Phosphorus supply does not affect Fusarium crown rot of winter wheat

Abstract

Fusarium crown rot (FCR) is a major limitation to the wheat (Triticum aestivum L.) industry in the inland Pacific Northwest, United States. Genetic resistance to FCR is poorly understood and major gene resistance is not available in adapted cultivars. Chemical control is ineffective and crop rotations, which disrupt cycles of the disease, are not feasible in the region’s precipitation-limited climate. Cultural control methods are the only realistic option for farmers who struggle to minimize the impact of this disease. It is well established that FCR is favored by moisture-limited environments and an oversupply of plant-available nitrogen in soil. Effects of the supply of phosphorus in soil have not been clearly delineated. We conducted a 2-year FCR experiment at two locations in the low-precipitation zone (<30 cm) of north-central Oregon. Phosphorus fertilizer was applied in-furrow with phosphorus (P) at rates of 0, 5, and 15 kg ha$^{−1}$, to plots planted with either a hard red or soft white winter wheat cultivar. The P at 15 kg ha$^{−1}$ application rate increased tissue phosphorus concentration, early-season dry matter, and phosphorus uptake at both locations and both years of this study. Phosphorus treatment had no effect on grain yield, protein, or test weight. Phosphorus had no effect on the severity of FCR. This research improved our knowledge of cultural management boundaries as they relate to the control of FCR.