Preferential outcrossing in Banksia ilicifolia (Proteaceae)

The breeding system of Banksia ilicifolia was assessed by performing controlled hand-pollination manipulations on flowers in a natural population in Perth, Western Australia. The percentage of 2000 flowers per treatment converted to fruits and seeds was assessed across 24 recipient plants following (1) self-pollination, (2) local outcross pollination (same population), (3) non-local outcross pollination (pollen sourced from another population 30 km away), (4) unpollinated but bagged flowers and (5) unpollinated, unbagged flowers (natural pollination). The relative performance of the resulting seeds was assessed by seed weight, germination rates and, in an unplanned component of the study, resistance to a fungal pathogen. The percentage of flowers converted to fruits following self-pollination was low (0.9%), but demonstrated self-compatibility. Fruit set following cross-pollinations (3.6 and 3.3% for non-local and local crosses, respectively) was significantly greater than that following self-pollination, open-pollination (0.4%) and autogamous (0.04%) treatments. Low fruit set for open-pollinated flowers, compared with self- and outcross-pollination treatments, suggests pollen limitation. Pollen tubes were observed in 15 and 20% of upper styles of flowers hand-pollinated with self and local outcross pollen, respectively. Seed germination was dependent on the source of pollen, where fewer selfed seeds germinated (37%) than did both non-local and local outcrossed seeds (83 and 91%, respectively). Selfed seedlings showed poorer survival (33.3%) following fungal attack than both non-local and local outcrossed seeds (69.2 and 68.5%, respectively). Only 13% of selfed seeds survived to be 2-month-old seedlings, compared with 63% for non-local and 57% for local outcrossed seeds. Ultimately, for 2000 flowers hand-pollinated with self pollen, only three seedlings survived to an age of 16 weeks, compared with 37 and 45 seedlings for local-cross and non-local cross treatments on 2000 hand-pollinated flowers, respectively. These results indicate that in this population, B. ilicifolia is self-compatible, but preferentially outcrossing, with strong early acting inbreeding depression. Consequently, the breeding system of B. ilicifolia promotes the maintenance of genetic variation and a high genetic load.

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Polygamous breeding system identified in the distylous genus Psychotria: P. manillensis in the Ryukyu archipelago, Japan

PeerJ ◽

10.7717/peerj.12318 ◽

2021 ◽

Vol 9 ◽

pp. e12318

Author(s):

Kenta Watanabe ◽

Akira Shimizu ◽

Takashi Sugawara

Keyword(s):

Breeding System ◽

Fruit Set ◽

Sexual Expression ◽

Ryukyu Islands ◽

Ryukyu Archipelago ◽

Open Pollination ◽

Flower Visitors ◽

Hand Pollination ◽

Self Compatibility ◽

Preliminary Study

Distyly is a genetic polymorphism composed of long-and short-styled flowers in a population. The evolutionary breakdown of distyly has been reported in many taxa, and mainly involves a shift toward monomorphism or dioecism. However, a shift toward monoecism has not been reported in distylous species. Psychotria (Rubiaceae), one of the world largest genera, consists of distylous species and their derivatives. In our preliminary study, however, we identified some monoecious individuals in a population of Psychotria manillensis. To understand the breeding system and reproductive biology of P. manillensis, we investigated floral traits, open fruit set, and flower visitors, and performed hand pollination and bagging experiments in five populations of Okinawa and Iriomote islands, Ryukyu Islands, Japan. The populations of P. manillensis were composed mainly of monoecious individuals (54%), followed by female (30%), male (14%), and hermaphroditic (2%) individuals at the time of flower collection. Of the collected flowers, 93% were functionally unisexual (male or female), whereas only 6.5% were perfect (hermaphroditic). However, some individuals changed sex mainly towards increasing femaleness during the flowering period. Moreover, 35% of the studied plants changed their sexual expression over the years. P. manillensis showed self-compatibility and no agamospermy. The fruit set under open pollination varied among populations and years (1.8–21.9%), but it was significantly higher than that of auto-selfing (0.68–1.56%). Wasps and flies were the main flower visitors and probably the main pollinators of the species. In conclusion, P. manillensis was revealed to be polygamous, involving monoecious, female, male, and hermaphroditic individuals. This is the first report of the polygamous breeding system not only in the genus Psychotria, but also in all heterostylous taxa.

