Plant Pathology Research at The Kearneysville Tree Fruit Research and Education Center
Plant Pathology Research at The
Kearneysville Tree Fruit Research and Education Center
Increased Suberin Accumulation in Peach X Almond Hybrids
Leucostoma canker is a major disease of peach in the
northern fruit-growing region of North America, including West Virginia. Infections are
initiated through injured tissues or cracks in the bark caused by cold-injury, pruning
cuts and other mechanical injuries, leaf scars, and shade-weakened twigs. There are no
known chemical or cultural treatments to prevent Leucostoma infections. Low levels of
natural resistance to Leucostoma spp. have been observed in peach cultivars and germplasm.
Resistance in peach has been correlated with the rate of suberin formation in wounds. The
heritability of suberin has been shown to be high for full sib families and moderately
high for individual trees. Suberin accumulation is moderately difficult to determine and
no phenotypic characters associated with it have been described. Reduced incidence of
lesser peachtree borer (LPB) infestation and Leucostoma canker has been observed in F1
peach X almond hybrids. Peach X almond hybrids could be valuable sources of resistance to
LPB and Leucostoma spp.; however, further studies were needed to elucidate the inheritance
and mechanism of resistance and linkage to almond traits. In this study, we examined peach
and F2 peach X almond hybrids developed from the F1 trees for suberin accumulation
following wounding. Wounding studies were conducted in April, 1994 (one peach cultivar and
one clonal selection, and six peach X almond hybrid selections) and 1995 (four peach X
almond hybrids) to quantify suberin accumulation in healthy phloem/cortex tissues adjacent
to the wound site. Wounds to the depth of the xylem were made with a cork borer on the
main stem of each plant, approximately 1 inch above the soil line. Samples for suberin
measurements were taken 10 days after wounding by removing the tissues supporting one of
the margins at the side of each wound. Suberin measurements were made with a fluorescence
microscope and microfluorometer. All measurements were made in the outer living bark. In
general, suberin accumulation following wounding was significantly greater for progeny
from almond-type than from peach-type hybrids. Hybrids from parents with almond tree type
combined with peach fruit type accumulated the highest suberin levels. These data may
partially explain the differences observed among peach and peach X almond hybrids in
relative susceptibility to Leucostoma canker and injury caused by lesser peachtree borer.
The association of higher suberin accumulation with specific phenotypic characteristics
could simplify the selection of desirable seedlings in a breeding program that includes
canker resistance as an objective.
A. R. Biggs and R. Scorza (July, 1996)
Download the full article in PDF format.
See: Biggs, A. R., and R. Scorza. 1997. Increased suberin accumulation in peach x almond hybrids. HortScience 32:717-718.
Web Site Author: Alan R.
Biggs 
Copyright ©1996-1999.
10/04/1999 01:47:33 PM