ISHS Acta Horticulturae 632: XXVI International Horticultural Congress: Citrus and Other Subtropical and Tropical Fruit Crops: Issues, Advances and Opportunities
IN VITRO SHOOT BUD INDUCTION AND PLANTLET REGENERATION IN GUAVA AS INFLUENCED BY GENOTYPE |
| Authors: | N. Joshee, M. Mutua, A.K. Yadav, F. Zee |
| Keywords: | Micropropagation, genotype, phenolics, multiple shoots |
| Abstract:
Despite being grown in more than 50 nations, guava is confined to only a few states in the USA. Moreover, a narrow germplasm base, limited genetic studies, small acreage, and lack of cold tolerant cultivars have impeded guava cultivation in America. Cold susceptibility of guava in Georgia requires costly frost protection. An in vitro plant regeneration system, amenable to gene delivery techniques could circumvent these problems. Guava is a recalcitrant species with heavy phenolic exudation that kills explants from sources outside the laboratory. Therefore, the primary objective of this investigation was to develop efficient regeneration protocols for guava. Germinating embryos of Beaumont, Ka Hua Kula, and Lucknow-49 (L-49) cultivars were utilized as explants. Seeds of these cultivars were germinated in the dark in MS basal medium supplemented with 2 mg/L BAP. Both plant growth regulator and guava genotypes influenced shoot bud induction and elongation. Shoot proliferation was the highest (10+) in Beaumont embryo and nodal explants when subjected to MS+ 4 mg/L, IAA. No phenolic exudation was observed in embryo explants whereas the phenolic problem in case of explants from mature trees was solved by incubating cultures in the dark at 18-20C for two to three weeks. It is concluded that the use of mature embryo explants minimizes phenolic exudation problem in the medium and, thus, improves shoot proliferation. | |
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