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Polygamous breeding system identified in the distylous genus Psychotria: P. manillensis in the Ryukyu archipelago, Japan

10.1101/2020.10.14.334318 ◽

2020 ◽

Author(s):

Kenta Watanabe ◽

Akira Shimizu ◽

Takashi Sugawara

Keyword(s):

Breeding System ◽

Fruit Set ◽

Sexual Expression ◽

Ryukyu Islands ◽

Ryukyu Archipelago ◽

Open Pollination ◽

Flower Visitors ◽

Hand Pollination ◽

Self Compatibility ◽

Preliminary Study

AbstractThe evolutionary breakdown of distyly has been reported in many taxa, and mainly involves a shift toward monomorphism or dioecism. However, a shift toward monoecism has not been reported in distylous species. Psychotria (Rubiaceae), one of the world largest genera, consists of distylous species and their derivatives. In our preliminary study, however, we identified some monoecious individuals in a population of Psychotria manillensis. To understand the breeding system and reproductive biology of P. manillensis, we investigated floral traits, open fruit set, and flower visitors, and performed hand pollination and bagging experiments in five populations of Okinawa and Iriomote islands, Ryukyu Islands, Japan. The populations of P. manillensis were composed mainly of monoecious individuals (44%), followed by female (38%), male (14%), and hermaphroditic (3%) individuals at the time of flower collection. Of the collected flowers, 94% were functionally unisexual (male or female), whereas only 6% were perfect (hermaphrodic). However, some individuals changed sex mainly towards increasing femaleness during the flowering period. Moreover, 35% of the studied plants changed their sexual expression over the years. P. manillensis showed self-compatibility and no agamospermy. The fruit set under open pollination varied among populations and years (1.8–21.9%), but it was significantly higher than that of auto-selfing (0.68–1.56%). Wasps and flies were the main flower visitors and probably the main pollinators of the species. In conclusion, P. manillensis was revealed to be polygamous, composed of monoecious, female, male, and hermaphroditic individuals. This is the first report of the polygamous breeding system not only in the genus Psychotria, but also in all heterostylous taxa.

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Breeding System and Tests for Pollen-Limitation in Two Species of Banksia

Australian Journal of Botany ◽

10.1071/bt9900063 ◽

1990 ◽

Vol 38 (1) ◽

pp. 63 ◽

Cited By ~ 9

Author(s):

RL Goldingay ◽

RJ Whelan

Keyword(s):

Breeding System ◽

Reproductive Output ◽

Fruit Set ◽

Pollen Limitation ◽

Floral Display ◽

Cross Pollination ◽

Self Pollination

Three factors that potentially influence fruit set (breeding system, inadequate cross-pollination and variable floral display) were examined for two species of Banksia. Firstly, self-pollination and autogamy treatments failed to produce any fruit in B. spinulosa and produced very few fruit in B. paludosa. This suggests that cross pollen is required to produce the level of fruit set observed in the field. Secondly, when plants were given abundant cross pollen, fruit set was not altered in B. spinulosa but was in B. paludosa. Although the number of follicles per inflorescence was was not different for open- pollinated (control) and manipulated B. paludosa inflorescences, the latter produced twice the proportion of inflorescences with follicles produced by control plants and twice the total number of follicles per plant. Thirdly, larger floral display in open-pollinated B. spinulosa plants was associated with a greater production of fruit. However, larger floral display was not associated with a greater reproductive output in B. paludosa, and we suggest that recurrent pollen-limitation in this species may be responsible for this result.

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Poor fruit set due to lack of pollinators in Aristolochia manshuriensis (Aristolochiaceae)

Plant Ecology and Evolution ◽

10.5091/plecevo.2021.1747 ◽

2021 ◽

Vol 154 (1) ◽

pp. 39-48

Author(s):

Olga V. Nakonechnaya ◽

Olga G. Koren ◽

Vasilii S. Sidorenko ◽

Sergey A. Shabalin ◽

Tatyana O. Markova ◽

...

