box auxin receptors. Auxin binding to the F-box receptor proteins promotes the formation of SCFTIR1 ubiquitin ligase complex that targets the auxin repressors, Aux/IAAs, for degradation via the ubiquitin/26S proteasome pathway. The release of auxin response factors (ARFs) from their Aux/IAA partners allows ARFs to mediate auxin-responsive changes in downstream gene transcription. In an attempt to understand the potential role of auxin during fruit development, a plum auxin receptor, PslTIR1, has previously been characterized at the cellular, biochemical and molecular levels, but the biological significance of this protein is still lacking. In the present study, tomato (Solanum lycopersicum) was used as a model to investigate the phenotypic and molecular changes associated with the overexpression of PslTIR1. Results: The findings of the present study highlighted the critical role of PslTIR1 as positive regulator of auxinsignalling in coordinating the development of leaves and fruits. This was manifested by the entire leaf morphology of transgenic tomato plants compared to the wild-type compound leaf patterning. Moreover, transgenic plants produced parthenocarpic fruits, a characteristic property of auxin hypersensitivity. The autocatalytic ethylene production associated with the ripening of climacteric fruits was not significantly altered in transgenic tomato fruits. Nevertheless, the fruit shelf-life characteristics were affected by transgene presence, mainly through enhancing fruit softening rate. The short shelf-life of transgenic tomatoes was associated with dramatic upregulation of several genes encoding proteins involved in cell-wall degradation, which determine fruit softening and subsequent fruit shelf-life. Conclusions: The present study sheds light into the involvement of PslTIR1 in regulating leaf morphology, fruit development and fruit softening-associated ripening, but not autocatalytic ethylene production. The results demonstrate that auxin accelerates fruit softening independently of ethylene action and this is probably mediated through the upregulation of many cell-wall metabolism genes. [ABSTRACT FROM AUTHOR]

Estimation of yield has always been one of the greatest concerns in the wine-making industry, which is why researchers have attempted to create models and methods that make accurate predictions. However, the variability of the yield components, which depends on the environmental factors, like light and temperature, and on cultural and natural factors which affect vigor, water status, photosynthetic and hormonal activity and the accumulation of reserve substances, make the prediction of the future harvest very difficult to calculate. In certain situations, fertility expressed as the number of bunches, tends to display very stable values from one harvest to the next. The weight of the cluster is the performance factor that has the greatest variability and mostly causes the variations in production. In this report, we analyze the influence of the number of flowers per cluster, the fruit-set percentage, the number of berries per cluster and the berry weight in the variability of the cluster weight of the Verdejo variety (Vitis vinifera L.). The cluster weight and its components have been determined along canes of 6 and 10 buds, in the harvests of 1999, 2000 and 2001. The yield component upon which cluster weight variation fundamentally depends has been the number of berries it contains, whereas the berry weight has had much less of an effect. The number of berries per cluster is mainly determined by the number of flowers per inflorescence, a yield component which has gone so far as to explain, by itself, an average of 75%of the variability in the number of berries per cluster and 70 % of the variability of the cluster weight. Despite the possible influence that the fruit-set percentage may have on the variability in the number of berries per cluster, measuring the number of flowers per inflorescence would make it possible to know, to a reasonable level of accuracy, the future number of berries per cluster long before the harvest date. At the same time, if a yield estimate is not needed far in advance, prediction of the future cluster weight can be determined by measuring the number of berries per cluster 15 or 20 days after fruit-set time, when the falling of small fruits is right minimal. In any case, whether by using the number of flowers per inflorescence or the number of berries per cluster, the berry weight on the harvest date would be the only yield component that would require estimation, which is usually much easier to achieve due to the lesser variability seen in this parameter.

