Manganese Deficiency and Toxicity Sensitivities of Soybean Cultivars

Abstract

Soybean [Glycine max (L.) Merr.] cultivars vary in plant growth response to Mn deficiency and toxicity. Cultivar selection for field studies to evaluate responses to Mn deficiency and toxicity is important. The objective of this study was to determine the differential sensitivity of cultivars to Mn deficiency and toxicity prior to regional field studies on the diagnosis and correction of Mn problems in the production of soybeans. For evaluating relative ranking of cultivars sensitive to Mn deficiency, seven soybean cultivars were grown in solution culture at severe (5 µg Mn/liter) and mild (50 µg Mn/liter) deficiency levels and compared with controls, (1,000 µg Mn/liter). For toxicity evaluations, seven cultivars were grown at severe (20 mg Mn/liter) and mild (10 mg Mn/liter) toxicity levels with controls at 0.5 mg Mn/liter. Cultivar sensitivity to Mn deficiency was partially dependent on the level of deficiency stress. ‘Davis’, ‘Lee 74’, ‘Bragg’, and ‘Pickett 71’ were the most sensitive under severe deficiency and Lee 74, Bragg and ‘Hutton’ were the most sensitive under mild deficiency. Davis, Lee 74, Pickett 71, Bragg, and ‘Ransom’ were the most sensitive to severe Mn toxicity at the severe Mn toxicity level. At mild toxicity, shoot weights as percent of control were similar for all cultivars. Visual symptom ratings and leaf blade Mn concentrations were significantly correlated with shoot dry weight as percent of control for Mn deficiency and toxicity stresses. The increased sensitivity to Mn toxicity by Lee 74 compared to that previously reported for the ‘Lee’ cultivar may be a result of genetic changes which occurred during the development of Lee 74.

Genotypic Differences in Tolerance to Manganese Deficiency

“…Graham, unpublished data). In contrast to our experience with cereals, Ohki et al (72) found that the Mn content of soybean seeds did not alter the varietal ranking in tolerance to Mn deficiency. Nevertheless, it appears that the genotype of the scion had a dominant role in determining the accumulation of minerals, including Mn, in soybean seeds, and that of the rootstock much less, or nil in the case of Mn (47).…”

Micronutrients in Soybeans in the State of São Paulo

“…Novais et al (1989) e Ohki et al (1980) também determinaram desempenhos diferenciados entre cultivares de soja, quanto à eficiência na absorção ou utilização de Mn, em condições de disponibilidade limitada do elemento no solo. Evidências quanto às diferenças genotípicas na absorção e utilização de Mn por plantas de soja também foram verificadas por Reddy e Dun (1987).…”

Occurrence and Correction of Manganese Deficiency in Plants

“…These inconsistencies among species may be attributed in part to the existence of large variations within species in sensitivity to Mn deficiency. Intraspecific variation has been reported for a number of crops including wheat (29,42), barley (43,103), oats (19,103), peas (37), soybeans (105) and lupins (159) and it almost certainly exists in all species (Chapter 17).…”