Effects of pollen tube number and archegonium number on reproduction in Douglas-fir: significance for seed orchard management

1992 ◽  
Vol 22 (10) ◽  
pp. 1483-1488 ◽  
Author(s):  
Reed W. Crook ◽  
William E. Friedman
Keyword(s):  
Pollen Tube ◽  
Effective Means ◽  
Seed Orchard ◽  
Douglas Fir ◽  
Clonal Variation ◽  
Tube Number ◽  
Orchard Management ◽  
Number Increase ◽  
Selection Of ◽  
Significant Bearing

Analyses of the relationships between pollen tube number and fertilization number and between archegonium number and fertilization number in Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) indicate strong trends toward higher levels of simple polyembryony as both pollen tube number and archegonial number increase on a per-seed basis. These relationships have a significant bearing on the management of conifer seed orchards. Simple polyembryony has been proposed to be an effective means of increasing competition on a per-seed basis in conifers and, potentially, the overall fitness of progeny. In conifers, supplemental mass pollination has the direct effect of increasing the number of pollen tubes per ovule. Clonal variation in average number of archegonia per ovule is also likely to exist among conifers. We propose that when used together, supplemental mass pollination and selection of clones with high archegonial averages may enhance the fitness of seed orchard progeny.

Clonal variation in pollen-related characteristics of Douglas-fir

1982 ◽  
Vol 12 (2) ◽  
pp. 403-408 ◽  
Author(s):  
W. T. Adams
Keyword(s):  
Genetic Variation ◽  
Pollen Grains ◽  
Seed Orchard ◽  
Douglas Fir ◽  
Clonal Variation ◽  
Pollen Production ◽  
The Mean ◽  
Pollen Cone ◽  
Grain Diameter

The mean number of pollen grains produced per pollen cone (P) ranged from 37 310 to 62 960 ([Formula: see text], SE = 1584) among eight seed-orchard clones of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and correlated significantly (r = 0.87, p < 0.05) with the mean number of microsporophylls per cone but not significantly with pollen cone length. The number of pollen grains per milligram (G) also differed among clones (range 2323–3112; [Formula: see text], SE = 32) and correlated significantly and negatively (r = −0.86) with grain diameter. Although this study provides evidence for genetic variation in both P and G, the differences were relatively small. Adjusting pollen-cone counts for P would add little, if any, precision to estimates of pollen production in seed-orchard clones. If balanced clonal representation in pollen mixes is desired, equal weights of pollen would probably suffice for most breeding applications.

scholarly journals A Practical Solution to Douglas-Fir Seed Orchard Pollen Contamination

1980 ◽  
Vol 56 (5) ◽  
pp. 237-241 ◽  
Author(s):  
A. M. K. Fashler ◽  
W. J. B. Devitt
Keyword(s):  
Irrigation System ◽  
Seed Orchard ◽  
Douglas Fir ◽  
Flight Period ◽  
Water Cooling ◽  
Flower Bud ◽  
Pollen Contamination ◽  
Threshold Temperatures ◽  
Bud Opening ◽  
Selection Of

Based on work by Silen and Keane (1969), research was carried out in the early 1970's to evaluate the effectiveness of delaying reproductive bud development in a Douglas-fir seed orchard by cooling the trees with water spray. The results from these first trials indicated a 10 to 14 day delay in reproductive bud opening giving up to 85% control of local pollen contamination. A solid set irrigation system was then installed for flower bud cooling and was applied to the 1976 and 1978 seed orchard cone crops. In both years phenological and pollen flight data showed results similar to the trials; the operational cooling treatment kept the female reproductive buds unopened through the major portion of the local pollen flight period in approximately 76% of the Douglas-fir clones in the orchard. No adverse side effects have been observed. Calculation of the heat sum and threshold temperatures for Douglas-fir reproductive buds will provide a means to measure the amount of cooling achieved through irrigation and a method to calibrate the irrigation system for most efficient use. The expense of water-cooling as a solution to pollen contamination is justified by the value of the improved seed derived from seed orchard production. The investment is also off-set by the selection of a multi-purpose system that can be applied for irrigation, fertilization and frost protection as well as cooling. Another advantage of the water-cooling is a decrease in the amount of insect infestation in the orchard trees.