The reproductive success of orchids is traditionally estimated by determining the fruit-set of individuals. Here, we investigated both the fruit and the seed production of three orchid species and the factors that may affect individual fruit-set, like pollination strategy, individual traits or the annual amount of precipitation. The species [Dactylorhiza sambucina (L.) Soó, Dactylorhiza majalis (Rchb.) P. F. Hunt & Summerhayes and Platanthera bifolia (L.) L. C. M. Richard] were studied in three consecutive years (2010-2012) in the Bükk Mountains, Hungary. All three species were proved to be non-autogamous by a bagging experiment. Data analyses showed significant differences between seed numbers but not between fruit-sets of species. There was no statistical difference in individual reproductive success between wet and dry years, however, the effect of the annual amount of precipitation is significant on the population level. Comparison of published fruit-set data revealed accordance with our results in P. bifolia, but not in D. sambucina and D. majalis. We assume that the surprisingly high fruit-set values of the two Dactylorhiza species may be due to the fact that the pollination crisis reported from Western European countries is not an actual problem in the Bükk Mountains, Hungary. [ABSTRACT FROM AUTHOR]

Gibberellins (GAs) play a critical role in fruit-set and fruit growth. Gibberellin is perceived by its nuclear receptors GA INSENSITIVE DWARF1s (GID1s), which then trigger degradation of downstream repressors DELLAs. To understand the role of the three GA receptor genes (GID1A, GID1B and GID1C) in Arabidopsis during fruit initiation, we have examined their temporal and spatial localization, in combination with analysis of mutant phenotypes. Distinct expression patterns are revealed for each GID1: GID1A is expressed throughout the whole pistil, while GID1B is expressed in ovules, and GID1C is expressed in valves. Functional study of gid1 mutant combinations confirms that GID1A plays a major role during fruit-set and growth, whereas GID1B and GID1C have specific roles in seed development and pod elongation, respectively. Therefore, in ovules, GA perception is mediated by GID1A and GID1B, while GID1A and GID1C are involved in GA perception in valves. To identify tissue-specific interactions between GID1s and DELLAs, we analyzed spatial expression patterns of four DELLA genes that have a role in fruit initiation (GAI, RGA, RGL1 and RGL2). Our data suggest that GID1A can interact with RGA and GAI in all tissues, whereas GID1C-RGL1 and GID1B-RGL2 interactions only occur in valves and ovules, respectively. These results uncover specific functions of each GID1-DELLA in the different GA-dependent processes that occur upon fruit-set. In addition, the distribution of GA receptors in valves along with lack of expression of GA biosynthesis genes in this tissue, strongly suggests transport of GAs from the developing seeds to promote fruit growth. [ABSTRACT FROM AUTHOR]

Gibberellins (GAs) play a critical role in fruit-set and fruit growth. Gibberellin is perceived by its nuclear receptors GA INSENSITIVE DWARF1s (GID1s), which then trigger degradation of downstream repressors DELLAs. To understand the role of the three GA receptor genes (GID1A, GID1B and GID1C) in Arabidopsis during fruit initiation, we have examined their temporal and spatial localization, in combination with analysis of mutant phenotypes. Distinct expression patterns are revealed for each GID1: GID1A is expressed throughout the whole pistil, while GID1B is expressed in ovules, and GID1C is expressed in valves. Functional study of gid1 mutant combinations confirms that GID1A plays a major role during fruit-set and growth, whereas GID1B and GID1C have specific roles in seed development and pod elongation, respectively. Therefore, in ovules, GA perception is mediated by GID1A and GID1B, while GID1A and GID1C are involved in GA perception in valves. To identify tissue-specific interactions between GID1s and DELLAs, we analyzed spatial expression patterns of four DELLA genes that have a role in fruit initiation (GAI, RGA, RGL1 and RGL2). Our data suggest that GID1A can interact with RGA and GAI in all tissues, whereas GID1C-RGL1 and GID1B-RGL2 interactions only occur in valves and ovules, respectively. These results uncover specific functions of each GID1-DELLA in the different GA-dependent processes that occur upon fruit-set. In addition, the distribution of GA receptors in valves along with lack of expression of GA biosynthesis genes in this tissue, strongly suggests transport of GAs from the developing seeds to promote fruit growth. [ABSTRACT FROM AUTHOR]

