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Ocotea porosa has been extensively exploited over the past few decades because of the quality of its wood. Today, populations are reduced and the species is now included in the Red List of threatened species by the International Union for Nature Conservation. For conservation and management purposes, it is extremely important that we understand its reproductive ecology. Floral morphology was described based on field and scanning electron microscopic examination. The reproductive system was determined through experimentally controlled pollination along with observations of pollen tube growth. Pollinators were identified through field observations. Flowers of O. porosa are small, shallow, inconspicuous, asynchronous and grouped in inflorescences. This species presented self-compatibility, but did not reproduce through apomixy and spontaneous self-pollination was very rare (5%). Despite being monoclinal, flowers were protogynic, and the gynoecium was receptive after the first day of anthesis when the anthers were closed. Spontaneous self-pollination was avoided by the extrorse position of the anthers of the internal stamens. Frankliniella gardeniae (Thysanoptera) was the only pollinating species observed and, after visiting several asynchronous flowers in the same inflorescence, favors geitonogamy. Together the small distance supposedly achieved by thrips in flight and the small population density of O. porosa can reduce the chances of cross-pollination in this species. If so, conservation measures must include preservation of the current population and possibly planting to increase population density. This would reduce the distance between individuals and increase genetic variability. Thrips as pollinators must be included in conservation planning for O. porosa. [ABSTRACT FROM AUTHOR]

Floral biology, sexual system, breeding system, pollinators, fruiting and propagule dispersal ecology of crypto-viviparous Avicennia alba Bl., A. marina (Forsk.) Vierh. and A. officinalis L. (Avicenniaceae) were studied in Godavari mangrove forests of Andhra Pradesh State, India. All the three plant species initiate flowering following the first monsoon showers in June and cease flowering in late August. The flowers are hermaphroditic, nectariferous, protandrous, self-compatible and exhibit mixed breeding system. Self-pollination occurs even without pollen vector but fruit set in this mode is negligible. In all, the flowers are strictly entomophilous and the seedlings disperse through self-planting and stranding strategies. [ABSTRACT FROM AUTHOR]

Switchgrass ( Panicum virgatum L.) is being targeted for use as a dedicated lignocellulosic feedstock crop for producing bioenergy in the United States. The breeding of new switchgrass cultivars with enhanced performance is a research emphasis supporting the targeted use. The species is considered allogamous due to wind facilitated cross-pollination and strong genetic self-incompatibility. Plants typically produce few or no seed when self-fertilized. No attempt has been made to identify selfing-compatible plants that would potentially enable developing inbred lines. Here, using a set of 12 simple sequence repeat-based molecular markers, we identified one lowland plant, 'NL94 LYE 16 × 13' (NL94), demonstrating high self-compatibility. A large potted plant of NL94 and a similar size plant of 'SL93 7 × 15' were grown in a growth chamber for the purpose of producing a hybrid full-sib mapping population. Marker analyses of 456 progeny from the NL94 plant indicated that 279 (61.2%) and 177 (38.8%) resulted from self- and cross-fertilization, respectively. SSR marker segregation analyses in both the selfed and hybrid progeny populations conclusively indicated disomic inheritance in the two switchgrass parents. Disomic inheritance of switchgrass is significant to the development of switchgrass inbreds as homozygosity is approached much faster via inbreeding under disomic vs. tetrasomic inheritance. Self-compatibility in switchgrass potentially enables the development of inbred lines for use in producing heterotic F1 hybrid cultivars. [ABSTRACT FROM AUTHOR]

An allopolyploid is an individual having two or more complete sets of chromosomes derived from different species. Generation of allopolyploids might be rare because of the need to overcome limitations such as co-existing populations of parental lines, overcoming hybrid incompatibility, gametic non-reduction, and the requirement for chromosome doubling. However, allopolyploids are widely observed among plant species, so allopolyploids have succeeded in overcoming these limitations and may have a selective advantage. As techniques for making allopolyploids are developed, we can compare transcription, genome organization, and epigenetic modifications between synthesized allopolyploids and their direct parental lines or between several generations of allopolyploids. It has been suggested that divergence of transcription caused either genetically or epigenetically, which can contribute to plant phenotype, is important for the adaptation of allopolyploids. [ABSTRACT FROM AUTHOR]

* Premise of the study: A useful, but seldom applied, measure of the effectiveness of different pollinators is their contribution to the rate of outcrossing. This measure is particularly useful in facultatively autogamous plants for which seed set cannot be used as a direct measure of pollinator effectiveness. We used selective exclusion experiments to assess the importance of insects for outcrossing in Protea caffra, a facultatively autogamous shrub with scented flowers that are visited frequently by both birds and insects (mainly beetles). * Methods and results: Pollen loads on stigmas, pollen tube growth, seed set, seed mass, germination, and early seedling survivorship were similar for vertebrate-excluded and open-pollinated infl orescences. Pollen-supplementation mostly did not increase seed set, revealing resource limitation. Mean multilocus outcrossing rates, estimated using eight polymorphic allozyme loci, were similar for progeny from inflorescences excluded from bird visitors (0.65) and for those visited by both birds and insects (0.59). Wright's fixation indices indicated that the adult population is near Hardy--Weinberg equilibrium but differed markedly for maternal plants ( FIS = --0.187 ± 0.065) and their early stage progeny ( FIS = 0.258 ± 0.002). Since seed from self and cross hand-pollinations were equally viable in terms of germination, this discrepancy in FIS could be explained by inbreeding depression that occurs between germination and reproductive maturity. * Conclusions: Since outcrossing rates were not reduced when birds were excluded, we infer that insects are effective agents of cross pollination in P. caffra. This helps to explain the evolution of traits associated with insect pollination, such as fruity floral scent, in this species. [ABSTRACT FROM AUTHOR]

Self-incompatibility is expressed by nearly one-half of all angiosperms. A large proportion of the remaining species are self-compatible, and they either outcross using various contrivances or self-fertilize to some extent. Because of the common occurrence of populations and individuals with intermediate levels of self-incompatibility, categorization of the expression of self-incompatibility as an approximately binary trait has become controversial. We collect a widely reported index (index of self-incompatibility [ISI]) used to asses the strength and variation of self-incompatibility from over 1200 angiosperm taxa. Its distribution is bimodal and positively associated with outcrossing rate, albeit with a weak relationship within self-compatible taxa. A substantial fraction of species has intermediate mean values of ISI. Their occurrence can be caused by segregating ephemeral self-compatible mutations, averaging artifacts, and experimental biases, in addition to the often invoked stabilizing selection acting on the expression of self-incompatibility. Selection may also generally favor taxa with high ISI values through increased lineage birth and death rates, and it may counter lower level selection advantages within taxa expressing intermediate and low values of ISI. Such a null hypothesis is nearly universally overlooked, despite the fact that it could adequately explain the observed distribution of mating and breeding systems. [ABSTRACT FROM AUTHOR]

