عوض عبد القادر, أسماء2025-09-032025-09-032018https://dspace.omu.edu.ly/handle/123456789/487Two field experiments were carried out at the experimental station of the faculty of Agriculture, Omar AL- Mukhtar University, EL-Baida Libya, during the growing seasons (2013 and 2014), to investigate the impact of the rate of nitrogen fertilization and yield trial of seven varieties (genotypes) of maize Zea mays L. on some growth characters, yield, and yield components. The experimental design was split- plot with three replicates was used for each precedent genotype The main plots included three levels of nitrogen fertilizer in the form of Urea (46% N), the levels of nitrogen were (0, 50, 100 kg N/ha), while the sub-plots included the maize genotypes, namely (White 30k8, Yellow 3062, Yellow 3084, White 310 Yellow 352, AL-Kufra.2 and Giza 2 open pollinated") The " 3 experimental unite was (2 X2 m) = (4m²), planting was on rows (50cm) a part, the distance between hills with row was (25 cm), each hill contained one plant after thinning planting date was on the first week of may during both growing seasons. Measurements of growth characters were preformed on five samples of each varieties chosen randomly from the mid- rows of each experimental units, the growth characters included, number of plants/experimental unit, number of plants without ears, number of ears/ experimental unit, plant height (cm), number of leaves / plant, length of the leaf of ear (cm) number of grains / row, weight of cobs (gm), dry weight of 100 - grain (gm) ear diameter (cm),number of rows /ear, length of ear (cm), percentage of protein of green leaves (%), percentage of protein of green stems (%), percentage of protein of grains (%), percentage of protein on dry leaves (%), percentage of protein on dry stems (%), weight of ears during harvest (gm), and chlorophyll content of the leaves (A, B, and total chlo.). Data of each agronomic character analyzed separately. The analysis of variance was performed - using M - Stat program and LSD was used for the comparison among means Main results obtained from this investigation can be summarized as follow: 1-Number of plants / experimental unit: Number of plants /experimental units as affected by different levels of nitrogen fertilizer and different varieties was observed. Nitrogen fertilizer levels had a significant impact of the number of plants /exp. Unit during the first growing season only However the effect of varieties and the interaction between the two factors (varieties x nitrogen levels )had no significant effect on this agronomic characters during both growing seasons 2-Number of plants without ears : Results obtained showed no significant effect on the number of plants without ears due to the impact of nitrogen fertilizer levels and varieties Interaction between the two factors showed no significant effect of this character due to the acting of both factors separately on this agronomic character during both seasons. 3-Number of ears /experimental unit : The results showed no significant difference between the corn plants dun to the effect of varieties and the application of nitrogen fertilizer on the number of ears /experimental unit during both growing season. The interaction between nitrogen fertilizer levels and varieties had no significant effect on this agronomic characters during first and second growing seasons. 4- Chlorophyll content of the leaves : Chlorophyll (A): Data obtained showed no significant effect of chlorophyll(A) due to the effect of nitrogen levels during both growing seasons, Also the impact 45 of varieties was not significant. Interaction between the two factors had a significant effect of this character during the first growing season only. Chlorophyll (B): Data obtained showed no significant effect of different levels of nitrogen fertilizer on the chlorophyll (B). However, high significant differences was shoed during the impact of different varieties on this characters due to both growing seasons Interaction effect was significant only during the second growing season. Total Chlorophyll : Adding of nitrogen fertilizer and the different varieties had no significant impact on the total chlorophyll during both growing seasons the interaction also had no significant effect on this char acts during both seasons 5-Plant height: Results showed no significant differences between varieties as affected by different levels of nitrogen fertilizer during both growing seasons, however, the varieties of maize differ from each other on plant height character on the first season only. In contrast differences did not reach the level of significant on second growth season. The interaction between varieties and nitrogen levels had no significant effect on the plant height during both growing season 6- Stem girth (cm): Stem girth as affected by different nitrogen fertilizer levels and different genotypes was observed no significant differences