Abstract SUPAN, RUSSEL AVENIR, 2022. Effect of Paclobutrazol on the Growth and Yield of Hybrid Corn. Pampanga State Agriculture University, Magalang, Pampanga. Adviser: Angelina C. De Jesus, PhD This study assessed the results of a field experiment on the effect of Paclobutrazol in different varieties of hybrid corn from May to September 2022 in Sitio Pitabacan, San ldefonso, Magalang, Pampanga. The treatment was laid out following the Split Plot Experimental in Randomized Complete Block Design (RCBD)with three replications. The field experiment was comprised of different levels of Paclobutrazol as the main treatment: TI (Control), T2 (300mg/L), T3 (400mg/L), and varieties of corm V1 (DeKalb 91 18), V2 (DeKalb 8282), V3 (Bioseed H102) and V4 (NK 6414). The results of the study showed T3-400mg/L generated a significant interaction influence on plant height that might change the height which was lower and semi-dwarf size with a hybrid maize variety named V1-91 18 with various amounts of Paclobutrazol. There was a substantial interaction between the various levels of Paclobutrazol and the four types of varieties, from 15,45 to maturity day V4-6414 got the highest and wider stalk diameter. The highest survival rate was V2-8282, while the three varieties were comparable. The four hybrid con varieties were comparable in ear height, ear diameter, and ear length but heavier than the ear weight shown in V4-64 14 which was recorded. Likewise, the root density and number of ears per plant had no significant interaction effects in paclobutrazol under the hybrid corn variety. On the other hand, the com variety under T1- Control produced the lightest ear than with Paclobutrazol. In addition, three types of hybrid maize had the highest shelling percentages while V4-6414 received the lowest of all. Therefore, total dry mass an V4-6414 was produced heaviest from fresh to dry while the three varieties were comparable. Moreover, V4-6414 in T3-400mg/L was registered to have the highest return on investment in the hybrid com variety.