EVALUATION OF INTRODUCED EGYPTIAN MAIZE (ZEA MAYS L.) VARIETIES FOR GRAIN YIELD AND YIELD COMPONENTS UNDER DIFFERENT PLANT DENSITIES IN MIDDLE AND WESTERN REGIONS OF IRAQ

Abstract

Two field experiments were conducted during the FALL season of 2024 at the Baghdad and Anbar locations to evaluate the response of four introduced Egyptian varieties of   maize (TW-78E, TW-345E, IY-355E, and IY-207E) compared to two local varieties (Baghdad 3 and Al Maha) at three plant densities of 60.000, 70.000, and 80.000 plants ha⁻¹. The experiments were conducted according to a randomized complete block design (RCBD) with a split-plot arrangement with three replications, where plant densities were distributed in the main plots and varieties in the subplots, and a combined analysis was performed for the two locations. The results showed significant differences between the two locations and most of the study factors and their interactions, as the Baghdad location was significantly superior in most of the studied traits, recording the highest average length of the ear (18.58 cm), ear diameter (4.11 cm), number of rows (14.88 rows), number of grains per row (38.18 grains   row⁻¹), number of grains per ear (569.7 grains per ear⁻¹), and yield per plant (187.10 g), compared to the Anbar location , which recorded 16.97 cm, 3.80 cm, 13.64 rows, 34.89 grains per row⁻¹, 473.1 grains per ear⁻¹, and 124.95 g, respectively. Plant density significantly affected most traits, with a density of 70.000 plants/ha achieving the best performance, recording the highest average ear length (18.28 cm), number of kernels per row (38.12 grains   row-1), number of grains   ear -1(540.0 grains  ear-1), and yield   plant -1(163.33 g). Ear diameter and number of rows were not significantly affected by plant density. Varieties showed clear variation in performance. The Egyptian variety IY-355E excelled in ear length (18.14 cm), while the Iraqi variety Al Maha recorded the highest number of rows (15.01 rows), and the Egyptian variety TW 345E achieved the highest number of grains   row-1 (39.93 grains   row-1). While the IY-207E variety excelled in the number of grains per ear (542.7 grains ⁻¹) and yield per plant (162.08 g), the two- and three-way interactions showed a clear difference in the response of the varieties depending on the location and plant density. The TW-345E variety at the Baghdad location recorded the highest number of grains, reaching 646.3 grains ⁻¹, while the Iraqi variety Baghdad 3, at a density of 70.000 plants ha⁻¹ at the Baghdad site, achieved the highest yield   plant-1, reaching 230.41 g. The results confirm the existence of a significant interaction between genotypes, environment and plant density, and that a density of 70.000 plants   hectare-1 represents the optimal level for most yield traits. The Egyptian varieties, especially IY-207E, TW-345E and IY-355E, showed high productive efficiency and good ability to adapt to Iraqi environmental conditions, which qualifies them for adoption in maize improvement and production programs.