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Nitrogen Fixation by Hybrids of White Clover ( Trifolium repens L.) and Trifolium nigrescens
Author(s) -
Abberton M. T.,
MacDuff J. H.,
Marshall A. H.,
MichaelsonYeates T. P. T.
Publication year - 1999
Publication title -
journal of agronomy and crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.095
H-Index - 74
eISSN - 1439-037X
pISSN - 0931-2250
DOI - 10.1046/j.1439-037x.1999.00309.x
Subject(s) - trifolium repens , biology , hybrid , backcrossing , repens , agronomy , nitrogen fixation , botany , horticulture , biochemistry , genetics , bacteria , gene
Development of hybrids between white clover ( Trifolium repens L.) and Trifolium nigrescens provides a novel route for genetically improving the reproductive capacity of white clover, provided the hybrids are agronomically viable, particularly with respect to N 2 fixation. A comparative study of growth and rates of N 2 fixation over 21 days was conducted with the parental species, F 1 hybrids and backcross hybrids, in flowing solution culture, without a supply of mineral N to the plants. T. nigrescens was unable to fix N 2 in association with the strains of Rhizobium leguminosarum biovar. trifolii selected for inoculation. Rates of N 2 fixation per plant increased in the order T. nigrescens < F 1 hybrid < T. repens < backcross 1. Specific rates of N 2 fixation (days 0–21) increased in the order T. nigrescens < F 1 hybrid < backcross 1 < T. repens . Dry matter production and nodule biomass per plant increased at a higher rate in backcross 1 hybrids than in T. repens. The results suggest that the potential for N 2 fixation by backcross 1 hybrids is at least as great as that by T. repens .