Behaviour study of seven varieties and three improved lines of pepper grown in unheated greenhouse : parthenocarpy ability

In Tunisia, the failure of pepper to set fruit during winter constitutes an important limiting factor affecting yield. Pepper crop reduction is often noted in unheated greenhouse during winter season where low temperatures are prevailing. Growth, fructification and parthenocarpy ability were evaluated using seven local varieties and three improved lines from INRAT. Three pollination treatments were applied to evaluate the ability of a genotype to develop parthenocarpic fruits: T1 (natural pollination), T2 (emasculation with pollination) and T3 (emasculation without pollination). Weight and size are similar to those of normal fruits (with seeds) based on: Percent weight and length reduction and the ratio of fruit weight on the number of seeds per fruit. The result of this investigation indicated that the magnitude of the expression of these traits are genotype and temperatures dependent. The varieties Marconi, Meski and the line Hj (L3) were less affected by low temperatures. Semmane, Meski, Marconi and the lines Hi (L2) and Hj (L3) developed parthenocarpic fruits with weight and length comparable to normal fruits, while Baklouti, D'hirat, Baker and Beldi showed a significant decrease for these traits. The line L3 has the most important ratio of weight to number of seeds per fruit and was characterized by a greater ability to set parthenocarpic fruits.