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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #156600
Title: FINE ROOT PRODUCTION AND UPTAKE EFFICIENCY BY PEACH ROOTSTOCKS WITH DIFFERING SITE-CONTROLLING POTENTIAL

Author
item Bryla, David
item BASILE, BORIS - UC DAVIS
item SALSMAN, MICHELLE - UC DAVIS
item DEJONG, TED - UC DAVIS

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/3/2003
Publication Date: 9/28/2003
Citation: FINE ROOT PRODUCTION AND UPTAKE EFFICIENCY BY PEACH ROOTSTOCKS WITH DIFFERING SITE-CONTROLLING POTENTIAL. Bryla, D.R., Basile, B., Salsman, M., Dejong, T.

Interpretive Summary: Growth and development of fine roots were compared among a vigorous rootstock, Nemaguard, and four semi-dwarfing rootstocks, K119-50, P30-135, Hiawatha, and K146-43, grafted to mature peach trees. The relative effect of each rootstock on tree size was as follows: Nemaguard >> K119-50 = P30-135 > Hiawatha >> K146-43. Root growth rates differed considerably among the rootstocks. Not surprisingly, Nemaguard had the highest root growth rate and tended to produce more roots deep in the soil profile than the other rootstocks, while K146-43 had the lowest root growth rate and tended to be shallow rooted. Compared to the semi-dwarfing rootstocks, Nemaguard also produced relatively fine roots with low tissue density, which reduced the total amount of energy expended on individual root growth and may have increased water uptake. Consequently, the potential efficiency by which water and nutrients are absorbed by Nemaguard appears higher than in the other rootstocks, which could enhance the water and nutrient status of the trees on Nemaguard and thereby increase their tree development over trees on semi-dwarfing rootstocks.

Technical Abstract: Growth and development of fine roots were compared among a vigorous rootstock, Nemaguard, and four semi-dwarfing rootstocks, K119-50, P30-135, Hiawatha, and K146-43, grafted to mature peach trees. The relative effect of each rootstock on canopy volume was as follows: Nemaguard >> K119-50 = P30-135 > Hiawatha >> K146-43. At several times over the growing season, in-growth containers filled with soil were buried near the base of the trees for 4 weeks. Roots were then collected from the containers, and length, diameter and tissue density of the fibrous roots (< 2 mm) were measured. Root production was also monitored non-destructively every 2 weeks using minirhizotrons. Root growth rates differed considerably among the rootstocks, ranging on average from 0.028 to 0.091 cm cm-3 soil wk-1. Not surprisingly, Nemaguard had the highest root growth rate and tended to produce more roots deep in the soil profile than the other rootstocks, while K146-43 had the lowest root growth rate and tended to be shallow rooted. Compared to the semi-dwarfing rootstocks, Nemaguard also produced relatively fine roots with low tissue density, which reduced the total amount of carbon expended on individual root growth and may have increased radial conductivity for water uptake. Consequently, the potential efficiency (cost:benefit ratio) by which water and nutrients are absorbed by Nemaguard appears higher than in the other rootstocks, which could enhance the water and nutrient status of the trees on Nemaguard and thereby increase their canopy development over trees on semi-dwarfing rootstocks.