Keyword(s):

Fruit Set ◽

Pollen Limitation ◽

Floral Morphology ◽

Pollen Grains ◽

Ex Situ ◽

Colour Pattern ◽

The Poor ◽

Self Pollination ◽

Hand Pollination ◽

Aristolochia Manshuriensis

Background and aims – Interactions of insects with trap flowers of Aristolochia manshuriensis, a relic woody liana with fragmented natural populations from south-eastern Russia, were studied. Pollination experiments were conducted to identify the causes of the poor fruit set in this plant.Material and methods – The study was carried out at two ex situ sites within the natural range of A. manshuriensis in the suburban zone of the city of Vladivostok (Russia). The floral morphology was examined to verify how it may affect the process of pollination in this species. To test for a probability of self-pollination, randomly selected flowers at the female phase of anthesis (day 1 of limb opening) were hand-pollinated with pollen from the same plant. The daily insect visitation was studied. The pollen limitation coefficient and the number of visitors to the flowers were determined. To identify insects that lay eggs on the flowers, the insects were reared from eggs collected from fallen flowers. Both caught and reared insects were identified.Key results – The floral morphology and the colour pattern of A. manshuriensis are adapted to temporarily trap insects of a certain size. The hand-pollination experiment showed that flowers of this plant are capable of self-pollination by geitonogamy and require a pollinator for successful pollination. The positive value (2.64) for the pollen limitation coefficient indicates a higher fruit set after hand-pollination compared to the control without pollination. The number of visitors to the flowers was low (0.17 visitors per flower per day). Insects from three orders were observed on the flowers: Diptera (up to 90.9%), Coleoptera (8.3%), and Hymenoptera (0.8%). Four species of flies (Scaptomyza pallida, Drosophila transversa (Drosophilidae), Botanophila fugax, and Botanophila sp. 1 (Anthomyiidae)) are capable of transferring up to 2500–4000 pollen grains on their bodies and can be considered as pollinators of A. manshuriensis. Data of the rearing experiment indicate that flies of the families Drosophilidae (S. pallida, D. transversa), Chloropidae (Elachiptera tuberculifera, E. sibirica, and Conioscinella divitis), and Anthomyiidae (B. fugax, B. sp. 1) use A. manshuriensis flowers to lay eggs. Beetles were also collected from the flowers, but they were probably not involved in pollination, because no pollen grains were observed on them during our study.Conclusions – Pollinators of A. manshuriensis include mainly Diptera that lay eggs on the flowers. The poor fruit set (2%) in A. manshuriensis is associated with pollen limitation due to the lack of pollinators, as the number of visitors to flowers was extremely low. This may be due to the fact that the flowers of this species are highly specialized on insects of a certain size for pollination.

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Olive Fertility as Affected by Cross-Pollination and Boron

The Scientific World JOURNAL ◽

10.1100/2012/375631 ◽

2012 ◽

Vol 2012 ◽

pp. 1-8 ◽

Cited By ~ 18

Author(s):

A. Spinardi ◽

D. Bassi

Keyword(s):

Pollen Germination ◽

Fruit Set ◽

Optimal Level ◽

Lake Area ◽

Open Pollination ◽

Cross Pollination ◽

Self Pollination ◽

Self Compatibility ◽

Source Sink

Self-compatibility of local olive (Olea europaeaL.) accessions and of the cultivars “Frantoio” and “Leccino” was investigated in Garda Lake area, northern Italy. Intercompatibility was determined for “Casaliva,” “Frantoio,” and “Leccino,” as well as the effects of foliar Boron applications (0, 262, 525, or 1050 mg·L−1) applied about one week before anthesis on fruit set, shotberry set, and onin vitropollen germination. Following self-pollination, fruit set was significantly lower and the occurrence of shot berries significantly higher than those obtained by open pollination. No significant effect of controlled cross-pollination over self-pollination on fruit set and shotberry set was detectable. B treatments increased significantly fruit set in “Frantoio” and “Casaliva” but not in “Leccino.” B sprays had no effect on shotberry set, suggesting that these parthenocarpic fruits did not strongly compete for resources allocation and did not take advantage of increased B tissue levels. Foliar B application enhancedin vitropollen germination, and the optimal level was higher for pollen germination than for fruit set. Our results highlight the importance of olive cross pollination for obtaining satisfactory fruit set and the beneficial effect of B treatments immediately prior to anthesis, possibly by affecting positively the fertilisation process and subsequent plant source-sink relations linked to fruitlet retention.