Abstract: Oxalis section Sagittatae (Oxalidaceae) is distinguished from other South African members of the genus by their diverging two lower reproductive organ levels. Here we investigate the floral morphology and reproductive strategy of members of Oxalis section Sagittatae. Flowers of two Sagittatae species, from seven populations, were compared in terms of corolla and reproductive organ morphology, reproductive organ level segregation and reproductive organ spatial arrangement. Self-incompatibility expression was also tested through crossing experiments in three of these populations. In members of Oxalis section Sagittatae sexual reproductive organs are arranged by height, angle of flexure from the central floral axis and by the orientation of the anthers and stigmas. This represents a tristylous form of three-dimensional reciprocity, a distylous form of which was recently described in Linum suffruticosum. Members of Oxalis section Sagittatae present self-compatibility, rendering the system more reliant on reciprocity. A consistent and precise pattern of flower visitation by pollinators is thus required in this Oxalis system to achieve out-crossing. Deviations in this visitation pattern can result in seed set through selfing. [Copyright &y& Elsevier]

Orchid species are well known for their highly specialized pollinator interactions. To better understand the reproductive biology of the tropical epiphytic orchid Bulbophyllum variegatum on Réunion, we investigated the floral morphology, breeding system, pollinator diversity, floral scent profile and fruiting success of about 30 individuals in three natural populations during two consecutive flowering seasons. Controlled hand-pollination experiments in two populations showed that the species is self-compatible, but requires pollinator service to achieve reproduction. Videotape pollinator observations were conducted during two flowering seasons for 56 h and revealed that B. variegatum is pollinated by a single species of fly from the Platystomatidae. This fly seems to be attracted by the unpleasant scent produced by the flowers, and does not receive any reward after achieving pollination. In addition, no egg-laying behaviour was observed. Bulbophyllum variegatum thus exhibits a typical sapromyiophilous pollination syndrome which constitutes the first proven case of sapromyiophily within the genus Bulbophyllum on the Mascarene Archipelago. Hand pollinations further showed that fruit set was not significantly higher for flowers that received outcross pollen than for those that were self-crossed (53% and 44% respectively). Fruit sets under natural conditions were significantly different among populations, ranging from 0.5% to 24.3%. This low fruit production is likely due to infrequent pollinator visits, particularly in disturbed forests where the pollinator has never been observed. [ABSTRACT FROM PUBLISHER]

Pollen germination and pollen-tube growth under natural conditions were observed in a population of a distylous species, Primula sieboldii, in which partial self-compatibility has been demonstrated in some long-styled genets. We observed post-pollination processes microscopically in styles collected after self-morph and inter-morph hand pollination (with standardized pollen load on the stigmas) in four genets each from the following three 'genet types': self-incompatible long-styled (SI), partially self-compatible long-styled (SC) and self-incompatible short-styled morph genets. Irrespective of the genet type, pollen germination began within 24 h after pollination and tubes of pollen reached to the style base with 48-96 h after inter-morph pollination. Although pollen tubes germinated after self-pollination in the SC genets, the number of germinated pollen tubes was significantly lower than in the case of inter-morph pollination. Few pollen tubes germinated after self-pollination of the SI or short-styled genets. In SC genets, the rate of pollen-tube growth did not differ between self-morph and inter-morph pollination (∼1.9 mm/day). Therefore, differences in self-compatibility between SC and SI genets in P. sieboldii are likely to be attributable to differential pollen germination rates rather than to differential pollen-tube growth rates. [ABSTRACT FROM AUTHOR]

The pear cultivar 'Zaoguan' ( S S) is the a self-compatible descendant of 'Yali' ( S S) × 'Qingyun'( S S). Two self-incompatible cultivars 'Xinya' and 'Yaqing', also S-genotyped as S S for the S- RNase gene, were used as controls. Field pollination data revealed that 'Zaoguan' displayed SC, whereas 'Xinya' and 'Yaqing' showed self-incompatibility (SI) upon self-pollination. Reciprocal pollinations between the varieties showed that most of the 'Zaoguan' flowers pollinated with 'Xinya' or 'Yaqing' pollen set fruits but that few of the 'Xinya' or 'Yaqing' flowers set fruit when pollinated with 'Zaoguan' pollen. The pollen performance was monitored with fluorescence microscopy, and we observed that 'Zaoguan' accepted self-pollen as well as 'Xinya' or 'Yaqing' pollen, whereas 'Xinya' or 'Yaqing' rejected self-pollen and 'Zaoguan' pollen. The S- RNase but not the S- RNase could be detected in all selfed progeny of 'Zaoguan'. Comparisons of the 2D-PAGE profiles of the stylar extracts from the three cultivars showed that the S-RNase protein expressed normally, but the S-RNase of 'Zaoguan' was not found. Thus, we concluded that the stylar S products were defective in 'Zaoguan' and that the S-allele functioned normally. The nucleotide sequences of the S- and S- RNase of 'Zaoguan' showed no differences from those of 'Xinya' or 'Yaqing', and they transcribed normally. These results indicate that SC in 'Zaoguan' was due to the loss of the S-RNase caused by unknown post-transcriptional factors. [ABSTRACT FROM AUTHOR]

Pear cultivar 'Sha 01' is a sport from 'Kuerlexiangli'. Field pollination data revealed that 'Sha 01' displayed self-compatibility (SC), whereas 'Kuerlexiangli' showed self-incompatibility upon self-pollination. Reciprocal pollinations between the two varieties showed that 76% of 'Kuerlexiangli' flowers pollinated with 'Sha 01' pollen set fruit, but only 7% of 'Sha 01' flowers set fruit when pollinated with 'Kuerlexiangli' pollen. The pollen performance was monitored with fluorescence microscopy, and it was observed that 'Sha 01' accepted self-pollen but rejected 'Kuerlexiangli' pollen, whereas 'Kuerlexiangli' rejected self-pollen but accepted 'Sha 01' pollen. Taken together, 'Sha 01' showed SC as a pollen-part mutant. Molecular S-genotyping of 'Sha 01', its selfed progeny, and wild-type 'Kuerlexiangli' showed that all contained S- RNase and S- RNase alleles, but showed no nucleotide sequence difference or changes in transcription. After flow cytometry and chromosome number analyses, 'Sha 01' was found to be a tetraploid (2 n = 68) and 'Kuerlexiangli' a diploid (2 n = 34). Thus, the S-genotype for 'Sha 01' was S S S S and for 'Kuerlexiangli' was S S. Ploidy level of 'Sha 01' selfed progeny were also determined from leaves using flow cytometry; all seedlings were tetraploids. The S-genotyping for the progeny was identified by S- RNase gene relative optical density for both alleles. Closer inspection of 52 progeny showed that they could be classified into three types S S S S: S S S S: S S S S with the distribution 28:10:14 ≈ 4:1:1; no individual homozygous for either allele was found. Therefore, it could be concluded that only heteroallelic diploid pollen S S could achieve 'Sha 01' fertilization through a so-called competitive interaction. [ABSTRACT FROM AUTHOR]

