Production of somatic hybrids between frost-tolerant Solanum commersonii and S. tuberosum: characterization of hybrid plants

Somatic fusion of mesophyll protoplasts was used to produce hybrids between the frost-tolerant species Solanum commersonii (2n=2x=24) and dihaploid S. tuberosum (2n=2x=24). This is a sexually incompatible combination due to the difference in EBN (Endosperm Balance Number, Johnston et al. 1980). Species with different EBNs as a rule are sexually incompatible. Fifty-seven hybrids were analysed for variation in chromosome number, morphological traits, fertility and frost tolerance. About 70% of the hybrids were tetraploid, and 30% hexaploid. Chloroplast counts in stomatal guard cells revealed a low frequency of cytochimeras. The frequency of aneuploids was relatively higher at the hexaploid level (hypohexaploids) than at the tetraploid level (hypotetraploids). The somatic hybrids were much more vigorous than the parents, and showed an intermediate phenotype for several morphological traits and moderate to profuse flowering. Hexaploid hybrid clones were less vigorous and had a lower degree of flowering than the tetraploid hybrid clones. All of the hybrids were female fertile but male sterile except for one, which was fully fertile and self-compatible. Many seeds were produced on the latter clone by selfing and on the male-sterile clones by crossing. The somatic hybrid plants showed an introgression of genes for frost tolerance and an adaptability to cold from S. commersonii. Therefore, the use of these somatic hybrids in breeding for and in genetic esearch on frost tolerance and cold-hardening is suggested.     

Analysis of somatic hybrids between two sterile dihaploid Solanum tuberosum L. breeding lines. Restoration of fertility and complementation of G. pallida Pa2 and Pa3 resistance

Fourteen somatic hybrids generated by electrofusion of mesophyll protoplasts from a non-flowering dihaploid S. tuberosum clone, DHAK-11, and a male-sterile dihaploid clone S. tuberosum, DHAK-33, were grown in the greenhouse and subjected to morphological assessments and tests for fertility and resistance to the white potato cyst nematode Globodera pallida pathotypes Pa2 and Pa3. The ploidy level of the hybrids ranged from 38 to 63 chromosomes. All hybrids developed flowers with violet petals except for one, hy-56, that possessed red petals. The colour of the tuber skin was purple in all hybrids except in hy-56 where the tuber skin was red. All of the hybrids were female fertile and generated viable seeds. Near-tetraploid hybrids produced the highest number of seeds per fruit and these seeds had a normal size. Hybrids with 58 or more chromosomes produced smaller seeds and less seeds per fruit. The germination frequency of the seeds was not influenced by the chromosome number of the hybrids. Pollen viability was determined and the male fertility of three hybrids was tested. Pollination with these three hybrids gave rise to fruit development, but only one produced viable seeds. The hybrids were tested for resistance to G. pallida pathotypes Pa2 and Pa3. A high level of resistance to Pa3, inherited from one parental clone, DHAK-11, and a high level of resistance to Pa2, inherited from the other parental clone, DHAK-33, was combined in four hybrids. These results demonstrate, that protoplast fusion is an efficient method for restoring the fertility of somatic hybrids generated from sterile parent clones, and is a powerful procedure for the complementation of multigenetic disease resistance traits in potato breeding lines.     

Variation in allocation to sexual and asexual reproduction among clones of cyclically parthenogenetic Daphnia pulex (Crustacea: Gladocera)

Organisms reproducing by cyclical parthenogenesis combine the benefits of both sexual and asexual reproduction within the same life cycle. Few studies have examined the evolution of variation in the pattern of investment in parthenogenetic compared to sexual reproduction. Seven clones of Daphnia pulex (Crustacea: Cladocera) varying in allocation to sexual reproduction, as measured by the production of males, were raised in isolation and together in a microcosm to study the pattern of sexual reproduction and the effect of this variation on clone fitness. Sex allocation for clones raised together a microcosm was similar to their allocation when raised in isolation, suggesting a genetic basis to the variation. Three clones showed a cost of producing males that lead to their extinction after about 30 days due to the lack of females required for the clones to persist by parthenogenetic reproduction. The remaining four clones persisted until the end of the 72-day experiment. Clones with little or no allocation to males showed no increased allocation to sexual females. The seven clones showed a greater variation in estimated fitness through male and female function than in total estimated fitness. The clone with the greatest total fitness gained most of its fitness through male function but also had a relatively high fitness through female function. Although one clone produced only females it had the next highest fitness. The three clones that went extinct because of a high investment in males had estimated fitness as high as some clones that persisted in the microcosm because of a higher investment in parthenogenetic reproduction. The similarity in total fitness among clones suggests that Daphnia pulex populations in temporary habitats maintain a sex polymorphism where different genotypes vary-in functional gender ranging from female to primarily male.     

