BLACKHEART RESISTANCE IN 3 CLONES OF PINEAPPLE [ANANAS-COMOSUS (L) MERR] IN SUBTROPICAL QUEENSLAND

Smooth Cayenne Queensland clone 13, and intergroup hybrids 53-116 and 73-50 were harvested in mid July 1994 and evaluated for blackheart res istance. Relative to C13, hybrids 73-50 and 53-116 had some level of f ield resistance to blackheart but only 53-116 was without blackheart a fter storage at 10 degrees C for 14 days followed by 20 degrees C for 8 days. Hybrid 53-116 had a high vitamin C content compared with clone 13. However, 73-50 had the highest level of vitamin C but still devel oped blackheart, although the symptoms were not as severe as C13. This indicates that factors other than vitamin C may playa role in blackhe art resistance. The level of field resistance to blackheart shown by 7 3-50 may be sufficient for winter production in some sites in south-ea st Queensland. Field testing is needed to determine the value of this resistance.