Summary [ABSTRACT FROM AUTHOR]

With 1 figure and 4 tables Self‐compatibility has become one of the most important traits in almond breeding programmes. This characteristic allows for the establishment of monovarietal almond orchards with many advantages for the grower. However, there are some uncertainties about the consequences of self‐fertilization regarding productivity and fruit quality. In this work, a new methodology was used to clarify the possible effects of self‐pollination on these parameters. Four different pollination treatments were applied to six self‐compatible almond genotypes by hand‐pollinating flowers on five different branches, so that along each branch the four treatments were distributed homogeneously. The pollinated flowers were later identified with wires of a particular colour for each treatment. Fruit set and fruit characteristics (weight in‐shell, kernel weight, percentage of kernel, percentage of defective kernels, double kernels and split kernels) were studied. With this methodology, results should only be influenced by the pollinator effect. In general, no significant differences were observed between self‐pollination and cross‐pollination for the characteristics studied. These findings demonstrate the absence of negative effects of self‐pollination on these agronomic traits. [ABSTRACT FROM AUTHOR]

Self-compatibility in Rosaceous fruit species is based on a single-locus qualitative trait. However, the evidence observed in different species has indicated the presence of modifier genes outside the S locus affecting the expression of self-compatibility/self-incompatibility. The study of a progeny obtained from the cross of the almond genotypes 'Vivot'× 'Blanquerna' has allowed the construction of a genetic map based on microsatellite markers and the identification for the first time in the Rosaceae family of two additional loci located outside the S locus and affecting the expression of self-compatibility/self-incompatibility. A quantitative trait locus (QTL) was located relatively close to the S locus, on linkage group 6 (G6), whereas the second one was located on G8. These QTLs appear to be involved in conferring self-compatibility to genotypes not possessing the S allele. These results are consistent with almond being a self-incompatible species with a genetic background of pseudo-self-compatibility controlled by modifier genes. The effect of the S allele and the two QTLs may contribute to explain the wide range of fruit sets observed when self-pollinating different almond genotypes. [ABSTRACT FROM AUTHOR]

Background and Aims Abolboda (Xyridaceae) belongs to the Poales, a predominantly wind-pollinated order whose phylogeny has been widely studied in recent years. The reproductive biology of Abolboda pulchella and A. poarchon was studied to determine the main pollination system of these species, providing the first experimental data on reproduction in the Xyridaceae. Methods A field study was conducted, including observations on the morphology and biology of the flowers, insect visits and pollinator behaviour. Experimental pollination treatments were performed to assess agamospermy, spontaneous self-pollination and self-compatibility. Pollination success was determined by pollen tube growth, and reproductive success was assessed by fruit- and seed-set. Key Results Abolboda pulchella and A. poarchon were pollinated by Apidae, Megachilidae and Halictidae bees. The floral resources were pollen and nectar that was produced by stylar appendages, an uncommom nectary type for monocotyledons. The species were self-compatible, and pollen tube growth from self-pollen was similar to that of cross-pollen. However, herkogamy prevented spontaneous selfing, rendering the plants dependent on the pollinator's activity. There was no production of seeds by agamospermy. Conclusions Melittophily is the main pollination system of these two Abolboda species. Nectar production was first recorded here for Xyridaceae, and along with self-compatibility, herkogamy and bee pollination, is an informative characteristic that can be used in future phylogenetic analyses of the family as well as Poales. [ABSTRACT FROM PUBLISHER]

Self-incompatibility in Prunus (Rosaceae) species, such as sweet cherry, is controlled by a multiallelic locus (S), in which two tightly linked genes, S-RNase and SFB (S haplotype-specific F-box), determine the specificity of the pollen and the style. Fertilization in these species occurs only if the S-specificities expressed in the pollen and the pistils are different. However, modifier genes have been proposed to be necessary for a full manifestation of the self-incompatibility response. ‘Cristobalina’ is a spontaneous self-compatible sweet cherry cultivar that originated in Eastern Spain. Previous studies with this genotype suggested that pollen modifier gene(s), not linked to the S-locus, may be the cause of self-incompatibility breakdown. In this work, an F1 population from ‘Cristobalina’ that segregates for this trait was used to identify molecular markers linked to self-compatibility by bulked segregant analysis. One simple sequence repeat (SSR) locus (EMPaS02) was found to be linked to self-compatibility in this population at 3.2 cM. Two additional populations derived from ‘Cristobalina’ were used to confirm the linkage of this marker to self-compatibility. Since EMPaS02 has been mapped to the sweet cherry linkage group 3, other markers located on the same linkage group were analysed in these populations to confirm the location of the self-compatibility locus. [ABSTRACT FROM PUBLISHER]

Niger ( Guizotia abyssinica (L. f.) Cass. (Asteraceae) is a strictly self-incompatible crop species with a sporophytic self-incompatibility mechanism. This characteristic presents a number of difficulties in plant improvement programs. The objective of this study was to determine the number and distribution of S-alleles in Ethiopian niger populations and to identify and develop self-compatible genotypes with various associated advantages. Several aspects of self-incompatibility in niger were compared in self- and cross-pollination experiments in which seed-set was considered to be a measure of compatibility. Our results indicate the presence of a minimum of ten self-incompatibility alleles and one self-compatibility allele at the S-locus in niger. Most of these alleles behave differently in the pollen and pistil. About two-thirds of the allelic interactions in both the pollen and pistil were dominant/recessive, and one-third were codominant. The reciprocal cross-pollinations (RCPs) resulted in progeny with similar levels of compatibility within and among populations because of a wide distribution of S-alleles in the populations and, consequently, low population differentiation at the S-locus. An analysis of molecular variance (AMOVA) revealed that only 2% of the total genetic variation at the S-locus differentiates the populations. In conclusion, self-compatible genotypes from the Ethiopian niger gene pool have been identified and developed for the first time. [ABSTRACT FROM AUTHOR]

