No abstract

Changes in concentrations of several endogenous phytohormones and metabolites were analyzed in the long shoots of nine genotypes of coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) at five developmental stages: (1) closed buds, (2) flushing buds, (3) rapidly elongating shoots, (4) growing shoots and (5) near full-length shoots during one growing season. When averaged across genotypes, indole-3-acetic acid (IAA) concentration was high at stages 1 and 3. The only pattern that correlated with cone productivity was the one that was unique to IAA, in which high concentrations at stages 3 and 4 were found in all genotypes with high female cone productivity. Concentrations of isopentenyl adenosine (iPA) decreased and zeatin riboside (ZR) concentrations increased as the buds initiated and differentiated; ZR was 30 and 28 ng g(-1) dry weight (DW) at stages 1 and 4, respectively, before increasing to 166 ng g(-1) DW at stage 5. Isopentenyl adenosine peaked at 92 ng g(-1) DW at stage 2 and declined to low concentrations at stages 4 and 5. Zeatin-O-glucoside was 30 ng g(-1) DW at stage 1, declined at stages 2 and 3 and increased at stages 4 and 5. High abscisic acid (ABA) concentrations were positively correlated with rapid shoot elongation (stages 1 and 2), but as growth slowed and terminated, ABA concentrations decreased. Abscisic acid was 7 microg g(-1) DW at stage 1, increased to 13 microg g(-1) DW at stage 2 and then declined. The glucosyl ester (GE) of ABA decreased rapidly in early summer, and increased inversely with an increase in ABA. Between stages 1 and 2, ABA-GE decreased from 10 to 0.2 microg g(-1) DW and then increased. Of the ABA catabolites studied, 7'-hydroxy-ABA was about 2 microg g(-1) DW at stage 1, declined at stages 2 and 3 and increased at stages 4 and 5; phaseic acid concentrations were low at all stages, whereas dihydrophaseic acid was detected only at stages 4 and 5.

Seed orchards’ parental reproductive success is often assessed through surveys of seed- and pollen-cone production (reproductive investment). Although the reliability of this approach has been questioned, its speed and ease made it the method of choice for providing approximate estimates for the genetic quality and quantity of seed orchard crops. In this study, reproductive investment data from various female and male phenotypic assessment methods from three seed orchards (lodgepole pine ( Pinus contorta Dougl. ex. Loud. var. latifolia Engelm.), Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco), and western larch ( Larix occidentalis Nutt.)) were compared with reproductive success estimates based on DNA fingerprinting and parentage analyses. The use of reproductive investment as a proxy to reproductive success on estimating seed crop’s volume genetic worth and diversity (measured by effective number of parents) was evaluated. Regression analyses indicated that the phenotypic assessment methods reflect the true parental reproductive success and that estimates of seed- and pollen-cone volume production appear to be the most appropriate indicators of female and male reproductive success, respectively. Although the best combination of female–male survey methods produced inflated effective number of parents estimates, the genetic worth estimates were similar to those based on DNA, highlighting their robustness to fertility variation assessment.