scholarly journals Genetic variation in southern Idaho ponderosa pine progeny tests after 11 years /

1980 ◽  
Author(s):  
G. E. Rehfeldt ◽  
Keyword(s):  
Genetic Variation ◽  
Ponderosa Pine ◽  
Progeny Tests

Genetic Parameters and Genotype-by-Environment Interactions in Regional Progeny Tests of Pinus taeda L. in the Southern USA

2020 ◽  
Author(s):  
Edwin Lauer ◽  
Andrew Sims ◽  
Steven McKeand ◽  
Fikret Isik
Keyword(s):  
Genetic Variation ◽  
Pinus Taeda ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Breeding Program ◽  
Model Fit ◽  
Genotype By Environment Interactions ◽  
Genotype By Environment ◽  
Progeny Tests ◽  
Pinus Taeda L

Abstract Genetic parameters were estimated using a five-series multienvironment trial of Pinus taeda L. in the southern USA. There were 324 half-sib families planted in five test series across 37 locations. A set of six variance/covariance matrices for the genotype-by-environment (G × E) effect for tree height and diameter were compared on the basis of model fit. In single-series analysis, extended factor analytical models provided generally superior model fit to simpler models for both traits; however, in the combined-series analysis, diameter was optimally modeled using simpler variance/covariance structures. A three-way compound term for modeling G × E interactions among and within series yielded substantial improvements in terms of model fit and standard errors of predictions. Heritability of family means ranged between 0.63 and 0.90 for both height and diameter. Average additive genetic correlations among sites were 0.70 and 0.61 for height and diameter, respectively, suggesting the presence of some G × E interaction. Pairs of sites with the lowest additive genetic correlations were located at opposite ends of the latitude range. Latent factor regression revealed a small number of parents with large factor scores that changed ranks significantly between southern and northern environments. Study Implications Multienvironmental progeny tests of loblolly pine (Pinus taeda L.) were established over 10 years in the southern United States to understand the genetic variation for the traits of economic importance. There was substantial genetic variation between open-pollinated families, suggesting that family selection would be efficient in the breeding program. Genotype-by-environment interactions were negligible among sites in the deployment region but became larger between sites at the extremes of the distribution. The data from these trials are invaluable in informing the breeding program about the genetic merit of selection candidates and their potential interaction with the environment. These results can be used to guide deployment decisions in the southern USA, helping landowners match germplasm with geography to achieve optimal financial returns and conservation outcomes.

An assessment of dairy bull station progeny tests carried out at two centres in Britain

1965 ◽  
Vol 65 (3) ◽  
pp. 315-331
Author(s):  
Lucia Pearson
Keyword(s):  
Genetic Variation ◽  
Milk Yield ◽  
Progeny Test ◽  
Selection System ◽  
Fat Percentage ◽  
Special Cases ◽  
Progeny Tests ◽  
Dairy Bull

1. Station progeny tests of twenty-four Ayrshire and twenty-two Friesian bulls were carried out by the British Oil and Cake Mills Ltd. at two centres in Britain between 1953 and 1961. The tests followed the Danish pattern: groups of ten to seventeen daughters were brought to the station approximately 6 weeks before first calving and milked under standardized conditions for an average of 270 days.2. The place of the station system in modern dairy practice in Britain and abroad was discussed.3. Earlier results had suggested that milk yield, butterfat percentage, S.N.F. percentage, milking rate and conception interval should be taken into account in a progeny test.4. Correlations were calculated between the bulls 305-day field ratings for milk yield and fat percentage and their 90- and 270-day station assessments. Possible reasons for the discrepancies were investigated.5. The selection system employed did not appear to lead normally to the choice of heifers whose dams' milk yield or fat percentage differed from the recorded averages for the breed. In two groups of special cases, deviations were apparent but the effect on the accuracy of the station test was shown to be small. It was concluded that bias due to maternal genetic variation was unlikely to be serious in the general case.

scholarly journals Genetics of Shrinkage in Juvenile Trees of Pinus radiata D. Don From Two Test Sites in Australia

