totally dependent upon control of this disease. The ultimate choice is production of disease-free banana plants through in vitro techniques to replace infected fields. In this study, various concentrations of BAP and kinetin were exploited to achieve
Aish Muhammad, Hamid Rashid, Iqbal Hussain and S.M. Saqlan Naqvi
Jane Kahia, Siaka Kone, Lucien Diby, Georges Ngoran, Colombe Dadjo and Christophe Kouame
-Baez et al. (2000) reported the use of two auxins (2, 4-D or 2, 4, 5-T) and two cytokinins (kinetin or 2 isopentyladenine) on modified Murashige and Skoog (1962) salts. Recently, some workers have reported success in inducing cacao embryogenic cultures
Jane Kahia, Margaret Kirika, Hudson Lubabali and Sinclair Mantell
cultured on half-strength MS media supplemented with 30 mg/L cysteine, 100 mg/L inositol, and 3% (w/v) sucrose. To this media, adenine type of cytokinins (kinetin or 2iP) tested at three concentrations and a control (0, 0.5, 5, or 25 µ m ) and phenylurea
Jose Pablo Morales-Payan
Flowering plants of `Kapoho' papaya were sprayed with aqueous solutions of kinetin and folcysteine. Plants were treated four times at 3-week intervals with 0-, 50-, 90-, or 130-ppm solutions of either biostimulant or their combinations. Fruit number, size, and weight were recorded weekly during 15 weeks after treatment. Folcysteine treatment at 90 to 130 ppm significantly increased `Kapoho' papaya yield. Kinetin treatment alone did not significantly affect fruit yield at any rate tested. Moreover, none of the kinetin plus folcysteine combinations significantly differed from the control in terms of fruit yield. These findings suggest that folcysteine rates of 90 to 130 ppm can increase fruit yield in this cultivar, and that kinetin had an antagonistic effect on the activity of folcysteine on the yield of `Kapoho' papaya.
Todd J. Rounsaville, Darren H. Touchell, Thomas G. Ranney and Frank A. Blazich
) found BAP alone was sufficient for shoot proliferation of M. trifoliata ; however, for several other Mahonia sp., low concentrations of kinetin (Kin) and the auxin, indole-3-acetic acid (IAA), were necessary to stimulate shoot initiation and
A.P. Papadopoulos, U. Saha, X. Hao and S. Khosla
Encouraging results from previous trials on field vegetables led to the expectation that a kinetin foliar spray from the commercial product KIN-Gro (5000 ppm kinetin) on greenhouse vegetables would positively affect their growth and productivity. Thus, in this study, we evaluated the usefulness of this product on rockwool-grown `Bodega' cucumber (Cucumis sativus), `Rapsodie' tomato (Lycopersicum esculentum), and `4-Ever' and `444' pepper (Capsicum annuum) at the Greenhouse and Processing Crops Research Centre of Agriculture and Agri-Food Canada, Harrow, Ont. Two replicated experiments were conducted to study the effect of kinetin spray on growth and production of all three crops: the first in Spring-Summer 2004 and the second in Fall-Winter 2004. Foliar sprays of kinetin at 2.5, 5, and 10 ppm concentrations were tested against a water spray (control) on each crop. A 2.5-ppm kinetin spray had beneficial effects on the growth of cucumber transplants (taller plants and greater leaf area and fresh weight of leaves and stems). Furthermore, this treatment resulted in higher marketable yield in the Spring-Summer crop and in larger fruit size in the Fall-Winter crop. Regression analysis showed that cucumber marketable yield had an overall quadratic response to kinetin spray concentration in Spring-Summer season maximizing at 5.1 ppm kinetin. Kinetin spray also had beneficial effects on the growth of tomato seedlings, but not on yield. On the other hand, significant beneficial effects were observed on the growth of pepper seedlings and on marketable yield and fruit quality. Regression analysis showed that the response of pepper marketable yield to kinetin spray concentration was positive and linear. It must be noted that, given the rather short-term nature of our experiments, the observed beneficial effects of the kinetin sprays on yield can only be interpreted as beneficial effects on early yield rather than on the total yield. We concluded that under our growing conditions, cucumber production would benefit from a dilute (2.5 ppm) kinetin spray, and pepper production from a high concentration spray (10 ppm); tomato transplant growth will also benefit from a kinetin spray at 2.5 ppm. The results of this study could be of considerable significance to the greenhouse vegetable industry.