Temporally changing male reproductive success and resource allocation strategy in protandrousHeracleum lanatum (Apiaceae)

Few observations have been made on temporal changes in the siring success of flowers in the male stage. In this study, we estimated both male and female contributions to fitness for 21 plants of protandrous andromonoeciosHeracleum lanatum with differing dates of first flowering. The results of multiple regression analysis showed that total male fitness significantly increases with the advance of the first-flowering date but does not depend upon plant size, whereas female fitness increases with plant size but does not depend upon the first-flowering date. We also showed that the earlier-flowering plants have more late-blooming male flowers in their secondary umbels. Based on these results, we suggest that polymorphism of the early- and late-bloomers may be maintained by frequency-dependent selection through temporally changing male reproductive success.     

Gene flow and mating system in five <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> D. Don seed orchards as revealed by analysis of microsatellite markers

We investigated gene flow in five Cryptomeria japonica D. Don seed orchards of two different types (common and miniature) at widely spaced locations using microsatellite markers. The quality of a seed crop is determined by many factors, including pollen contamination from outside sources, self-fertilization, and the proportion of contributions from constituent clones. Contamination rates were found to vary among ramets both within seed orchards (10.0–76.7% in the most variable seed orchard) and among seed orchards (35.0–65.8% on average). Among ramets, there were significant negative correlations between pollen contamination rate and their distance from the orchard edge; among seed orchards, there were significant positive correlations between the pollen contamination rate and the C. japonica forest area nearby. Some proportion of the pollen (10.7% of total contamination) also migrated from parts of the orchards that had not been treated with gibberellin to induce flowering. Self-fertilization rates varied among seed orchards (1.4–4.4% on average), and there were significant positive correlations between self-fertilization rate and the number of ramets per clone in both types of seed orchard. Contributions as pollen donors differed significantly among clones in all seed orchards. The distance between planted ramets, flowering phenology, and relative pollen fecundity may also have contributed to observed differences in paternal contribution. The influence of these factors on genetic potential did not differ greatly between the two types of orchards. This work was supported by grants from the Pioneer Special Studies Program of the Japanese Ministry of Agriculture, Fishery, and Forestry; the Program for Promotion of Basic Research Activities for Innovative Biosciences; and research fellowships from the Japan Society for the Promotion of Science for Young Scientists.     

Molecular analysis of single copy and repetitive genes on chromosome 2 in intergeneric tomato somatic hybrid plants

Restriction fragment polymorphisms were used to identify and quantify the nuclear contributions from each parent to somatic hybrid plants between tomato (Lycopersicon esculentum Mill.) cv. Sub-Arctic Maxi and Solanum lycopersicoides Dun. Three single-copy clones, 2–13, 2–17, and 3–288, and a clone for the 45s ribosomal RNA, pHA2, all mapped to chromosome 2 of tomato, were used in analysis of 47 somatic hybrids. The amount of hybridizing probe for each parental band was quantified by densitometry of the autoradiograph film. Analyses with the three single-copy clones indicated that there were more than two S. lycopersicoides copies in most somatic hybrid plants. For at least one somatic hybrid there was a loss of one tomato copy. No evidence was found for more than two copies donated from tomato or loss of a copy from S. lycopersicoides. Most of the observed variation in copy number of the single-copy clones was consistent with chromosomal changes occurring in the suspension cells from which S. lycopersicoides parental protoplasts were derived.The number of copies of rDNA derived from each parent varied independently of the number of copies of single-copy clones from each parent. Changes in the copy number of rDNA occurred in both tomato and S. lycopersicoides genomes.     

