Jr. Caradus et al., NITROGEN AND PHOSPHORUS CONCENTRATIONS OF WHITE CLOVER GENOTYPES DIFFERING IN RESPONSE TO ADDED PHOSPHORUS, New Zealand Journal of Agricultural Research, 36(1), 1993, pp. 79-86
The phosphorus (P) response of 110 white clover (Trifolium repens L.)
genotypes was determined in a glasshouse pot experiment. The nitrogen
(N) and P contents of leaf, stolon, and flower components were determi
ned for the seven most responsive and seven least responsive genotypes
. The most P-responsive genotypes had lower % N and % P levels, lower
N/P ratios, but higher total N and P contents compared with the least
P-responsive genotypes. While the present study showed that selection
for variation in P response may result in associated differences in %
P content, the converse was not true. Leaf % N and N/P ratio, which pr
ovide an indication of the plant's ability to utilise P for N fixation
and N assimilation into dry matter, provided a better explanation of
differences in P response than leaf % P alone. Broad-sense heritabilit
ies for % P, % N, and N/P ratio in leaf tissue were 0.52, 0.65, and 0.
66, respectively, determined over all 110 genotypes at a P level givin
g 80-90% maximum yield.