A field experiment was carried out during winter season of 2019-2020 at Al-Mhanawyah Research Station - Agriculture Research Directorate - Babylon Governorate / Iraqi, to study the gene expression of Sgr gene responsible for controlling the duration of staying green in varieties of wheat under effect of plant growth regulator during the two growth stages (vegetative and reproductive) by using quantitative reverse transcription-PCR (RT-qPCR) technique and achieving the highest grain yield for a number of wheat varieties. Randomized complete block design (RCBD) arranged according to split plots used with three replicates. The experiment included twelve wheat varieties (Saberbic, Al-Rasheed, Iraq, Tamoz-3, Al-Adnaniya, Babel, IPA-99, Al-Latifeya, Al-Hashemia, Al-Naeema, Buhooth-10 and Al-Baraka) within main plots and nine treatments of plant growth regulator spraying (spraying of distilled water at tillering and anthesis stages, spraying of Abscisic acid (ABA) at tillering stage, spraying of ABA at anthesis stage, spraying of ABA acid at tillering and anthesis stages, spraying of kinetin at tillering stage, spraying of kinetin at anthesis stage, spraying of kinetin at tillering and anthesis stages, spraying of ABA at tillering stage + kinetin at anthesis stage and spraying of ABA at anthesis stage + spraying of kinetin at tillering stage) within sub plots. The results showed that ABA spraying caused a significant increase in the gene expression of Sgr gene, whereas the spraying of kinetin caused a significant decrease in gene expression. It was observed that the Saberbic variety gave the highest gene expression of Sgr gene (1.44). Al-Rasheed and Iraq varieties showed that the decrease in the vegetative growth period which accounted 65% of lives cycle compared with reproductive stage (35%). Also, It is observed that the spraying of ABA was decreased the number of days of the stage in which it is sprayed or after, while the spraying of kinetin was increased the number of days of the stage in which it is sprayed or after. Besides, the spraying of kinetin at tillering stage revealed a significant increase in the biological yield (11.68-ton ha-1), whereas the spraying of ABA at tillering stage + kinetin at anthesis stage had the highest mean of grain yield of (4.63-ton ha-1). Al-Rasheed variety gave the highest mean of grain yield (5.56-ton ha-1).