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EFFECT OF FUNGICIDES (CALIXIN AND CAPTAFOL) ON THE GERMINATION PHYSIOLOGY, GROWTH, NITROGEN METABOLISM AND YIELD OF PHASEOLUS AUREUS

RN RAUNLYAR

Amrit Science Campus, Tribhuvati University, Kathmandu, Nepal

Background and objectives
The pulses (nitrogen-fixing plants) are the most important source of protein in the diet of almost all developing countries. Among them mung (Phaseolus aureus) is the most important, containing about 24% protein which is easily digestible. This source of protein is cheaper than animal protein. Mung is attacked by several fungi, and a number of fungicides are being used for crop protection but their phytotoxic effects have been often ignored. Therefore the objective of the present study is to assess the phytotoxic effects of fungicides (calixin and captafol) on the germination, growth and nitrogen metabolism of mung bean.

Materials and methods
Seeds were treated with four different concentrations of calixin: 0.25, 0.50, 0.75 and 1%, and also four different concentrations of captafol (0.10, 0.20, 0.30 and 0.40%). Then the treated seeds were allowed to germinate in earthen pots. After treatment, seed germination, growth, nitrogen metabolism and yields were studied.

Results and conclusions
The results indicate that both calixin and captafol had a phytotoxic effect at the higher concentration. However, the lower concentration showed a stimulatory effect on the different parameters such as seed germination, reducing sugar level, amylase activity and yields. Calixin inhibited soluble, insoluble and total nitrogen of the primary leaf and nodules. On the contrary, captafol showed little effect on nitrogen metabolism. Furthermore, it was observed that nitrate reductase activity was effected by calixin in the primary leaf of mung. Thus it can be concluded that calixin is phytotoxic in nature, while captafol showed little effect on nitrate reductase activity. The effects of calixin, however, were recoverable during the growth of plant. Thus calixin, if necessary, can be used against fungal infection in mung [1, 2].

References
1. Tekrotley DM, Egli DB, Philips A, Waynes ST, 1974. Proceedings of the Association of Official Seed Analysts 64, 80-89.
2. Siegel MR, 1977. In Sisteg HD, ed., Antifungal Compounds, pp. 399-438.