Ecophysical Traits and Production of a Semi-domesticated Hot Pepper Genotype (Capsicum frutescens L.) under Different Plastic Mulches

Abstract

Diurnal and seasonal water relations and ecophysiological variables (soil humidity, transpiration, evapotranspiration, stomatal resistance, morphological changes, production), matched with some microclimatological variables, were studied in a hot pepper (Capsicum frutescens) experimental plot. Two treatments of plants with plastic mulches were assigned, black and blank-opaque, to compare them with plants without a mulch, established at the Experimental Station of CIBNOR in La Paz Baja California Sur, Mexico. Plants with blank-opaque plastic mulch showed the highest values of flower number, fruit production, leaf area, and canopy-projected area. Also, the biggest evapotranspiration rates were recorded from January to April for plants under the blank-opaque plastic mulch. Soil water content appeared to be a primary determinant factor for production. Soils under the blank-opaque plastic mulch had the biggest water content along the experiment. Plants without any plastic mulch had the lowest availability of soil water, rendered the lowest fruit production, and registered the highest evapotranspiration rates. May and June were the months with the highest air temperature during the experiment. Plants with black plastic mulch had intermediate records among the other two groups. When plants were allowed to face a drought stress, they responded through an osmotic adjustment for maintaining a low water potential, and thus supporting a partial turgor pressure. This adjustment was evident to be coupled with a stomatal regulation in order to minimize the loss of water through the transpiration process. Some drought tolerance strategies as a leaf size reduction were more evident in plants without a mulch.