Most legislation pertaining to non-native organisms is implicitly focussed at the individual species level. However, in some cases interspecific hybrids can be more invasive than any of the parent species. This is problematic for policy makers, and for horticulturists developing or trading in new ornamental cultivars. We explore these issues in the context of the need to manage naturalized populations of Kangaroo Paws ( Anigozanthos species) in South Africa. Self-sustaining, dense populations of naturalized Kangaroo Paws occur at several localities and are highly attractive to local nectar-feeding birds. The populations show high levels of seed set with or without bird pollination. Given the known propensity of Kangaroo Paws to hybridise in their native range in Australia, and confusion about the species identity of naturalized populations in South Africa, it was essential to resolve some key taxonomic issues in the group. We constructed the first molecular phylogeny for all species of the Kangaroo Paw group (genera Anigozanthos and Macropidia; family Haemodoraceae). As previously determined by taxonomists working on herbarium specimens, naturalized populations were identified as A. flavidus. In addition, we also identified a second species, A. rufus. Relative genome size estimates for Anigozanthos species indicated that small inter-specific differences in genome sizes are positively correlated to hybrid fitness. Anigozanthos flavidus and A. rufus have relatively 'compatible' genomes and may produce fertile hybrids under field conditions. However, for species whose genome size differ more than ~30%, there is little inter-specific compatibility and consequently a very low risk of producing fertile hybrids. In conclusion, we recommend that trade in Kangaroo Paws in South Africa should be temporarily restricted and that particular cultivars should first be subjected to a careful risk assessment. [ABSTRACT FROM AUTHOR]

1. Pollen-mediated gene flow from ecological core populations may hamper the ability of populations to invade new, closely adjacent habitats. The potential for the invasion of a new habitat is enhanced when selection against immigrants is augmented by the elevation of self-fertilization. This shift imparts a measure of reproductive isolation to the invader. 2. Whereas genetically mediated changes in selfing often accompany niche shifts in plants, the elevation of self-fertilization by plastic responses to novel, stressful, environments has not been explored. Here I will show that invaders of novel habitats may have elevated levels of self-fertility mediated by alterations in floral form and self-compatibility. 3. Heightened selfing facilitates the evolution of local adaptation by increasing the additive genetic variance for tolerance to the new habitat. Heightened selfing also facilitates local adaptation by increasing reproductive assurance. 4. Elevated levels of selfing based on developmental responses are immediate, as opposed to that obtained by multigenerational selection. 5. Synthesis. The likelihood of a niche shift will be substantially enhanced if the invader is protected from the swamping effect of gene flow from a nearby core population. This protection may be afforded by an environment-induced elevation of self-fertility. The likelihood of a niche shift also is enhanced by an increase in reproductive assurance which may be vital to the survival of an invading population whose reproductive success is density-dependent. [ABSTRACT FROM AUTHOR]

Outcrossing is the prevalent mode of reproduction in plants and animals despite its substantial costs, while selfing and mixed mating occur at much lower frequency. Comparative research on plants has demonstrated the lability of self-incompatibility, but there is little information about the transition on a within-species level from self-incompatibility to predominant selfing. We studied variation in mating system among 18 populations of Arabidopsis lyrata within a phylogenetic context to shed light on the evolution of selfing. Realized and potential mating systems were assessed by genetic analysis with microsatellite markers and hand-self-pollinations on 30 plants from each population. The fraction of self-incompatible plants in a population was highly correlated with the outcrossing rate, showing that the spread of self-compatibility is accompanied by or soon followed by an increase in the rate of selfing. The four predominantly selfing populations (outcrossing rates < 0.25) fell into more than one phylogenetic cluster, suggesting that the transition to selfing occurred more than once independently. Hence, A. lyrata offers an opportunity for the comparative analysis of outcrossing as a predominant mode of reproduction in plants and of the causes of the shift to selfing. [ABSTRACT FROM AUTHOR]

• Premise of the study: Embryonic inbreeding depression is a key influence on mating system evolution and can be difficult to estimate in self-incompatible species. A pollen chase experiment was used to estimate the magnitude of embryonic inbreeding depression in Costa Rican Witheringia solanacea, a species polymorphic for self-incompatibility (SI). In a pollen chase experiment, bud self-pollinations are followed after anthesis by outcross pollinations, with a comparable pair of outcross pollinations used as a control. Lowered seed set for the self-precedence treatment indicates embryonic inbreeding depression. • Methods: Embryonic inbreeding depression was assayed for self-compatible (SC) individuals and for SI plants from two populations that differ quantitatively in the onset and enzymatic activity of their SI response. Microsatellite markers were used to assay the selfing rate of a sample of surviving progeny from the prior self-pollination treatment. • Key results: SC individuals showed no evidence of embryonic inbreeding depression. In SI plants, prior self-pollination reduced seed number by 28-70%, depending on population. Microsatellite genotyping revealed that embryonic inbreeding depression was even more severe than estimated by the phenotypic data: for mature fruits resulting from self-pollination precedence, the majority of the progeny were the result of outcross fertilization. • Conclusions: Lineage-specific purging of recessive lethals has accompanied the evolution of SC in this species. SI populations show contrasting levels of embryonic inbreeding depression, with nearly complete embryonic lethality upon selfing in the Monteverde population. In the face of high embryonic inbreeding depression, an increase in selfing rate can evidently occur only under severe pollen limitation. [ABSTRACT FROM AUTHOR]

Genetic diversity at the S-locus controlling self-incompatibility (SI) is often high because of negative frequency-dependent selection. In species with highly patchy spatial distributions, genetic drift can overwhelm balancing selection and cause stochastic loss of S-alleles. Natural selection may favor the breakdown of SI in populations with few S-alleles because low S-allele diversity constrains the seed production of self-incompatible plants. We estimated S-allele diversity, effective population sizes, and migration rates in Leavenworthia alabamica, a self-incompatible mustard species restricted to discrete habitat patches in rocky glades. Patterns of polymorphism were investigated at the S-locus and 15 neutral microsatellites in three large and three small populations with 100-fold variation in glade size. Populations on larger glades maintained more S-alleles, but all populations were estimated to harbor at least 20 S-alleles, and mate availabilities typically exceeded 0.80, which is consistent with little mate limitation in nature. Estimates of the effective size ( Ne) in each population ranged from 600 to 1600, and estimated rates of migration ( m) ranged from 3 × 10−4 to nearly 1 × 10−3. According to theoretical models, there is limited opportunity for genetic drift to reduce S-allele diversity in populations with these attributes. Although pollinators or resources limit seed production in small glades, limited S-allele diversity does not appear to be a factor promoting the incipient breakdown of SI in populations of this species that were studied. [ABSTRACT FROM AUTHOR]

