INFLUÊNCIA DA COMPOSIÇÃO DO MEIO DE CULTIVO E DO TIPO DE EXPLANTE NA MICROPROPAGAÇÃO DO PORTA-ENXERTO DE Prunus sp. ‘GXN-9’

Abstract

RESUMOObjetivou-se estudar a composição de diferentes meios de cultura, concentrações de BAP e tipos de explante, na multiplicação in vitro do porta-enxerto 'GxN-9', como também a influência desses fatores na ocorrência de vitrificação. Explantes basais cultivados em meio QL e WPM apresentaram as melhores respostas para porcentagem de brotação (80%). O número de brotações por explante também foi maior com explantes basais, porém apenas aqueles cultivados no meio QL (3 brotações por explante). Os meios QL e WPM permitiram obter o melhor desempenho de crescimento das brotações formadas, para ambos os tipos de explante. Contudo, explantes basais cultivados em meio QL, apresentaram 55% de vitrificação, ao passo que explantes provenientes do meio WPM, não apresentaram esta anormalidade. Concluiu-se que a redução na concentração de sais com adição de 0,5 mg dm -3 de BAP reduz a vitrificação, promovendo aumento no crescimento das brotações, sem influenciar na formação das mesmas.Palavras-chave: Produção de mudas; pessegueiro, in vitro, citocinina; vitrificação. ABSTRACTThe objective of the present work was to study the composition of different culture medium, BAP concentration and explants types on in vitro multiplication of the rootstock 'GxN-9', like the influence of this factors in the vitrification. Basal explants cultivated in QL and WPM medium had the better results regarding shooting percentage (80%). The shoot number per explants was also higher with basal explants when cultivating in QL medium (3 shoot a explant). The medium QL and WPM allowed better growth performance of formed shoots to both explants types. Nevertheless, basal explants cultivated in QL medium had 55% of vitrification, whereas explants from WPM medium did not show this abnormality. The lower level of salt concentration with 0.5 mg dm -3 BAP reduced vitrification, promoting an increase in shoot growth without affecting formation rates.

Artificial Neural Network Genetic Algorithm As Powerful Tool to Predict and Optimize In vitro Proliferation Mineral Medium for G × N15 Rootstock

“…Earlier, for GF677, WPM was found to have a better effect on shoot proliferation rate than either the MS or QL medium, and an explanation given for this was the reduced nitrogen content in WPM (Andreu and Marín, 2005). In addition, other researchers have reported MS, EM, and QL media to be more efficient than other media for in vitro proliferation of Prunus rootstock (Andreu and Marín, 2005; Radmann et al, 2009). These findings led us to utilize YAS (MS-modified) medium in this study and to compare its effects with those of MS, EM, QL, and WPM media.…”

“…Our observation is in agreement with previous findings in which applications of other well-established media, such as WPM and/or QL, containing a reduced proportion of ammonium appeared to have effected efficient Prunus micropropagation (Pérez-Tornero et al, 2000). That the reduced amount of ammonium was the causative agent of this improved efficiency is supported by noting that a high dose of ammonium ions (vs. nitrate ions) has been shown to have a negative impact on some growth parameters during Prunus rootstock micropropagation (Ivanova and Van Staden, 2009; Radmann et al, 2009; Yu et al, 2011). In our study, plantlets growing on medium containing a high level of ammonium showed hyperhydricity, suggesting that the impact of this factor on the efficiency of micropropagation and quality of plantlets can also be related to additional factors such as the ${\text{NH}}_4^{+}$/${\text{NO}}_3^{-}$ ratio and the presence of cytokinins, which regulate plant growth (Bosela and Michler, 2008; Shirdel et al, 2011).…”

“…The MS, WPM, and Quoirin and Lepoivre (QL) basal salt formulations were not optimized for in vitro proliferation of G × N15 but became widely used because many other Prunus species grew well on them (Arab, unpublished data). Each plant species has its own characteristic requirement for nutrients, which can be used to adapt the medium formulation (Nas and Read, 2004; Ruzic and Vujovic, 2008; Radmann et al, 2009; Unek et al, 2010; Zhou et al, 2010; Pérez-Jiménez et al, 2012; Vujović et al, 2012; Jamshidi et al, 2016). …”

In vitro multiplication of pear tree cultivar Cascatense

“…However, the most important variables are the number and length of shoots, as well as the number of axillary buds per shoot. These variables jointly determine efficiency of the multiplication process, and further, as suggested by Radmann et al (2009), the growth of shoots formed during the multiplication phase is a determining variable in the quality of the material for the rooting phase. In the present work, it was possible to identify the conditions suitable for in vitro multiplication of pear cultivar Cascatense using the commercial MS Himédia medium.…”

“…WPM was developed for growing woody plants (LLOYD;McCOWN, 1980) and presents positive results in the micropropagation of species such as blueberry (SILVA et al, 2006) and Prunus sp. (RADMANN et al, 2009). MS is still the most used medium for the in vitro culture of Pyrus spp.…”