Egypt .J. of Appl. Sci., 24 (4A): 91-110 (2009).

EFFICIENCY OF MICROELEMENTS AS INDUCER RESISTANCE FACTOR OF PEANUT POD ROT DISEASES AND AFLATOXIGENIC FUNGI

Mahmoud1, E.Y., Wagida1 A. M. Saleh and Thanaa2 A.  Marei

1Plant Pathology Res. Inst., Agric. Res. Center, Giza., Egypt

2 Desert Res. Center, Cairo., Egypt

ABTRACT

Greenhouse and field experiments  were conducted in 2007 and 2008 to study the effect of microelements, namely copper (Cu), iron (Fe), zinc (Zn), manganese (Mn), and their mixture at 0,50,100 and 200 ppm as sulphate form on incidence of peanut pod rots, occurrence of aflatoxigenic fungi (Aspergillus flavus Link and A. parasiticus Speare) and aflatoxin content. Generally, treatment with micronutrients showed a significant reduction in peanut pod rots and frequency of occurrence of aflatoxigenic fungi, in addition it increased peanut yield compared with control. Microelements mixture at 200 ppm followed by copper sulphate at the same concentrate gave the best effect on reducing of pod rot incidence, frequency of occurrence aflatoxigenic fungi, seed aflatoxin contaminations and yield loss. The highest occurrence of aflatoxigenic fungi and seeds aflatoxin contaminations were recoded in zinc sulphate treatments, this effect was increased by increasing zinc sulphate from 100 to 200 ppm in both greenhouse and field trials during the two growing seasons 2007 and 2008.

Results of the present study indicated that treatment with microelements like many of inducer resistance factors was associated with specific biochemical defense reactions. Among these biochemical changes the increase in phenol contents (free, conjugate, & total phenols) and the increase in oxidative enzyme activity (peroxidase, polyphenoloxidase and catalase). Other biochemical changes were recoded i.e. an increase in sugars content (reducing, non- reducing and total sugars), total free amino acids and crude protein.

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Keywords: Peanut, groundnut, inducers resistance, pod rots, aflatoxin production, aflatoxin contaminations, aflatoxigenic fungi, microelements, trace-elements, copper (Cu), iron (Fe), zinc (Zn), manganese (Mn), Fusarium solani, Macrophomina phaseolina, Rhizoctonia solani, Sclerotium rolfsii, Aspergillus parasiticus, Aspergillus flavus and peanut yield