Morphological traits of phytomers and shoots in the first year of growth as markers for predicting apple tree canopy architecture

Abstract

Apple tree canopy architecture is very important for productivity, fruit quality and ripening. Our objective was to evaluate inheritance traits of an apple tree canopy and to identify morphological phytomer or shoot parameters, which could be used as a marker for selection of apple trees with desired canopy architecture. Crosses between apple trees with different canopy architecture using top-cross scheme were performed. Combining ability of parental cultivars and clones was evaluated. Progeny of columnar and spur ideotype apple trees will have the shortest internodes according to general combining ability effects. Offspring of standard and weeping apple trees will have moderate and long internodes. Data show that apple phytomer parameters, such as internode length and lamina angle to shoot, are inherited and related to future plant canopy architecture. These phytomer traits are easily detected in the first year of growth of apple hybrid. It was shown that short internode is directly related to columnar tree canopy, and high lamina angle to shoot in the juvenile phase is a morphological marker of weeping apple tree canopy.