Area-based breeding zones to minimize maladaptation

2004 ◽  
Vol 34 (3) ◽  
pp. 695-704 ◽  
Author(s):  
Gregory A O'Neill ◽  
Sally N Aitken

A new breeding zone delineation scheme identifies for a given number of zones the zone-boundary placement that minimizes regional maladaptation in breeding programs. First, an adaptive map is created by using conventional genetic test data. Then, the large array of predicted adaptive values is subjected to cluster analysis, which assigns each grid cell of the region to one of a predetermined number of clusters (breeding zones) such that the sum of the squared distances between each cell's adaptive value and its cluster mean is minimized. This approach minimizes the average adaptive distance between the origin of a breeding program's selected trees and planting locations throughout the region of focus. The procedure is illustrated by the use of adaptive values of 69 interior spruce (Picea engelmannii Parry ex Engelm. × Picea glauca (Moench) Voss) open-pollinated families (sources) from southeast British Columbia, Canada. Adaptive values of each 1.5 km × 1.5 km grid cell in the 80 000-km2 region were predicted using a geneco logical model (R2 = 0.64), and the values were subjected to cluster analysis to identify breeding zone boundaries that were then mapped using a geographic information system. Regardless of the number of zones created, a regional maladaptation index was consistently smaller when zones were devised with area-based cluster (ABC) analysis than when zones were created by dividing the region into bands of equal elevational or adaptive-value widths. Application of the ABC procedure should assist in identifying the optimum breeding-zone alignment for a given number of zones.

2014 ◽  
Vol 203 (2) ◽  
pp. 578-591 ◽  
Author(s):  
Sam Yeaman ◽  
Kathryn A. Hodgins ◽  
Haktan Suren ◽  
Kristin A. Nurkowski ◽  
Loren H. Rieseberg ◽  
...  

2003 ◽  
Vol 33 (6) ◽  
pp. 959-966 ◽  
Author(s):  
B D Miller ◽  
B J Hawkins

Six full-sib families of interior spruce (Picea glauca (Moench) Voss × Picea engelmannii Parry ex Engelm.) of contrasting growth rates (three fast-growing, three slow-growing families) were grown from seed in a greenhouse under three fertility regimes (25, 75, and 125 mg nitrogen/seedling over 175 days). The use of vector analysis showed that the lowest fertility regime was nitrogen-limited while the highest indicated luxury consumption. After 175 days, fast-growing families were larger than slow-growing at all fertility levels. At the lowest fertility level, fast-growing families exhibited greater nitrogen productivity and utilization of internal nitrogen. At higher fertility levels, fast-growing families took up nitrogen more quickly and efficiently thus accumulating greater nitrogen reserves. Fast-growing families also exhibited a greater plasticity in dry mass allocation between shoots and roots with different fertility levels.


1998 ◽  
Vol 28 (6) ◽  
pp. 820-830 ◽  
Author(s):  
Shihe Fan ◽  
Steven C Grossnickle

Physiological response of interior spruce (Picea glauca (Moench) Voss x Picea engelmannii Parry ex Engelm.) to drought conditions was compared for somatic seedlings from clones G351, T703, N366, and W460. Seedlings were subjected to four cycles of progressive soil drought by withholding water. Changes in net photosynthesis (Pn), stomatal conductance (gwv), and predawn water potentials ( psi pd) were measured during and after each drought cycle. Shoot tissue water relations parameters were measured using pressure-volume analysis at the beginning and end of the fourth drought cycle. When comparing drought cycle 1 with drought cycle 4, clones G351, N366, and T703 showed significantly reduced Pn, but gwv of all clones was not affected. Net photosynthesis and gwv decreased with psi pd more rapidly in clone W460 than in the remaining clones. When rewatered after drought, clone T703 had the most rapid Pn and gwv recovery whereas clone G351 had the slowest recovery of Pn and gwv. Over four drought cycles, all clones photosynthesized at progressively lower psi pd, but adjustments in tissue water relations parameters were marginal. These results implied that gas exchange parameters were more sensitive than shoot tissue water relations parameters in detecting clonal variation in the physiological response of interior spruce under simulated drought conditions.


2004 ◽  
Vol 34 (4) ◽  
pp. 855-862 ◽  
Author(s):  
Lara vanAkker ◽  
René I Alfaro ◽  
Robert Brockley

The effects of six fertilization treatments on tree height and incidence of attack by the white pine weevil, Pissodes strobi (Peck), on interior spruce (a hybrid, Picea glauca (Moench) Voss × Picea engelmannii Parry ex Engelm.) were explored in a field study. In a corresponding laboratory study, changes in constitutive and traumatic resin canal defences in response to fertilization were measured. Incidence of weevil attack increased with fertilization intensity. This trend was explained by increased resources available for weevil feeding (adults and larvae) as a result of increased leader size and bark thickness, as well as by an observed weakening in the tree's constitutive resin canal defences. The ability of interior spruce to produce a traumatic resin response was not influenced by fertilization. Although incidence of weevil attack was greatest in trees from the most intense fertilization treatments, height losses due to weevil attack were not as great as height gains due to fertilization treatment. Therefore, we concluded that fertilization is a feasible option for increasing productivity of interior spruce plantations, particularly if other weevil control alternatives are implemented.


