Greenhouse Evaluations of Strains of Rhizobium for Peanuts1
- J. C. Wynne,
- G. H. Elkan,
- C. M. Meisner,
- T. J. Schneeweis and
- J. M. Ligon2
The use of effective strains of Rhizobium can increase the yield of peanuts (Arachis hypogaea L.) substantially. Preliminary screening of rhizobial strains for effectiveness in leguminous crops is generally done in greenhouse tests. This study was conducted to develop reliable greenhouse procedures for the evaluation of rhizobial strains for peanuts and to determine the variability in N-fixing ability of rhizobial strains in symbiosis with genetically diverse peanut hosts.
Using ‘Argentine’ (a Spanish genotype) and ‘NC 4’ (a Virginia genotype), 18 rhizobial strains, 9 in each of two tests, were compared with an uninoculated control for N-fixing ability. Strains of Rhizobium varied in their N-fixing ability in both tests as evaluated by nodulation, nitrogenase activity, plant color and weight and N content. Plants of NC 4 were larger and greener and had larger nodules, greater nitrogenase activity and higher N content than plants of Argentine. Host-strain specificity was found for several traits indicative of N-fixing activity.
Nodulation, plant color and weight, nitrogenase activity, and N content were significantly correlated. The high significant correlation of total nitrogen and plant dry weight (r = 0.99** and r = 0.97**) and total nitrogen and plant color (r = —0.95** and —0.97**) indicates that either plant color and/or plant dry weight can be used as a measure of strain effectiveness in preliminary tests
Greenhouse screening of rhizobia for effectiveness on peanuts using plant weight or color was determined to be an excellent initial evaluation of strain efficiency. Because of host differences and host-strain specificities, the peanut genotype should also be considered in rhizobial testing.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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