Volume 30 Number 1 Article 21 Pages: 21-22
Year 1976 Month 1
Title: Breeding for Aphid Resistance and Virus Tolerance in Rubus
Author: D.K. Ourecky
Citation
Abstract:
The decline of the raspberry industry
in the United States can be attributed
to the susceptibility of nursery
stock and commercial plantings to
virus infection.
Today, many states
have established a virus free program
for the identification and production
of superior stock.
Significant increases
in yield and plant production have
been demonstrated from this stock.
Nematodes, aphids and leaf hoppers
are vectors which transmit serious
virus diseases.
The nematode transmits
Tomato-ringspot virus, one of our
most serious virus problems.
To date,
little information is available on the
resistance of Rubus species to nematode
infection.
The aphid vector, Amphorophora
agathonica Hottes is responsible for
the spread of mosaics.
Four major
sources of immunity to Amphorophora
agathonica have been identified,
namely, 'Lloyd George', 'Pynes Royal',
'Burnetholm', and 'La France'. The
only' commercial cultivars available
which are immune include 'Canby',
'Indian Summer', 'Haida', 'Reveille'
and 'Citadel'. A few cultivars have
been shown to be resistant but none
of these are available for commerce.
Aphis rubicola Oestlund is responsible
for the spread of raspberry stunt.
Of the materials screened, only the
'Willamette' variety appears to be resistant.
There appears to be no correlation
between the susceptibility and
immunity of these two aphids. 'New
York 632', a purple raspberry soon to
be released, appears to be immune to
Amphorophora agathonica and resistant
to Aphis rubicola.
Various techniques are being studied
to facilitate the screening of seedlings
in the greenhouse and to correlate
the findings with field results.
Since many sources of immunity to
Amphorophora rubi, the major vector
of red raspberry viruses in Europe,
have been identified in a number of
species, further screening of native
North American species should be
done.
Breeding for immunity should
be one of the major objectives of any
raspberry breeding program.
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