Apple seed stocks affected scion tree vigor and performance based on maternal self(in)compatibility

Abstract

In a breeding program to increase uniformity of apple saplings size, shape and vigor the genetic improvement of seed rootstocks was considered as a key point. The Half-Sib seeds of two selected native crab parents, self-compatible “Morabbaei” and self-incompatible “Azayesh”, both dwarf, were considered as the main sources of variances into the six grafted scions. The inductive effects of the two seed masses were assessed on vegetative traits of 6 and 7-year-old scion trees. According to the results, shoot length, shoot thickness and internode length as main components of tree vigor showed significant differences at 1% level in all the six scions. The shoot length mean of the grafted scions on “Azayesh” seed progeny was higher than “Morabbaei” seed stock. The grafted scions on self-compatible “Morabbaei” seed stock gave place to the shoots with higher thickness than the same grafted on “Azayesh” seed source. Combinations of “Red Delicious”-“Morabbaei” and “Braeburn”-“Azayesh” demonstrated max and min values of internodes length during two consecutive years. Both rootstock and scion trunk diameters on self-incompatible “Azayesh” seeds resulted higher than seed progeny of self-compatible “Morabbaei”. Shoot number was not affected by rootstock type, whereas the effect of rootstock × scion, scion and year resulted significant.

Keywords

• breeding
• dwarfness
• genetic purity
• inductive effect
• Malus × domestica Borkh.