The effect and transmission of one isolate of the rust Puccinia minussensis on five clones of Lactuca sibirica

In a greenhouse experiment, one isolate of the systemic rust fungus Puccinia minussensis was applied to the host clone from which it was collected and to four other clones of the host Lactuca sibirica. The plants were grown in fertilized potting compost (N+) to promote growth and in peat (N-) to hamper growth, for three growing periods during one year. The results show that the expression of host plant resistance could not be determined visually, but there were differences in effects on the clones. The rust isolate was found to produce a significantly higher percentage of diseased shoots on clone A (the clone it was taken from). Furthermore, the rust also had the strongest effect on both biomass and shoot production on clone A compared to the other four clones. The data suggest that the rust isolate is highly adapted to the clone from which it originated. We suggest that selection in this system has not favoured a benign pathogen and that similar patterns are likely to occur for plants that (i) rarely establish by seeds; (ii) have strong lateral growth; and (iii) may persist for long periods once established.     

Pollination by sexual deception promotes outcrossing and mate diversity in self‐compatible clonal orchids

The majority of flowering plants rely on animals as pollen vectors. Thus, plant mating systems and pollen dispersal are strongly influenced by pollinator behaviour. In Australian sexually deceptive orchids pollinated by male thynnine wasps, outcrossing and extensive pollen flow is predicted due to floral deception, which minimizes multiple flower visitations within patches, and the movement of pollinators under mate‐search rather than foraging behaviours. This hypothesis was tested using microsatellite markers to reconstruct and infer paternity in two clonal, self‐compatible orchids. Offspring from naturally pollinated Chiloglottis valida and C. aff. jeanesii were acquired through symbiotic culture of seeds collected over three seasons. In both species, outcrossing was extensive (t_m = 0.924–1.00) despite clone sizes up to 11 m wide. The median pollen flow distance based on paternity for both taxa combined was 14.5 m (n = 18, range 0–69 m), being larger than typically found by paternity analyses in other herbaceous plants. Unexpectedly for orchids, some capsules were sired by more than one father, with an average of 1.35 pollen donors per fruit. This is the first genetic confirmation of polyandry in orchid capsules. Further, we report a possible link between multiple paternity and increased seed fitness. Together, these results demonstrate that deceptive pollination by mate‐searching wasps enhances offspring fitness by promoting both outcrossing and within‐fruit paternal diversity.     

Variation in lifetime male fitness in Ipomopsis aggregata: tests of sex allocation theory

Sex allocation theory assumes that a shift in allocation of resources to male function both increases male fitness and decreases female fitness. Moreover, the shapes of these fitness gain functions determine whether hermaphroditism or another breeding system is evolutionarily stable. In this article, I first outline information needed to measure these functions in flowering plants. I then use paternity analysis to describe the shapes of the fitness gain functions in natural populations of the hermaphroditic herb Ipomopsis aggregata. I also explore the relationships of male fitness (number of seeds sired) and female fitness (number of seeds produced) to the number of flowers produced by a plant. Plants with greater investment of biomass in the androecium, compared to the gynoecium and seeds, showed increased success at siring seeds, assumed by the models. That sex allocation trait, however, explained only 9% of the variance in estimates of male fitness. The shapes of the fitness gain functions were consistent with theoretical expectations for a hermaphroditic plant, but the model predicted a more female-biased evolutionarily stable strategy (ESS) allocation than was observed. These results lend only partial support the classical sex allocation model.     

不同水稻品种种子固有细菌群落的多样性

种子固有细菌是植物内生细菌的重要来源, 对植物的健康以及接种细菌的定殖能产生重要影响。该文以杂交水稻(Oryza sativa)种子为研究对象, 比较研究了不同品种水稻种子中固有细菌群落的多样性。利用799f和1492r这对引物成功地从水稻种子中扩增出固有细菌16S rDNA片段; 通过构建16S rDNA文库和扩增核糖体RNA基因酶切分型(ARDRA)的方法, 对杂交水稻 ‘丰优611’ (‘丰源A’ × ‘远恢611’)、‘金优611’ (‘金23A’ × ‘远恢611’)和‘金23A/09H013’ ( ‘金23A’ × ‘09H013’) 3个组合的子代及其各自亲本的种子固有细菌群落结构的多样性进行了研究。构建的7个克隆文库中, 每个文库含有200-300个克隆, 30-40个操作分类单元(OTU), 对ARDRA分型得到的代表序列进行分析, 在16S rDNA文库中发现多种细菌类群, 包括α变形杆菌(α-Proteobacteria)、β变形杆菌、γ变形杆菌、放线菌(Actinobacteria)、厚壁菌(Firmicutes)和拟菌(Bacteroidetes), 优势菌属是泛菌属(Pantoea)和芽孢杆菌属(Bacillus)。不同品种的水稻种子固有细菌群落结构不同, 而杂交子代种子中的优势菌与亲本种子中的优势菌在种类和数量上都具有一定的相关性。此外, 子代种子中丰度5%以上的细菌也能在各自父本或母本中检测到。     

