Mating system variation among individual ramets in a Douglas-fir seed orchard

1990 ◽  
Vol 20 (10) ◽  
pp. 1672-1675 ◽  
Author(s):  
V. J. Erickson ◽  
W. T. Adams
Keyword(s):  
Mating System ◽  
Seed Orchard ◽  
Floral Biology ◽  
Douglas Fir ◽  
Pollen Production ◽  
Male And Female ◽  
Floral Phenology ◽  
Female Flowering ◽  
High Degree

Proportions of outcrossed progeny (ti) in five ramets of five clones with variable floral phenology and pollen production were investigated in a Douglas-fir (Pseudotsugamenziesii var. menziesii (Mirb.) Franco) seed orchard. Estimates of ti[Formula: see text] were significantly heterogeneous among the five ramets, ranging in value from 0.50 to 1.07. Variation in [Formula: see text] corresponded well with variation among ramets in floral biology. Ramets that flowered much earlier than other individuals in the orchard and (or) had a high degree of synchrony in timing of male and female flowering produced the lowest [Formula: see text].

Interaction between gibberellin A4/7 and root-pruning on the reproductive and vegetative process in Douglas-fir. I. Effects on flowering

1985 ◽  
Vol 15 (2) ◽  
pp. 341-347 ◽  
Author(s):  
S. D. Ross ◽  
J. E. Webber ◽  
R. P. Pharis ◽  
J. N. Owens
Keyword(s):  
Seed Orchard ◽  
Douglas Fir ◽  
Individual Treatment ◽  
Root Pruning ◽  
Male And Female ◽  
The Poor ◽  
Female Flowering ◽  
Pollen Cone ◽  
Sexually Mature ◽  
Effective Cone

In two seed orchard trials, profuse female flowering was induced in young, but ontogenetieally mature grafts of inherently poor-flowering clones (1979) and in 9-year-old seedling-origin trees of both good- and poor-flowering families (1981) of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) by the cultural treatment of root-pruning in conjunction with stem injections of the gibberellin A4 and A7 (GA4/7) mixture. Promotion of male flowering, however, was confined to the more sexually mature grafts. As an individual treatment in the 1981 study, root-pruning was more effective than GA4/7, particularly for the poor-flowering families which did not respond well to GA4/7 alone. The two treatments combined had a highly synergistic effect on both male and female flowering, the synergism being relatively greater for the poor-flowering than for the good-flowering families. Although GA4/7 was not tested alone on grafted propagules, its use with root-pruning enhanced an already significant increase in seed- and pollen-cone buds from root-pruning alone by 540 and 92%, respectively. These and subsequent trials have shown root-pruning +GA4/7 to be a most effective cone-bud enhancement treatment for use in young Douglas-fir breeding and seed production orchards.

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 Temporal quantification of mating system parameters in a coastal Douglas-fir seed orchard under manipulated pollination environment

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Jiayin Song ◽  
Blaise Ratcliffe ◽  
Tony Kess ◽  
Ben S. Lai ◽  
Jiří Korecký ◽  
...  
Keyword(s):  
Mating System ◽  
Seed Orchard ◽  
Douglas Fir ◽  
System Parameters ◽  
Pollination Environment

Mating system and pollen contamination in a Douglas-fir clone bank

1986 ◽  
Vol 16 (6) ◽  
pp. 1314-1319 ◽  
Author(s):  
Willi Fast ◽  
Bruce P. Dancik ◽  
Ralph C. Bower
Keyword(s):  
Mating System ◽  
Seed Orchard ◽  
Douglas Fir ◽  
Pollen Contamination ◽  
Outcrossing Rates ◽  
Natural Stands

Pollen contamination and mating system of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) clone banks used as an interim seed orchard near Nanaimo, B.C., were estimated. Pollen contamination (m) from surrounding clone banks and natural stands ranged from 0.44 to 0.89. Overall contamination over 2 years was estimated to be 0.65. Pollen contamination varied significantly over 2 pollination years. Multilocus outcrossing rates (t) of four clone banks over 2 years ranged from 0.51 to 1.09, with an unweighted mean outcrossing estimate of 0.72. Outcrossing varied significantly among clone banks and pollination years. An excess of homozygotes suggests that these seed may be inbred. Although pollen contamination and inbreeding may be a problem in these clone banks, the seed may still be useful operationally.

scholarly journals Reproductive Ecology of Male and Female Strobili and Mating System in Two Different Populations ofPinus roxburghii

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Chandra Mohan Sharma ◽  
Vinod Prasad Khanduri ◽  
Sunil Kumar Ghildiyal
Keyword(s):  
Mating System ◽  
Natural Populations ◽  
Production Capacity ◽  
Pollen Grains ◽  
Seed Orchard ◽  
Reproductive Period ◽  
Female Cone ◽  
Lower Altitude ◽  
Female Ratio ◽  
Male And Female

