Effect of Putrescine and Humic Acid on Growth, Yield and Chemical Composition of Cotton Plants Grown under Saline Soil Conditions

This study was carried out to determine the effects of putrescine(Put) and humic acid (HA) foliar applications on growth, yield and chemical composition of Egyptian cotton (Gossypium barbadense L. cv. Giza 90)plants grown under saline soil condition. A soil mixture of, clay: sand (1:1), was used as a plant growing media. Three different doses of putrescine (0, 1 and 2 ppm) and humic acid (0, 1 and 2%) were sprayed eight times started at 45 days after planting. Before sowing cotton, different concentrations (0, 3000, 6000 and 9000ppm) of salt mixture (2 NaCl: 2 CaCl : 1 MgSO ) were added into soil for each pot. Application of Put and 2 4 HA positively affected cotton plants grown under salt stress. The results indicated that there is an increase in morphological characters e.g. plant height, number of leaves per plant, leaf area per plant, fruiting branches per plant, shoot fresh and dry weight. Also, Put and HA increased chemical constitutes related to salt tolerance either inorganic, N, P and K, while Na, Cl, Ca and Mg were decreased, or organic constitutes e.g. proline, total free amino acids, total sugars, total soluble phenols, chlorophyll a, b, total chlorophyll and total carotenoids. As a result of promoting growth induced by previous foliar applications, yield components e.g.; number of total, open and closed bolls, seed cotton yield/plant, lint percentage and seed index were increased. Application of 2 ppm Put and 1% HA recorded the highest values of growth and yield characters.