Jose Pablo Morales-Payan
Field experiments were conducted in the Dominican Republic to determine the effects of different rates of the biostimulants folcysteine and kinetin on fruit yield of `Sunrise' papaya. Aqueous solutions of either 50, 70, 90, 110, or 130 ppm. Four applications were made at 3-week intervals. Fruit number, size, and weight were recorded weekly during 15 weeks after application. Yields for the control and kinetin-treated plants were not significantly different. Significant yield increase was found in plants treated with 70 and 90 ppm of folcysteine solution. Fruit yield in plants treated with 30, 50, 110, or 130 ppm of folcysteine did not differ significantly from that of the control. These results indicate that folcysteine treatment at 70 and 90 ppm at flowering can significantly increase fruit yield in `Sunrise' papaya.
Tim D. Davis, Daksha Sankhla, N. Sankhla, A. Upadhyaya, J.M. Parsons and S.W. George
Seeds of Aquilegia chrysantha Gray were germinated under a variety of temperature regimes. Germination was nearly 90% under a day/night cycle of 25/20C, but was reduced to ≤ 40% under constant 25C or a 25/10C day/night cycle. With days between 25 and 29C (night = 20C), germination percentage dropped gradually to ≈ 60% with increasing temperature. With days >29C, germination declined dramatically such that no germination occurred at 31C. Neither kinetin (4.6 to 46 μm) nor ethephon (6.9 to 207 μm) was able to reverse the inhibitory effects of 33C days. Our results indicate that germination of A. chrysantha seed is sensitive to temperature and that germination ≈ 75% can be obtained under a 25 to 27C day/20C night regime. Chemical names used: 2-chloroethylphosphonic acid (ethephon); 6-furfurylaminopurine (kinetin).
J.P. Morales-Payan and B.M. Santos
Container experiments were conducted in the Dominican Republic to determine the effects of nitrogen, gibberellic acid, triadimefon, and kinetin on the seedling growth of sapodilla (Achras sapota) and tamarind (Tamarindus indica). Plants were started from seeds on cylindrical plastic containers (20 × 20 cm) filled with an artificial a 1:1 mixture of sand and loamy soil, allowing the growth of only one plant per container. Nitrogen rates (0.5, 0.75, and 1.0 g N per plant, applied as ammonium sulfate) were factorially combined with the rates (0, 25, 50, 75, and 100 ppm each) of the regulators. When the plants had three true leaves, nitrogen was applied to the growing mixture, whereas the growth regulators were applied foliarly. Plants were allowed to grow during 60 days after treatment. There were no nitrogen and regulator interactions. Kinetin treatments did not significantly influence shoot dry weight and height in either species. Both species responded with linearly increased height, internode length, and dry weight to increasing GA3 concentrations. Increasing rates of the growth retardant triadimefon significantly reduced the internode length and total height of sapodilla and tamarind seedlings. These results suggest that gibberellin and triadimefon could be effectively used as a means to stimulate or retard, respectively, the growth of sapodilla and tamarind.
Servet Kefi, Paul E. Read, Alexander Pavlista and Stephen D. Kachman
To determine the influence of gibberellic acid (GA3) and 6-furfuryl aminopurine (kinetin) concentrations alone and in combinations on in vitro tuberization of potato, nine treatments consisting of combinations of gibberellic acid and kinetin at three levels of concentration (0, 2, and 5 mg·liter–1) were included in Murashige and Skoog medium supplemented with 6% sucrose. Four single nodes of in vitro plantlets from Solanum tuberosum L. cultivar Atlantic were placed into each magenta box. All magenta boxes were arranged in a randomized complete box design with five replications and cultured under a short photoperiod condition (8 h light/16 h dark). Gibberellic acid strongly inhibited tuberization when used alone or with kinetin, whereas kinetin induced tuberization at both 2 and 5 mg·liter–1. Although tuberization was initiated in the absence of kinetin because of the high concentration of sucrose and short photoperiod, the presence of kinetin accelerated the in vitro tuberization process of potato.