<b>Self- and cross-compatibility of macadamia cultivars</b>

Abstract

Two 5x5 diallel experiments were conducted to estimate the relative fertility of cross- and self- pollinations amongst macadamia cultivars as measured by pollen tube growth and initial fruit set. Experiment 1 involved the Hawaiian cultivars 246 (Keauhou), 344 (Kau), 660 (Keaau), 741 (Mauka) and 800 (Makai), and experiment 2 studied 246, 508 (Kakea), 660, 741 and 800. Results were similar in the two experiments and in the two methods of measurement. All selections showed poorer pollen tube growth and initial fruil set following self- than cross-pollination. In both experiments there was significant specific combining ability and general combining ability amongst the cultivars and there were significant reciprocal effects. The selection 246 showed consistently high fertility in both experiments, as assessed by both methods, and as both female and male parent. The selection 508 performed well as female parent as assessed by both methods but was included in experiment 2 only. A number of cultivar combinations consistently showed relatively low fertility. These included 741 x 660, 741 x 800 and 800 x 660.