Effect of split application of nitrogen and potassium as well as spraying growth regulators on growth and yield attributes of hybrid rice

Two field experiments were carried out during 2020 and 2021 summer seasons at the experimental farm of Research and training center in rice, FCRI, ARC, Egypt, to study the effect of split application of nitrogen and potassium as well as some growth regulators for some growth attributes of the female line of rice hybrid NO.1. Split-split plot design with three replicates was used. Results indicated that, adding N in three splits (N 20- 20- 20kg) significantly surpassed the other two ones for plant height and leaf area index. Added N in two splits (N 30- 30kg) significantly exceeded the other splits for chlorophyll content, panicle exertion and flag leaf area. For application splits of potassium, the third split (K 9- 9- 7kg) had significantly higher than the other ones for plant height, chlorophyll content and flag leaf angle, while the second split (K12.5- 12.5kg) surpassed the others for flag leaf area and leaf area index. However, panicle exertion was significantly affected by the first split (K 25kg). Spraying GA3 had significantly higher values for plant height and leaf area index, while spraying with IAA significantly surpassed the other two growth hormones for chlorophyll content, panicle exertion and grain yield. However, ascorbic acid (AA) significantly exceeded the others for flag leaf area only. Plant height, chlorophyll content and panicle exertion were significantly affected by first and second order interactions except for panicle exertion where the first order N x K interaction was only observed. It was concluded Finally could be concluded that, the desirable treatment was adding the nitrogen in three splits N 20-20-20, while, the potassium in two splits and apply the GA3 with (30g/ha.) to produced highly seed yield (t/ha.)