More than 70% of world's crops benefit from biotic pollination, and bees are their main pollinators. Despite the fact that some of these insects have been broadly studied, understanding the interactions between plant crops and their pollinators with a local scale approach is necessary when aiming to apply proper protective and management measures to pollinators and their respective crops. In this context, we analyzed the pollination status of open-field tomato crops (Solanum lycopersicum L.), regarding fruit-set, visitation rate and the quality of fruits. We recorded the formation of fruits through spontaneous self-pollination and open-pollination, and the occurrence of pollinators in 24 areas of open-field tomato crops. We performed experiments of apomixis, spontaneous self- pollination, manual cross pollination and supplemental cross pollination (simulating the pollinator behavior) in a greenhouse. The fruit quality was evaluated according to circumference, weight, volume and number of seeds. Higher production of fruits after open-pollination compared to spontaneous self-pollination indicates the importance of pollinators to increment productivity of S. lycopersicum in the study area. The circumference and the number of seeds from tomatoes of the greenhouse plantation did not differ between spontaneous self-pollination and the manual cross pollination. In the open-field crops the number of seeds was higher for fruits resulting from open-pollination. Our results indicate that the importance of bees is mainly related to the increase in fruit production, thus incrementing the productivity of tomato crops. [ABSTRACT FROM AUTHOR]

Impact of environmental changes (temperature and RH) on reproductive biology in Duranta repens (Verbenaceae) growing at ten different sites of Agra was studied. It flowers throughout the year, with optimum flowering in September. The flowers are arranged in loose clusters on terminal or axillary racemes. They are either blue or lavender in colour, hermaphrodite, actinomorphic and complete. The plants exhibit floral polymorphism (increase and decrease in number of petals and stamens) and considerable variation in extent of pollen fertility, floral density, insect pollinators and fruit-set percentage. The changes in temperature and relative humidity during the entire flowering period, was found associated with the variation in floral structure, pollen fertility and fruit-set percentage. Based on the percentage of fruit-set during different seasons of a year, there were three distinct periods, namely maximum, moderate and minimum periods. The present paper deals with the comparative view of reproductive biology of this ornamental plant in these periods. During the months of August—November when temperature ranges between 13.7-36.6 °C and RH between 79-89% the plant exhibits maximum fruit-set percentage (68-85%). This was associated with maximum flowering, increase in floral size, and increase in visitation rates of pollinators and higher degree of pollen fertility. On the other hand, with temperature reaching to the maximum (15.1-41.5 °C) and reduction in RH (14.1-41.3%), the percentage of fruit-set was reduced to the minimum (21-30%). During this period, number of flowers/plant, floral size, pollen fertility, visitation rates of pollinators were reduced to the minimum. During this period floral polymorphism was also 'recorded.

Source/sink ratios are known to be one of the main determinants of oil palm growth and development. A long-term experiment (9 years) was conducted in Indonesia on mature oil palms subjected to continuous bunch ablation and partial defoliation treatments to artificially modify source/sink ratios. During the experiment, all harvested bunches were dissected and phenological measurements were carried out to analyse the effect of source/sink ratios on yield components explaining variations in bunch number, the number of fruits per bunch and oil dry weight per fruit. An integrative variable (supply/ demand ratio) describing the ratio between the assimilate supply from sources and the growing organ demand for carbohydrate was computed for each plant on a daily basis from observations of the number of developing organs and their sink strength, and of climate variables. Defoliation and bunch ablation affected the bunch number and the fruit number per bunch. Variations in bunch number per month were mainly due to variations in the fraction of aborted inflorescence and in the ratio between female and male inflorescences. Under fluctuating trophic conditions, variations in fruit number per bunch resulted both from changes in fruit-set and in the number of branches (rachillae) per inflorescence. For defoliated plants, the decrease in the number of developing reproductive sinks appeared to be sufficient to maintain fruit weight and oil concentration at the control level, without any major decrease in the concentration of non-structural carbohydrate reserves. Computation of the supply/demand ratio revealed that each yield component had a specific phase of sensitivity to supply/demand ratios during inflorescence development. Establishing quantitative relationships between supply/demand ratios, competition and yield components is the first step towards a functional model for oil palm. [ABSTRACT FROM AUTHOR]

