Effects of foliar zinc stage on the accumulation and distribution of dry matter and zinc in summer maize with different genotypes

【Objective】 To investigate the effect of foliar zinc(Zn) stage on the accumulation and distribution of dry matter and Zn in summer maize with different genotypes, so as to provide a theoretical basis for optimal management of Zn fertilizer in the maize production.【Method】 Four foliar Zn stages(no foliar, foliar 1:1 at seedling and jointing stage, foliar 1:1 at jointing and flare opening stage, and foliar at flare opening stage, application rates were all 4.5 kg/ha ZnSO₄·7H₂O) were set to analyze the accumulation and distribution of dry matter and Zn of plant organs, and the variation of grain yield, yield increase ratio and Zn use efficiency of 10 summer maize varieties(DH605, DK653, XY335, QL618, WK702, LP638, YF303, DD5H, ZD958 and GSY66) in the filed condition.【Result】 The highest stem was obtained in the foliar Zn 1:1 at seedling and jointing stage(3.18 t/ha), and the highest grain weight was found in foliar 1:1 at jointing and flare opening stage and foliar at flare opening stage among different foliar Zn stages. QL618, YF303 and DD5H had the highest grain weight among all the genotypes. Grain ratio greatly increased after the Zn application, the highest value 50.98% was observed in the foliar at flare opening stage, 53.29% in DD5H among all genotypes and 54.50% in no foliar of DD5H among all the treatments, which was the highest of the all. Among the organs, the highest Zn concentration was obtained in the leaf (149.43 mg/kg) and then grain (38.40 mg/kg). The highest grain Zn concentration was found in the foliar 1:1 at jointing and flare opening stage(43.94 mg/kg) among different foliar Zn treatments, and GSY66(50.74 mg/kg) among all genotypes. The ratio of stem, bract and grain Zn accumulation greatly decreased and the highest grain Zn distribution ratio was obtained in the DD5H(62.13%) among the genotypes, and in no foliar of DD5H(79.52%) among all the treatments. Compared with no Zn foliar, the yields in foliar 1:1 at jointing and flare opening stage and foliar at flare opening stage were high with an average of 8.80 t/ha, YF303 had the highest grain yield among all genotypes, YF303 in the foliar 1:1 at jointing and flare opening stage had the highest grain yield among all treatments(10.63 t/ha). Average yield increasein DK653 was the highest(12.92%) and the lowest in LP638(1.61%), average yield increaseinGSY66 and ZD958 in the foliar 1:1 at jointing and flare opening stage were the highest, with an average of 15.39%. After Zn foliar, Zn utilization efficiency increased by 7.96% on average and the maximum increase value was 22.75% in the foliar at flare opening stage of YF303.【Conclusion】 In summer maize planting, screening YF303 and foliar Zn 1:1 at jointing and flare opening stage(4.5 kg/ha ZnSO₄·7H₂O), can promote photosynthetic matter and Zn to tranfer into grain and achieve the goal of increasing grain yield and Zn content.