Weather factors associated with stress in soybean in northwestern Argentina during the 2021/20022 growing season

BLECKWEDEL, J.; REZNIKOV, S.; GONZALEZ, V.; PLOPER, L.D.

Viena

Congreso; World Soybean Research Conference XI (WSRC XI); 2023

Donau Soja Association (Vienna, Austria) - Institute of Field and Vegetable Crops (Novi Sad, Serbia)

Book of Abstracts “Soybean Research for Sustainable Development. p. 460. Disease surveys on soybean are carried out every year in nothwestern Argentina (NWA), a region, located between latitudes 22º and 29º South and longitudes 63º and 68º West that includes the subtropical provinces of Tucumán, Salta, Jujuy, Santiago del Estero, and Catamarca. During the 2021/2022 season, these surveys revealed the presence of soybean plants affected by heat canker and sunscald. In December 2021 and January 2022, when soybean plants were in the early vegetative stages, NWA experienced unusually high temperatures combined with scarce precipitations. These conditions induced the occurrence of symptoms such as heat canker, visible in plants at the V1-V3 growth stage, and sunscald, observed at the V2-V8 growth stage. Heat canker was observed as a darken area where the hypocotyl was in contact with the soil surface, indicating cell death due to high temperatures. The root system remained white and looked normal but affected plants often died. Leaves affected by sunburn presented a brown to rusty appearance. Incidence of heat canker and sunburn was recorded in different commercial soybean fields in Tucumán province. In San Agustín, Cruz Alta department, crops presented 10% of plants with heat canker at the V1-V2 growth stage. In Villa Benjamín Araóz, Burruyacu department, heat canker was present in 5% of the soybean plants at the V1-V2 stage. With respect to sunburn, a 70% incidence was determined at V3-V4 in San Agustín, whereas in La Cruz, Burruyacu department, incidence was 5% at V5. Finally, 5% of sunburn was registered on a soybean commercial field in Villa Benjamín Araóz at the R1-R2 stage. Differences in the incidence of heat canker and sunburn could be explained by the environmental conditions recorded in both departments. From 1 December 2021 to 15 January 2022, Cruz Alta presented 148.8 h and Burruyacu 115.8 h of temperature above 35°C, compared to the 10-year average 2011-2021 (91.2 h and 80.2 h, respectively). Also, Cruz Alta presented 85.8 mm of rainfall and Burruyacu 114.8 mm compared to 210.9 mm and 215.3 mm, respectively, for the same 10-year