Yes in apple the leaf as well as fruit having cuticles on skin is pest resistance charecter while oily glands on fruit is a charecter of disese resistance

Thank you very much, dear colleagues for the help. I dont have much experience with breeding, so any practical information is of great use for me.

Dear Tomislav, i work with maize and chili pepper drought and disease resistance, perhaps the researchers at Washington -usda-ARS would work with apple because there are a great acreage with apples...

Dear Jose, thanks for the information. I'll contact them.

You can refer to morphological markers papers in mango and papaya, which were presented in the International symposiums, these have come in different volumes of Acta Horticulturae

Thank you very much.