Influência do Ethrel na expressão do sexo, produtividade e qualidade de frutos de cultivares de melão

Abstract

Use of Ethrel in cucurbits like melon has showed a promising technology. However, further developments are needed in issues like pH effect, concentration of the product influencing sex expression, yield of the different melon types, and fruit quality. Such issues gave the motive to carry out four trials at Norfuit Farm, near Mossoró-RN, Brazil. In the first trial trhree solutions of Ethrel (pH 7.0, 9.0 and 11.0) and the control were apllied when plants had two definitive leaves. Use hybrid melon Orange Flesh. Sex expression, yield, and quality were evaluated in a randomized block design. For quality determinations, fruits were taken to the Post Harvest Laboratory at UFERSA and stored for three periods (0, 21 and 30 days) according to a time split plot design. Use of Ethrel caused the following effects: decrease in buds and staminate flowers; increase in the number of buds and pistillate flowers, with a indirect increase in fruits developed; and anticipation of pistillate flowers appearing. The three solutions caused increase in the number of fruits per plot, with solutions pH 9.0 e 11.0 providing higher total fruit number. When compared to the control, Ethrel did not influence the following characteristics, untill 30 days storage: fruit mean wheight; yield of fruits; fruit weight loss; external and internal aspect; pulp firmness; and total soluble solids. In the second trial, four Ethrel concentrations (50, 100, 150 and 200 ppm.L-1) and the control were tested. Characterisitic evaluated were the same as in the fisrt trial, except for the quality characteristics which were evaluated only at harvest time. Application of Ethrel did not influence characteristics like sex expression; anticipation of flowering; mean weight of fruits; and quality characteristics. Use of Ethrel provided higher fruit number per plot for the total harvest, with better results for concentrations of 100, 150 and 200ppm.L-1 in the first harvest. Higher yield in the first harvest was obtained with concentrations of 100,150 e 200 ppm L-1. In the third and fourth trials two Ethrel solutions (pH 9.0 and 11.0) and the control were evaluated in melon hybrids AF-646 and Hy Mark. Characteristics evaluated were the same as in the second trial. Application of the different Ethrel solutions influenced sex expression, by reducing staminate buds and flowers, and increasing buds and pistillate flowers, with an indirect increase in fruits developed. Recommendation of Ethrel use can be made because its application did not influence fruit yield, mean fruit weight, and quality characterisitics. All Ethrel solutions provided higher fruit number per plot at second harvest, while total harvest had higher fruit number using Ethrel at pH 9,0.