RESPONSE OF GIZA 90 COTTON CULTIVAR TO FOLIAR APPLICATION OF SOME DROUGHT TOLERANCE INDUCERS UNDER WATER STRESS AND HIGH TEMPERATURE CONDATIONS IN UPPER EGYPT

Abstract

Two field experiments were carried out in El-Mattana Agric. Res. St., Agric. Res. Cent., Luxor Governorate, Egypt during 2010 and 2011 seasons to study the response of Giza 90 cotton cultivar to the application of some drought tolerance inducers to increase the tolerance of cotton plants to drought under high temperature condations in Upper Egypt. The experimental design was a split plot with four replications. Main plots included two irrigation intervals (15 and 21 days) and sub plot included the foliar application of four drought tolerance i.e CaBoron, Pix, Humex and Methanol) and a control (untreated plants), The obtained results could be summarized as follows: Irrigation every 15 day significantly increased plant height, no. of fruiting branches/plant, no. of days to first flower and first open boll. Prolonging irrigation interval to 21 day significantly decreased no. of open bolls /plant, boll weight, seed index, seed cotton yield/fed., fiber length, uniformity index and fiber strength, but lint % was significantly increased. All drought tolerance inducers significantly increased plant height, number of fruiting branches and open bolls/plant, boll weight, seed index, seed cotton yield /fed., earliness %, fiber length, uniformity index and fiber strength as compared with the untreated plants. In general, plants which were sprayed with methanol gave the highest averages of growth, yield and its components and earliness %, followed by plants which were sprayed with CaBoron, while the Pix sprayed plants came the last in this respect in both seasons. Well watered plants every 15 day showed greater response to Methanol than to any other drought tolerance inducer, while the plants irrigated every 21 day and treated with pix gave the lowest average in this respect. The interaction between studied factors had a significant effect on fiber strength in both seasons and upper half mean length in the first season only. Finally it could be concluded from this study that the CaBoron, Humex, Pix and Methanol applications to plants under normal and water stress conditions could induce drought tolerance of cotton plants and in turn improved plant growth, fruiting and yield particularly under water stress and high temperature conditions.