Studies on the anatomy of root formation and rooting of semi-hardwood pecan cuttings

This study evaluated rooting response and survival of cuttings from several pecan cultivars to pre-cutting banding and girdling. Also observed were vascular connections between the adventitious roots formed and their parent axis. Six pecan cultivars were involved in the study in 2000, and only three in 2001. Current season shoots were banded, using black electrical tapes, and girdled in the third week of April. Cuttings were collected in the third week of May and in the second week of June. The cuttings were inserted in three rooting media, styrofoam, vermiculite, and vermiculite/perlite mixture and placed under intermittent mist in the greenhouse. After two months, cutting survival and rooting characteristics were observed. Banding increased rooting percentage, and total root count and total root length per rooted cutting compared to control and pre-girdled cuttings. Girdling banded shoots enhanced the banded effects, although not significant statistically. Only two cultivars, Shosnoni and Pawnee, exhibited sufficient rooting, over 45%, when exposed to banding and girdling. Cuttings rooted better when inserted in either vermiculite or vermiculite/perlite mixture, compared to when inserted in styrofoam. Rooting of pecan cuttings did not vary with year, but varied significantly with collection date. Cuttings rooted significantly higher when collected in June, compared to when they were collected in May. Adventitious roots seemed to originate outside of the cambium. Their connections to the xylem of the parent axis were observed after three months in rooting media. Rooted cuttings died instantly due to water stress when taken off the mist two months after the date the cuttings were planted in rooting media. By delaying transplanting for another month, the cuttings survived until mid Fall, although no above ground growth was observed.