Comportamiento de híbridos de sorgo granífero a roya (Puccinia purpurea) bajo diferentes condiciones climáticas conductivas = Behaviour of graniferous sorghum hybrids to rust (Puccinia purpurea) under different conductive climate conditions

Abstract

In Argentina, sorghum (Sorghum spp.) is negatively affected by diseases that decrease grain and forage production, as well as the nutritional value of the crop. Among the rusts that affect the crop, the one caused by Puccinia purpurea is the most widely distributed worldwide. The different climatic scenarios that occur in each agricultural cycle greatly affect the moment of appearance and subsequent development of this disease, causing variable levels of incidence and severity. The objective was to determine the behaviour of graniferous sorghum hybrids to rust, under different conductive climatic conditions. The work was carried out in the agricultural cycles 2017/18 and 2018/19, in Oro Verde, Entre Ríos, on 25 and 16 genotypes of grain sorghum, respectively. The 2017/18 cycle was characterized by low rain and high temperatures in relation to the historical series. On the contrary, in 2018/19 there were excessively humid conditions, with mild temperatures. The levels of the area under the disease progress curve (AUDPC) constructed from severity data discriminated the behaviour of the hybrids to rust and during the 2018/19 cycle were higher than those of the 2017/18 cycle. The use of the AUDPC is an adequate methodology that allows to characterize hybrids, even under non-conductive climatic conditions.