Influence of Temperature and UV radiation in the development of strains of Trichoderma spp.

Abstract Climate change is a threat to the agricultural sector. The objective of this study was to evaluate the influence of temperature and ultraviolet radiation (UV) on the in vitro development of Trichoderma spp. The experiments were conducted at the Postharvest Pathology Laboratory, at Embrapa Agroindústria Tropical (Fortaleza - CE). It was evaluated the influence of the incubation temperature (30, 35 and 40 °C) on mycelial growth, as well as sporulation (conidia.mL-1) and germination (%) of the conidia of the Trichoderma spp. (T. asperellum - SF 04, Quality WG®; T. harzianum - IBLF 006, Ecotrich WP®; and T. harzianum ESALQ - 1306, Trichodermil 1306). To evaluate the influence of UV, the Petri dishes of the fungal strains were exposed to light at different time intervals (0, 2, 4, 6 and 8 minutes) and obtained relative germination. The most temperature sensitive strain was T. asperellum (SF 04), in which the temperature of 35 °C showed a lower area of mycelial growth and lower relative germination (38.4%). The T. harzianum strain (ESALQ 1306) presented the lowest percentage of conidia germinated at 30 °C (63%), but had the highest number at 35 °C (100%). The UV radiation decreased the germination of the conidia and the strains that had the highest germination relative to the end of the exposure period were T. asperellum (SF 04) and T. harzianum (ESALQ 1306). These results may demonstrate a higher adaptability of the T. harzianum strain (ESALQ 1306) to extreme temperature conditions.