Seed-zinc concentration and the zinc-efficiency trait in navy bean

Some navy bean (Phaseolus vulgaris L.) cultivars are susceptible to Zn defi ciency. Norstar and Voyager are examples of Zn-efficient cultivars; Avanti and :Ubion are examples of Zn-inefficient cultivars, The objective of this study was to compare growth and Zn accumulation, especially in seed, of the se four cultivars. In field and greenhouse experiments, except under extrem ely low soil-Zn levels, the two Zn-efficient cultivars contained >25% highe r seed-Zn concentrations than did the two Zn-inefficient cultivars, Both Al bion and Avanti, but not Norstar and Voyager, were Zn deficient at a field site with a relatively high level of Zn (1.7 mg kg(-1)) extractable by diet hylenetrinitritopentaacetic acid (DTPA), The Zn-efficieny trait was associa ted with higher levels of Zn in plant tops and was not associated with diff erences in P or Fe nutrition, Zinc deficiency delayed pod maturity most in the two Zn-inefficient cultivars. Analysis for Zn in seed from routine bree der-yield trials, in which a Zn-efficient cultivar is not Zn deficient, is proposed as a suitable technique for selecting navy bean genotypes that are both agronomically Zn efficient and better sources of Zn for human nutriti on.