Screening Hard Red Spring Wheat Cultivars for Reduced Phosphorus Fertilizer Requirement

Phosphorus (P) is a common macronutrient required for hard red spring (HRS) wheat (Triticum aestivum L.) growth and yield expression, and is a significant expense for farmers. The objective of this study was to screen 89 cultivars of historical, current, and pending HRS wheat genotypes for relative P requirement. The cultivars were grown in a greenhouse over two years, using four rates of sodium phosphate for a rate response to the fertilizer. The genotypes were assessed using the Klepper-Haun technique for Haun stage and tiller initiation, and the plant material was analyzed for total P. It was found that as P rate increased, so did dry matter production, Haun stage, tiller initiation, P concentration, and P uptake. Significant cultivar and P*cultivar interactions were observed and regression analysis indicated that rapidly developing cultivars tillered less and required more P fertilizer for initiation of T1 + T2 tillers than slowly developing cultivars