Parameterizing crop models for more accurate response to climate factors such as temperature is important considering potential temperature increases associated with climate change, particularly for tomato (Lycopersicon esculentum Mill.), which is a heat-sensitive crop. The objective of this work was to update the cardinal temperature parameters of the CROPGRO-Tomato model affecting the simulation of crop development, daily dry matter (DM) production, fruit set, and DM partitioning of field-grown tomato from transplanting to harvest. The main adaptation relied on new literature values for cardinal temperature parameters that affect tomato crop phenology, fruit set, and fruit growth. The new cardinal temperature values are considered reliable because they come from recent published experiments conducted in controlled-temperature environments. Use of the new cardinal temperatures in the CROPGRO-Tomato model affected the rate of crop development compared with prior default parameters; thus, we found it necessary to recalibrate genetic coefficients that affect life cycle phases and growth simulated by the model. The model was recalibrated and evaluated with 10 growth analyses data sets collected in field experiments conducted at three locations in Florida (Bradenton, Quincy, and Gainesville) from 1991 to 2007. Use of modified parameters sufficiently improved model performance to provide accurate prediction of crop and fruit DM accumulation throughout the season. Overall, the average root mean square error (RMSE) over all experiments was reduced 44% for leaf area index, 71% for fruit number, and 36% for both aboveground biomass and fruit dry weight simulations with the modified parameters compared with the default. The Willmott d index was higher and was always above 0.92. The CROPGRO-Tomato model with these modified cardinal temperature parameters will predict more accurately tomato growth and yield response to temperature and thus be useful in model applications. [ABSTRACT FROM AUTHOR]

Heat stress can cause severe crop yield losses by impairing reproductive development. However, the underlying mechanisms are poorly understood. We examined patterns of carbon allocation and activities of sucrose cleavage enzymes in heat-tolerant (HT) and -sensitive (HS) tomato (Solanum lycopersicum L.) lines subjected to normal (control) and heat stress temperatures. At the control temperature of 25/20 °C (day/night) the HT line exhibited higher cell wall invertase (CWIN) activity in flowers and young fruits and partitioned more sucrose to fruits but less to vegetative tissues as compared to the HS line, independent of leaf photosynthetic capacity. Upon 2-, 4-, or 24-h exposure to day or night temperatures of 5 °C or more above 25/20 °C, cell wall (CWIN) and vacuolar invertases (VIN), but not sucrose synthase (SuSy), activities in young fruit of the HT line were significantly higher than those of the HS line. The HT line had a higher level of transcript of a CWIN gene, Lin7, in 5-day fruit than the HS line under control and heat stress temperatures. Interestingly, heat induced transcription of an invertase inhibitor gene, INVINH1, but reduced its protein abundance. Transcript levels of LePLDa1, encoding phospholipase D, which degrades cell membranes, was less in the HT line than in the HS line after exposure to heat stress. The data indicate that high invertase activity of, and increased sucrose import into, young tomato fruit could contribute to their heat tolerance through increasing sink strength and sugar signalling activities, possibly regulating a programmed cell death pathway. [ABSTRACT FROM PUBLISHER]

