Effects of some fungicides on pollen morphology and anatomy of tomato (Lycopersicon esculentum Mill.)

In this investigation, the effects of fungicides Switch 62.5 WG (%37.5 Cyprodinil + % 25 Fludioxonil) and Mythos SC 300 (300 g/ L Pyrimethanil); widely used on greenhouse grown tomatoes against grey mould (Botiytis cinerea) were studied on the morphology and anatomy of tomato (Lycopersicon escidentum Mill.) pollens. Application of excessive dosages of fungicides affected fruit production and quality, as such possible effects due to overdose applications were put forth. Fungicides were applied to tomatoes grown in pots in the greenhouse at recommended dosage (60 g/100 L water for Switch; 125 mL/100 L water for Mythos) and double the recommended dosage (120 g/100 L water for Switch; 250 mL/100 L water for Mythos). The pollen width-length, exine-intine layer thickness, pore width-length, crevice width-length were measured using an ocular micrometre. The data obtained revealed that there was a reduction in the values of the groups getting fungicide application as compared to the control. Increased dosage resulted in a decrease in the values of fertile pollen percentages in all fungicide applied groups and the toxic effect became more evident at higher doses. Generally there was an overall increase in the percentage of oblate spheroidal type pollens at higher dosages as compared to the control, but the percentage of prolate spheroidal types decreased. Furthermore, some pollen morphological structures that are not observed in the control group were encountered in the pollens in polar view at 60 g/100 L Switch and 125 mL/100 L Mythos.