Rukiye Kiliç, Çetin Karademir
ABSTRACT. This study was carried out to determine the effect of SA (salicylic acid) application on the yield, yield components, and fibre quality characteristics of cotton at different growth stages (squaring, flowering and squaring + flowering). The experiment was carried out at Siirt University, Faculty of Agriculture, Department of Field Crop’s experimental area during the 2022 cotton growing season. The experimental design was a split-plot design with four replications. The main plot and sub-plots consisted of SA applications [Control (0.0 mM), squaring (1.0 mM), flowering (1.0 mM), squaring (0.5 mM) + flowering (0.5 mM)] and varieties (MAY 455, Stoneville 468, Fiona), respectively. SA application and variety interactions were significant in terms of the first boll opening days and the number of nodes. There were significant differences between varieties, except for the number of monopodial branches, number of bolls, chlorophyll content value, normalised difference vegetation index value, and micronaire and fibre strength. The MAY 455 cotton variety had the highest values in terms of seed cotton yield (2993.1 kg ha-1) plant height (62.14 cm), boll weight (6.51 g), seed cotton weight per boll (4.90 g), number of seeds per boll (29.46), number of nodes to first fruiting branch (8.65), fibre yield (1361.0 kg ha−1) and 100-seed weight (8.82 g), while the Fiona variety came to the fore in terms of number of days to first boll opening (118.0 d), number of sympodial branches (7.56), number of nodes per plant (17.79), ginning percentage (46.45%), fibre length (828.52 mm) and fibre reflectance (82.18 Rd). There was a slight increase in yield (223.8 kg ha−1) compared to the control. SA application may show different effects on each cotton variety, and the positive effect may increase by applying SA at different intervals.
Keywords: cotton; fibre quality; growth; physiology; salicylic acid; yield.
