Genetic variation in growth traits and morphological characteristics of eastern cottonwood (Populus deltoides Bartr.) hybrids at nursery stage

Abstract

Eastern cottonwood (Populus deltoides Bartr.) clones obtained from intraspecific and interspecific crosses were tested at Izmit nursery in Turkey. Growth traits and various morphological characteristics were assessed after two growing seasons. Significant clonal differences were observed regarding height, diameter, volume index and survival rate. Ten intraspecific crosses had significantly better growth performances than control clones Samsun and I-214 based on volume index values, but most of the clones showed poor survival rates in comparing control clones. High heritability values were found for the clone means of tree dimensions and survival rate, ranging from 0.51 to 0.65. Factor analysis was applied for 13 components and 71.46% of total variance was explained by the first five components. Volume index was determined as the most important variable in component 1. Groups of the clones were separated by discriminant functions and five highest groups were indicated with the most effective variable volume index.