GROWTH-RESPONSE OF KENAF CULTIVARS IN ROOT-KNOT NEMATODE SOIL-BORNE FUNGI INFESTED SOIL

The southern root-knot nematode (RKN) [Meloidogyne incognita (Kofoid and White) Chitwood] is a severe pathogen of kenaf (Hibiscus cannabinus L.) capable of reducing growth, yield, and harvesting efficiency, as well as predisposing kenaf to pathogenic soil fungi. In 1991 and 1992, field studies were conducted to evaluate growth and yield response of six kenaf cultivars grown on a soil naturally infested with RKN and various pathogenic soil fungi. Cultivars included in the studies were Everglades 71 (E71), Tainung 1 (TA1), Cuba 108 (C108), Indian (IND), SF459, and 117. Early to midseason growth rate differed among cultivars. Across years, cultivars 117 and SF459 grew approximate to 73 and 55%, respectively, faster than E71 and IND. Total stalk yields differed among cultivars, with 117 and SF459 producing greater yields than the other four cultivars, including a >250% yield increase compared with E71, a widely grown kenaf cultivar in the USA. Based on the presence of root galls, all cultivars appeared to be good hosts for RKN; however, the ability of 117 and SF459 to maintain better plant growth and dry matter accumulation indicated a significant level of field tolerance when grown In the presence of the RKN/soil-borne fungi complex.