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Floral traits, pollination ecology and breeding system of three Clematis species (Ranunculaceae) in Yunnan province, southwestern China

Australian Journal of Botany ◽

10.1071/bt09163 ◽

2010 ◽

Vol 58 (2) ◽

pp. 115 ◽

Cited By ~ 8

Author(s):

Nan Jiang ◽

Wen-Bin Yu ◽

Hong-Zhe Li ◽

Kai-Yun Guan

Keyword(s):

Inbreeding Depression ◽

Breeding System ◽

Pollen Limitation ◽

Mating Strategies ◽

Breeding Systems ◽

Floral Traits ◽

Pollination Syndrome ◽

Self Pollination ◽

Hand Pollination ◽

Integrative Study

Flowers of Clematis display showy corollas and diversified shapes. This diversity motivates study of adaptive evolution of flower–pollinator interactions and the functional association between floral traits and plant mating strategies. An integrative study was undertaken, which focused on pollination and reproductive biology of three species representing all three floral types of Clematis. Floral traits were measured, and pollinator assemblages were observed in the field. Bagging, hand-pollination and removal treatments were used to examine breeding systems. The inbreeding depression and pollen limitation were estimated by fruit-set and seed production obtained from pollination treatments. Their floral traits are distinctly different, but are highly associated with pollination syndrome and breeding system. Among them, Clematis akebioides and C. rehderiana may be facultative autogamy (the former was delayed selfing, and the later competing selfing), and C. chrysocoma may be nearly obligate outcrossing. These conclusions are reflected in their stamen-pistil ratios. The levels of inbreeding depression are negatively associated with autonomous self-pollination. Evolution of self-pollination in C. akebioides and C. rehderiana, and pollen limitation in reproduction of the three Clematis species are discussed. This present study, integrating with previous results, will help us to comprehensively recognise and understand the pollination system and reproductive characteristics of Clematis.

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Nectar production and pollination in peach

International Journal of Horticultural Science ◽

10.31421/ijhs/6/3/113 ◽

2000 ◽

Vol 6 (3) ◽

Author(s):

J. Nyéki ◽

Z. Szabó ◽

P. Benedek ◽

L. Szalay

Keyword(s):

Foraging Behaviour ◽

Fruit Set ◽

Open Pollination ◽

Bee Pollination ◽

Nectar Production ◽

Self Pollination ◽

Hand Pollination ◽

Artificial Hand

Observations were made at two growing sites, Siófok and Szatymaz, in the years 1998 and 1999, on 16 peach varieties. The production of nectar was measured, the foraging behaviour of bees, fruit set and the effect of exclusion of bee visits for different periods were observed systematically. Production of nectar confirmed earlier data, 9.09 mg per flower in average. There was large variation due to variety and date of observation. Bee visits were relatively abundant. At favourable weather, 1 to 30 visits/flower/day occurred in the average. Artificial hand pollination increased fruit set, substantially. Open pollination yielded superior fruit set than self pollination, without bees. Supplementary bee pollination can be regarded to be beneficial to peach production as well.

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Effect of flowering phenology and habitat on pollen limitation in Erica multiflora

Canadian Journal of Botany ◽

10.1139/b99-015 ◽

1999 ◽

Vol 77 (5) ◽

pp. 734-743 ◽

Cited By ~ 4

Author(s):

Marc Santandreu ◽

Francisco Lloret

Keyword(s):

Flowering Time ◽

Breeding System ◽

Fruit Set ◽

Pollen Limitation ◽

Pine Forest ◽

Flowering Period ◽

Erica Multiflora ◽

Western Mediterranean Basin ◽

Hand Pollination ◽

Insect Visitors

Pollination can be a major factor influencing reproductive success in plants. Pollination may be influenced by variability in pollen production and vector activity associated with environmental heterogeneity in time and space. These factors were addressed experimentally using hand pollinations of Erica multiflora L., a shrub occurring in the western Mediterranean Basin that exhibits a long flowering period. Variation in pollen limitation was considered three times (early, peak, and late) over the flowering season and between two habitats (shrubland and pine forest). The breeding system and the pollination vectors were also studied by hand pollination and exclusion experiments. Xenogamy and natural pollination (control) treatments produced more seed and fruit set than geitonogamy and autogamy treatments. Insect visitors were less abundant at the end of the flowering period and in the pine forest habitat. Pollen limitation was not different between habitats, but it changed over the flowering period. Fruit set was pollen limited at the early flowering time, when less flowers were available. Both seed and fruit set were pollen limited at the late flowering time, when both flower density and insect visitors were lower. Seed and fruit set were not pollen limited at the peak of the flowering period, but their low values suggest resource limitation associated with a large number of developing fruits.Key words: breeding system, fruit set, hand pollination, insect pollinator, phenology, seed production.

