No abstract

A field experiment was carried out in 2021 season and repeated in 2022 season at Sakha Agricultural Research Station, Kafr El-Sheikh Governorate, Egypt to assess the effect of using hill spacing and topping time in addition to their interactions on productivity and quality of cotton cultivar Super Giza 97 (Gossypium barbadense L.). The experimental design was a split-plot with 3 replicates. The main plots were devoted to hill spacing (25, 30 and 35 cm), whereas plant topping time (no topping, manual topping at the formation of 12, 14 and 16 fruiting branches/plant) was allocated in the sub-plots. Data indicated that the widder hill spacing (35 cm) significantly increased total bolls number set/plant and bolls setting%, yield of seed cotton per feddan and its contributory characters as well as fiber length. However, plant height, bolls shedding% and the number of actual plants per feddan at harvest in both seasons were decreased. No topping treatment gave a significant excess in the final plant height and sympodia number/plant in the two seasons of study. Topping when 16 fruiting branches were formed on the plant gave a significant decrease in bolls shedding% and significant increase in numbers of total fruiting points and total bolls set/plant and bolls setting%, yield of seed cotton per feddan and its contributory characters in the two seasons in addition to length in the first season.Sowing cotton at 35 cm between plants interacted with topping cotton plants just after the formation of 16 fruiting branches gave the best results. It could be advised to apply this interaction treatment under Sakha region, to increase cotton productivity of cotton cultivar Super Giza 97.

A field experiment was carried out through the two growing seasons of 2021 and 2022 to find out the impact of the addition of humic acid and sulphur at soil and foliar spraying with chelated Zn and/or chelated B in addition to their interactions on cotton cultivar Super Giza 94 (Gossypium barbadense L.) grown under calcareous soil located at El-Nubaria Station Farm, Agricultural Research Center, Egypt. The layout of the experiment was a split plot design with three replications. The obtained results revealed that humic acid as well as a mixture of chelated Zn and chelated B increased numbers of monopodia and sympodia/plant, plant height at harvest, total fruiting points number/plant and total bolls number set/plant, bolls setting%, seed cotton yield /feddan, yield components and fiber length in both seasons. Bolls shedding% was decreased in this respect. Humic acid alone significantly improved fiber fineness and decreased the 1 st sympodium node. Similarly, a mixture of chelated Zn and chelated B significantly increased fiber strength. Using humic acid interacting with a mixture of chelated Zn and chelated B significantly increased numbers of monopodia and total bolls set/plant, yield of seed cotton/feddan, yield components, fiber fineness and strength in the two seasons of study. In addition, it increased bolls setting% and number of sympodia/plant only in the 1 st season. However, bolls shedding% was decreased. Addition of humic acid to the soil interacting with chelated Zn foliar spraying recorded taller plants. It could be concluded that using humic acid interacting with a mixture of chelated Zn and chelated B alleviated and counteracted harmful effects of calcareous soil in El-Nubaria region on cotton productivity of cultivar Super Giza 94.