Determinación de la variabilidad genética de la región ITS2 en poblaciones de Eotetranychus lewisi (MCGREGOR) en el cultivo de Rubus glaucus Bent (mora)

Abstract

Eotetranychus lewisi (Acari: Tetranychidae) is a phytophagous mite able to feed on a wide range of host plant species. Since this mite was recently reported in Ecuador, information on bioecological aspects of the pest is scarce. In this study, the morphological variability evaluated by Principal Component Analysis (PCA) and the genetic variation by genetic distance analysis using the ITS2 region were determined in populations of E. lewisi collected in blackberry plants from different localities from Tungurahua. In this study, blackberry leaves infested with E. lewisi populations were collected from different localities of Tungurahua, Cevallos (C), Quero (Q), Montalvo (M) and Pasa (P), all of these located at different altitude levels. In relation to the genetic study, it was observed that the percentages of the nitrogenous bases in the ITS2 fragment from the different localities show very little variable results. For Adenine, the values coincide with 29.72% for the populations of Cevallos, and 29.91% for Montalvo and Pasa, while the percentage of Cytosine is similar for the four localities (17.06%), likewise there were little variation for Guanine (18.17% for Cevallos; 18.35% for Quero; 18.72% for Montalvo and 18.90% in Pasa. Finally, the percentage of Thymine showed greater variation in Cevallos with 35.05 % with respect to the other populations of Quero (34.86%), Montalvo (34.31%) and Pasa (34.13%). In relation to the nitrogenous bases in the ITS2 fragment there is a greater presence of Thymine followed by Adenine, Guanine and finally Cytosine. On the other hand, the ACP showed that 93.14 and 94.67% of the morphometric variation of E. lewisi in blackberry plants from different locations was explained in 10 components. Of these, the variables that showed greater weight in the first two components were the length of the setae c1, c2, c3, d2, e2, f2 and h3, Sc1, d1, e1, f1 and f2 and in c Regarding the distances between setae, most of the variables were located in the first component (v2- v2, sc1-sc1, c3-c3, d1-d1, d2-d2, e2-e2, f1-f1, h2-h2 and h3-h3).