DETERMINATION OF THE OPTIMUM IRRADIATION TIME TO ELIMINATE SEED·BORNE DISEASES OF RICE (Oryza sativa L.) AND MAIZE (Zea maize L. ).

Abstract

Seed-borne diseases caused by microorganism are common in rice and maize and oftencontribute to pour stand establishment thus contributing to considerable yield losses.

The purpose of this study was to evaluate the effect of microwave irradiation for thecontrol of seed-borne fungi in four varieties of paddy and maize cultivars, and todetermine the effect of irradiation on seed qualities.

Experiment was consisted of four paddy varieties Bg 94 -1, Bg 352, Bg 403, Bg 450, andmaize variety ruwan. Irradiation at 0, 5, 10, 15, 30, 45 and 60 second full strengthmicrowave (820 W, 2450 MHz) and a fungicide treatment (Captan 50% WP) were usedas seed treatments. Application of microwave treatment was done on seeds in opened andclosed petri dishes. Each treatment had four replications. Immediately after given themicrowave treatments seeds were subjected to germination, viability, vigour tests andblotter test to take diseases couts

The results reveled that the disease percentages were decreasing with the increase ofmicrowave exposure duration. Thus germination, viability and vigour were reduced.Specifically at 45 and 60 seconds all the seeds were non viable and showed nogermination. Difference on openness and closeness of the petri dish did not affect muchon seed borne diseases as well as on seed qualities

For maize seeds 10 second and for paddy 05 second were the optimum microwaveirradiation durations to eliminate seed-borne diseases without greatly affecting the seedqualities.