© 2007 Heron Publishing—Victoria, Canada
Growth patterns and morphology of fine roots of size-controlling and invigorating peach rootstocks
Boris Basile (1), David R. Bryla (2), Michelle L. Salsman (3), Jordi Marsal (4), Chiara Cirillo (1), R. Scott Johnson (5) and Theodore M. DeJong (5, 6)
1. Dipartimento di Arboricoltura, Botanica e Patologia Vegetale, Università degli Studi di Napoli Federico II, Via Università
100, 80055 Portici, Napoli, Italy / 2. USDA ARS, Horticultural Crop Research Laboratory, 3420 NW Orchard Avenue, Corvallis, OR 97330, USA / 3. USDA ARS Water Management Laboratory, 9611 S. Riverbend Avenue, Parlier, CA 93648, USA / 4. Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Area de Tecnologia Frutícola, Centre UdL-IRTA, Avda Rovira Roure
177, E-25198 Lleida, Spain / 5. Department of Plant Sciences, University of California, 1035 Wickson Hall, One Shields Avenue, Davis, CA 95616, USA / 6. Corresponding author (tmdejong@ucdavis.edu) / Received December 7, 2005; accepted April 18, 2006; published online November 1, 2006
Summary
We compared growth patterns and morphology of fine roots of size-controlling and invigorating peach (Prunus persica (L.) Batsch) rootstocks. Peach trees were grafted on five rootstocks: a vigorous control (Nemaguard), three intermediate
vigor rootstocks (K119-50, P30-135 and Hiawatha), and a semi-dwarfing rootstock (K146-43). Minirhizotron tubes were installed
at the base of trees on each rootstock and root images captured with a minirhizotron digital camera system. Number, visible
length, and diameter of new roots were recorded at fixed soil depths from April 19, 2000 to December 19, 2001. Root diameter,
specific root length, root tissue density and root length density were also measured periodically for each rootstock on roots
collected from in-growth cores. Rootstocks had similar seasonal patterns of new root production. Fine root production was
lowest in winter and appeared to decline during the final stages of fruit growth. A rootstock with almond in its genetic background
(K119-50) produced the greatest quantity of fine roots and had the greatest number of new roots below 69 cm, whereas there
were no differences among the other four rootstocks in the total number of roots produced. Rootstock K146-43 had thicker fine
roots than the other rootstocks. Independent of rootstock, fine roots produced during spring had greater specific root length
than those produced later in the season. The seasonal pattern of fine root production did not appear to be associated with
the previously reported effects of these dwarfing rootstocks on shoot growth and stem water potential early in the growing
season.
Keywords:
dwarfing rootstocks, in-growth core, minirhizotron, root diameter.