Molecular discrimination and phylogeographic patterns of clones of the parthenogenetic gecko Lepidodactylus lugubris in the Japanese Archipelago

Vertebrates usually reproduce sexually in which males and females contribute their offspring genome and produce genetically diverse offspring. However, some of them are asexual without genetic contribution from males. The nocturnal gecko, Lepidodactylus lugubris, is all females and reproduces parthenogenetically. This gecko is known to consist of diploid and triploid clones in the tropical and subtropical regions, which can be identified by their dorsal marking patterns, ploidy, and protein polymorphism. This gecko is also distributed in the southern parts of Japan, and several clones have been reported. In this study, we investigated the origins and genetic diversity of Japanese L. lugubris by clonal discrimination using microsatellite and mitochondrial DNA analyses. A total of 748 individuals were collected from 21 islands of five island groups (Ogasawara, Okinawa, Miyako, Yaeyama and Daito Islands) and 17 clones were distinguished genetically. Mitochondrial cyt b sequences of these clones suggested that they were all closely related and differentiated recently. Clonal diversity was much higher (14 clones) in the Daito Islands than in the other island groups in which only one or two clones coexisted. Judging from the dorsal marking patterns and ploidy known so far, six clones were cosmopolitan and may be colonized from the outside of Japan. However, other 11 clones were endemic to the Daito Islands and explained by possible hybridization between the one female diploid clone and one male diploid clone because other 9 clones were triploid and all had the combinations of polymorphic microsatellite alleles of these female and male diploid clones. Although the males have never been recorded in the Daito Islands, males might appear in the past. These findings contribute to understanding of clonal diversity and dynamics of asexually reproducing animals. If diploid parthenogenetic geckos can produce triploid clones by mating with the diploid males, clonal diversity would increase rapidly in a small island, and such newly produced triploid clones would expand widely.     

利用等位酶对油松无性系种子进行父本分析

利用水平淀粉凝胶电泳8种酶10个位点34个等位基因,对辽宁兴城油松无性系种子园中17个无性系20个单株的200粒种子作了父本分析。无性系雄花量的多少与授粉果率并不成正比;不同无性系对花粉的接受存在一定的选择性,分析试样单株与周围的无性系并没有构成固定的授粉组合,说明授粉期风向等气象因子,无性系的雌雄花器的构造,受精等对受粉的成败都有作用,种子园结实初期自交现象并不明显,在分析试样中只有16＃,17＃,19＃无性系存在自交现象;种子园内花偻的有效传播一般在半径30m范围内,同时,分析了种子园子代的等位酶变异和空间遗传结构,从另一侧面反映出采种母树周围花粉分布比较均匀,并说明散粉期间风向等气象因子对授粉成败影响较大。     

Flowering phenology and female fitness: impact of a pre-dispersal seed predator on a sexually polymorphic species

In order to produce seeds, animal-pollinated plants must flower synchronously with and be attractive to their pollinators while avoiding antagonists. Here, we explore temporal and inter-individual patterns in pollination and pre-dispersal seed predation of Dianthus sylvestris by Hadena moths, within and among three sex morphs. We scored plants that started flowering at different periods in 2001 and 2003 and found that fruit set decreased and predation rates increased over one season, and most of the other season, granting a female reproductive advantage to early flowering plants, though, we found no morph-specific temporal patterns. Female plants set more fruits, and more of their fruits escaped predation in one year, but this did not grant them a reproductive advantage since they produce fewer flowers per plant than the other morphs. Instead, mixed plants showed a clear female reproductive advantage. We also examined predation types by Hadena and seed production in attacked and intact fruits of individually marked flowers. Though female Hadena moths laid eggs preferentially into perfect flowers, flower sexes suffered similar predation by itinerant caterpillars. Attacked fruits contained fewer and lighter seeds than un-attacked ones. We conclude that pre-dispersal seed predation by Hadena may select on flowering onset of this sexually polymorphic species.     

