<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Planting Populus cuttings based on calendar days neglects soil temperature extremes and does not promote rooting based on specific genotypes. Our objectives were to: 1) test the biological efficacy of a thermal index based on belowground growing degree days (GDD) across the growing period, 2) test for interactions between belowground GDD and clones, and 3) identify beneficial planting windows based on combinations of genotypes and belowground GDD. We tested two clones of Populus deltoides Bartr. ex Marsh (D133, D134) and four hybrid clones of P. deltoides × P. maximowiczii A. Henry (DM101, DM105, NC14105, NC14107). Cuttings, 20 cm long, were planted in randomized complete blocks at 15- × 15-cm spacing across three planting dates during 1999 at Alexandria, Minnesota, USA (45.9°N, 95.4°W) and Fertile, Minnesota, USA (47.3°N, 96.2°W). Temperatures at 20 cm belowground were converted to GDD with a base temperature of 10°C. We measured root, top, and total dry weight, along with number of roots after 14 d of growth. Relatively warmer and cooler soil temperatures promoted rooting for the cottonwoods and hybrids, respectively. We recommend planting after reaching a threshold of 163 belowground GDD for P. deltoides clones and planting before reaching a threshold of 173 belowground GDD for P. deltoides × P. maximowiczii clones.</p></abstract>

Planting Populus cuttings based on calendar days neglects soil temperature extremes and does not promote rooting based on specific genotypes. Our objectives were to: 1) test the biological efficacy of a thermal index based on belowground growing degree days (GDD) across the growing period, 2) test for interactions between belowground GDD and clones, and 3) identify beneficial planting windows based on combinations of genotypes and belowground GDD. We tested two clones of Populus deltoides Bartr. ex Marsh (D133, D134) and four hybrid clones of P. deltoides × P. maximowiczii A. Henry (DM101, DM105, NC14105, NC14107). Cuttings, 20 cm long, were planted in randomized complete blocks at 15- × 15-cm spacing across three planting dates during 1999 at Alexandria, Minnesota, USA (45.9°N, 95.4°W) and Fertile, Minnesota, USA (47.3°N, 96.2°W). Temperatures at 20 cm belowground were converted to GDD with a base temperature of 10°C. We measured root, top, and total dry weight, along with number of roots after 14 d of growth. Relatively warmer and cooler soil temperatures promoted rooting for the cottonwoods and hybrids, respectively. We recommend planting after reaching a threshold of 163 belowground GDD for P. deltoides clones and planting before reaching a threshold of 173 belowground GDD for P. deltoides × P. maximowiczii clones.

Use of Belowground Growing Degree Days to Predict Rooting of Dormant Hardwood Cuttings of Populus

Silvae Genetica

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Planting Populus cuttings based on calendar days neglects soil temperature extremes and does not promote rooting based on specific genotypes. Our objectives...

Use of Belowground Growing Degree Days to Predict Rooting of Dormant Hardwood Cuttings of Populus

Published Online: Oct 27, 2017

Page range: 154 - 160

Received: Sep 10, 2004

DOI: https://doi.org/10.1515/sg-2004-0028

Keywords
Populus deltoides, P. maximowiczii, hybrid poplar, soil temperature, genotype × environment interaction

© 2017

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Use of Belowground Growing Degree Days to Predict Rooting of Dormant Hardwood Cuttings of Populus

Published Online: Oct 27, 2017

Page range: 154 - 160

Received: Sep 10, 2004

DOI: https://doi.org/10.1515/sg-2004-0028

KeywordsPopulus deltoides, P. maximowiczii, hybrid poplar, soil temperature, genotype × environment interaction

© 2017

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
Populus deltoides, P. maximowiczii, hybrid poplar, soil temperature, genotype × environment interaction