were recorded due to the effect of nitrogen fertilizer and different maize genotypes and the interaction between the two factors were recarded during the 7-Numbers of Leaves/plant: The results obtained from the experiment were very interesting where the growth of different maize varieties was examined at different rates of nitrogen fertilizer. Increasing the levels of the essential nutrient, increased the number of leaves, plant, as would be expected, during both growing seasons However, the increment did not reach the levels of significant. Results indicated that no significant effect of the varieties on the number of leaves/plant during 1st and 2nd growing seasons. There was no significant effect of the interaction between varieties and nitrogen fertilizer levels on the number of leaves /plant. 8- Width of leaf of ear (cm): Results indicated that no significant effect of nitrogen fertilizer on the Width of leaf of ear during both growing seasons. However, the genotypes significantly effect the agronomic character during the first season, whiletwo growing seasons. differences did not reach the level of significant during the second season. Interaction between the two factors had a significant impact in the growth character during 1st season only. 9- Length of the leaf of ear: The results showed no significant different on the length of the leaf of ear due to the effect of nitrogen fertilization during both growing seasons Differences between corn varieties in response to different nitrogen levels did not reach the significant degree. Also, the impact of the interaction between nitrogen levels and varieties was not significant. 10- Ear height (cm): Results indicated that application of nitrogen fertilizer had no 3 significant difference on ear height in both growing seasons. Varieties showed a significant effect on ear height during first growth season, and not during the second season. Variety (352- Yellow) gave the highest value (124.233)cm, as compared with (Kufra 2-hybrid) which gave the lowest (91.133) cm. There was not a significant effect of the interaction between nitrogen fertilizer levels and varieties on the ear height during tooth two seasons. 11-Numbers of ears / plant : Results obtained Showed no significant impact of the two factors of this experiment and the interaction during both growing seasons on the number of ears/plant. 12- Number of rows/ ear: During the first growing season, results showed that the application of nitrogen fertilizer had no significant effect on the number of rows/ear, however, significant differences observed during the second growing seasons due to the impact of nitrogen levels on the number of rows/ear. Varieties had a significant effect on this agronomic character during 1st growing season only. High significant effect of the interaction between nitrogen fertilizer levels and varieties was observed during first season, in contrast, differences between varieties did not reach the level of significant in the second growing season. 13- Number of grains/row: Results indicated that nitrogen fertilizer had a significant effect on the number of grains/row at harvest time in the first growing season. the (100 kgN/ ha¹) treatment gave the beigest values of the number of grains/row as compared with the other two treatments. Although there was different response of the plants on their response to nitrogen fertilizer during the second growing season but the differences did not reach the level of significant. Varieties had no significant effect on the number of grains/row during growing seasons Interaction between nitrogen fertilizer and varieties had no significant impact on this growth character. 14- Ear diameter: The results showed no significant effect of nitrogen fertilizer kevels on ear diameter among corn verities during the two growing seasons. High performance of the varieties has been observed when the plants grown at a considerably nitrogen levels (100 kg N/ha¹) as compared with the other two levels. Also it was observed that the interaction between nitrogen levels and varieties had no significant effect on the ear diameters in both growing seasons. 15- Dry - weight of cobs : Application of nitrogen fertilizer had no significant effect of the dry weight of cobs during first growing season. In contrast, results showed a significant differences on the dry weight of cobs due to the effect of nitrogen application levels on the second growing season, however, (100 kg N/ha¹) treatment indicated, as aspect the highest values as compared with the other two treatments. Varieties also showed significant differences in their response to nitrogen levels on the dry weight of cobs in the first growing season only also, there was a significant effect of the interaction between nitrogen levels and varieties during the first season only. 3 16- Dry weight of ears at harvest: Table (10): showed the dry weight of ears at harvest with respect