Zinc Response in Corn as Influenced by Genetic Variability¹

Abstract

Influence of genetic variability on Zn response in recently improved corn (Zea mays L.) genotypes has not been investigated. Therefore, eight genotypes representing indigenous, hybrid, and composite varieties, were evaluated in the greenhouse using a Zn deficient loamy sand soil (Typic Torripsamments) at 0 (original soil), 5, and 10 ppm Zn applied to the soil. Zinc deficiency symptoms, dry matter yield response (6 weeks after sowing), Zn concentration, and P/Zn and Fe/Zn ratios were the criteria for evaluation. There was considerable variation among the eight genotypes in the severity of Zn deficiency symptoms, growth depression, Zn concentration, P/Zn, and Fe/Zn ratios under Zn stress conditions. The depression in shoot and root dry matter yield under Zn stress conditions ranged from 78 to 95 and 72 to 94%, respectively, as compared to 5 ppm supplemental Zn level. Zinc concentration in different genotypes under Zn stress condition varied from 7.4 to 20.5 ppm. The differential response among the genotypes was found to be associated with their capability to exploit soil Zn and/or translocate it to the shoot. The contribution of P/Zn and/or Fe/Zn balance in tissues to the variability in Zn responses was not significant.

Efect of zinc and iron deficiency on phytos1derophore release in wheat genotypes differing in zinc efficiency

“…Phytosiderophores released from Fe-deficient (33,34) or Zn-deficient roots (36) possess a high capacity to enhance solubility and mobility of Zn by chelation from sparingly soluble Zn compounds in calcareous soils. As indicated by the present results, the different susceptibility to Zn deficiency of genotypes within a graminaceous species such as in wheat (8,9,28), maize (5,30), sorghum (29), rice (7), and oat (4) may be related to different capacities of genotypes to release Zn-mobilizing phytosiderophores from roots. In the case of Fe deficiency, the rate of phytosiderophore release by various graminaceous species (13,23) or cultivars within a graminaceous species (6,10) is positively correlated with their chlorosis resistance on calcareous soils.…”

“…Alternatively, the selection and breeding of plant genotypes with higher efficiency in acquisition of Zn from soils is a realistic approach. The existence of such genotypes within a given species is well known as shown for maize (5,30), navy beans (3), soybean (22), grapevine (17), and wheat (8,28).…”

Influence of genotypical variability on zinc response in cotton (Gossypium hirsutum L.)

“…The variability of the Zn response among cultivars of various crops has been reported by several workers (Ambler and Brown, 1969;Safaya and Singh, 1977;Shukla and Ra], 1974, 1976, 1980Shukla et al 1973). This variability has been attributed to the differential capacity of cultivars to exploit soil Zn and translocate it to the metabolically active parts of the plant.…”

Effect of P and Zn fertilization on biomass yield and its uptake by maize lines (Zea mays L.)

“…Pavliková et al (1997) confirmed the positive effect of humate on the decrease of Zn content in barley and oats but in maize and poppy Zn content increased. Moreover, maize genotypes (inbred lines, hybrids) differ in their zinc requirements as well as in the uptake and translocation ability (Shukla and Ray 1976). Also, the maize inbred lines property of high or low zinc concentrations could be inherited in hybrids.…”