Background and Aims Determining the sources of variation in floral morphology is crucial to understanding the mechanisms underlying Angiosperm evolution. The selection of floral and reproductive traits is influenced by the plant's abiotic environment, florivores and pollinators. However, evidence that variations in floral traits result from mutualistic interactions with insects other than pollinators is lacking in the published literature and has rarely been investigated. We aimed to determine whether the association with either Camponotus femoratus or Pachycondyla goeldii (both involved in seed dispersal and plant protection) mediates the reproductive traits and allocation of Aechmea mertensii, an obligatory ant-garden tank-bromeliad, differently. Methods Floral and reproductive traits were compared between the two A. mertensii ant-gardens. The nitrogen flux from the ants to the bromeliads was investigated through experimental enrichments with stable isotopes (15N). Key Results Camponotus femoratus-associated bromeliads produced inflorescences up to four times longer than did P. goeldii-associated bromeliads. Also, the numbers of flowers and fruits were close to four times higher, and the number of seeds and their mass per fruit were close to 1·5 times higher in C. femoratus than in P. goeldii-associated bromeliads. Furthermore, the 15N-enrichment experiment showed that C. femoratus-associated bromeliads received more nitrogen from ants than did P. goeldii-associated bromeliads, with subsequent positive repercussions on floral development. Greater benefits were conferred to A. mertensii by the association with C. femoratus compared with P. goeldii ants. Conclusions We show for the first time that mutualistic associations with ants can result in an enhanced reproductive allocation for the bromeliad A. mertensii. Nevertheless, the strength and direction of the selection of floral and fruit traits change based on the ant species and were not related to light exposure. The different activities and ecological preferences of the ants may play a contrasting role in shaping plant evolution and speciation. [ABSTRACT FROM AUTHOR]

Viticulture in Michigan is limited by a cool and humid climate and as a result, there is a problem of harvest season cluster rot, especially in cultivars with compact cluster morphology. Economically important wine grape varieties in eastern North America possess varying susceptibility, to harvest season cluster rot. Some important cultivars that are susceptible are Pinot gris, Pinot noir, Riesling (Vitis vinifera L.) as well as Seyval and Vignoles (French-American hybrids or interspecific hybrid cultivars). A common characteristic of these cultivars is the compactness of the berries held on the cluster rachis. The aim of this work was to determine whether a quantified amount of leaf removal or a temporary reduction in carbon assimilation at the beginning of bloom would reduce fruit set and cluster compactness. Vines subjected to removal of four or six basal leaves had an average fruit set reduction of ≈45% from a non-treated control. Cluster weight and berries per cluster were similarly reduced with a greater effect on the basal than the apical cluster of the shoot. Reduced fruit set was associated with a reduction in cluster compactness and harvest season rot. This was also reflected in yield and basic fruit chemistry parameters associated with the importance of basal leaves to the developing cluster. Multiple applications of stylet oil at different time intervals resulted in significant reduction in net photosynthesis (Pn). A single application had no significant impact on Pn, whereas multiple applications reduced leaf assimilation rates. However, this reduction in Pn did not reduce fruit set or improve cluster compactness. There was a strong negative effect of early leaf removal in Year ! on vine performance in Year 2; this carryover effect increased shootless nodes per vine, reduced the number of clusters per shoot and per vine, and dramatically reduced fruit set and consequently yield per vine. [ABSTRACT FROM AUTHOR]

The article presents a study on the impact of experimental pollen reduction or addition of pollen on the fruit and seed-set of Thalassia testudinum at Puerto Morelos reef lagoon in Mexico. For the study, researchers examined flowers and flower buds at pre-anthesis in April of 2008 and 2009. They analyzed pollen production and potential restriction of pollen availability in the seagrass. They observed a decline of fruit production from 83 to 60 percent following experimental removal of half of the male flowers in April 2008.

