Fig. 1

Intraspecific uniformity test and interspecific distinctness analysis of Malus floral phenotypic traits. A The intraspecific uniformity of floral organs qualitative traits using 90% as the criteria. If \(\overline{MF}\)≥90%, then the qualitative trait has met the uniformity requirements. B The intraspecific uniformity of floral organs quantitative traits using 10% as the criteria. If \(\overline{C.v.}\)≤10%, then the quantitative trait has met the uniformity requirements. C The interspecific distinctness of floral organs qualitative traits using \(k\,{1}\left/{f}\right.\) as the reference. k is a coefficient that depends on the number of ranks (f) of each trait appeared in all taxa. The specific assignment is indicated in the C. If \(MF\le k\,{1}\left/{f}\right.\), the qualitative trait is more differentiated among all taxa. D The interspecific distinctness of floral organs quantitative traits using 15% as the criteria. If C. v.≥15%, it was considered that the differentiation degree of this trait is high among all the taxa. For more accurate expression, the one-way ANOVA (Tukey’s method) was performed. * represents that the difference of quantitative traits reached a significant level between different Malus taxa (P < 0.05)