2008 ◽  
Vol 57 (1-6) ◽  
pp. 145-151 ◽  
Author(s):  
W. J. Gapare ◽  
M. Ivković ◽  
M. B. Powell ◽  
T. A. McRae ◽  
H. X. Wu
Keyword(s):  
Genetic Variation ◽  
Genetic Control ◽  
Pinus Radiata ◽  
Wood Quality ◽  
Microfibril Angle ◽  
Radiata Pine ◽  
Longitudinal Shrinkage ◽  
Individual Tree ◽  
Radial Shrinkage ◽  
Progeny Tests

Abstract To examine the genetic control of wood shrinkage (radial, tangential and longitudinal) in juvenile wood of radiata pine (Pinus radiata D. Don), we assessed samples collected at breast height in two related progeny tests of age 8 and 9 years, established at two different sites in Australia. Green to oven-dry tangential and radial shrinkage for the outer-rings was similar at both sites. Similarly, mean longitudinal shrinkage for the outer-rings was similar at both sites (0.3%, ranging from 0.1 to 1.9 at Flynn and 0.4%, ranging from 0.02 to 1.6, at Kromelite). Mean longitudinal shrinkage for the inner-rings was 4 times greater than that of the outerrings at both sites. The magnitude of the gradient of longitudinal shrinkage from pith to bark (0.001 to 2.9%) is large enough to cause distortion problems including twist and warp, during drying of sawn boards. These values also suggest that shrinkage in the juvenile core of radiata pine is of major economic importance and therefore should be improved either through genetics or silviculture. Individual-tree narrow-sense individual heritability for tangential and radial shrinkage in the outer-rings (4-6) was moderate at Flynn (0.24 ± 0.09 and 0.26±0.07, respectively). There was a lack of significant genetic variation for longitudinal shrinkage in the outer-rings but significant genetic control for the inner-rings (1-2) (h2 = 0.26 ± 0.07). More samples per family are required to detect significant genetic variation for shrinkage traits than other traits due to higher background variation in sampling and measuring shrinkage traits relative to other wood quality traits such as density, microfibril angle (MfA), spiral grain and modulus of elasticity (MoE).

Variation in seedling budburst phenology and structural traits among southwestern ponderosa pine provenances

2020 ◽  
Vol 50 (9) ◽  
pp. 872-879 ◽  
Author(s):  
Aalap Dixit ◽  
Thomas Kolb
Keyword(s):  
Genetic Variation ◽  
Leaf Area ◽  
Specific Leaf Area ◽  
Ponderosa Pine ◽  
Mean Annual Precipitation ◽  
Total Biomass ◽  
Mass Ratio ◽  
Shoot:Root Ratio ◽  
Structural Traits ◽  
Budburst Phenology

We used a common garden study to investigate genetic variation in spring budburst phenology, growth, and structural traits of ponderosa pine (Pinus ponderosa Lawson & C. Lawson var. scopulorum Engelm.) seedlings from 10 provenances of different elevations in Arizona and New Mexico, United States. Seedlings were grown with ample resources for two growing seasons in a greenhouse in northern Arizona. Budburst date was measured at the onset of the second growing season; seedling growth, biomass, biomass ratios (shoot:root ratio, root mass ratio, stem mass ratio, and leaf mass ratio), and specific leaf area were measured at the end of the second season. Low-elevation provenances (<2000 m) had earlier budburst and lower specific leaf area than middle- (2000–2500 m) and high-elevation (>2500 m) provenances. Height, leaf length, biomass, and biomass ratios were similar for elevational groups. Total biomass was positively correlated (r = 0.824) with provenance mean annual precipitation. Shoot:root ratio was positively correlated (r = 0.652) with longitude. Results suggest adaptation of low-elevation provenances to warm spring temperatures (early budburst) and aridity (low specific leaf area), inherently faster growth of provenances from wet locations, and greater allocation to shoots in eastern provenances. Such information about geographic patterns of genetic variation may be useful for selecting seed sources for planting in a changing climate.

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