THE SIGNIFICANCE OF OUTCROSSING IN AN INTIMATE PLANT-HERBIVORE RELATIONSHIP. II. DOES OUTCROSSING POSE A PROBLEM FOR THRIPS ADAPTED TO THE HOST-PLANT CLONE?

The thrips herbivore Apterothrips apteris reproduces both sexually and parthenogenetically and exhibits fine-scale local adaptation to individual phenotypes of its host plant, Erigeron glaucus. We ask whether we can disrupt the ability of thrips to use progeny of their “home”-plant clone by outcrossing females with males from other plant clones. We compare the performance of sexually produced thrips to that of parthenogenetically produced thrips on plant progeny of the home clone. Because we use thrips from plant clones experiencing both high and low infestations by thrips, we also ask whether the relative performance of “sexuals” versus “parthenogens” differs with the infestation level of the home clone. Plant progeny of 10 E. glaucus clones were either the product of selfing or of outcrossing with the other 9 clones. We have shown in previous work that selfing preserved the parental phenotype with respect to attack by thrips. Because of this result, we predicted that parthenogens should fare better than sexuals on the selfed progeny of the home-plant clone. Our results, however, showed the contrary: sexuals outperformed parthenogens on these selfed plants. We also found that plant characters appear to influence thrips performance more than the mating system of thrips. We found no evidence for outbreeding depression in this system.     

A model for estimating infection levels of anthracnose disease of mango

Anthracnose disease of mango caused by Colletotrichum gloeosporioides var. minor, spreads by water-borne conidia from vegetative parts of the tree to attack inflorescences and prevent fruit set. An analysis of data from laboratory studies demonstrated that infection by conidia during wet periods was related both to the temperature and to the duration of the wet period. A model was used to estimate infection levels of anthracnose disease in two mango orchards over three seasons. The number of infection periods recorded and the estimated percentage of conidia forming appressoria in these periods matched disease development during flush growth and flowering. In 1980, only two infection periods were detected during flowering in one of these orchards and blossom blight did not prevent fruit set. In 1981 and 1982 however, higher estimated levels of infection were recorded more frequently during the same time and severe blossom blight developed. A second orchard, situated in an area less favourable to disease, was also monitored during 1982. Nine infection periods were recorded during flowering in this orchard compared to 14 in the first. A moderate level of blossom blight developed in this orchard.     

The causes of selection on flowering time through male fitness in a hermaphroditic annual plant

Flowering is a key life‐history event whose timing almost certainly affects both male and female fitness, but tests of selection on flowering time through male fitness are few. Such selection may arise from direct effects of flowering time, and indirect effects through covariance between flowering time and the environment experienced during reproduction. To isolate these intrinsically correlated associations, we staggered planting dates of Brassica rapa families with known flowering times, creating populations in which age at flowering (i.e., flowering time genotype) and Julian date of flowering (i.e., flowering time environment) were positively, negatively, or uncorrelated. Genetic paternity analysis revealed that male fitness was not strongly influenced by seasonal environmental changes. Instead, when age and date were uncorrelated, selection through male fitness strongly favored young age at flowering. Strategic sampling offspring for paternity analysis rejected covariance between sire age at flowering and dam quality as the cause of this selection. Results instead suggest a negative association between age at flowering and pollen competitive ability. The manipulation also revealed that, at least in B. rapa, the often‐observed correlation between flowering time and flowering duration is environmental, not genetic, in origin.     

The effects of nutrient addition on floral characters and pollination in two subalpine plants, <Emphasis Type="Italic">Ipomopsis aggregata</Emphasis> and <Emphasis Type="Italic">Linum lewisii</Emphasis>

The availability of soil and pollination resources are main determinants of fitness in many flowering plants, but the degree to which each is limiting and how they interact to affect plant fitness is unknown for many species. We performed resource (water and nutrients) and pollination (open and supplemental) treatments on two species of flowering plants, Ipomopsis aggregata and Linum lewisii, that differed in life-history, and we measured how resource addition affected floral characters, pollination, and reproduction (both male and female function). We separated the direct effects of resources versus indirect effects on female function via changes in pollination using a factorial experiment and path analysis. Resource addition affected I. aggregata and L. lewisii differently. Ipomopsis aggregata, a monocarp, responded to fertilization in the year of treatment application, increasing flower production, bloom duration, corolla width, nectar production, aboveground biomass, and pollen receipt relative to control plants. Fertilization also increased total seed production per plant, and hand-pollination increased seeds per fruit in I. aggregata, indicating some degree of pollen limitation of seed production. In contrast, fertilization had no effect on growth or reproductive output in the year of treatment on L. lewisii, a perennial, except that fertilization lengthened bloom duration. However, delayed effects of fertilization were seen in the year following treatment, with fertilized plants having greater aboveground biomass, seeds per fruit, and seeds per plant than control plants. In both species, there were no effects of resource addition on male function, and the direct effects of fertilization on female function were relatively stronger than the indirect effects via changes in pollination. Although we studied only two plant species, our results suggest that life-history traits may play an important role in determining the reproductive responses of plants to soil nutrient and pollen additions.     

