Plant height, trunk diameter, leaf length, and chlorophyll content
showed significant positive correlation with earliness in apple
during juvenile phase. Principal component analysis confirmed that
four traits including leaf length and chlorophyll content justified
87% of total variances, cumulatively. Path analysis results in the
groups of early ripening cultivars showed that max and min rates
of direct effects were 8.71 and
−7.47 for leaf length and leaf width
traits, respectively. High indirect effects were observed in other
traits such as pedicle length, tree height, leaf chlorophyll, trunk
diameter and annual growth rate through leaf width. So, it was
confirmed the existence of a positive correlation between studied
morphological markers and ripening time. As a consequence, this
method may be applied with high confidence for selection of hybrid
seedlings obtained from a high range of cross combinations in apple
breeding programs. This screening method is a low cost, practical
approach compared with other classic methods in apple breeding.