effect of source manipulation with defoliation and nitrogen on maize

Maize is one of the most important grains in the world. the leaves play an important role in providing grain reserves in cereals by performing ‎photosynthesis. the leaf is known as the source and the seed is known as the sink. removing part of ‎the leaf can decrease the amount of photosynthetic material produced by the plant. a c4 plant, maize has been widely cultivated as a summer plant in western  ‎iran in recent years. utilizing maize for both grain and forage can reduce the amount of woody ‎residues left by this plant in the soil while providing part of the forage for livestock. field and laboratory experiments were conducted to investigate the effect of defoliation and nitrogen on seed yield and germination characteristics of seeds derived from the maternal plant. defoliation intensities (removing none, half of the leaves, or all of the leaves per plant) and nitrogen rates (zero and 100 kg ha-1) were among the variables examined. nitrogen and defoliation as two source manipulations were used. the results demonstrated a significant decrease in the number of seeds per ear row and column, cob length and weight, and seed yield upon complete defoliation during the tasselling stage. germination features of generated seeds were also affected by the maternal plant environment. under removal of all leaves per plant, seed germination percentage, seed vigor, and seedling weight were reduced. harvesting of the half-green leaves prior to the ripening of the seeds did not result in a decrease in seed yield or ‎germination characteristics of the generated seeds. nitrogen had less application of an impact on the analyzed maize features than defoliation. in conclusion, half of the green leaves in maize can be harvested before seed maturity without reducing seed yield and seed germination.