Effect of time of planting on nodulation, growth and seed yield of kharif urdbean genotypes

A field investigation was carried out at the Punjab Agricultural University, Ludhiana during kharif 2005 and 2006 to study the effect of time of planting (July 5, 15, 25 and August 5) on growth, nodulation and seed yield of three urdbean genotypes (‘KUG 114’, ‘KUG 173’ and ‘Mash 338’). Results revealed that planting urdbean during July 15–25 was optimum under the existing situation. Delayed planting on August 5 resulted in drastic reduction in seed yield. Nodulation and pods/plant were also higher in case of July 15 and July 25 planting over the other dates of planting. Accumulated growing degree days (GDD) and accumulated photothermal units (PTU) for 50% flowering as well as maturity were highest in July 5 planted crop and decreased further with delayed planting. Genotype ‘KUG 114’ produced 5.9 and 22.2% higher yield over ‘KUG 173’ and ‘Mash 338’, respectively. It had also more nodules/plant, dry weight of nodules/plant and pods/plant over the other two. ‘KUG 114’ required more or less higher GDD and PTU over the other two genotypes to attain 50% flowering and physiological maturity.