Natural disturbances and masting: from mechanisms to fitness consequences

The timing of seed production and release is highly relevant for successful plant reproduction. Ecological disturbances, if synchronized with reproductive effort, can increase the chances of seeds and seedlings to germinate and establish. This can be especially true under variable and synchronous seed production (masting). Several observational studies have reported worldwide evidence for co-occurrence of disturbances and seed bumper crops in forests. Here, we review the evidence for interaction between disturbances and masting in global plant communities; we highlight feedbacks between these two ecological processes and posit an evolutionary pathway leading to the selection of traits that allow trees to synchronize seed crops with disturbances. Finally, we highlight relevant questions to be tested on the functional and evolutionary relationship between disturbances and masting. This article is part of the theme issue ‘The ecology and evolution of synchronized seed production in plants’.

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The Impact of Alkaloid-Producing Epichloë Endophyte on Forage Ryegrass Breeding: A New Zealand Perspective

Toxins ◽

10.3390/toxins13020158 ◽

2021 ◽

Vol 13 (2) ◽

pp. 158

Author(s):

Colin Eady

Keyword(s):

Seed Production ◽

Health Issues ◽

Abiotic Stressors ◽

Livestock Health ◽

The Right ◽

The Impact ◽

The Relationship ◽

And Storage ◽

Selection Of ◽

Epichloë Endophyte

For 30 years, forage ryegrass breeding has known that the germplasm may contain a maternally inherited symbiotic Epichloë endophyte. These endophytes produce a suite of secondary alkaloid compounds, dependent upon strain. Many produce ergot and other alkaloids, which are associated with both insect deterrence and livestock health issues. The levels of alkaloids and other endophyte characteristics are influenced by strain, host germplasm, and environmental conditions. Some strains in the right host germplasm can confer an advantage over biotic and abiotic stressors, thus acting as a maternally inherited desirable ‘trait’. Through seed production, these mutualistic endophytes do not transmit into 100% of the crop seed and are less vigorous than the grass seed itself. This causes stability and longevity issues for seed production and storage should the ‘trait’ be desired in the germplasm. This makes understanding the precise nature of the relationship vitally important to the plant breeder. These Epichloë endophytes cannot be ‘bred’ in the conventional sense, as they are asexual. Instead, the breeder may modulate endophyte characteristics through selection of host germplasm, a sort of breeding by proxy. This article explores, from a forage seed company perspective, the issues that endophyte characteristics and breeding them by proxy have on ryegrass breeding, and outlines the methods used to assess the ‘trait’, and the application of these through the breeding, production, and deployment processes. Finally, this article investigates opportunities for enhancing the utilisation of alkaloid-producing endophytes within pastures, with a focus on balancing alkaloid levels to further enhance pest deterrence and improving livestock outcomes.

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Mass occurrence and habitat selection of Common Redpolls (Carduelis flammea) after a large seed crop year: snow-covered ground facilitates food access

Journal of Ornithology ◽

10.1007/s10336-021-01912-x ◽

2021 ◽

Author(s):

Svein Dale

Keyword(s):

Climate Change ◽

Habitat Selection ◽

Snow Cover ◽

Breeding Season ◽

Boreal Forests ◽

Large Seed ◽

Mass Occurrence ◽

Seed Crops ◽

Ecosystem Changes ◽

Selection Of

AbstractIn boreal forests, food supplies typically have cyclic variations, and many species here fluctuate in numbers from year to year. One group of species showing large variations in population size is birds specialized on seeds from masting trees. Here, I analyze spatial patterns of a mass occurrence and habitat selection of the Common Redpoll (Carduelis flammea) during the breeding season in southeastern Norway in 2020 after a year with large seed crops from Norway Spruce (Picea abies) and Downy Birch (Betula pubescens). I found that Common Redpoll numbers increased with elevation and towards the northwest. Numbers were also strongly and positively correlated with snow depth in early April when snow was present mainly above 400 m elevation. Sites with snow cover in early April (30% of all sites) held 96.4% of all individuals recorded. Field observations indicated that Common Redpolls foraged extensively for spruce seeds on the snow until the end of May when young were independent. I suggest that the mass occurrence was due to a unique combination of exceptionally large seed crops of two tree species coinciding in the same year. The masting produced large amounts of food both for overwintering (birch seeds) and for breeding (spruce seeds), and during the breeding season snow cover facilitated access to food resources. Dependency of Common Redpolls on snow cover suggests that climate change may negatively impact some seed-eaters in boreal regions. On the other hand, higher temperatures may induce more frequent masting which may be beneficial for seed-eaters. Thus, climate change is likely to lead to complex ecosystem changes in areas where snow cover may disappear.

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Sugar beet seed production and marketing in the United Kingdom

Outlook on Agriculture ◽

10.1177/003072707500800507 ◽

1975 ◽

Vol 8 (5) ◽

pp. 284-289

Keyword(s):

United Kingdom ◽

Sugar Beet ◽

Seed Production ◽

The United Kingdom ◽

Seed Crops ◽

The Impact

Sugar beet differs from most other farm seed crops, in that “varieties” are mixtures of hybrids from a blend of genotypes. Growing and processing are two equally important aspects of seed production. In this article, cultural and harvesting methods are described, and processing and marketing procedures are briefly outlined. The impact of EEC regulations affecting seeds is also considered.