The fragmentation of natural habitat is considered to be a major threat to biodiversity. Decreasing habitat quality and quantity caused by fragmentation may lead to a disruption of plant–pollinator interactions and to a reduction in sexual reproduction in plant species. We conducted a 6-year field experiment to investigate the effects of small-scale fragmentation on plant–pollinator interactions and genetic diversity in the self-compatible Betonica officinalis. We examined the abundance and composition of pollinators, the foraging behaviour of bumblebees and the performance, outcrossing rate and genetic diversity of B. officinalis after 2 and 6 years in experimentally fragmented nutrient-poor, calcareous grassland in the northern Swiss Jura mountains. Fragments of different size (2.25 and 20.25 m2) were isolated by a 5-m-wide strip of frequently mown vegetation. Control plots of corresponding size were situated in adjacent undisturbed grassland. Experimental grassland fragmentation altered the composition of B. officinalis pollinators and reduced their flower visitation rate. Furthermore, the foraging behaviour of bumblebees was changed in the fragments. After 6 years of fragmentation seed weight was higher in fragments than in control plots. However, the densities of B. officinalis rosettes and inflorescences, plant height and inflorescence length were not affected by fragmentation. The outcrossing frequency of B. officinalis growing in fragments was reduced by 15% after 2 years and by 33% after 6 years of experimental fragmentation. This resulted in a significant reduction of the genetic diversity in seedlings emerging in fragments after 6 years. Our study shows that small-scale habitat fragmentation can disturb the interaction between B. officinalis and pollinators resulting in a reduced outcrossing frequency and genetic diversity in plants growing in fragments. However, the response to fragmentation was considerably delayed. This finding strengthens the claim for long-term field experiments with proper replications and controls to assess delayed effects of habitat fragmentation. [ABSTRACT FROM AUTHOR]

Fluorescence microscopy is used to compare frequencies of pollen tube penetration in in situ populations of Cypripedium bardolphianum W.W. Smith et Farrer, Cypripedium flavum W.W. Smith, Cypripedium montanum Dougl. ex Lindl., Cypripedium parviflorum Salisbury var. pubescens (Wildenow) O.W. Knight, Cypripedium reginae Walter, and Cypripedium tibeticum Schltr. The average natural (insect-mediated) pollination rates measured over five seasons are wide ranging among the six species (0.08-0.74). However, the pollination rate of hand-manipulated populations (self and/or cross) is significantly greater than the rate of insect-mediated pollinations in all species studied. A few pollen tubes in both self- and cross-pollinations display aberrant growth in the styles and/or ovaries, but their numbers are too small to suggest evidence of self-incompatibility. Pollen tubes germinate and grow up to the bases of styles within 48 h in C. bardolphianum, C. flavum, and C. tibeticum. Pollen tubes remain at the bases of the styles in C. montanum for 5 d after pollination. In C. parviflorum, pollen tubes penetrate ovaries at 7 d. Pollen tube penetration of ovaries is observed within 15 d after hand pollination in all six species but remains incomplete at this time, with the greatest number of ovule penetrations observed in C. reginae (which has the shortest floral life span). Therefore, we suggest there are additional factors aside from low pollinator visitation for low conversion rates of flowers into fruits in these Cypripedium species. These include inadequate pollen loads deposited on receptive stigmas (pollen limitation), coupled with environmental stress and/or predation disrupting or destroying the slow processes of fertilization and/or fruit maturation. [ABSTRACT FROM AUTHOR]

•Allopolyploid speciation is common in plants and is frequently associated with shifts from outcrossing, for example self-incompatibility, to inbreeding (i.e. selfing). Senecio cambrensis is a recently evolved allohexaploid species that formed following hybridization between diploid self-incompatible S. squalidus and tetraploid self-compatible S. vulgaris. Studies of reproduction in wild populations of S. cambrensis have concluded that it is self-compatible. •Here, we investigated self-compatibility in synthetic lines of S. cambrensis generated via hybridization and colchicine-induced polyploidization and wild S. cambrensis using controlled crossing experiments. •Synthetic F1 S. cambrensis individuals were all self-compatible but, in F2 and later generations, self-incompatible individuals were identified at frequencies of 6.7–9.2%. Self-incompatibility was also detected in wild sampled individuals at a frequency of 12.2%. The mechanism and genetics of self-incompatibility were tested in synthetic S. cambrensis and found to be similar to those of its paternal parent S. squalidus (i.e. sporophytic). •These results show, for the first time, that functional sporophytic self-incompatibility can be inherited and expressed in allopolyploids as early as the second (F2) generation. Wild S. cambrensis should therefore be considered as possessing a mixed mating system with the potential for evolution towards either inbreeding or outcrossing. [ABSTRACT FROM AUTHOR]

We propose an alternative breeding methodology for common buckwheat ( Fagopyrum esculentum Moench), involving the use of the self-compatibility ( S h) gene derived from F. homotropicum Ohnishi. This methodology involves inbred development of homostyle ( S h S h) and pin ( ss) lines by using the self-compatibility gene ( S h). Further, single-cross hybrid seeds are produced using these inbred homostyle and pin lines as pollen and seed parents, respectively. This strategy successfully produced self-compatible homostyle hybrids ( S h s); the percentage of hybrid plants among the progeny was more than 90%. In a greenhouse trial, the heterosis (best parent) in top dry weight, including stem and leaves, was 29.1–48.1% during the early growth stage. The seed yield of the progeny obtained in single-cross experiments was superior to that of an open-pollinated standard variety “Kitawasesoba” by 10% on average. These results suggest that heterosis breeding can be used to increase seed yield in common buckwheat. [ABSTRACT FROM AUTHOR]

The degree to which plants self-fertilize may impact their potential for genetic adaptation. Given that the mating system influences genetic processes within and among populations, the mating system could limit or promote local adaptation. I conducted a literature survey of published reciprocal transplant experiments in plant populations to quantify the effect of mating system on the magnitude of local adaptation. Mating system had no effect on local adaptation. I detected no effect when species were categorized as either self-compatible or self-incompatible or when accounting for environmental differences between source populations. The results suggest that, despite limited genetic variation in selfing species and greater potential for gene flow in outcrossing species, mating system has little influence on adaptation of populations. [ABSTRACT FROM AUTHOR]

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The article reports on the self-compatible almond cultivar 'Matan.' Topics discussed include the pollenizers of the cultivar Um ElFahem that are Kochav, Gilad, and Shefa. Also being discussed are the characteristics of Matan including vigor and growth habit, foliage, and pruning, along with its productivity, time of bloom, and self-compatibility.

