Barnes D K, Heichel G H, Vance C P, Viands D R and Hardarson G 1981 Successes and problems encountered while breeding for enhanced N2 fixation in alfalfa. pp 233–248.In Genetic Engineering of Nitrogen Fixation and Conservation of Fixed Nitrogen. Eds. J M Lyonset al. Plenum Press, New York.
Barnes D K, Sheaffer C C nd Heichel G H 1983 Breeding alfalfa for improved residual nitrogen production. Agron. Abst. 54–55.
Boller B C and Heichel G H 1983 Photosynthate partitioning in relation to N2 fixation capability of alfalfa. Crop Sci. 23, 655–659.
Carter P R and Sheaffer C C 1983 Alfalfa response to soil water deficits. III. Nodulation and N2 fixation. Crop Sci. 23, 985–990.
Ellis W R and Barnes D K 1983 Characteristics ofRhizobium meliloti isolates from alfalfa in the U.S. Proceed. Eighteenth Central Alfalfa Improvement Conf. pp 15–16.
Groat R G, Vance C P and Barnes D K 1984 Host plant nodule enzymes associated with selection for increased N2 fixation in alfalfa. Crop Sci. 24, 895–898.
Hardarson G, Heichel G H, Barnes D K and Vance C P 1982 Rhizobial strain preference of alfalfa populations selected for characteristics associated with N2 fixation. Crop Sci. 22, 55–58.
Heichel G H, Barnes D K and Vance C P 1983 Nitrogen fixation of alfalfa in the seeding year. Crop Sci. 21, 330–335.
Heichel G H, Barnes D K and Vance C P 1981 Evaluating elite alfalfa lines for N2 fixation under field conditions, pp 217–232.In Genetic Engineering of Nitrogen Fixation and Conservation of Fixed Nitrogen. Eds. J M Lyonset al. Plenum Press, New York.
Heichel G H and Barnes D K 1984 Opportunities for meeting crop nitrogen needs from symbiotic nitrogen fixation. pp. 49–59.In Organic Farming. Eds. D F Bezdicek and J F Power. Special Publication. American Society of Agronomy. Madison, Wisconsin.
Jessen D L, Barnes D K and Vance C P 1983 Selection for gluatamate synthase and phosphoenolpyruvate carboxylase enzyme activities in alfalfa nodules. Agron. Abst. 68.
Nelson D L, Vance C P, Barnes D K and Heichel G H 1983 Variability for nitrate reductase enzyme activity (NRA) in alfalfa. Proceed. Eighteenth Central Alfalfa Improvement Conf. pp 14–15.
Peterson M A and Barnes D K 1981 Inheritance of ineffective nodulation and non-nodulation traits in alfalfa. Crop Sci. 21, 611–616.
Seetin M W and Barnes D K 1977 Variation among alfalfa genotypes for rate of acetylene reduction. Crop Sci. 17, 783–787.
Vance C P 1983Rhizobium infection and nodulation: A beneficial plant disease? Annu. Rev. Microbiol. 37, 399–424.
Vance C P and Heichel G H 1981 Nitrate assimilation during vegetative regrowth of alfalfa. Plant Physiol. 68, 1052–1056.
Vance C P, Heichel G H and Barnes D K 1984 Nitrogen and carbon assimilation inMedicago sativa L. mediated by host plant genes for nodule effectiveness.In Advances in Nitrogen Fixation Research. Eds. C Veeger and W E Newton. Nyhoff Publ., The Hague/Pudoc, Wageningen. pp 565–571.
Vance C P and Johnson L E B 1983 Plant determined ineffective nodules in alfalfa (Medicago sativa L.): structural and biochemical comparisons. Can. J. Bot. 61, 93–106.
Viands D R, Barnes D K and Frosheiser F I 1980 An association between resistance to bacterial wilt and nitrogen fixation in alfalfa. Crop Sci. 20, 699–703.
Viands D R, Barnes D K and Heichel G H 1981 Nitrogen fixation in alfalfa—response to bidirectional selection for associated characteristics. USDA Tech. Bull. 1643. 18 p.