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Habitat selection when killing primary versus alternative prey species supports prey specialization in an apex predator

10.26686/wgtn.12469328 ◽

2020 ◽

Author(s):

B Cristescu ◽

S Bose ◽

LM Elbroch ◽

ML Allen ◽

Heiko Wittmer

Keyword(s):

Habitat Selection ◽

Prey Species ◽

Puma Concolor ◽

Apparent Competition ◽

Selection Function ◽

Alternative Prey ◽

Odocoileus Hemionus Columbianus ◽

Ecological Processes ◽

Habitat Features ◽

Selection Of

© 2019 The Zoological Society of London Many predators specialize on one or several prey species that they select from the range of potential prey. Predator specialization on primary versus alternative prey is driven in part by encounter rates with prey and a predator’s habitat selection. Although habitat selection changes with behavioural state, this has not been well-recognized in the resource selection function (RSF) literature to date, often because auxiliary data on the predator’s behavioural states (e.g. hunting) are absent. We monitored habitat selection of pumas Puma concolor in a multi-prey system in northern California, where pumas specialized on black-tailed deer Odocoileus hemionus columbianus. We employed multiple RSF analyses on different datasets to test the following three hypotheses: (1) Pumas utilize habitats in proportion to their availability; (2) Pumas select specific habitat features when killing black-tailed deer, their primary prey; (3) Pumas do not select distinct habitats from those identified under hypothesis 1 when killing alternative prey. We found that pumas in our study selected for specific habitats and habitat features in general, but that their selection was more pronounced when killing black-tailed deer. In summer, kill sites of deer were associated with rugged terrain, but gentle slopes and northerly aspects. In winter, pumas killed deer at low elevations, on gentle slopes and on northerly and westerly aspects. Overall, evidence suggested that pumas tracked their primary prey across seasonal migrations, which were short in distance but resulted in pronounced changes in elevation. When killing alternative prey, pumas showed little evidence of habitat selection, suggesting they may kill alternative prey opportunistically. Our results hold implications for how data should be partitioned when modelling baseline habitat selection of predators, hunting habitat selection and predation risk for prey species, as well as for how we model ecological processes such as apparent competition.

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NUCLEUS SEED MULTIPLICATION

NZGA: Research and Practice Series ◽

10.33584/rps.5.1998.3338 ◽

1990 ◽

Vol 5 ◽

pp. 30-31

Author(s):

E. Kevern

Keyword(s):

Seed Production ◽

Perennial Ryegrass ◽

Selection Of

The multiplic,ation of Nucleus Seed to produce Breeders' Seed of any of the Grasslands Division cultivars not covered by Head Licensees is handled by the Grasslands Division Seed Production Specialist. The procedure for the selection of increase areas is as follows. The Region: Wherever possible, cultivars are kept to districts that produce that type of cultivar already. As an example, 'Grasslands Ruanui' perennial ryegrass is grown at Waitohi in South Canterbury. This helps eliminate chance of crosspollination, provides better isolation, and reduces the likelihood of disagreements between

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Insects Affecting Seed Production in Red Pine: Part I Conophthorus resinosae Hopk. (Coleoptera: Scolytidae)

The Canadian Entomologist ◽

10.4039/ent88599-10 ◽

1956 ◽

Vol 88 (10) ◽

pp. 599-608 ◽

Cited By ~ 18

Author(s):

L. A. Lyons

Keyword(s):

Seed Production ◽

Pacific Coast ◽

Large Numbers ◽

The Pacific ◽

Future Success ◽

Loblolly Pines ◽

Unfavourable Weather ◽

Cone And Seed Insects ◽

Seed Crops ◽

Seed Insects

Natural and artificial reforestation, which basically depend on an abundance of sound seed, are adversely affected when insects destroy large numbers of cones, seeds, and cone-bearing shoots. Other factors, such as unfavourable weather, incomplete seed development, and damage by birds and mammals also reduce seed production, but they are rarely of such widespread importance as insects, whose damage often results in the failure of seed crops over large areas. Cone and seed insects sometimes restrict the natural regeneration of trees for a few years at a time, as, for example, in conifers on the Pacific coast (16), loblolly pines in Virginia (13), and oak in Michigan (5), but they become particularly important when the seeds they destroy are required for use in artificial reforestation. The future success of much reforestation, which is inclining more and more toward the use of seed obtained from trees cultivated especially for that purpose, may largely depend on a thorough understanding of cone and seed insects and their effect on seed production.

