Effect of plant population densities and application of growth retardants on cottonseed yield and quality

Abstract

In field trials at Giza in 1986-1987, cotton cv. Giza 75 was sown at 166,000, 222,000 and 333,000 plants/ha and given foliar applications of 0, 250, 500 and 750 ppm Cycocel {chlormequat) or Alar (daminozide}. As plant density increased, there was a decrease in cottonseed yield]ha, seed index, seed protein content, oil and protein yields/ha, oil refractive index, iodine value, unsaponifiable matter and unsaturated fatty acids {myristoleic, oleic and linoleic). In contrast, as plant density increased, there was an increase in oil acid value, saponification value and saturated fatty acids (caprylic, capric, lauric, tridecylic, myristic, palmitic and stearic). Application of Cycocel or Alar increased cottonseed yield/ha, seed index, seed protein content and oil and protein yield/ha, oil refractive index, iodine value, unsaponifiable matter and unsaturated fatty acids. However, there was a decrease in oil acid value and saponification value. There were no differences among application rates of either chemical on cottonseed yield/ha. The highest oil and protein yield/ha was observed with Cycocel applied at 750 ppm, followed by Aiar at 250 ppm. Applying Cycocel at 250 ppm gave the highest oil refractive index and unsaponifiable matter, and the lowest acid value. Application of Aiar at 250 ppm gave the highest oil iodine value and the lowest saponification value, and also at 250 or 500 ppm gave the highest oil unsaturated fatty acid composition. Interaction was positive between plant density, Cycocel and Aiar and affected cottonseed yield/ha. The 166,000 plants/ha and application of Cycocel at 750 and Aiar at 250 ppm are recommended for the improvement of cottonseed yield and quality.KEY WORDS: Cottonseed yield, growth retardants, oil fatty add composition, plant density, seed index, seed oil content, seed oil prope~ ties, seed protein content.

Cottonseed yield and its quality as affected by mineral fertilizers and plant growth retardants

“…Application of all PGR significantly increased seed index as compared to untreated control; Pix gave the highest seed index, followed by Cycocel [35]. These agree with previous works of Sawan et al [52], by applying Cycocel and Alar; Carvalho et al [54] by applying Pix and Cycocel; Abdel-Al [50], by applying Pix. Zinc significantly increased seed index compared with the untreated control [35].…”

“…Similar results were obtained by Gebaly and El-Gabiery [14]. Sawan et al [52] observed that application of Cycocel and Alar (250 -750 ppm, 105 days after planting) increased oil yield ha −1 . Application of Zn resulted in an insignificant increase in seed oil content over that of the control.…”

“…Pípolo et al [51] found that spraying cotton plants at an age of 70 d after emergence with Cycocel at rates ranging from 25 to 100 g·ha −1 resulted in yield increases. Sawan et al [52] stated that application of Cycocel and Alar, at rates ranging from 250 to 700 ppm (105 days after planting) increased cotton seed yield ha −1 . Similar results were obtained by Sarwar Cheema et al [33].…”

“…Kler et al [64] found that when cotton was sprayed using Cycocel rates of 40, 60, or 80 ppm at the age 63 days after planting, seed protein content increased. Sawan et al [52] stated that application of Cycocel or Alar increased seed protein content and protein yield ha ) over the untreated control [35]. In these circumstances Ibrahim et al [13] found that application of Zn to cotton plants increased seed protein content and protein yield ha…”

“…Sawan et al [56] reported that applying Pix to cotton plants caused a general decrease in oil saturated fatty acids, associated with an increase in oil unsaturated fatty acids. Sawan et al [52] stated that application of Cycocel and Alar to cotton increased oil unsaturated fatty acids. Osman and Abu-Lila [65] when applied Cycocel at rates of 25 -100 ppm to flax plants found that generally the higher concentrations (50 and 100 ppm) caused in the total oil saturated fatty acids, while they increased the unsaturated fatty acids.…”