evaluation of different combinations of nitrogen and zinc on maize by path analysis of yield and grain filling rate

this research was conducted to evaluate the effect of different nitrogen and zinc combination on grain yield and its component in maize by path analysis. this experiment was carried out through split plot based on rcbd, varieties as main plot and fertilizers as sub plot, with three replication at badjgah (experimental farm of shiraz university). nitrogen fertilizer in (120,260 and 400 kg/ha) and zinc fertilizer in (0, 15 and 30 kg/ha) were applied in soil. according to the path analysis, 1000 grain weight showed the highest direct and indirect effects on grain yield (0.96).also, the number of row was positive and significant .while the number of grain per row was negative. therefore as breeding point, the weight of 1000grain has the highest potential for increasing the yield, means it can be significant under the effect of nitrogen and zinc. grain filling rate due to its effective role on grain yield can be good criteria for assessing of produced grain yield in different genotypes. based on the obtained results, intermediate mature hybrid 540 has the better grain filling rate comparing to 704,meanwhile, grain filling rate at 120  kg/ha urea and 15 kg/ha zinc sulphate gave the highest rate, as 3.19 gr/m2  per day. according to the experiment and assessment of grain filling rate and using path analysis, it is clear that different combinations of nitrogen and zinc had a positive effects on grain yield and it is projected to evaluate more related researches in future.