Variation in partitioning and percentage nitrogen and phosphorus content of the leaf, stolon, and root of white clover genotypes

Abstract

As part of a programme to breed a productive white clover (Trifolium repens L.) tolerant of low soil phosphorus (P) levels, 98 white clover and 2 Lotus pedunculatus Cav. genotypes were examined for partitioning of P, nitrogen (N), and dry matter within the plant, and for concentration of P and N within leaves, stolons and roots. Genotypes were grown in pots with either 300 or 2000 mg P per kg soil. Differences among genotypes for % P content and partitioning of P within the plant did not result in differences in dry matter response to added P fertiliser between genotypes. Genotypes that allocate a high proportion of total P to shoots and have low shoot % P were large-leaved and had high herbage yields, but a low proportion of dry matter in stolons suggested that they would be nonpersistent in grazed, low P swards. Ge~otypes collected from hill country swards had a high proportion of dry matter in stolons but were low yielding, had a high shoot lifo P and a low NIP ratio. There was sufficient variation among genotypes to suggest that selections of persistent plants that have a low harvest index, low shoot lifo P, and high NIP ratio may be successful.

Keywords:

• white clover
• phosphorus
• plant nutrition
• nitrogen
• screening
• genotypes
• roots
• stolons
• shoots