Articles
Could meta-Topoline improve the multiplication and rooting of micropropagated walnut plants? a case study with Lara (Juglans regia L.)
Article number
1359_10
Pages
87 – 94
Language
English
Abstract
Persian or English walnut (Juglans regia L.) is a very important species as a healthy food and a source of valuable timber.
But Juglans is considered among the most recalcitrant genera for in vitro culture.
The commercial micropropagation and significant breeding efforts for improving marketable traits of walnut is limited because of variable and highly genotype dependent results.
The aim of this study was to improve the micropropagation protocol using meta-topolin (mT) instead 6-benzylaminopurine (BAP) at multiplication stage.
An in vitro culture was maintained on a modified DKW culture medium supplemented with mT (1.25, 2.5, 5.0, 7.5 μM) or BAP (1.25, 2.5 μM). The results obtained in this study showed that cytokinin meta-Topolin could be successfully applied in micropropagation of Juglans regia L. Lara. A good multiplication factor (Km 3) could be achieved by culturing of plantlets on Driver and Kuniyuki nutrient medium, enriched with 5 μM mT. By applying a two-step rooting protocol, in which these shoots are grown for one week in the dark on agar root inducing medium with auxin IBA (12.5-17.5 μM) and then on a liquid hormone-free nutrient medium with perlite for root elongation, a high rooting rate could be achieved (between 50 and 60%). This approach would also be useful for the micropropagation of other recalcitrant walnut genotypes and other woody species.
But Juglans is considered among the most recalcitrant genera for in vitro culture.
The commercial micropropagation and significant breeding efforts for improving marketable traits of walnut is limited because of variable and highly genotype dependent results.
The aim of this study was to improve the micropropagation protocol using meta-topolin (mT) instead 6-benzylaminopurine (BAP) at multiplication stage.
An in vitro culture was maintained on a modified DKW culture medium supplemented with mT (1.25, 2.5, 5.0, 7.5 μM) or BAP (1.25, 2.5 μM). The results obtained in this study showed that cytokinin meta-Topolin could be successfully applied in micropropagation of Juglans regia L. Lara. A good multiplication factor (Km 3) could be achieved by culturing of plantlets on Driver and Kuniyuki nutrient medium, enriched with 5 μM mT. By applying a two-step rooting protocol, in which these shoots are grown for one week in the dark on agar root inducing medium with auxin IBA (12.5-17.5 μM) and then on a liquid hormone-free nutrient medium with perlite for root elongation, a high rooting rate could be achieved (between 50 and 60%). This approach would also be useful for the micropropagation of other recalcitrant walnut genotypes and other woody species.
Authors
L. Nacheva, S.I. Gandev
Keywords
micropropagation, shoot culture, in vitro, rooting, woody plants
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