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EFFECTIVENESS OF IAA, GA₃ AND KINETIN BLENDED WITH RECYCLED ORGANIC WASTE FOR IMPROVING GROWTH AND YIELD OF WHEAT (TRITICUM   AESTIVUM L.)

ZAHIR A. ZAHIR^*, M. IQBAL, M. ARSHAD, M. NAVEED AND M. KHALID

Abstract: Plant hormones play a vital role in coordination of many growth and behavioral processes in the plant life. They regulate the amount, type and direction of plant growth. Organic waste recycling in the form of compost is an effective way of organic waste management, turning it into a high quality and inexpensive soil amendment. In this study, plant growth regulators like IAA, GA₃ and kinetin were blended with composted organic wastes and their bioavailability to affect the growth and yield of wheat was evaluated in a field trial. The compost was prepared from fruit and vegetable waste material and enriched with 25% of full dose of N fertilizer (100 g kg^-1 compost). Each of indole 3-acetic acid (IAA), gibberellic acid (GA₃) and kinetin were added @ 1.0 mg kg^-1 compost. Effectiveness of IAA/GA₃ or kinetin-blended N-enriched compost was compared in the presence of 50% of full dose of N fertilizer for improving growth and yield of wheat. Compost was applied @ 300 kg ha^-1 and full P and K fertilizers (@100-60 kg ha^-1) were applied as basal dose to all plots. Full dose of N fertilizer (120 kg ha^-1) was used for comparison. Results indicated that IAA-blended N-compost with half dose of N fertilizer was comparable with full dose of N fertilizer for improving growth and yield of wheat, saving 25% N fertilizer. However, application of kinetin blended N-enriched compost increased the grain yield (9.1%) and uptake of nutrients i.e. NPK uptake (5.6, 8.6 and 7%, respectively) over full dose of N fertilizer. The findings also proved that exogenously supplied PGRs may undergo several metabolic processes in the soil resulting in loss of their activity and reduced availability to plants. In this study, such type of behavior was only seen with IAA & GA₃ but not in case of kinetin as its bioavailability to wheat was not affected when blended with compost resulting in improved growth and yield. This study also demonstrated that huge amount of organic waste could be converted into a value-added product for improving growth, yield and nutrient uptake of wheat.

Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad-38040, Pakistan