|
|
||||||||||||||||||||||||||||||||||||||||||||||||||
|
20
PNL Volume 20
1988 RESEARCH
REPORTS |
||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||
|
IMPROVING
RESISTANCE TO APHANOMYCES ROOT ROT IN PEAS VIA RECURRENT SELECTION
Lewis, M. E. and E. T.
Gritton
Department of
Agronomy
University of Wisconsin,
Madison, WI 53706, USA
Common
root rot, incited by Aphanomyces eutieches Drech., is the most
serious disease of peas in the upper midwestern and middle Atlantic United
States. It was first identified in
1925 (3) but to date no cultivars with high levels of tolerance nor
other economically effective means of control have been developed. Resistance appears to
be quantitatively inherited with
low heritability (5,6).
We have
initiated a phenotypic recurrent selection breeding program for root rot
tolerance. The base population involved a series of intercrosses among twelve pea lines: MN 494-A11
(4); MN 108 (1); NY 5; B275-191; WIS 7101 (2); 8221; 8615; 8617; Badger; a
backcross derived line of 'Dark Skin Perfection' with afila
foliage and resistance to Erysiphe polygony; and two lines with large
root systems from the Lamprecht collection, 1073 and 1532.
Lines are
evaluated in a root rot infested field nursery during the summer; seeds
from superior lines are sown in the greenhouse in the fall and selected lines crossed in diallel;
crosses are advanced to the F2 generation in the greenhouse in the
spring, and then the cycle is repeated by growing the F2 lines in the root rot
infested field nursery. One cycle
can thus be completed per
year. Approximately 190 F2 lines are evaluated each summer, and 20
lines are selected for intercrossing in the fall. Check plots of Dark Skin
Perfection (very root rot susceptible) and MN 108 (one of the most root rot tolerant
lines known) are grown along with
the test entries in the
summer nursery. Evaluation is based on percent survival, a
root rot rating score, and production of dry seed. Selection is
also practiced to maintain or increase the frequency of genes giving green wrinkled seed, lack of pigment,
determinate growth, resistance to Erysiphe polygoni,
afila foliage, and general desirable plant type.
The results to date are shown in Table
1. |
||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||
|
Table 1.
Performance of recurrent selection lines compared to MN 108
on
Aphanomyces root rot infested soil. Arlington, Wisconsin, L985-1987. (MN 108 values set as
100%). |
||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||
|
The lower
the score the better the root rot tolerance.
Selected
lines are becoming earlier in maturity, have greater survival, a lower root rot score, and improved yield
per plot as compared to |
||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||
|
PNL Volume 20 |
1988
RESEARCH REPORTS |
2] |
||
|
|
||||
|
earlier cycles of selection and to
the performance of MN 108. Recurrent selection appears to be an effective
breeding technique for improving tolerance to common root
rot. |
||||
|
|
||||
|
1. Davis, D. W., M. A. Shehata, and H. L.
Bissonette. 1976. HortScience
11:434.
2. Gritton, E. T. and D. J. Hagedorn. 1971.
Crop Sci. 11:941.
3. Jones, F. R. and C. Drechsler. 1925. J.
Agr. Res. 30:293-325.
4. King, T. H., D. W. Davis, M. A. Shehata,
and F. L. Pfleger. 1981. HortScience 16:100.
5. Marx, G. A., W. T. Schroeder, R.
Provvidenti, and W. Mishanec. 1972. J. Amer. Soc. Hort. Sci.
97:619-621.
6. Shehata, M. A., D. W. Davis, and F. L.
Pfleger. 1983. J. Amer. Soc. Hort. Sci. 108:1080-1085.
*****
|
||||
|
|
||||