Age-age correlation and early selection in black alder (Alnus glutinosa (L.) Gaertn)
Plant breeding is a long term activity and is generally composed of repeated cycles of recombination and selection. At each stage of the selection process, material needs to be tested and this can often lead to a long generation time to complete a breeding cycle and the associated costs involved in establishing and maintaining large progeny trials can be prohibitively high. Early selection is a technique that can be used to reduce the time needed to evaluate genetic gain especially if the genetic gain correlation between juvenile and mature traits is heritable. Two black alder progeny field trials were established in 2008, located in Cavan and Clare, and a third trial was established in 2009 in Sligo. The trials were established with plants raised from seed collected from 85 Irish plus-tree selections. The plus trees were selected from 17 sites throughout the country. All plants were measured for height and root collar diameter at planting and heights were recorded for the two subsequent growing seasons. Height and diameter at breast height (dbh) were recorded again when the trees were seven and nine years old. This study will utilize this data to observe relationships of growth at early and later ages on the same trees with the aim of obtaining valuable information about the genetic variability and effectiveness of phenotypic selection for black alder.