Effect of level of relative humidity on fungi and germination capacity of paddy (oryza sativa l.) Grains in egypt

Abstract

The changes in the composition of paddy grain-borne fungi in the germination capacity, and in the moisture content of paddy grains at various levels of relative humidity (r.h.) (~ 0-100%) stored at 20°C for 1, 2, 3 and 4 months, were investigated. The total count of fungi significantly increased with the increase of moisture content and storage periods and the highest counts were estimated at 92% and 100% r.h. after 4 and 3 months, respectively. The preceding increases up in the total counts were mainly related to the flourishing of numerous species such as. Aspergillus Candidas, A. sydowii, A. tamarii, A. versicolor, A. flavus, Penicillium chrysogenum, Fusarium oxysporum and Cladosporium cladosporioides. At all levels, except at ~ 0%, of relative humidity the germination capacity of grain decreased slowly or rapidly with the increase of the storage period and the rate of decrease was enhanced with the rise of relative humidity which increased the moisture contents of grains, and complete mortality (100%) was recorded at 92% r.h. after 4 months and at 100% after 3 months, when the moisture contents of paddy grains rose to 21.6%'and 22.6% respectively.