1998 ◽  
Vol 28 (6) ◽  
pp. 831-840 ◽  
Author(s):  
Steven C Grossnickle ◽  
Shihe Fan

Interior spruce (Picea glauca (Moench) Voss x Picea engelmannii Parry ex Engelm.) somatic seedlings from a range of clones were measured for gas exchange processes in relation to summer atmospheric parameters. Carbon isotope composition ( delta 13C) of needles was compared with gas exchange parameters and intrinsic water use efficiency (WUEi). Needle conductance (gwv) decreased as vapour pressure deficit (VPD) increased. Clone T703 had the lowest gwv level across all VPD conditions, with clones G351, N366, and W460 having significantly greater gwv than clone T703 at VPD levels <2.0 kPa. Response of net photosynthesis (Pn) to photosynthetically active radiation (PAR) for all clones showed Pn to increase to PAR levels of around 1000 µmol ·m-2 ·s-1 and then, Pn rates were stable at higher PAR levels. Clones N366 and W460 had significantly greater Pn than clone T703 at all PAR levels. All clones showed Pn to decline as VPD increased, with clone W460 having the highest predicted Pn level across all VPD conditions and significantly greater Pn than clone T703. Higher WUEi was related to an increase in delta 13C, with clone T703 having the highest WUEi and delta 13C, followed by clone W460. Changes in delta 13C, for all clones, indicated a stronger relationship with gwv than with Pn.


1996 ◽  
Vol 74 (1) ◽  
pp. 115-124 ◽  
Author(s):  
C. John Runions ◽  
John N. Owens

Pollination drops are secreted from the ovules of interior spruce (Picea glauca or Picea engelmannii and their hybrid) as seed cones begin to close at the end of the pollination period. Secreted pollination drops persist within spaces surrounding the micropylar opening in closed seed cones. Saccate pollen floats into the micropyle within the pollination drop. Pollination drops become voluminous enough, within the enclosed spaces, to scavenge pollen adhering to the micropylar arms and other surfaces in proximity with the micropyle. Scavenging of pollen from cone surfaces adjacent to the integuments is sometimes facilitated by rainwater that can float pollen into the opening of the micropyle before cone closure and pollination drop secretion. In practice, periodic, light misting of seed orchard trees during seed cone receptivity might increase pollination efficiency by mimicking rainwater involvement in the pollination mechanism. Rainwater involvement in pollination of some modern conifers may reflect a similar situation in the pollination mechanisms of ancestral conifers. Environments with limited rainfall combined with the requirement for moisture in the pollination mechanism may have provided the selective pressure for evolution of the pollination drop. Keywords: pollination drop, Picea, conifer, sacci.


2000 ◽  
Vol 30 (7) ◽  
pp. 1096-1105 ◽  
Author(s):  
C DB Hawkins ◽  
K B Shewan

Fifteen seed lots, five each from natural-stand, seed-orchard, and full-sib collections, of interior spruce (Picea glauca (Moench) Voss, Picea engelmannii Parry ex Engelm., and their naturally occurring hybrids) were sown in February 1993. One half of each seed lot received an ambient photoperiod (control) treatment, while the other half got a blackout (short-day) treatment. All seedlings were grown under ambient photoperiod except during the 17 days of blackout. Frost hardiness assessments were done between July and May. Blackout treatment was effective in regulating height and promoting frost hardiness in all seed lots, particularly vigorous ones. Seed lots originating from high latitude or elevation were more frost hardy both at fall lift and spring planting. Full-sib seed lots from similar latitude displayed no elevational frost-hardiness trend. Blackout treatment promoted seedling dormancy (estimated with days to bud break) at lift, but it had little or no effect on dormancy at planting. Seedling dormancy and frost hardiness were acquired and lost differently, suggesting that they are independent physiological processes. Blackout treatment significantly reduced new roots at planting in all lots. This could retard early field performance and negate the apparent utility of blackout treatment.


2006 ◽  
Vol 131 (6) ◽  
pp. 770-779 ◽  
Author(s):  
Santiago Pereira-Lorenzo ◽  
María Belén Díaz-Hernández ◽  
Ana María Ramos-Cabrer

Morphological characters (six traits) and isozymes (four systems, five loci) were used to discriminate between Spanish chestnut cultivars (Castanea sativa Mill.) from the Iberian Peninsula. A total of 701 accessions (representing 168 local cultivars) were analyzed from collections made between 1989 and 2003 in the main chestnut growing areas: 31 were from Andalucía (12 cultivars), 293 from Asturias (65 cultivars), 25 from Castilla-León (nine cultivars), four from Extremadura (two cultivars) and 348 from Galicia (80 cultivars). Data were synthesized using multivariate analysis, principal component analysis, and cluster analysis. A total of 152 Spanish cultivars were verified: 58 cultivars of major importance and 94 of minor importance, of which 18 had high intracultivar variation. Thirty-seven cultivars were clustered into 14 synonymous groups. Six of these were from Galicia, one from Castilla-León (El Bierzo), four from Asturias, one from Asturias and Castilla-León (El Bierzo), and two from Asturias, Castilla-León (El Bierzo), and Galicia. The chestnut cultivars from Galicia and Asturias were undifferentiated in genetic terms, indicating that they are not genetically isolated. Overall, chestnut cultivars from southern Spain showed the least variation. Many (58%) of Spanish cultivars produced more than 100 nuts/kg; removing this low market-value character will be a high priority. The data obtained will be of use in chestnut breeding programs in Spain and elsewhere.


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