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Reproductive biology and breeding system in Casuarina equisetifolia (Casuarinaceae) – implication for genetic improvement

Australian Journal of Botany ◽

10.1071/bt15184 ◽

2016 ◽

Vol 64 (2) ◽

pp. 120 ◽

Cited By ~ 4

Author(s):

Y. Zhang ◽

C.L. Zhong ◽

Q. Han ◽

Q.B. Jiang ◽

Y. Chen ◽

...

Keyword(s):

Reproductive Biology ◽

Breeding System ◽

Genetic Improvement ◽

Fruit Set ◽

Seed Set ◽

Pollen Limitation ◽

Casuarina Equisetifolia ◽

Open Pollination ◽

Floral Longevity ◽

Improvement Programs

Understanding the reproductive biology of plant species is essential for successful domestication and genetic improvement programs. Casuarina equisetifolia L. is an important plantation species in China and India but information on reproductive biology is limited. To address this issue, grafted ramets of C. equisetifolia were used to study floral biology, breeding system and progeny performance. The female floral longevity of C. equisetifolia reached 28.4 days under non-pollination conditions, which was significantly longer than that of supplementary pollination (5.5 days) and open pollination (12.2 days), implying successful pollination would accelerate senescence of female flowers. Higher fruit set (88.8%) and seed set (35.7%) under supplementary pollination were obtained, compared with 75.9% and 21.7%, respectively, under open pollination, although there were no fruit set and seed set under non-pollination conditions. Pollen limitation was evident based on pollen limitation index (0.39) in seedling plantations of C. equisetifolia. Selfed seedlings had low height and diameter growth in both nursery and field trials and markedly lower survival in field trial, indicating inbreeding depression. Microsatellite-based estimates of selfing rate of open pollinated, monoecious individuals was 42%, suggesting that monoecious C. equisetifolia individuals are self-compatible, and that the breeding system should be classified as facultative xenogamy.

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Reproductive success of Acacia longifolia (Fabaceae, Mimosoideae) in native and invasive populations

Australian Journal of Botany ◽

10.1071/bt14318 ◽

2015 ◽

Vol 63 (5) ◽

pp. 387 ◽

Cited By ~ 7

Author(s):

Marta Correia ◽

Sílvia Castro ◽

Susana Rodríguez-Echeverría

Keyword(s):

Reproductive Success ◽

Seed Size ◽

Fruit Set ◽

Lower Number ◽

Open Pollination ◽

Native Range ◽

Reproductive Assurance ◽

Acacia Species ◽

Self Compatibility ◽

Selfing Ability

The reproductive biology of exotic species affects their capacity to become naturalised and invasive in non-native areas. Selfing is a common trait in many invasive plants probably because it provides reproductive assurance under low availability of pollination vectors and sexual partners. Nonetheless, the predominantly self-incompatible Australian Acacia species are among the most aggressive plants worldwide. To address whether there have been changes in selfing ability and natural reproductive success of A. longifolia during invasion, we compared one population in the invaded area (Portugal) with one population in the native range (Australia). We specifically assessed floral traits, fruit set and offspring traits for selfing and open-pollination treatments. Within each pollination treatment, no differences were found between areas, suggesting that the level of self-compatibility has not changed during invasion. However, the number of aborted seeds and seed size were significantly different between pollination treatments in Australia but not in Portugal. There were significant differences in the number of seeds per pod and in seed weight between ranges. A lower number of aborted seeds, a higher number of fully developed seeds and a greater seed size were found in the invaded area for both pollination treatments. In spite of the low selfing ability of A. longifolia in the invaded area, there was an increase in the quantity and size of the seeds produced in the new region, even for self-pollinated fruits, which might contribute to A. longifolia invasiveness.

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