Fruit development is usually triggered by ovule fertilization, and it requires coordination between seed development and the growth and differentiation of the ovary to host the seeds. Hormones are known to synchronize these two processes, but the role of each hormone, and the mechanism by which they interact, are still unknown. Here we show that auxin and gibberellins (GAs) act in a hierarchical scheme. The synthetic reporter construct DR5:GFP showed that fertilization triggered an increase in auxin response in the ovules, which could be mimicked by blocking polar auxin transport. As the application of GAs did not affect auxin response, the most likely sequence of events after fertilization involves auxin-mediated activation of GA synthesis. We have confirmed this, and have shown that GA biosynthesis upon fertilization is localized specifically in the fertilized ovules. Furthermore, auxin treatment caused changes in the expression of GA biosynthetic genes similar to those triggered by fertilization, and also restricted to the ovules. Finally, GA signaling was activated in ovules and valves, as shown by the rapid downregulation of the fusion protein RGA-GFP after pollination and auxin treatment. Taken together, this evidence suggests a model in which fertilization would trigger an auxin-mediated promotion of GA synthesis specifically in the ovule. The GAs synthesized in the ovules would be then transported to the valves to promote GA signaling and thus coordinate growth of the silique. [ABSTRACT FROM AUTHOR]

In the new introducing almond areas, it is necessary to test the more promising almond cultivar and rootstock combinations able to guarantee the best agronomic performances according to the specific pedoclimatic conditions. With this aim, two almond trials have been established in an experimental farm located in the Latium region (Italy). The first trial (A) focused on the phenological, and agronomical influences induced by the clonal rootstock 'GF677' on the grafted cultivars 'Tuono', 'Supernova' and 'Genco', in comparison to those induced by peach seedling rootstocks, in order to identify the best grafting combination for developing "high density" plantings in this new growing area. The second trial (B) tested the phenological and agronomical influences induced by three different clonal rootstocks ('GF677', 'Rootpac® 20' and 'Rootpac® R'), on the Spanish cultivar 'Guara' to identify suitable dwarfing rootstocks for "super high density" plantings in the same environment. Flowering and ripening calendars of the trial A highlighted as the medium-late flowering cultivars 'Genco', 'Supernova' and 'Tuono' could be subject to moderate risk of cold damages. The clonal rootstock 'GF677' seems to anticipate flowering and vegetative bud break by a few days in 'Tuono' when compared to the same cultivar grafted on peach seedling rootstocks. Furthermore, the yield per plant was always higher in plants grafted on 'GF677'. The observations carried out in trial B highlighted as the flowering of cultivar 'Guara' were affected by the rootstock, with 'Rootpac® 20', which postponed its full bloom of about one week when compared to other rootstocks, whereas 'GF677' imposed more vigor to the cultivar than 'Rootpac® 20' and 'Rootpac® R'. [ABSTRACT FROM AUTHOR]

Understanding complex factors controlling yield is very crucial to the improvement of cashew in major producing countries currently experiencing very low yield and consequently making cashew farming unprofitable and the whole industry unsustainable. Eleven cashew clones were evaluated for their compatibility and fruit set between 2000 and 2002 seasons, in a diallel cross using randomized complete block design with three replications. Data collected on number of fruit set at 6 weeks after pollination were statistically analyzed. Significant differences between the parents at the 1% level, revealed the existence of variability for compatibility and fruit set, with 34% cross-compatibility, 51% partial cross-compatibility and 15% cross-incompatibility recorded, while 37% of the parents were self-compatible. Parents sharing the same apples colors tend to be highly cross-compatible, while some clones showed evidence of unilateral compatibility. Maximum value of 55% fruit set obtained from cross-pollination probably indicates upper limit for fruit set in cashew. Significant correlation between compatibility and variation in fruit yield suggests the important role of parental compatibility in selection of planting materials for the establishment of cashew plantation. [ABSTRACT FROM AUTHOR]

