Improved in vitro rooting of Prunus dulcis Mill. cultivars

Abstract

A highly reproducible system was developed for efficient rooting of cultivars Boa Casta (BC) and Peneda and a BC seedling-derived clone (BC VII) of almond (Prunus dulcis Mill.). Twenty-four accessions derived from the clone BC VII and subjected to various in vitro culture treatments were screened. The long induction pre-treatment (LIP, 5 d), the brief induction pre-treatment (BIP, 16 h) and the hormonal shock by short dipping in hormone solution (1 min), were tested. BIP was the only that allowed rooting of cultivars. In BC VII, it induced high rooting frequencies (47 -100 %) when using a solution of 0.4 mM indole-3-butyric acid solidified with 2 g dm -3 gellam gum for 16-h. The response to the auxin type was variable depending on the cultivar and the root induction pre-treatment used. Root number was significantly different between the two cultivars and BC VII. Root length was significantly higher when using 0.005 mM IBA in LIP but this concentration induced apical necrosis. The improved acclimatization procedure for up to 4 weeks increased the survival to 45 %. The initiation and development of adventitious roots were proved to be asynchronous.Additional key words: adventitious root, indole-3-acetic acid, indole-3-butyric acid, mother plant age.

Recalcitrant effects associated with the development of basal callus-like tissue on caulogenesis and rhizogenesis in Sclerocarya birrea

“…The experiments were arranged in a completely randomized design and each experiment was repeated twice. Percentage data were arcsin transformed to validate the one-way analysis of variance (ANOVA) assumption of normality of data distribution (Tereso et al 2008), and then subjected to statistical analysis. For all the tested parameters ANOVA was used to find differences among treatments, Duncan Multiple Range Test for separating mean values and significant effects were accepted at P B 0.05.…”

“…New emerging evidence further suggests that part of the effects of IBA are caused solely by its direct action (Ludwig-Müller et al 2005), and this may partially account for the differences in rooting abilities observed in this study. Tereso et al (2008) attributed the differential rooting abilities of auxins to differences in affinity for the auxin receptors involved in the rhizogenic process.…”

“…Working on Pseudotsuga menziesii, Pullman and Timmis (1992) achieved ex vitro rooting and soil establishment success of 5-17% depending on the genotype, and this increased to 8-60% when the in vitro culture period was prolonged by 1 to 2 years. Tereso et al (2008) reported limited acclimatization success as only a few in vitro rooted Prunus dulcis Mill. plantlets survived the ex vitro environment.…”

“…When dedifferentiated cells acquire competence the formation of adventitious shoots can be induced by the application of exogenous cytokinins (Sugiyama 1999). In the micropropagation of woody plant species, adventitious rooting and high shoot multiplication remain some of the major bottlenecks due to their recalcitrance to in vitro manipulation (Feito et al 1996;Baltierra et al 2004;Tereso et al 2008). Recalcitrance occurs when plant cells, tissues or organs do not respond to in vitro manipulations.…”

Rooting response of Prunus domestica L. microshoots in the presence of phytoactive medium supplements

“…Rooting difficulties occur in micropropagation of plants belonging to Prunus genus (Gonzales Padilla et al 2003;Š tefančič et al 2005;Tereso et al 2008). Shoots of both fruit-bearing and ornamental species are considerably easily multiplicated in vitro (Nowak and Miczyński 2002;Kalinina and Brown 2007;Petri and Scorza 2010), while root formation remains problematic.…”