In vitro PROPAGATION OF ALMOND X PEACH HYBRID H1

Abstract

The almond x peach hybrid H1 has the potential to be used as a peach (Prunus persica L.) rootstock, because it its highly resistant to drought, dry soils with low fertility, nematods, root asphyxia, andchlorosis induced by Fe deficiency. Since a hybrid propagated by seeds would produce segregation, for maintaining the desired plant traits the hybrid should be multiplied by vegetative methods. An alternative for commercial vegetative propagation is the in vitro culture, which can be used to obtain free pathogen plants genetically uniform. In this research shoot tips and stem nodal sections from a mature tree were used as explants for the establishment of the in vitro cultures. Exposure time to chlorine was evaluated for disinfection. Two culture media were tested: Woody Plant Medium (WPM) and WPM modified (WPMm). During the proliferation stage, four levels of ammonium nitrate and three levels of benzyl adenine were tested, and during the in vitro rooting four levels of auxin were tested. The lowest percent of contamination (6.6 %) was accomplished on apices; the best establishment in vitro (44 %) was achieved with stem nodal sections growing on the WPM medium. For the in vitro multiplication the best treatment was the WPM medium added with 2 mM of ammonium nitrate plus 2.5 µM of BA. For the in vitro rooting, indole butyric acid promoted an increase in the number of roots, but this auxin also shortened the roots. The rooting and acclimatization can be performed simultaneously with Radix 10 000® at 20 % (p/p) if it is applied during transplant. The protocol generated here allows the propagation of the hybrid almond x peach H1 of explants obtained from adult plants grown in field conditions.