Application of a chloroplast DNA marker in seed orchard management evaluations of Douglas-fir

1998 ◽  
Vol 28 (2) ◽  
pp. 187-195 ◽  
Author(s):  
M U Stoehr ◽  
B L Orvar ◽  
T M Vo ◽  
J R Gawley ◽  
J E Webber ◽  
...  
Keyword(s):  
Dna Marker ◽  
Gene Diversity ◽  
Polymerase Chain Reaction Amplification ◽  
Variable Region ◽  
Seed Orchard ◽  
Flowering Phenology ◽  
Douglas Fir ◽  
Base Pairs ◽  
Orchard Management ◽  
Cp Genome

We evaluated pollen contamination, supplemental mass pollination efficacies, and natural selfing in a Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) clonal-row seed orchard using a genetic marker on the paternally inherited chloroplast (cp) genome. A primer pair for the polymerase chain reaction amplification of a variable region on the cpDNA in Douglas-fir was developed. The amplified DNA product was highly variable in size, yielding 13 different haplotype bands from 20 orchard genotypes growing in the clonal-row seed orchard. Observed band sizes ranged from 859 to 1110 base pairs (bp). To estimate variation levels in the orchard background pollen pool, 96 assayed genotypes from surrounding stands gave rise to 36 different haplotypes, ranging from 367 to 1119 bp in size, resulting in a gene diversity estimate of 0.91. Most orchard clones' haplotypes were also present in the background. After adjusting for the presence of orchard-type haplotypes in the background, contamination was found to be 40%. Natural selfing in six individual clones ranged from 0 to 19% with an average of 6%. Supplemental mass pollination efficacy was estimated to be 55%, ranging from 39 to 73%, depending on the maternal clone and flowering phenology. This DNA marker proved to be very useful in assessing seed orchard mating dynamics and orchard management efficacies for Douglas-fir.

scholarly journals Estimation of Clonal Variation in Seed Cone Production Over Time in a Scots pine (Pinus sylvestris L.) Seed Orchard

2009 ◽  
Vol 58 (1-6) ◽  
pp. 53-62 ◽  
Author(s):  
Johan Kroon ◽  
Ulfstand Wennström ◽  
Finnvid Prescher ◽  
Dag Lindgren ◽  
Tim J. Mullin
Keyword(s):  
Pinus Sylvestris ◽  
Scots Pine ◽  
Genetic Correlations ◽  
Seed Orchard ◽  
Clonal Variation ◽  
Annual Data ◽  
Single Observation ◽  
Cone Production ◽  
Seed Cone ◽  
Selection Of

Abstract Possibilities for early selection of clones for future seed cone production were studied in a clonal seed orchard of Scots pine (Pinus sylvestris L.) in northern Sweden over the first 30 years following establishment. The annual data were modelled as series of bivariate analyses. The correlations between cone production of clones in any individual year and that of a previous year, and cumulative cone production over all years were studied. The corresponding multivariate analysis for a full data fit simultaneously was best estimated with a genetic distance-based power model (AR). The genetic (variation among clones) and environmental variation were of the same magnitude. The genetic correlations were larger than the phenotypic correlations and both increased with orchard age. Basing selection of clones on a single observation at an early age to improve future cone production was not effective, but efficiency increased if cumulative cone count over many years was used. Year-to-year genetic correlations indicated that early forecasts by clone of cone production at mature ages are highly uncertain. Reliable predictions (moderate correlations) could be achieved only if based on rather mature grafts, 14 or more years after establishment.

