Relative humidity around the fruit influences the mineral composition and incidence of blossom-end rot in weet pepper fruit

Abstract

SummarySweet pepper plants of cultivar Domino were grown using the hydroponic recirculating nutrient film technique (NFT) at an EC of 2 dS m -1 during the autumn season. Two experiments examined the effects of relative humidity (r.h.) around the fruit on the accumulation of Ca, Mg and K on fruit of known age from date of anthesis. The humidity treatments used in the first experiment were on average 30%, 50% and 80% and an ambient humidity achieved by covering sweet pepper fruit with polyethylene bags containing 50 g each CaCl2, NaCl or polyethylene bags without salts. The second experiment used an airflow system to generate average r.h. levels of 20%, 40% and 80%. In both experiments high r.h. levels reduced the accumulation of Ca by the fruit. The r.h. treatments particularly reduced the Ca concentration in the distal end of the fruit, which resulted in a higher incidence of blossom-end rot in experiment I, and with no statistically signficant effect in experiment II. The incidence appears to be related to the Ca concentration as well as the ratio of this element to Mg and K at the distal end. On the other hand, low r.h. promoted the accumulation of Ca in fruit particularly towards fruit maturity. R.h. had little effect on accumulation of Mg and K in sweet pepper fruit and affected fruit mass only at maturity.