Importance of wheat rusts in Chile

Ernesto Hacke E.1

The severity of P. graminis, P. recondita and P. striíformis on several hundreds of advanced lines and cultivars of wheat included in yield trials, were studied during long periods. In the case of P. graminis only moderate to high attacks at Vallenar, La Serena and Ovalle were observed during the last 30 years. In the rest of the country, where the Regional Trials were grown, no evidence of the disease was detected except at Pirque, in 1963 and at Machalí, in 1978, where slight attacks were observed. This situation differ widely with severe epiphytiotics of stem rust observed befare 1960. In relation to P. recondita it was demonstrated that this rust has attacked with more o less the same severity bread wheats (Triticum aestivum L.) and durum wheats (T. turgidum var. durum) at the North Central Zone during 1961-1963 and 1986-1989 as well as in 1980 and 1982. The most severe leaf rust attacks ofthe countrywere observed in the South Central Zone. These affected with similar intensity to winter, alternative and spring wheats. On the other hand the attacks of this rust in the Southern Zone are in general late and therefore the damage caused by the rust is smaller. In relation to P.striiformis the severity ofthe attacks increases from North to South. In the North Central Zone, insignificant attacks have been observed during the last 5 years. Nevertheless this phenomenon could be regarded as transitory based on the results obtained. The estimation of damage caused by the three rusts in the country reaches to an annual average loss of 6.25% ofthe total harvest of wheat. That is: P. striiformis cause 4%, P. recondita 2% and P. graminis 0.25% of loss. The 6.25% loss applied to the harvest in 1988/89 means a loss of 1.177.826 metric quintals that correspond to 20.1 million dollars.

Keywords: Triticum aestivum, Puccinia graminis, P. recondita, P. striiformis, wheat, rusts, losses of yield.
1 Estación Experimental La Platina (INIA). Casilla 439, Correo 3. Santiago, Chile.