Abstract
This paper reports mode of anthesis, raceme-related traits, nut set, and nut retention in two macadamia cultivars viz., Keauhou and Kakea under the mild tropics of South India where this nut crop was introduced recently. Significantly longer racemes (15.4cm.) were produced by Keauhou, but the racemes of cv. Kakea contained greater mean number of flowers (154). In most of the racemes anthesis commenced between 3pm to 6pm. The period required for completion of anthesis by the racemes ranged from 41-150h in Keauhou and 51-130h in Kakea providing better opportunity for cross-pollination in these two self-incompatible cultivars. Besides basipetal and acropetal flowering, anthesis also started in some racemes in the middle and progressed towards base and apex. Nut set count 2-months post anthesis showed that about 61% and 80% of the racemes in Keauhou and Kakea were unproductive. Flower to nut set ratio was significantly different in Keauhou and Kakea, and nut retention was better in the former (1.3%) as against 0.8% in the latter. The racemes with smaller number of flowers were found to set more nuts. Based on the nut set and retention, cv. Keauhou was found to do well in the mild tropics of South India.
