Parthenocarpic Fruit Growth Reduces Yield Fluctuation and Blossom-end Rot in Sweet Pepper

Abstract

The aim of this work was to investigate whether parthenocarpic fruit growth could avoid flushing, i.e. an irregular yield pattern, in sweet pepper. Plants were grown in a greenhouse compartment from April until August. Half of the plants were grown without a fruit set treatment (control), whereas parthenocarpic fruits were allowed to develop on the other plants by preventing self-pollination and applying auxin to the stigma. For node positions 3 to 17, fruit set per node varied between 21 and 55% for control plants [coefficient of variation (CV)=11%], whereas auxin-treated plants showed much less variation in fruit set(41–57%; CV=5%) and average fruit set was higher. In agreement with fruit set, fruit yield was also much more regular in the auxin-treated plants. Fruit fresh yield varied between 0.2 and 1.0kgm−2for control plants (CV=20%), and between 0.4 and 0.8kgm−2for auxin-treated plants (CV=9%). Results showed that developing seeds in sweet pepper fruits are the main cause of the abortion of new flowers, and irregular fruit set and yield. Parthenocarpic fruit growth resulted in flatter, 30% smaller fruits, because of a reduction in fruit growth rate; the duration of fruit growth was 1 week longer than for fruits from control plants. Parthenocarpic fruits were hardly affected by blossom-end rot (BER) with only 1% of fruits being affected compared to 31% in the control. Total dry mass production was the same for treated and control plants; however, in auxin-treated plants, 50% of the total dry mass was allocated to the fruits, compared to 58% in control plants.