Impact of Planting Date on Growing Degree Units, Grain Yield and Growth Traits of Some Egyptian Yellow Maize Inbred Lines

This study was conducted in 2021 to the impact of planting date on maize inbred lines and determine their accumulated growing degree units (GDU).The experiment held at three agriculture research stations (Gemmeiza, Ismaelia Sids) with RCBD four replications. It planned provide also some insights optimize production mitigate climatic changes all researchers scientific community. Three dates i.e. April 20th (early), May20th (optimal) June (moderately late) were applied investigate effect number days 50% tasselling silking, plant height grain yield 16 Egyptian yellow lines. In addition, (GDU) from silking. Results revealed highly significant differences among tested inbreds for studied traits indicating presence genetic diversity inbreds. Also, same trend found locations x location variability testing that behaved differently different due conditions Number silking reduced as a result increased temperatures during development. Longest heights obtained prolonged vegetative growth cool - moderate prevailing early growth. Grain reduced, few exceptions, high time which resulted pollen, stigma or fertilization abortion caused poor seed setting. Highest Gemmeize it is recommended suitable Inbred Sakha 3 best performing under variable dates. 1, 11, Gz 639 Gm 1021 performed well certain Determination big variation them matched present specified earliness lateness GDU would help expectation timing many agricultural practices such beginning detasselling process harvest hybrid breeding programs.