Demands for sustainable agricultural systems have forested the development of biological control techniques, such as the use of the egg parasitoid Trichogramma Westwood. However, the arduous identification of the parasitoid at the species level, due to the tiny size and the morphological similarities is an obstacle to increasing its use. Molecular markers are useful to reach the specimen genome and avoid environmental effects that could misguide identification. Several molecular markers techniques are available and the ISSR technique has been used to differentiate close individuals, due to its high polymorphism level, reproducibility and low cost. The objective of this study was to measure the level of genetic differentiation among five lines of Trichogramma, using ISSR markers: three belonging to the species T. pretiosum Riley, one to T. atopovirilia Oatman & Platner and one to T. bruni Nagaraja. Morphological identification of the parasitoids was conducted at ESALQ/USP - Piracicaba, SP. After DNA removal and standatization, PCR reactions were performed with 26 ISSR primers; 11 of them were selected because they presented greater polymorphism and consistency. Molecular data were converted into a binary matrix and analyzed (NTSYS v. 2.1). The 11 primers produced 172 polymorphic sections. Genetic similarity ranged from 19% to 96%, showing that the ISSR technique can efficiently identify DNA polymorphism in Trichogramma. Results also indicate important inter and intra-specific variations among the parasitoid lines.
Molecular biology; microhymenopteran; identification; biological control