The sex type of Trillium camschatcense has been considered to be strictly monomorphic, composed of only hermaphroditic individuals. However, field observations have detected anther-degenerated (AD) plants coexisting with hermaphrodites. The present study aimed to elucidate whether AD plants could be regarded as females and, if so, how their loss of male function is compensated. Because T. camschatcense retains both self-compatible (SC) and self-incompatible (SI) populations, the frequencies of AD plants in multiple populations (22 SC and eight SI) were examined to predict the fate of these individuals under contrasting breeding systems. Morphological and genetic analyses in a SC population demonstrated that AD plants were completely male sterile, but female fertile. Although the quantity of seed produced was similar, hermaphrodites produced seeds predominantly via selfing, whereas seeds of AD plants were entirely outcrossed. Because inbreeding depression was severe, AD plants achieved a fitness advantage through inbreeding avoidance. However, the frequency of AD plants varied among SC populations (0–42%), suggesting that environmental variance can modify the relative fitness. Conversely, the frequency was suppressed among SI populations (0–2%). Because SI hermaphrodites are free from inbreeding, AD plants would not benefit from inbreeding avoidance and would find it difficult to invade a SI population. [ABSTRACT FROM AUTHOR]

Background and Aims: Cucumis melo subsp. agrestis (Cucurbitaceae) is cultivated in many African regions for its edible kernels used as a soup thickener. The plant, an annual, andromonoecious, trailing-vine species, is of high social, cultural and economic value for local communities. In order to improve the yield of this crop, the first step and our aim were to elucidate its breeding system. [ABSTRACT FROM PUBLISHER]

Self-fertilization can provide reproductive assurance during periods of low or unreliable pollinator visitation. Therefore, periods of low pollen receipt may favor evolutionary shifts from cross-fertilization to self-fertilization. Although reproductive assurance is hypothesized to be important in mating system evolution, it has been quantified in relatively few species. Leptosiphon jepsonii shows variation in the mode of selfing, with transient self-incompatibility conferring delayed selfing seen in some individuals and early self-compatibility present in others. Autofertility, reproductive assurance, and pollen limitation were quantified in three populations of L. jepsonii that vary in the timing of self-compatibility and rate of self-fertilization. Plants in all three populations were capable of high seed set through autonomous self-fertilization, and selfing provided significant reproductive assurance in two populations, including one with the highest frequency of delayed selfing. Confidence intervals revealed no difference in reproductive assurance among populations. We conclude that both early and delayed self-compatibility can confer reproductive assurance and alleviate pollen limitation in this species. Results from this study are integrated with previous studies on the same three populations.We synthesize data on inbreeding depression, outcrossing rates, and floral biology for a comprehensive evaluation of the factors affecting the evolution of mixed mating in L. jepsonii. [ABSTRACT FROM AUTHOR]

The breeding system of Eichhornia azurea (Pontederiaceae) has been described as being both self- and heteromorphic incompatible based on crossing experiments performed on plants grown in an experimental garden. We studied the breeding system of tristylous E. azurea population under natural conditions in the Pantanal wetlands, Brazil. Controlled pollinations were conducted using 35 individuals of each floral morph. Legitimate pollinations produced more fruits than self- and illegitimate pollinations, except for the mid-styled morph which was highly self- and heteromorphic compatible. The number of seeds per fruit was higher under legitimate pollinations than in the other treatments, but self- and illegitimate pollinations produced more fruits and seeds in the Pantanal than for individuals of E. azurea in other populations. The higher fruit and seed production resulting from legitimate pollinations corroborate previous studies, but self-compatibility of mid-styled plants was not previously reported. Overall results indicate a partially self- and heteromorphic compatible system for this species in the Pantanal. [ABSTRACT FROM AUTHOR]

Self-incompatibility is a widespread mechanism in flowering plants which prevents self-fertilisation and promotes out-crossing. In this investigation, self-compatible and self-incompatible cultivars of Petunia hybrida Vilm. were discriminated based on the study of pollen tube growth in vivo, seed set percent and index of self-incompatibility (ISI) after self- and cross-pollination. After 48 hours of self- and cross- pollination, the pollen tube growth was studied by aniline blue staining and fluorescent microscopy. Fluorescent microscopy studies showed normal germination and growth of pollen tubes on stigmas but some abnormalities of pollen tube growth were observed in self-pollinated styles in some cultivars. These abnormalities include pollen tube growth inhibition in 2/3 upper part of the style, variable pollen tube diameter in middle and lower part of the style and irregular deposition of callose plugs. ISI studies showed a significant decrease in the seed set of self-pollinated pistils compared with cross-pollinated pistils in some cultivars. The self-pollinated cultivars contain abnormalities in pollen tube growth after self-pollination as well as those with decreasing ISI was defined as self-incompatible in our study. [ABSTRACT FROM AUTHOR]

Coffea anthonyi Stoff. & F. Anthony from Cameroon and the Republic of Congo is formally described. Morphological, biochemical and molecular characteristics, isozyme diversity and phylogenetic relationships are discussed. The new diploid species has strong relationships with the East African C. eugenioides and the allotetraploid cultivated C. arabica. As such, it could be related to a progenitor species of C. arabica. The new species is self-compatible, being a rare character within the genus Coffea. This new small-leaved Central African species is of particular interest from a phylogenetic as well as from a breeding point of view. [ABSTRACT FROM AUTHOR]

The summer-blooming annual forbs Cleome lutea and Cleome serrulata (Cleomaceae) are native across the US Intermountain West and Rocky Mountains, respectively. Their farmed seed is sought to help rehabilitate western rangelands in those regions. This study of the reproductive biologies and pollinator faunas of C. lutea and C. serrulata is the first for this cosmopolitan family, the sister family to the Brassicaceae. Unlike the S-allele self-incompatibility systems of some Brassicaceae, both species of Cleome were found to be self-fertile and capable of some autogamy. Compared with selfing, outcrossing did not enhance seed set, seed viability or seedling vigor for either species (in fact, selfed progeny were more robust). Large, openly visited plants yielded >20 000 seeds each. Like several species of the sister family Capparaceae, flowers of both species first shed their pollen, secreted nectar and became receptive nocturnally. Although no nocturnal visitors were found, both Cleome species attracted a diverse array of diurnal native bees, wasps and butterflies. Among the many floral generalist bees that work Cleome flowers for pollen and nectar are two managed agricultural pollinators, Apis mellifera and Megachile rotundata. These observations bode well for pollinating C. lutea and C. serrulata in small commercial seed fields. It appears that diverse wild bees would benefit from the addition of native Cleome to restoration seed mixes, with the objective of sustaining native pollinator faunas during the first few years of postfire plant community rehabilitation. [ABSTRACT FROM AUTHOR]

