ROOTING SHOOTS OF APPLE VARIETIES AND THEIR TETRAPLOIDS OBTAINED BY THE in vitro TECHNIQUE

Abstract

For breeding purposes, the number of neo-tetraploids of apple cultivars have been derived by in vitro technique. The first attempts at rooting and acclimatization of tetraploid shoots failed. The aim of the study was to develop an effective method for rooting microcuttings of apple neo-tetraploids. In the first stage of the study, in vitro rooting method was optimized for the shoots of diploid donor cultivars. Shoots were rooted on Murashige and Skoog [1962] (MS) medium with a reduced content of nitrogen, in the presence of auxins alone or in combination (indole-3-butyric acid -IBA, 1-naphthaleneacetic acid -NAA and indole--3-acetic acid -IAA) with addition of putrescine, arginine or ornithine. The compounds were applied continuously for 25 days (one-step rooting system) or for seven days with subsequent transplanting shoots onto a medium without these compounds (two-step rooting method). Tetraploid microcuttings of the cultivars 'Free Redstar', 'Gala Must', 'Pinova' and 'Redchief' were evaluated for rooting on the selected medium considered optimal for their diploid counterparts. The shoots of all diploid apple scion cultivars had low rooting capacity. IBA alone poorly stimulated root formation. Significant improvement of rooting to 60-80% was achieved through the application of auxins, 2.5 µM IBA or 1.3 µM NAA combined with 5 µM IAA and 50 µM putrescine in the two-step rooting system with darkness and increased temperature of 26°C during seven-day induction phase. The replacement of benzyladenine (BA) by meta-Topolin (m-T) in the last multiplication subculture influenced positively shoot acclimatization. Tetraploids had comparable or slightly lower rooting and acclimatization ability compared to their diploid counterparts.

In Vitro Propagation Method for Production of Phenolic-Rich Planting Material of Culinary Rhubarb ‘Malinowy’

“…During the last decade, meta -topolin has been widely used in micropropagation of many plant species, improving multiplication and rooting efficiency [ 41 , 42 , 43 ]. Our previous observation showed that the shoot of rhubarb ‘Malinowy’ treated with meta -topolin had higher rooting capacity than those cultured in BAP medium before rooting (data not shown).…”

In vitro tissue culture of apple and other Malus species: recent advances and applications

“…When two strains (EEL16010B and EEL37810) of Rhizobia were used, 100% rooting of Marubakaido rootstock was achieved (Muniz et al 2013). Podwyszyńska and Cieślińska (2018) found that the use of putrescine, a polyamine, when used in combination with NAA and IBA, was able to improve the rooting and subsequent acclimatization of neo-tetraploids of four apple cultivars, 'Free Redstar', 'Gala Must', 'Pinova' and 'Redchief' (more details in Table 2). Phloroglucinol (PG), a phenol derivative, has been successfully employed for the in vitro rooting of many plants including apple, a species that is generally considered to be difficult to root (Webster and Jones 1989;Sharma et al 2000; and is as or even more effective than commonly used auxins (Dobránszki and Teixeira da Silva 2010).…”

In vitro tetraploid induction of the blackcurrant (Ribes nigrum L.) and preliminary phenotypic observations

“…The substitution of BAP with meta-topolin enabled the multiplication of the obtained tetraploids and their rooting in vitro as well as acclimatization in the greenhouse. During the last decade, this cytokinin has widely been used in micropropagation of many plants improving not only multiplication rate and shoot quality, but also rooting ability and acclimatization efficiency (Wojtania, 2010;Podwyszyńska, Cieślińska, 2018). The positive effect of this cytokinin was ascribed to its fast metabolism in plant tissue (Werbrouck et al, 1996).…”