Viability and Vigour Response of Hybrid Melon (Cucumis melo L.) to Sargassum Extract Priming under Salinity Stress

Abstract

Salinity intrusion often limits seed germination and early seedling growth in coastal agricultural areas. Organic biostimulants, such as seaweed extracts, are a possible way to reduce this problem. This study aims to evaluate the effect of Sargassum sp. extract on the germination and early seedling growth of hybrid melon (Cucumis melo L.) cv. Melani F1 under saline conditions simulated using diluted seawater (brackish water). A completely randomized design with five treatments was used: an unprimed control, and four priming treatments in which seeds were soaked for 12 h in aqueous Sargassum extract at 0, 1, 2, or 3%, then germinated on paper moistened with diluted seawater. Priming significantly affected fresh weight, hypocotyl length, radicle length, and vigour index, while germination percentage was unaffected. Contrast analysis showed that this effect came mainly from the difference between the control and the primed treatments as a group, with no dose-dependent effect among Sargassum concentrations. Notably, the control had the highest fresh weight and length measurements but the lowest vigour index. Because vigour index here reflects the proportion of seeds forming normal seedlings by the first count rather than seedling size, and because the control differed from the primed treatments in both priming exposure and germination salinity at once, this divergence likely reflects their combined effect rather than Sargassum concentration itself. These findings offer preliminary laboratory evidence for developing seed priming protocols with Sargassum extract for coastal melon cultivation