DEVELOPMENT OF SURFACE COLOR IN RED PEPPER FRUIT VARIETIES: INFLUENCE OF SUBSTRATES AND LOW LEVELS OF PHOSPHORUS AND POTASSIUM FERTILIZATION

Abstract

This paper describes changes in the chromatic attributes (C^{* * *}, H^*, and S^*) referring to the surface color of the red paprika pepper (Capsicum annuum L.) varieties, Americano and Fibola, grown in two substrates (sand and perlite) and under three fertilizer regimes (control and low levels of phosphorus and potassium). Three color attributes are related to the ripeness stages in the fruit and the best moment for their harvesting. Chroma (C^*) and metric saturation (S^*) increase rapidly between 60 and 70 days, particularly in Fi�bola due to the great increase in the coordinate a^*, reflecting the earlier ripening qualities of this variety compared with Americano. At the same time, the hue angle (H^*) values decrease sharply in both varieties, with Fi�bola once again leading the way and demonstrating its earlier ripening properties. In this way it can be calculated that Fi�bola ripens at 65–70 days after fruit set and Americano at 70–75 days. The type of substrate has no significant effect, although at 60 days (at the beginning of ripening) C^* and S^* show slightly lower minimum values in sand than in perlite. Low phosphorus and potassium treatments result in lower color values than the control, although the differences are not significant.

Acknowledgments