Item – Theses Canada

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OCLC number
61862873
Link(s) to full text
LAC copy
LAC copy
Author
Rweyongeza, Deogratias Max,1964-
Title
Genetic analysis of seasonal seedling height growth curves and early selection in white spruce.
Degree
Ph. D. -- University of Alberta, 2002
Publisher
Ottawa : Library and Archives Canada = Bibliothèque et Archives Canada, [2005]
Description
3 microfiches.
Notes
Includes bibliographical references.
Abstract
Genetic analysis was conducted on parameters of the logistic growth curve for seasonal height growth, absolute height and height increments, stem tissue components, root collar diameter, fresh and dry weights, seedling architectural traits, dated for budburst, and branch and needle characteristics of white spruce seedlings grown in the greenhouse at the University of Alberta, Canada. The objective was to identify which of these juvenile traits best predict 10 and 11-year field height at Chinchaga (site A) and Saddle Hills (site B), Alberta. The 58 open-pollinated families tested were selected for their superior phenotype from the Peace River area Alberta. Because of very low heritability for height at site B, only the results with site A provide better estimates of selection efficiencies, the measure used to judge the feasibility of early selection in this study. At age 11 years on site A (AH11), the selection efficiency for first season height (FH2-FH18) was 41.5-55.5% and that of the second season height increment (SH2-SH18) and 36-week height (TH36) was -8.9-7.7% and 8.4%, respectively. The rate of growth ('r') and age at the point of inflection ('t'0.5) of the growth curve had respectively, selection efficiencies of -6.2% and 22.3% (first season) and 17.2% and -26.2% (second season). Thus, first season height was a better predictor of field height than the second season height, and seasonal height growth curve parameters. Branch length (BL), the number of stem units (NSU) and stem unit length (MSUL) had selection efficiencies of 17.6%, 3.2% and 33.6%, respectively. Terminal (TB2) and branch (BB2) budburst, and needle length (NL) had selection efficiencies of 15.3% and 13.9%, and 17.6%, respectively. Considering the short time involved in greenhouse testing, selection for FH2-FH18 and MSUL would be efficient in improving field height growth at site A for the tested families. Selection indices combining AH11 and two greenhouse traits would increase genetic gain of field height by 1-8% compared with selection for AH11 alone. This shows that apart from identifying juvenile traits that are good indicators of field height, retrospective studies can provide additional information to enhance selection efficiency of field height.
ISBN
0612963470
9780612963474