EFFECT OF PINCHING AND FERTILIZATION TREATMENTS ON VEGETATIVE GROWTH, SEPAL PRODUCTION AND CHEMICAL COMPOSITION OF ROSELLE (Hibiscus sabdariffa L.) | ||||
Journal of Plant Production | ||||
Article 5, Volume 28, Issue 12, December 2003, Page 8281-8305 PDF (1.2 MB) | ||||
Document Type: Original Article | ||||
DOI: 10.21608/jpp.2003.246336 | ||||
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Authors | ||||
H. A. Mansour,; Safia H. EI-Hanafy; S. M. N. Milad | ||||
Ornarnental Horticulture Department, Faculty of Agriculture, Cairo University | ||||
Abstract | ||||
This study was conducted in the Experimental Nursery of the Ornamental Horticulture Department, Faculty of Agriculture, Cairo University Giza, during the two successive seasons or 1999 and 2000, with the aim of investigaling the effect of manual and chemical pinching (using foliar kinetin application), as well as NPK and biofertilization treatments, on growth, sepal production and chemical composition of roselle (Hibiscus sabdariffa L. var. sabdariffa, cv. Sabahia 17. dark color). Roselle (Hibiscus sabdariffa L.) plants were either: (1) left unpinched, (2) pinched manually (twice: one month after planting, and one month later), or (3) pinched chemically using foliar spray applications of lIinetin at concentrations of 15, 30 or 45 ppm (3 applications, at 15 day intervals, starting 30 days from planting). Also, the plants were supplied with NPK fertilization [using ammonium sulphate (20.5% N) at 400 kglfed., calcium superphosphate (15.5% P20~) at 150 kg/fed., and potassium sulphate (48% K20) at 50 kg/ fed.], or with biofertilizatfon (alone or In ccrnblnation with NPK fertilization at 100% or 50% of the above rates). Plants suppliad with 100% NPK (with no blofertilization) were used as the control. In treatments indudlng biofertilization, the biofertillzer (a mixture of vermiculite and Azotobacter chroococcum, at a concentration of 109 bacterialg vermiculite) was mixed with the seeds prior to planting at a rate 500 g bioferillizer/250 9 seeds. In addition. biofertllization was applied after planling as a liquid top dressing 3 times/ season (at 30 day in\eNals). The Hquid inoculum consisted of a mix'Lure 01 molasses and Az%bacter chroococcum. Among the different manual and chemical pinching treatments, appllcation \ of kinetin at 15 ppm gave the highest values (or most of the studied growth and yield charaeterlsucs (plant height. number of branches. leaves and fruits/plant, as well as fresh and dry weights of leaves and sepals/plant). Kinetin at 15 ppm also increased \ the leaf contents of total chlorophyll, carotenoids, total carbohydrates, N. P and K, as well as the total acidity and anthocyanin contents of the sepals. Supplying the plants with 100% NPK + biofertllization gave the highest values for number of branches. leaves and fruits/plant. fresh and dry weights of leaves/plant, the contents of total \ carbohydrates, P and K In Ihe leaves, as well as the anthocyanin content in the sepals, compared to all other fertilization treatments. However, using 50% HPK + biofertili:ation gave the highest fresh and dry weights of sepals/ptant, and insignificantly increased the number of branchesrplaru, compared to those formed on \ plants fertilized with 100% NPK alone (control plants), l.e. biofertitization reduced the need for chemical NPK fertilization (for branching and sepals production) by at least 50%. Fertilization with 50% NPK .•. biofertilization also gave the highest contents of \ total chlorophyll and N In the leaves, as well as the highest total acidity and total soluble solids contents in the sepals. Moreover. combining kinetin al15 ppm with application of 50% NPK .•. biofertilizalion gave the best results, in terms of number of branches and fruits/ptant. fresh and dry weights of sepals/plant, | ||||
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