Towards management of fertilization to control wheat crown rot caused by Fusarium culmorum.

IPNI-2014-MAR-3

29 Apr 2016

2015 Annual Interpretive Summary


Fusarium crown rot of wheat, caused by Fusarium culmorum, has become a yield-limiting disease in the dryland wheat production areas in Morocco, and is usually enhanced in water-stressed plants due to over fertilizing with N. This project was initiated in 2014 with the objective to investigate: 1) the relationship between wheat crown caused by Fusarium culmorum and fertilization (N and K forms), and 2) develop a fertilization management package to control this disease in durum wheat. Field experiments were established in November 2014 at three locations (Sidi El Aydi, Jamaat Shaim and Khemis Zemamra) that represent semi-arid regions of Morocco. Within each experimental station, two trials were undertaken: one under irrigated condition, and the other one under rainfed conditions. The experimental design was a strip plot with four blocks, where treatments were seed inoculation, with two levels, inoculated and non-inoculated seeds. The inoculation treatment was crossed with six fertilizer treatments: diammonium phosphate (DAP), DAP+potassium sulfate (KS), DAP+ammonium nitrate, DAP+urea, DAP+KS+ammonium nitrate (AN), and DAP+KS+urea.

White wheat head development was significantly greater under rainfed compared to irrigated conditions, and seed inoculation induced this development by 1 to 3 times, and 0.5 to 2 times in these respective systems. These findings may explain why wheat crown rot is much more prevalent under semi-arid rainfed conditions. DAP, DAP+KS, DAP+AN, DAP+urea, DAP+KS+AN, and DAP+KS+urea induced white head development at a rate of 10, 14, 23, 26, 21, and 20/10 m², respectively. Under rainfed conditions, DAP+AN and DAP+urea significantly increased white head development by 130 and 160%, respectively, compared to DAP treatment alone. However, the presence of KS in the treatments DAP+KS+AN and DAP+KS+urea, decreased significantly white heads development even though the two forms of N were added. Besides seed inoculation, these results also point out that N is the main cause of white head development, but urea increased this effect. In contrast, the application of KS reduced the effect of N on white head development, for both AN or urea forms.