Potential pollen contamination effects on progeny from an off-site Douglas-fir seed orchard: 9-year field results

2004 ◽  
Vol 34 (4) ◽  
pp. 981-984 ◽  
Author(s):  
M U Stoehr ◽  
J E Webber ◽  
C CA Hollefreund ◽  
R A Painter
Keyword(s):  
Transition Zone ◽  
Seed Orchard ◽  
Douglas Fir ◽  
Coastal Site ◽  
Management Implications ◽  
Pollen Contamination ◽  
Growing Seasons ◽  
Orchard Management ◽  
Pollen Sources ◽  
Contamination Effects

To evaluate the potential effects of seed orchard pollen contamination from surrounding background sources, we made control pollinations with outside orchard pollen and inside orchard pollen on trees of a Douglas-fir (Pseudo tsuga menziesii (Mirb.) Franco) coastal–interior transition zone seed orchard. The resulting progeny were tested on a transition zone and a coastal site. After nine growing seasons, survival was above 90% on both sites for both pollen sources, and the trees height differences due to pollen source were statistically nonsignificant. Wildstand operational seedlots, used as controls, were 17% shorter than the "contaminated" seedlings. Orchard management implications of these results are discussed.

Sedimentation in Storage Tank Structures

1994 ◽  
Vol 29 (1-2) ◽  
pp. 363-372 ◽  
Author(s):  
Virginia R. Stovin ◽  
Adrian J. Saul
Keyword(s):  
Numerical Models ◽  
Effective Means ◽  
Design Guidelines ◽  
Laboratory Model ◽  
Shear Stresses ◽  
Model Situation ◽  
Combined Sewer ◽  
Urban Watercourse ◽  
Storage Structures ◽  
Selection Of

Although storage tanks provide an effective means of reducing the magnitude and frequency of combined sewer overflow discharges, and thereby of alleviating urban watercourse pollution, poorly designed storage structures frequently suffer from maintenance problems arising from sedimentation. The development of design guidelines that optimise the self-cleansing operation of storage structures is clearly a priority for urban drainage research. This paper describes a system that has been developed to study sediment deposition in laboratory model-scale storage structures. The patterns of deposition resulting from a selection of flow regimes are described, and the need for time-varying and time series storm tests is highlighted. Sedimentation patterns are shown to predominantly depend on the flow field, and the critical bed shear stresses for deposition and erosion in the model situation are identified. Hence, the potential application of numerical models to the design problem is discussed.

scholarly journals Five Challenges for Intelligent Text Entry Methods

AI Magazine ◽  
2009 ◽  
Vol 30 (4) ◽  
pp. 85 ◽  
Author(s):  
Per Ola Kristensson
Keyword(s):  
Error Correction ◽  
Effective Means ◽  
Historical Context ◽  
Research Literature ◽  
Error Rates ◽  
Localization Error ◽  
Text Entry ◽  
Context Of Use ◽  
Selection Of

For text entry methods to be useful they have to deliver high entry rates and low error rates. At the same time they need to be easy-to-learn and provide effective means of correcting mistakes. Intelligent text entry methods combine AI techniques with HCI theory to enable users to enter text as efficiently and effortlessly as possible. Here I sample a selection of such techniques from the research literature and set them into their historical context. I then highlight five challenges for text entry methods that aspire to make an impact in our society: localization, error correction, editor support, feedback, and context of use.

scholarly journals Selection of the assortment of trees for protective forest plantations

2020 ◽  
Author(s):  
A.I. Petelko ◽  
Keyword(s):  
Species Composition ◽  
Tree Species ◽  
Effective Means ◽  
Water Erosion ◽  
Current Status ◽  
Forest Plantations ◽  
Forest Stands ◽  
Protective Forest ◽  
Selection Of ◽  
Hydrographic Network

Reclamation of land on community land funds and the hydrographic network contributes to the most effective means of protecting the soil from water erosion. However, the condition, growth, and productivity of the protective forest stands themselves depend on the species composition. Many years of studies have clearly shown that not all tree species and shrubs can successfully grow on washed soils. Extensive scientific material provides a description of the growth and current status of the studied species, a detailed taxation description of the forest plantations. Of particular value are those species that can grow on eroded lands and protect the soil from erosion.

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