Investigation on rooting ability of twenty olive cultivars from Southern Italy

Abstract

The effects of two different types of auxins (660 ppm alpha-naph-thaleneacetic acid - NAA - in liquid solution or 750 ppm alpha-naphthaleneac- etamide - NAD - dispersed in a talcum powder) and cuttings from three differ- ent portions of the shoots (basal, middle and apical) on the rooting ability of twenty autochthonous olive cultivars were investigated in two growing seasons (spring and autumn). The results showed that the autochthonous olive cultivars of the Campania Region are characterized by a wide variability in the potential rhizogenic ability. The two periods of cutting collection (March and September) significantly affected the rooting aptitude of the cultivars, indicating that in some cultivars the cuttings collected in autumn had a higher rooting rate than those collected in spring. The effects of NAA and NAD on rooting strongly depended on interaction with the cultivar, time of collection (autumn or spring) and type of cuttings (basal, medium or apical). Among the twenty cultivars tested, we found only eight cultivars with a satisfactory rooting ability after hor- monal applications (Ortolana, Racioppella, Tenacella, Tonda, Biancolilla, Carpellese, Cornia and Pisciottana). In general, the apical and the median portions of the shoots gave the best rooting results.