Differential Susceptibility of Corn Cultivars to Zinc Deficiency
1979
Safaya, N. M. | Gupta, A. P.
Due to widlespread deficiency of Zn in the northwestern plains of India, germplasm screening for identifying less susceptible cultivars of crop plants has become as essential as recommending proper methods of Zn fertilization. To study the relationship between differential susceptibility to Zn deficiency and nutrient composition of plants, 13 cultivars of corn (Zea mays L.) were grown in the greenhouse at 0 and 2.5 ppm of applied Zn, with uniform N-P-K rate, in 4-kg lots of Zn-deficient loamy sand of pH 8.5. After 45 days of growth, dry matter yield (DMY), and P, K, Ca, Mg, Fe, Mn, Cu, and Zn in the leaf, culm, and root fractions were measured. Significant cultivar differences in DMY and nutrient composition and the degree of their response to Zn were observed. The reduction in IBMY of whole plants due to Zn deficiency ranged from 26.6% (‘Basi’) to 74% (White Opaque 2). However, the differential susceptibility of corn cultivars to Zn deficiency was not related to their Zn absorption characteristics. Zinc-deficient plants revealed higher concentration of all nutrients (except Zn) in their tissues. The uptake of P was significantly higher in the shoots of Zn-deficient plants. From regression analysis between the percent reduction in shoot DMY and the relative increase m the concentration of different nutrients in Zn-deficient plants, only leaf and culm P concentrations were found to bear a high positive correlation (P<O.Ol) with the susceptibility index of cultivars. Relative increase in Fe concentration of shoots showed a positive correlation and in roots a negative correlation (P<0.05 for both) with the percent reduction in shoot DMY. These results show that the susceptibility to Zn deficiency in corn is intimately related to the P and Fe absorption and transport mechanisms
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