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Problems of amenity grass seed production in New Zealand

NZGA: Research and Practice Series ◽

10.33584/rps.1.1979.3291 ◽

1980 ◽

Vol 1 ◽

pp. 26-30

Author(s):

L. Corkill ◽

W. Rumball

Keyword(s):

New Zealand ◽

The Netherlands ◽

Seed Production ◽

Direct Selection ◽

Usual Practice ◽

Grass Seed ◽

Breeding Management ◽

Selection For ◽

Seed Yields ◽

Selection Of

The problems of seed production of amenity grasses in New Zealand are considered from two aspects - (a) increasing seed potential by breeding; (b) achieving that potential by good management as practised in the Netherlands, (a) In terms of breeding, the strategies to increase seed yield depended to some degree on the species concerned. With browntop it was necessary to discard about two-thirds of the most promising genotypes because of poor heading, but the remaining genotypes flowered freely and in unison, and gave good seed yields. With fescue even the best original plants were sparsely heading, so direct selection for prolificacy has been needed. This was also carried out for perennial ryegrass, as well as selection of early-heading genotypes to avoid infection by stem rust. (b) It is suggested that areas for seed of amenity grasses in New Zealand should be used for seed production only rather than for both forage and seed as is the usual practice. Techniques used in the Netherlands could serve as guidelines to procedures. The implications of low seeding rates, good weed control, high fertilizer applications and minimum cutting or grazing in promoting strong individual plants capable of high seed yields are discussed. Keywords: Amenity grass, seed production, New Zealand, breeding, management, Netherlands, Agrostis tenuis, Festuca rubra, Lolium perenne

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Shortleaf Pine Seed Production in Natural Stands in the Ouachita and Ozark Mountains

Southern Journal of Applied Forestry ◽

10.1093/sjaf/20.2.74 ◽

1996 ◽

Vol 20 (2) ◽

pp. 74-80 ◽

Cited By ~ 5

Author(s):

Michael G. Shelton ◽

Robert F. Wittwer

Keyword(s):

Seed Production ◽

Natural Regeneration ◽

Stand Age ◽

Good Seed ◽

Pinus Echinata ◽

Ozark Mountains ◽

Shortleaf Pine ◽

Natural Stands ◽

Seed Crops ◽

Production Areas

Abstract Seed production of shortleaf pine (Pinus echinata Mill.) was monitored from 1965 to 1974 to determine the periodicity of seed crops in both woods-run stands and seed-production areas. One bumper and two good seed crops occurred during the 9-yr period. The two largest crops occurred in successive years, then seed production was low for 4 yr before another good crop occurred. Mean annual seed production ranged from 84,000/ac in the western Ouachitas to 167,000/ac in seed-production areas in the southern Ozarks. Certain stand-level variables significantly influenced seed production. Seed production was positively related to stand age and negatively related to pine and hardwood basal areas; although frequently significant, no consistent relationship occurred with stand elevation. Results indicate that shortleaf pine seed production will usually be adequate for natural regeneration within most of the study area. South. J. Appl. For. 20(2):74-80.

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SPONTANEOUS SELF-FERTILIZATION IN RELATION TO SEED PRODUCTION IN SWEET CLOVER (MELILOTUS)

Canadian Journal of Research ◽

10.1139/cjr31-104 ◽

1931 ◽

Vol 5 (6) ◽

pp. 660-664 ◽

Cited By ~ 2

Author(s):

L. E. Kirk ◽

T. M. Stevenson

Keyword(s):

Seed Production ◽

Pollen Grains ◽

Sweet Clover ◽

Flower Structure ◽

Melilotus Officinalis ◽

Stigmatic Surface ◽

Melilotus Alba ◽

Self Fertilization ◽

Determining Factor ◽

Selection Of

The chief determining factor in spontaneous self-fertilization in white sweet clover (Melilotus alba) appears to be the distribution of pollen within the unopened flowers. This in turn depends on (1) length of stamens, (2) length of style, (3) amount of pollen, and (4) size of cavity within the upper part of the keel. When the flower structure and quantity of pollen is such as to insure the deposition of pollen grains on the stigma before the blossom is likely to be disturbed by insects, the plant will be normally self-fertilized. In the yellow flowered species of sweet clover (Melilotus officinalis) spontaneous self-fertilization is effectively prevented, except in certain varieties, by a characteristic of the stigma which makes it unreceptive. Scarification of the stigmatic surface appears to be necessary before fertilization can take place. Variation occurs also, as in M. alba, in the length of stamens and style, size of keel cavity, and the amount of pollen.There is a high correlation in M. alba between the percentage of flowers which are naturally self-pollinated and the percentage of flowers which produce pods when the plants are caged to exclude insects. Selection of plants which are normally self-fertilized can be made by examining the early flowers, thus obviating the necessity of bagging or caging plants which do not possess this character.A strain of M. alba which is normally self-fertilized was found to produce almost twice as much seed as another strain which is normally cross-pollinated under comparable conditions in the field.

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Multi‐trait Selection of Pumpkin Genotypes Aimed at Reducing the Growth Habit and Improving Seed Production

Crop Science ◽

10.1002/csc2.20386 ◽

2020 ◽

Author(s):

Rebeca Lourenço Oliveira ◽

Ronaldo Silva Gomes ◽

Cleverson Freitas Almeida ◽

Ronaldo Machado Júnior ◽

João Romero A. S. de C. Rocha ◽

...

Keyword(s):

Seed Production ◽

Growth Habit ◽

Selection Of

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