Factors Influencing Population Dynamics of Fusarium Oxysporum f. sp. cumini in the Presence and Absence of Cumin Crop in Arid Solis

Abstract

In a 16-month field experiment, the effects of fungi, bacteria, actinomycetes, total microbial population, soil moisture and soil temperature on the population dynamics of Fusarium oxysporum f. sp. cumini were studied in soils with or without a cumin (Cuminum cyminum L.) crop at different soil depths. The greatest fungal population and survival in cumin-planted soil were recorded at 0–5 cm depth, but the population density tended to decline progressively with increasing soil depth. The population of Fusarium increased progressively with continuous cultivation of cumin for two seasons, but remained almost stationary in fallow soil without a host. Correlations and path coefficient analyses were carried out to determine the role of individual factors influencing the population of F. o. f. sp. cumini. In soil planted with cumin, there were significant positive correlations of the Fusarium population with maximum soil temperature (r=0.50), bacteria (r=0.51) and total microbial population (r=0.53) at 0–5 cm soil depth. In path coefficient analyses, total bacteria had the highest direct effect on the Fusarium population, followed by microbial population and maximum soil temperature. However, in the soil not planted with a cumin crop, none of the studied factors had significant correlations with the Fusarium population at any soil depth,.