STUDIES ON <i>Macrophomina phaseoli</i> (Maub.) ASHBY GROWTH AND SOME PHYSIOLOGICAL ASPECT OF GROUNDNUT (<i>Arachis hypogaea</i> L) PLANT INFECTED WITH THE FUNGUS

Abstract

Some synthetic media used to investigate the best media to support growth of Macrophomina phaseoli. The fungus grew in both solid and liquid synthetic media, but best growth was recorded in peanut leaflet Oat meal (POMA) and potato dextrose agar (PDA). There was no absolute nutrient requirement for its growth. The best inoculation technique for disease symptom development was a juxtaposition of 48 - hour old mycelial mat on wounded roots of 10-day old groundnut plants. Infection of the groundnut plants increased with higher inoculum potential in the soil. Dry weight of diseased plants was drastically reduced as infection advanced, possibly due to decreased anabolic activities of the plants. In addition, the reduction in the leaf area equally led to reduction of photosynthesis. Transpiration in inoculated plants decreased and remained lower than that of the uninoculated plants. The disease may have caused plugging of the xylem vessels, hence reduction in the plants' water absorption capacity.


KEY WORDS: Groundnut, Macrophomina phaseoli, physiology, juxtaposition, inoculum potential, dry weight, leaf area.


Global Jnl Pure & Applied Sciences Vol.10(1) 2004: 23-29