Grevillea beadleana (Proteaceae) is an endangered species known from five populations in northern New South Wales, Australia. The reproductive ecology of G. beadleana was compared in two populations with a ten‐fold difference in the number of plants. Grevillea beadleana was found to be self‐compatible in both populations and an examination of pollen viability and stigma maturation revealed that the species is protandrous. Flowering within inflorescences is acropetallous. In the first season plants in the largest population produced approx. ten‐fold more inflorescences than those in the smaller population and, although the number of flowers per inflorescence did not vary significantly between populations the first season, the larger population produced more fruit per inflorescence than the smaller population. However, fruit to flower ratios were less than 0·2 in both seasons and populations. In both populations the number of fruit was significantly greater at the proximal end of the inflorescence, where flowers open first, compared with medial and distal positions. Several bird species were observed visiting flowers, although few birds were recorded foraging at plants in the smaller population. Within both populations, birds tended to make more within‐ than between‐plant visits. Self‐compatibility, acropetally and proximal fruit‐set, combined with the predominantly within‐plant movement of honeyeaters, suggests inbreeding may be common within both populations of G. beadleana. Pollination and fruiting success are discussed for G. beadleana and breeding systems among rare and common taxa in Grevillea are reviewed. [ABSTRACT FROM PUBLISHER]

Differences in fruit-set success reputed to exist between Heveabrasiliensis genetic clones were verified by an analysis of breeding recordsfor the clones PB 5/51, RRIM 600 and PR 107. Although the bestfruit-set success was obtained with PB 5/51 following artificial (hand)pollination, this clonal trait was not reflected in terms of greater numbersof pollen tubes developing it the styles of hand-pollinated PB 5/51 femaleflowers. It was observed, however, that more pollen tubes reached theovules in PB 5/51 than in RRIM 600 or PR 107. Significantly, PB 5/51female flowers required fewer pollen tubes to effect penetration of all threeof its ovules. As fruit formation in Hevea is dependent on all threeovules of the flower being successfully fertilised, PB 5/51 female flowershave hence a greater propensity for successful fruit-set. In all the threeclones studied, the frequency distribution of female flowers with 0, 1, 2 or3 of the ovules penetrated by pollen tubes did not conform to binomialexpectations. Flowers with no ovule penetrated and flowers with all threeovules penetrated were greatly over-represented. One explanation for thisnon-random distribution is the existence of `receptive' female flowers thatfavour successful fertilisation whereas `non-receptive' flowers tend to remainunfertilised even when hand-pollinated. [ABSTRACT FROM AUTHOR]

The flowering phenologies of three sympatric legumes, Dillwynia hispida Lindley, D. uncinata (Turcz.)J.Black and Pultenaea densifolia F.Muell. (Fabaceae), were measured over a three-year period in a semi-arid ecosystem. Each species produced a single flowering episode per year which lasted about 15 weeks and which overlapped considerably with those of the remaining two species. A comparison of the actual flowering schedules over two years with those generated from Monte Carlo simulations showed that the flowering schedules of the three species were significantly clumped. Fruit-to-flower ratios on D. hispida plants were calculated over two flowering periods and these values were correlated with conspecific and heterospecific flower abundances to determine whether the extent of overlap in flowering schedules was associated with elevated or depressed levels of fruit set. Partial correlations between heterospecific floral densities and fruit-to-flower ratios were usually positive, indicating a possible selective advantage favouring these convergent flowering schedules. [ABSTRACT FROM AUTHOR]

The recovery of vegetation following fire has been studied intensively in Mediterranean-type ecosystems. Little attention, however, has been given to floral traits, and almost no data have been collected on the effects of fire on pollinator activity and fruit-set. This paper reports the effects of fire on flower visitation rates and the possibly related fruit-set. We compared visitation rates of the main pollinators on four plant core-species in burned and adjacent unburned areas. Measurements were performed at an unburned phrygana (scrub lands), and at a burned area (5–7 years post-fire). Bumble bees and solitary bees were the main taxa of visitors, while few honeybees were recorded. Solitary bees were almost absent from the burned area. Fruit-set was significantly higher in the unburned area for three out of the four plant species. The lower fruit-set in the burned area was possibly the result of low activity of solitary bees which are the main effective pollinators of the examined species. We hypothesize that the populations of the solitary bees were diminished or extirpated either directly by the fire, or indirectly by the scarcity of nectar in the early post-fire years due to dominance of young pine and Cistus spp. seedlings. The short foraging range of the solitary bees and their slow invasion rate into the burned area may explain our results. [ABSTRACT FROM AUTHOR]