Uniparental reproduction has often been regarded as advantageous for colonization. In pseudogamous apomicts, reproduction via single individuals requires self-pollination and consequently self-compatibility (SC) for production of viable seeds. SC and reproductive fitness have been studied in diploid and polyploid taxa of the Ranunculus auricomus complex via pollinator exclusion tests, assessment of seed set, and germination rates. Reproductive fitness of sexuals exceeds that of apomicts and of F1 hybrids but may fluctuate more strongly between years than is the case in apomicts. Diploid sexual taxa and also their F1 hybrids are completely self-incompatible (SI). Autopolyploid sexual cytotypes are also predominantly SI, which may have restricted their range expansion. The observed breakdown of SI in the rather widespread allohexaploid apomicts may be explained by initial partial SC inherited from semi-self-compatible ancestors and strong selection for SC genotypes. It is concluded that higher reproductive fitness of sexualsmay help tomaintain sexual populationswhen cross-pollination is available,whereas SC in apomicts may be advantageous in temporally and spatially unstable environments and also for colonization events. Results suggest that SC in connection with pseudogamous apomixis is an important factor for the observed distribution pattern of geographical parthenogenesis. [ABSTRACT FROM AUTHOR]

Abstract: The floral biology, pollinators and breeding system of Echinodorus longipetalus Micheli were studied in a marshy area of the district of Taquaritinga (State of São Paulo), southeastern Brazil. E. longipetalus is gynodioecious and as far as is known, this is the first record of unisexual flowers, besides perfect flowers, in Echinodorus. Proportion of female individuals in the studied population is 50% and produces 31% more flowers than hermaphrodites. Perfect and pistillate flowers of E. longipetalus are similar in appearance and are pollinated by several species of Hymenoptera (mainly by Xylocopa (Neoxylocopa) suspecta Moure & Camargo). Perfect flowers offer pollen as a reward. Pistillate flowers attract floral visitors by deceit with their staminodes that resemble the stamens of the perfect flowers. Visits to pistillate flowers are quick (1–2s), while visits to perfect flowers last up to 120s. The perfect flowers are self-compatible and produce fruits through spontaneous self-pollination (control flowers), whereas the pistillate ones only set fruits through cross-pollinations. Perfect and pistillate flowers set more fruits under natural conditions than in manual treatments, respectively. Although the pistillate and perfect flowers bear a strong similarity, the selective pollinator behavior seems to be responsible for the increase of fruit set in perfect flowers. [Copyright &y& Elsevier]

Abstract: The breeding system determines different ways whereby seeds will be produced, and the degree of dependency of plants on pollinators for seed set. The genus Chloraea (Orchidaceae) has its main center of diversity in southern South America. There is only poor knowledge concerning its breeding system and pollination. We determined the breeding system of C. crispa, C. chrysantha, C. galeata, and two color forms of C. bletioides (yellow- and white-flowered forms). None of the species in this study produced fruits through apomixis or autogamy, thereby indicating a complete dependency on pollen and pollinators. Geitogamy did not differ significantly with respect to xenogamy excepting in the yellow-flowered form of C. bletioides. Thus, the indexes of self-incompatibility for the white- and yellow-flowered forms of C. bletioides, C. galeata, C. crispa, and C. chrysantha, were 1.00, 0.56, 0.82, 1.09, and 0.81, respectively; indicating that, excluding the yellow-flowered form of C. bletioides which must be regarded as partially self-incompatible, all orchids assessed are totally self-compatible plants. Natural fruiting in the yellow-flowered C. bletioides, C. chrysantha and C. galeata was high, in spite of being nectarless orchids, since the availability of pollinators under natural conditions seemingly resulted unlimited. However, no pollinator was observed visiting C. chrysantha and C. galeata, whereas the yellow-flowered form of C. bletioides was visited by hymenopterans and coleopterans. At contrast, reproductive success of the white-flowered form of C. bletioides and C. crispa was pollen limited, the former being visited by hymenopterans, dipterans, and colepterans; and the latter by two hymenopterans. [Copyright &y& Elsevier]

The breeding system, fruit set, seed set, floral visitors and pollination of Cologania broussonetii were studied. Four pollination treatments were applied: autogamy, geitonogamy, xenogamy, and natural pollination (flowers exposed to pollinators). The frequency of visits was recorded, and pollen grains deposited per stigma on bagged (self pollen deposition) and exposed flowers were counted. The results indicate that this species is self-compatible and autogamus. A small number of low quality fruits and seeds (lowest mass and germination capability) were obtained by spontaneous self-pollination. When fruits obtained by natural pollination were analyzed, a specific pattern of seed formation was detected: ovules were successively fertilized from the apical to the basal portion of the ovary. However, no pattern was observed for seed abortion. The frequency of visits of possible pollinators (species of Bombus) was very low. The number of pollen grains per stigma was similar on bagged and exposed flowers. Nevertheless, the comparison of quantity and quality of fruits and seeds obtained by natural and autonomous self-pollination suggests that the visits of pollinators contribute to increase the quality of seeds (higher mass and germination capability). [ABSTRACT FROM AUTHOR]

As most plants of the Mediterranean region bloom in spring, there have been few studies of the reproductive biology of species with autumn–winter flowering. In this study, we investigate the breeding system of Anagyris foetida, one of the few shrubs that blooms at this time. The floral, phenological, and reproductive aspects of two populations of this Mediterranean legume from south-west Spain were studied via field and laboratory experiments. The variability of fruit and seeds was studied in another 12 Iberian populations with respect to certain meteorological parameters (temperature and rainfall). Anagyris foetida shows cauliflory, marked floral longevity, and adichogamy. The peak of flowering is in January–February. It is self-compatible, with no clear advantage of cross- over self-pollination, and with virtually no autonomous self-pollination. This is because the stigma, like some other legumes, prevents the germination of pollen if its surface is not ruptured by pollinators. The number of seeds per fruit under natural pollination was positively correlated with the total rainfall during the fruiting period (from January to May), and significantly influenced the percentage of fruit weight represented by the pericarp, in the sense that the smaller the number of viable seeds in the fruit, the greater the percentage of pericarp weight. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157, 519–532. [ABSTRACT FROM AUTHOR]

