Plant Zinc and the Zinc‐Efficiency Trait in Navy Bean

Abstract

Seed of zinc (Zn)‐efficient and Zn‐inefficient navy bean (Phaseolus vulgaris L.) genotypes differ in Zn concentration [Zn]. Greenhouse studies were conducted to determine how Zn and P fertilizers influence seed [Zn] and within‐plant distribution of Zn in the navy bean genotypes Voyager (Zn‐efficient) and Albion (Zn‐inefficient). Addition of 60 and 120 mg P kg−1 in the absence of added Zn to a Calciaquoll low in available P and Zn decreased seed yields of Albion by 18 and 59%, respectively, but increased seed yields of Voyager by 32 and 41%, respectively. However, addition of fertilizer P with 4 mg Zn kg−1 increased seed yields of both genotypes. Seed [Zn] was generally higher in Voyager than in Albion, was increased by Zn fertilizer, and decreased by P fertilizer. In a follow‐up experiment seed [Zn] of Voyager and Albion converged as fertilizer Zn was increased from 8 to 64 mg kg−1. In contrast to seed [Zn], leaf, stem and pod‐wall [Zn] of Albion at maturity were higher than those of Voyager at elevated levels of fertilizer Zn. This crossover pattern for maternal‐plant [Zn] at maturity also occurred in shoots of 18‐d‐old plants. Differences in seed [Zn] between the two genotypes were generally most pronounced when Albion contained greater than 20 and less than 35 mg kg−1 of seed [Zn]. Seed [Zn] is superior to leaf and stem [Zn] for selection of Zn‐efficient navy bean genotypes in plant breeding research.