Combining ability for fruit set in macadamia cultivars

A 5 x 5 diallel experiment was conducted at Experimental Station of Tiete, SP, aiming to evaluate the combining ability amongst macadamia nut trees (M acadamia integrifolia Maiden & Betche) cultivars IAC Campinas A, IAC 2-23 A , IAC 4-12 B, IAC 4-20 e IAC 5-10. The initial fruit set was evaluated 14 d ays after manual pollination and showed that every cultivar presented self incompatibility. There were significant general and specific combining abil ity amongst cultivars and reciprocal effects. The cultivar IAC Campinas A r educed the initial fruit set at all crossing in which was used as female pr ogenitor. The best results for initial fruit set were showed by crossings b etween following cultivars: IAC 4-20 x IAC Campinas A, IAC 4-12 B x IAC 2-2 3 A, IAC 4-20 x IAC 4-12 B, IAC 5-10 x IAC 2-23 A, IAC 5-10 x IAC 4-20, IAC 4-20 x IAC 2-23 A e IAC 5-10 x IAC 4-12 B.