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Copyright of Nova Scientia is the property of Nova Scientia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The pepper (Capsicum annuum L.) is an important crop in Mexico due to its growing demand in recent years. Therefore, alternatives should be sought to increase their production, one of them is the use of growth regulators, of which gibberellins are important growth regulators involved in mooring and fruit development, flowering, cell elongation and expansion in plants. In order to evaluate the effect of the application of gibberellins (GA3) on the yield of jalapeño pepper produced in greenhouse, the present investigation was carried out in two successive experiments. In experiment 1, five doses of gibberellins were evaluated: 0 (control), 10, 30, 50 and 500 mg L-1 that were sprayed in one and two applications. The fertilization in this experiment was with nutritive solution (N, P, K and microelements). In experiment 2 the same doses of GA3 were evaluated, also in one and two applications, but the fertilization was carried out with calcium nitrate and potassium nitrate soluble in water. In experiment 1, no increase in yield was detected. In contrast, in experiment 2, the 10 mg L-1 dose of GA3 in combination with the fertilization with calcium nitrate and potassium nitrate increased the yield of jalapeño pepper. The results show gibberellins as key elements combined with low fertilization to increase pepper production. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Trichoderma harzianum fungus is one of the most widely used biological control agents in agriculture. A new T. harzianum THITR01 strain was isolated and their spores were mutagenized with ethyl methane sulfonate obtaining 174 mutants. M7, M14, M21 and M24 are mutant strains that showed 97.4%-100% antagonist effect against Sclerotium rolfsii, Rhizoctonia solani and Sclerotinia sclerotiorum compared to the wild strain. Under potato dextrose agar (PDA) medium with either NaCl, sorbitol or NaHCO3 there were nonsignificant growth rate differences between the mutants and the wild strain. M14 and M21 mutant strains were inoculated on 'Jalapeño' pepper plants (Capsicum annuum L. var. annuum) with unavailable P promoted a significant increase in root fresh weight (54% and 40%, respectively) and dry weight (28% in both strains), compared to plant inoculation with the wild strain. The M14 strain presented the highest P solubilization ability (13.4 μg g-1) in the substrate and promoted a change on root architecture. There was a higher relative water content (82.9%) in drought stressed plants inoculated with the M24 mutant than in plants that were inoculated with the wild type strain (76.3%), and also higher levels of proline in chili pepper plants inoculated with the M24 mutant (939.5 μg g-1 dry weight) than in plants inoculated with the wild type strain (419.8 μg g-1 dry weight). Therefore, M14, M21 and M24 mutant strains could potentially be used as biocontrol agents and plant protector from abiotic stress. [ABSTRACT FROM AUTHOR]