Serogroup Distribution of Rhizobium Leguminosarum in Peas in the Palouse of Eastern Washington
- R. L. Mahler and
- D. F. Bezdicek
The serogroup distribution of Rhizobium leguminosarum in peas (Pisum sativum L. cv. ‘Alaska’) was determined for a Palouse catena in the summer of 1976. Three major serogroups were found, although the distribution was uneven across the catena. Thirty-four and thirty-eight percent of the nodules on the bottomland and north slope, respectively, were of serogroup WA-01, whereas it comprised only 5 to 12% of the root nodule population on the south slope and ridgetop, respectively. Serogroup WA-02 distribution of 81 to 89% was dominant for the ridgetop and south slopes. Only on the bottomland and soil did serogroup WA-03 represent a sizeable portion (12%) of the root nodule population.
Nine Palouse catenas were selected as study sites in the summer of 1977 to determine the geographical distribution of the three serogroups of R. leguminosarum. The three serogroups represented > 94% of the root nodules sampled. Chisquare analysis suggested that serogroup distribution was related to temperature, moisture, and slope position on a catena. Microclimate as well as macroclimate were responsible for serogroup distribution in the Palouse. Cooler temperatures and higher soil moisture appeared to favor serogroup WA-01, as its largest population existed in the northern part of the Palouse, and on north-slope and bottomland soils. Population of serogroup WA-02 was maximum under the warmer and drier conditions of the southern and western Palouse as well as on south slopes and ridgetops. No pattern was found for the distribution of serogroup WA-03.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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