to applied nitrogen rates and the impact of different genotypes did not had a significant effect due to the two experimental factors on both growing seasons. However, the interaction effect showed a significant difference during the 1 growing season only. No significant effect between the two factors during the 2nd season, indicated that both factors act separately on the dry weight of ears at harvest time. 17- Dry weight of 100- grains (gm): During the first growing season, application of nitrogen fertilizer had a significant effect on the dry weight of 100- grains, the (50 kg N/ha¹) treatment gave the highest value (32.520)mg, while the control treatment (0 kg/N/ha¹) recorded significant differences recorded during the second growing season. Varieties and the interaction between nitrogen levels and varieties showed no significant impact on the dry weight of 100- grains during both growing seasons 18-Green leaf protein content (%): Results obtained showed no significant effect of nitrogen fertilizer levels on the percentage of protein in the green leaves during first growing season In contrast, significant differences recorded during the second growing season, when nitrogen fertilizer applied at a rate of (100 kg N/ha¹) compared with the control treatment. Varieties differ from each other significantly on the protein percentage of the green leaves during second season only. "Giza .2 "open variety gave the highest value (7.163%), while "Kufra .2. hybrid" gave the lowest value (5.593 %). Interaction between nitrogen levels and varieties had a significant impact during the second growing season. 19- Green stem protein content (%): Results indicated that application of nitrogen fertilizer had a significant effect on the protein content in the green stems during both growing seasons the (100 kg N/ha¹) treatment recorded the highest values (7.195%) and (17.838%)during 1st and 2nd seasons, respectively. However, the control treatment gave the lowest values (6.153%) and (5.310 %)during first and second growing seasons, respectively. Varieties had no significant effect during first season, compared with the second season that showed a high significant differences between corn varieties tested moreover the (352. Yellow) variety gave the beigest value of protein content (8.075%), while the (3062-Yellow) variety gave the least value (6.245%). During the second growing season interaction between nitrogen fertilizer levels and varieties had a significant effect on the percentage at protein in the green stems However, the differences did not reach the level of significant during the first growing season. 20- Protein content in grains (%) Nitrogen fertilizer levels had a significant effect on the percentage of protein in grains. Increasing nitrogen levels increased protein content of grains during the first growing season, (100 kg N/ha) treatment gave the highest value (7.313%) compared with control which gave the least value (5.954%).However, application of nitrogen fertilizer during second season had no significant effect on this agronomic character varieties had no significant impact on the protein content in the grains during both growing seasons of this study. The interaction of nitrogen levels and verities had a significant effect on the protein content in grains during 1 growing season while, the effect on this interaction during the 2nd growth season did not reach the level of significant. 21- Protein content in dry leaves (%) Dry leaves protein content as affected by nitrogen fertilizer treatment was observed. Application of nitrogen had a significant effect on the protein content in dry leaves. During both growing seasons A range at (7.693)to (6.227%) was observed in the first growing season while a range at (6.939 )to (5.599)% observed in the second season. Varieties did not represent a significant effect on dry leaves protein in first season In contrast, a significant effect on this agronomic characters was conducted in the second season the variety (30k8- white) was superior in protein content in the dry leaves (6.867%), however, the variety (352- Yellow recorded the lowest protein content (5.920%).the interaction of nitrogen levels and varieties had a significant impact on the dry leaves protein content (%), only in the second growing season in this study. 22- Protein content in dry stems (%) Results showed that application of nitrogen fertilizer had a significant effect on protein content in dry stem in both growing seasons the (100kg N /ha¹) treatment gave the highest values were (7.637% and 7.101%) during first and second growing seasons, respectively. In contrast, the control treatment (0 kg N/ha¹) gave the lowest values (6.301% and 5.646%) during 1st and 2nd seasons respectively. Varieties effect and the interaction between nitrogen levels and varieties had a significant impact on the protein content in dry stems during the second growing season only.otherThesis