EFFECT OF PHOSPHORUS ON THE YIELD AND YIELD COMPONENTS OF WHEAT VARIETY INQLAB-91 UNDER RAINFED CONDITIONS

A field experiment to determine the judicious use of phosphorus was conducted at Adaptive Research Farm, Dera Ghazi Khan (D.G. Khan) during winter 2001-02 to find out the effect of best phosphorus level on wheat variety Inqlab-91. Five different phosphatic fertilizer levels i.e. 32, 42, 84, 96 and 128 kg P ha-1 keeping128 kg N ha-1 constant, were studied in randomized complete block design to evaluate their effect on germination count per unit area, number of fertile tillers m-2 , 1000 grain weight, number of grains spike-1 and grain yield ha-1 of the crop. The results showed that maximum wheat yield of 3557 kg ha-1 was obtained in the plots where NP ratio was 1:1 i.e. 128-128 kg ha-1 indicating importance of phosphorus at its highest dose in achieving maximum wheat productivity. Maximum germination count and fertile tillers m-2 were obtained in plots treated with NP 128-84 kg ha-1 indicates that at germination stage seed uses its internal resources and does not depend largely upon external material. Similarly, maximum dose of phosphorus combined with fix N, yielded maximum number of grains spike-1 i.e. 26 in plots treated with 128-128 kg NP ha-1. Maximum phosphorus dose contributed in achieving highest 1000 grain weight and finally resulted in statistically significant grain yield ha-1. These findings indicate that application of the highest dose of phosphorus in combination with fix nitrogen, i.e. in 1:1 ratio contributed maximum to translocate dry matter and physiological attributes towards the yield attributes in wheat variety, Inqlab-91 and therefore maximum phosphorus dose helped in achieving highest number of grains spike, 1000 grain weight and ultimately wheat yield