Abstract:
The inheritance mode of pea-resistance to the Lentil
Strain of Pea Seedborne Mosaic Virus (PSbMV-L) was
studied. In addition, commercial pea cultivars, Plant
Introduction (P.I.) lines and Oregon State University
(OSU) breeding lines were tested for susceptibility to
this virus. These lines were also tested for their
reaction to Bean Yellow Mosaic Virus (BYMV) and pathotype
1 of Pea Seedborne Mosaic Virus (PSbMV-Pl) to further
elucidate the relationships of Pisum resistance to the
three viruses.
Susceptible cultivars, 'Sounder', 'Abador', 'Quincy'
and 'Avon' were hybridized with resistant cultivars,
'Little Marvel' and OSU B445-66. Data on reaction to
PSbMV-L inoculation were obtained for Fl, F2, and F3
progeny and selected backcrosses. Fl tests indicated that
resistance was recessive. Most F2 populations segregated
as ratios of 3 susceptible: 1 resistant indicating that a
single recessive gene controls resistance. Populations of
most F3 families fit ratios of 3 susceptible or
segregating: 1 resistant. The F3 family data fit ratios
of 1 susceptible: 2 segregating: 1 resistant in some of
the tests. In remaining tests, failure to fit this
expected ratio was assumed to be due to random escapes
(susceptible, but not infected), or to a klendusic
reaction in progenies from 'Quincy'. Segregation of
backcrosses from two crosses in a 1 susceptible: 1
resistant ratio supported the single recessive gene
hypothesis.
Of 202 commercial cultivars screened screened for
PSbMV-L resistance, 144 were resistant and 58 were
susceptible. Cultivars resistant to PSbMV-L were also
resistant to BYMV, and cultivars susceptible to PSbMV-L
were susceptible to BYMV except for 'Quincy' and 'Avon',
which were susceptible to PSbMV-L but resistant to BYMV.
All of 9 OSU lines and all 32 of selected P.I. lines
tested were resistant to PSbMV-L. The P.I. lines had been
previously tested and were known to be resistant to PSbMV-Pl.
All 9 OSU breeding lines and all but one P.I. line
were resistant to BYMV, indicating a possible linkage
relationship between resistance to PSbMV-L and BYMV.
Three of 178 cultivars, 27 of 32 P.I. lines, and all of 9
OSU breeding lines tested were resistant to both PSbMV-Pl
and PSbMV-L. The results suggested that there is a
tendency for resistance to PSbMV-Pl and resistance to
PSbMV-L to be associated in pea cultivars.
