INFLUENCE OF POTASSIUM ON THE GROWTH AND DEVELOPMENT OF FIBER IN EGYPTIAN COTTON

The present investigation was carried out to study the effect of potassium foliar application on cotton fiber length, rate of elongation, cellulose deposition, fiber quality properties and some yield traits. Giza 94 and Giza 95 LS Egyptian cotton varieties were used in pots experiment at the wire green house during 2017 and 2018 seasons. Potassium foliar treatments included four doses, namely control and (10,15 and 20 g/l), where each dose was divided into three equal parts; the first part was applied 80 days after planting (the beginning of flowering), the second was added after two weeks from the first part application (in the middle of fiber elongation stage), and the third part was added after two weeks from the second (in the middle of secondary wall thickening). The results indicated that the foliar application of k proved to have a great effect in improving and raising the productivity and fiber quality. K foliar application in the beginning and during flowering caused clear overlapping between fiber elongation and cellulose deposition (maturity) phases. Furthermore, boll weight, seed index, lint % and most of fiber properties were improved by K foliar treatments. 15g/l of K foliar application showed the longest and more mature fibers and the highest levels of the other fiber properties besides improving boll weight, lint and seed index. Key word: Cottonquality – Fiber development – Potassium – foliar application.