We studied several flowering traits, namely, male-female cone phenology, male-female cone production per tree, mating system, sex ratio, air-borne pollen grains and pollen migration, over four successive years in two different natural populations ofP. roxburghiifrom Garhwal Himalaya, India. Assessment of each trait mentioned except pollen dispersion was done by selecting five representative trees randomly in each population. The pollen migration was studied on naturally isolated source trees. The pollen trapping was done in all directions up to 2.5 km. The average reproductive period inP. roxburghiiwas 36 days with 3–5 days protandry. There were significant year and population effects for male and female cone output and pollen grains production per tree. In mass production year (1999), an average production of pollen cone per tree was estimated as42.44±8.32×103at lower altitude and28.1±0.89×103at higher altitude. The controlled pollination results in high level of outcrossing with 90% seed setting. We conclude that the high male-female ratio and tremendous pollen production capacity inP. roxburghiiindicate high male competition among trees within populations. The isolation strip of 600 m is considered minimal for the management of seed orchard.

Mating success in a coastal Douglas-fir seed orchard as affected by distance and floral phenology

1989 ◽  
Vol 19 (10) ◽  
pp. 1248-1255 ◽  
Author(s):  
V. J. Erickson ◽  
W. T. Adams
Keyword(s):  
Genetic Markers ◽  
Mating Success ◽  
Strong Influence ◽  
Seed Orchard ◽  
Douglas Fir ◽  
Combined Effects ◽  
Regression Analyses ◽  
Mating Patterns ◽  
Floral Phenology ◽  
Cross Fertilization

The effect of distance and stage of phenological development on cross-pollination in a Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seed orchard was investigated by estimating the proportion of viable embryos resulting from fertilization by designated male trees. The pollen source was identified by unique allozyme genetic markers that occurred in two clones in the orchard. In 38 mother trees, the proportion of embryos fertilized by the male marker ranged from 0 to 71.4%. Very little pollen was dispersed beyond 30 m. Within 30 m, mating success was only weakly associated with distance. Multiple regression analyses determined that phenological factors strongly influenced mating patterns; nearly one-third of the variation was dependent on a phenological variable (LMmf), which measured the combined effects of floral overlap and relative pollen fecundity of potential male parents. The interaction between LMmf and distance was highly significant, indicating that the floral status of mating pairs had a strong influence on the effect of distance. Our results suggest that a lack of complete floral synchrony between near neighbors may reduce preferential mating and thus help to promote cross-fertilization within Douglas-fir seed orchards.

scholarly journals Motives and Obstacles of Using Internet as A Source for Learning By The Students of Human Sciences at the World Islamic Science & Education University( WISE)

2016 ◽  
Vol 8 (1) ◽  
pp. 181
Author(s):  
Mohammed Bader Alyousef
Keyword(s):  
Science Education ◽  
Female Students ◽  
T Test ◽  
Human Sciences ◽  
Male And Female ◽  
University Courses ◽  
The World ◽  
Islamic Science ◽  
High Degree ◽  
Use Of Internet

<p>The study aimed at revealing the motives and the obstacles of using internet as a source of<br />learning by the human colleges at WISE. And to achieve the study’s goals , a questionnaire<br />was developed consisting of 40 items; 20 items addressed motives of using internet as source<br />of learning and other 20 items addressed obstacles of using internet as a source of learning .<br />The sample of the study which consisted of 520 male and female students was selected<br />randomly in the second semester for 2012/2013. After data were collected, they were<br />analyzed using descriptive methods, t-test and ANOVA. Results showed the motives of using<br />internet ranged from high degree to moderate. The degrees of obstacles facing using internet<br />were moderate.<br />The researcher recommended the necessity of activating the students’ use of internet with<br />their teachers’ guidance, facilitating the use of internet by increasing the number of computer<br />labs and supervisors, in addition to provide flexible and easy electronic programs for studying<br />university courses.</p>

Evaluational Reactions to Erotic Literature

1965 ◽  
Vol 16 (3) ◽  
pp. 985-994 ◽  
Author(s):  
Leon A. Jakobovits
Keyword(s):  
Short Stories ◽  
Hard Core ◽  
Cumulative Effect ◽  
Sampling Bias ◽  
Male And Female ◽  
Warm Up ◽  
Erotic Literature ◽  
High Degree ◽  
Very High

On the basis of analysis of a variety of erotic literature Kronhausen and Kronhausen (1959) have suggested that there seem to be two general types: erotic realism ( ER) and hard-core obscenity ( O). Using three of the distinguishing criteria which were identified (context, exaggeration, and anti-eroticism), 20 short stories were specifically written in such a way that 10 had the characteristics of ER and the others had the characteristics of O. Study I showed a very high degree of agreement between judges in their classification of these stories as either ER or O. Study II revealed that male and female readers react differentially to the two types of stories. Females consistently rate O as more interesting and sexually stimulating than males do, the latter finding ER as more arousing than O. Other evaluational reactions are also described. A “warm-up” cumulative effect with successive reading was found with both sexes. The possibility of sampling bias affecting the data was noted.

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