Brassinosteroid analogues effects on the yield and quality parameters of greenhouse-grown pepper (Capsicum annuum L.)

The effects of spraying two brassinosteroid analogues, DI-31 and DI-100, were evaluated at concentrations of 4, 8 and 12?ppm together with a seaweed extract and amino acid mixture called Tomex Amin (2.5?l/ha) to enhance their activity. These were sprayed ten times to foliage of pepper var. Orlando grown under greenhouse conditions. Treatment with DI-31 at a dose of 12?ppm (30?mg/ha) resulted in the highest production increases, which were 13.55?% relative to the control with Tomex Amin (T02). Correlation between net photosynthesis increase and yield increase due to DI-31 treatment, which produced the maximum yield increase and also the highest net photosynthesis with significant differences with respect to the control, was observed. This increased yield was caused by an increase in pepper/plant number. The physic-chemical variables related to pepper quality, such as fresh weight, h/d ratio, lobe number/fruit, firmness, colour and ripening index, were similar in the control and treated peppers. Total antioxidant activity and phenolic content was higher in pepper treated over T02. The results showed that sprayed DI-31 may play an important role in increasing the yield of field grown pepper due to an increase in fruits number per plant without any undesirable effects on their nutritive and organoleptic properties.