BIOTECHNOLOGIES FOR THE PRESERVATION OF SELECTED RED CHICORY (CICHORIUM INTYBUS L.) LINES

Abstract

Red chicory (Cichorium intybus L.) is one of the most economically important vegetables produced in the Italian region of Veneto. Here, a programme for the medium-term (by slow-growth storage) and long-term (by cryopreservation) conservation of red chicory selected lines was initiated in 2002. As regards slow growth storage, shoots from the proliferation stage were stored in one of the following conditions: (i) at 4°C, in darkness or under a 8-h photoperiod (with 15 μmol m -2 sec -1 of light intensity), (ii) on a storage medium added of osmotically active compounds (OACs), i.e., NaCl (4.48 g L -1 ) or mannitol (40 g L -1 ), and (iii) at 4°C and in darkness, comparing the storage in gas-tight plastic cylinders, in slow gas-permeable glass jars or in gas-permeable plastic bags ('StarPac'). After 9 months, best storage conditions for the 'Treviso precoce' line in terms of shoot survival (95%) were obtained with the conservation at 4°C, with the shoots maintained in the dark showing a lower relative growth rate (RGR). As for the storage in OACs, a higher shoot survival (70%) and a lower RGR was obtained with the use of mannitol. A general lower adaptability to SGS was evidenced by the 'Chioggia' line, as 100% shoot survival was recorded after 6 months of conservation at 4°C in darkness, but this value dramatically dropped to 45% after 9 months. All the tested containers allowed a very satisfactory conservation of shoots at 4°C in the dark for the whole period (9 months). However, higher RGR values were always recorded from shoots stored in the 'StarPac' gas-permeable plastic bags. As regards cryopreservation, red chicory shoot tips survived and regrew satisfactorily from the storage at -196°C when a procedure of vitrification/one-step freezing, consisting in loading the explants in the PVS2 vitrification solution, was applied.