Morphological variability of Quercus robur L. plus trees and clones in Podillia

Abstract

The results of the study of English oak (Quercus robur L.) plus trees based on the morphological features of their leaves, acorns, and peduncles are presented. Samples were collected from both plus trees in forest stands and clones in clonal archive of English oak in Vinnytsia Region. In total, 41 trees were analyzed by 7 features of their leaves and 30 of those trees – by 9 morphological features of their acorns and peduncles. A point assessment was used for nonmetric indicators. To compare plus trees by morphological features, the graphical method of morphotypes image representation with the usage of radar charts is suggested. Given that absolute indicators may depend on the year’s weather conditions, only relative indicators assessed in points were used to plot charts. The average indices for the trees as well as the variability level between them are determined. The most variable features were identified and offered to use for clone identification. It has been suggested that 8 plus trees whose leaves’ base is rounded are the hybrids of English and sessile oaks. It is confirmed that all the studied plus trees of Vinnytsia origin differed in one or several morphological features of their leaves, acorns, or peduncles. However, two plus trees of Odesa origin were similar in their leaves’ characteristics and two clones of Vinnytsia origin were similar in their acorns and peduncles’ features. It is noted that the use of morphological indicators of leaves and reproductive organs, taken as a whole, allows obtaining a rather complete description of a plus tree or its clone, and the usage of the graphical method allows determining the difference and similarity of individuals and their groups. Graphic images of morphotypes given as radar charts can be used to compare individuals, their groups, populations, variants in both progeny test and provenance trial, so to identify clones in clonal seed orchards.

Keywords

• leaf
• lamina
• acorn
• cap
• peduncle
• point assessment
• morphotype