Effect of exogenous gibberellins on flowering in Pinus sylvestris grafts

Ethanolic sprays of gibberellins were applied to developing shoots of about 12-year-old Scots pine (Pinus sylvestris L.) grafts during the shoot elongation period in two consecutive years. Both male and female flowering was increased by these treatments in both years. The effect was particularly distinct in male flowering. However, different clones showed varying responses to the treatment. This variation was associated with both the genotype and the environmentally determined year-to-year fluctuation in flowering. Differences among clones were analysed further by introducing a model earlier developed for comparisons of the growth rhythm in various woody and herbaceous species.     

Size-dependent sex allocation in hermaphroditic plants: the effects of resource pool and self-incompatibility

The effects of the resource pool and resource obtained during a season for seed maturation and self-incompatibility on the size-dependency of evolutionarily stable sex allocation were analysed theoretically. In hermaphroditic plants, reproductive resources allocated between male and female function may not be paid from a single resource pool, because plants can mature seeds using not only reserved resources but also newly gained resources after flowering. But the resource investment to male function is limited to the flowering stage. Under the assumption of constant reserve efficiency and diminishing resource return per investment to leaves, large plants should use both reserved and newly gained resources for seed maturation, while small plants should use only new resources. When both reserved and new resources are used, the optimal allocation for self-compatible species is to invest a constant amount of resources into male function irrespective of resource size, because the female fitness curve increases linearly and the male curve decelerates due to local mate competition. In self-incompatible species, on the other hand, fitness gain per investment through male function and the optimal amount of resources invested in male function decrease with size. Thus a decrease in maleness with size should be emphasized more in self-incompatible species than in self-compatible one. When only new resources are used for seed growth, the female fitness curve as well as male one decelerates with investment. Consequently, the investment in both male and female functions should increase with size, in both self-compatible and self-incompatible species. The magnitude of reserve efficiency relative to efficiency of resource gain after flowering affects size-dependent pattern of sex allocation, while the cost of seed maturation relative to ovule production has little effect on it. The plant size variation in a population emphasizes size-dependency of sex allocation. When size variation is large enough, it is possible that large plants become complete female in self-incompatible species, but it is not in self-compatible species.     

Dissecting components of flowering pattern: size effects on female fitness

Flowering synchrony is essential for plant reproductive success, especially in the case of small‐sized populations of self‐incompatible species. Closely related to synchrony, flowering intensity influences pollinator attraction and pollinator movements. Thus, a high flowering intensity may increase pollinator attraction but, at the same time, may also increase the probability of geitonogamous pollinations. Depending on the mating system, the female fitness of plants in small populations may be affected by both the positive effects of higher flowering synchrony and pollinator attraction and the negative effects of geitonogamous pollinations induced by a high flowering intensity. It was hypothesized that different‐sized plants in a population would show contrasting flowering patterns, resulting in differences in pollinator behaviour. These influences could result in differences in mating and female reproductive success. This hypothesis was tested by studying the flowering pattern of Erodium paularense (Geraniaceae), a rare and endangered endemic of central Spain. The temporal distribution of flower production was explored throughout the reproductive season, and the probability of xenogamy and geitonogamy and their relationship to plant size and fitness components were calculated. The analysis of this partially self‐compatible species showed diverse flowering patterns related to different plant sizes. Small plants produced a larger number of seeds per fruit in spite of having lower values of flowering synchrony. By contrast, large plants produced a larger number of seeds from geitonogamous pollinations. The effect of different flower displays and outcrossing rates on seed set varied throughout the season in the different groups. Our findings highlight the relevance of individual plant size‐dependent phenology on female reproductive success and, in particular, on the relationship between flowering synchrony and fitness. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 156 , 227–236.