PRATCHAYA VASSANACHAROEN, NATTASAK KRITTIGAMAS, SA-NGUANSAK THANAPORNPOONPONG
Chiang Mai University, Department of Agronomy, Thailand
Macrophomina phaseolina is the main seed-borne fungus in many of seed crops eseptically in sesame. This study was to evaluate possibility using radio frequency heat treatment to control seed-borne fungus. Three variety of sesame from Thailand, Mahasarakam 60 (MK60, white seed), MG 18 (black seed) and Aubon 1 (AU1, red seed) with initial seed moisture content of 5 and 10 percent were treated with various of radio frequency heat treatment of 60, 70, 80, 85, 90 degree Celsius for 180 seconds. Seed-borne fungi were assayed by using 2 method. PAD method (Potato Dextrose Agar), at seed moisture content 5 percent the existing of M phaseolina was 16, 11, 18 percent in MK60, MG18, AU1 whereas at seed moisture content 10 percent was 17, 15, 21 in MK60, MG18, AU1. Besides that, other 5 fungi viz. Rhizopus sp., Aspergillus niger, A flavus, Curvularia sp., Penicillium were found. Blotter method, at seed moisture content 5 percent the existing of M phaseolina was 15, 10, 13 percent in MK60, MG18, AU1 whereas at seed moisture content 10 percent was 16, 14, 15 in MK60, MG18, AU1., other 9 fungi viz. Rhizopus sp., Aspergillus niger, A. flavus, Fusarium, Curvularia sp., Penicillium, Cladosporium, Alternalia and A. terrieus were also found. However, among all fungi, M phaseoliana was the main principle decreasing germination percentage. Radio frequency had significantly showed the efficiency in controlling M phaseolina. The best level was at 70 degree celcious with seed moisture content of 10 percent, all fungi invasion was decreased to 51 percent whereas the percentage of seed germination was 73 percent. Sesame variety AU1 response to the treatments better than the others.
Keywords: Macrophomina phaseoliana, radio frequency, seed-borne fungus, sesame seed