Abstract: Knowledge of the factors that limit reproduction is critical to an understanding of plant ecology, and is particularly important for predicting population viability for threatened species. Here, we investigated the pollination biology of a globally threatened plant, Polemonium vanbruntiae, using hand-pollination experiments in four natural populations to determine the degree of pollen limitation. In addition, we investigated the mating system and extent to which plants can self-fertilize by comparing geitonogamously and autonomously self-fertilized plants with purely outcrossed and open-pollinated plants. In contrast to several of the more common species of Polemonium, we found no pollen limitation in any of the four populations of P. vanbruntiae over two years. The lack of pollen limitation was best explained by the capacity for P. vanbruntiae to both geitonogamously and autonomously self-fertilize, unlike some of its more common congeners. Geitonogamously selfed flowers set equivalent numbers of seeds when compared to purely outcrossed and open-pollinated flowers. However, autonomously selfed flowers produced significantly fewer seeds, demonstrating that pollinators play an important role as inter- and intra-plant pollen vectors in this system. Our results support the reproductive assurance hypothesis, whereby the ability to self assures fertilization for plants in small populations. Self-compatibility in Polemonium vanbruntiae may decrease extinction risk of isolated populations experiencing a stochastic pollinator pool within a restricted geographic range. In addition, a mixed-mating strategy, including the ability for clonal reproduction, may explain the ability for this rare species to persist in small, fragmented populations. [Copyright &y& Elsevier]

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]

An autotuning system, which takes into account the self-compatibility of power converters, is proposed in this paper. It is based on a startup routine and a self-disturbance evaluation board, which selects the optimal switching frequencies for the power converter in order to decrease the internal disturbances in terms of electromagnetic interference between the power section and the control one. The entire test and tuning system does not require any field or current sensor but just digital comparators and counters. This configuration allows achieving a robust and low-cost autotuning system for internal compatibility of power converters. [ABSTRACT FROM AUTHOR]

Many plant species have been introduced from their native ranges to new continents, but few have become naturalized or, ultimately, invasive. It has been predicted that species that do not require the presence of compatible mates and the services of pollinators for reproduction will be favored in establishment after longdistance dispersal. We tested whether this hypothesis, generally referred to as Baker's law, holds for South African species of Iridaceae (iris family) that have been introduced in other regions for horticultural purposes. Fruit and seed production of flowers from which pollinators had been experimentally excluded was assessed for 10 pairs of species from nine different genera or subgenera. Each species pair comprised one naturalized and one nonnaturalized species, all of which are used in international horticulture. On average, species of Iridaceae that have become naturalized outside their native ranges showed a higher capacity for autonomous fruit and seed production than congeneric species that have not become naturalized. This was especially true for the naturalized species that are considered to be invasive weeds. These results provide strong evidence for the role of autonomous seed production in increasing potential invasiveness in plants. [ABSTRACT FROM AUTHOR]

The breeding system of an annual Cruciferae, Arabidopsis kamchatica subsp. kawasakiana, was studied in three natural populations. We applied four experimental treatments, open pollination, bagging, emasculation + bagging, and emasculation + hand-pollination + bagging. None of the emasculated flowers with bags produced fruits but we observed high fruit sets in the other three treatments. The results confirmed that A. kamchatica subsp. kawasakiana is a self-compatible, non-apomictic species that can produce seeds through auto-pollination. Considering the life cycle as an annual, increased reproductive assurance through auto-pollination should be critical for the maintenance of populations of A. kamchatica subsp. kawasakiana. [ABSTRACT FROM AUTHOR]

‘Kronio’ is a Sicilian cultivar of sweet cherry (Prunus avium), nominally with the incompatibility genotype S5S6, that is reported to be naturally self-compatible. In this work the cause of its self-compatibility was investigated. Test selfing confirmed self-compatibility and provided embryos for analysis; PCR with consensus primers designed to amplify S-RNase and SFB alleles showed that the embryos were of two types, S5S5 and S5S6, indicating that S6 pollen failed, but S5 succeeded, perhaps because of a mutation in the pollen or stylar component. Stylar RNase analysis indicated active S-RNases for both S5 and S6. The S-RNase alleles were cloned and sequenced; and sequences encode functional proteins. Cloning and sequencing of SFB alleles showed that S6 was normal but S5 had a premature stop codon upstream of the variable region HVa resulting in a truncated protein. Therefore, the self-compatibility can be attributed to a pollen-part mutation of S5, designated S5′, the first reported case of breakdown of self-incompatibility in diploid sweet cherry caused by a natural mutation at the S-locus. The second intron of the S-RNase associated with S5′ contained a microsatellite smaller than that associated with S5; primers designed to amplify across this microsatellite effectively distinguished S5 from S5′. Analysis of some other Sicilian cherries with these primers indicated that S5′ is also present in the Sicilian cultivar ‘Maiolina a Rappu’, and this proved to be self-compatible. [ABSTRACT FROM PUBLISHER]

The outcome of species interactions is often difficult to predict, depending on the organisms involved and the ecological context. Nectar robbers remove nectar from flowers, often without providing pollination service, and their effects on plant reproduction vary in strength and direction. In two case studies and a meta-analysis, we tested the importance of pollen limitation and plant mating system in predicting the impacts of nectar robbing on female plant reproduction. We predicted that nectar robbing would have the strongest effects on species requiring pollinators to set seed and pollen limited for seed production. Our predictions were partially supported. In the first study, natural nectar robbing was associated with lower seed production in Delphinium nuttallianun'i, a self-compatible but non-autogamously selfing, pollen-limited perennial, and experimental nectar robbing reduced seed set relative to unrobbed plants. The second study involved Linaria vulgaris, a self-incompatible perennial that is generally not pollen limited. Natural levels of nectar robbing generally had little effect on estimates of female reproduction in L. vulgaris, while e4erimentai nectar robbing reduced seed set per fruit but not percentage of fruit set. A meta-analysis revealed that nectar robbing had strong negative effects on pollen-limited and self-incompatible plants, as predicted. Our results suggest that pollination biology and plant mating system must be considered to understand and predict the ecological outcome of both mutualistic and antagonistic plant-animal interactions. [ABSTRACT FROM AUTHOR]