الفهرس 
Introduction
Growth charecteristicsOnly 14 pages are availabe for public view
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Abstract
This present investigation was carried out at the private farm at Minia Governorate during the two successively seasons 2003 and 2004 to study the effect of four irrigation treatments (normal irrigation (without skipping) ” every 12 days”, skipping 3rd irrigation at elongation stage, skipping 4th at flowering stage and skipping 5th at milk ripe stage) and four time of N application (20 % at planting+ 40 % before 1st irrigation + 40 % before 2nd irrigation, 25 % at planting + 50 % before 1st irrigation + 25 % before 2nd irrigation, 1/3 at planting + 1/3 before 1st irrigation + 1/3 before 2nd irrigation and 50 % before 1st irrigation + 50 % before 2nd irrigation) on growth characters, yield and its components of three maize hybrids (Sc-10, Sc-2010 and Twc ”Nefertety”). The experimental design was split- split plot with four replications in two growing seasons. The obtained results could be summarized as follows:
I: Growth characters:
1- Number of days to 50 % tasseling was significantly affected by irrigation treatments in both seasons as well as hybrids in the first season, while time of N application had no significant effect on this trait. The latest pollen shedding was resulted from hybrid maize Sc-10 hybrid while, Twc ”Nefertety” hybrid gave the shortest period to 50 % tasseling. While, exposing plants to skipping 3rd irrigation at elongation stages increased number of days to 50 % tasseling compared with the other irrigation treatments. The effect of interaction between the different combinations for the three studied factors on this trait had no significant effect in both seasons except, irrigation treatments x time of nitrogen application in 2004 season and time of N application x hybrids in 2003 season.
2- Number of days to 50 % silking was significantly affected by irrigation treatments in both seasons as well as hybrids in the first season, while time of N application had no significant effect on this trait in both seasons. The least number of days to 50 % silking was recorded when applied normal irrigation (without skipping), while the longest period was obtained when skipping 3rd irrigation at elongation stage. Sc-10 maize hybrid gave the tallest period to 50 % silking, while Twc ”Nefertety” gave the shortest period. The effect of interaction between the different combinations for the three studied factors on this trait had no significant effect in both seasons except, irrigation treatments x time of nitrogen application as well as time of N application x hybrids in 2003 season. The lowest number of days to 50 % silking was obtained by normal irrigation (without skipping) when splitting N application into three doses (25 % at planting + 50 % before 1st irrigation + 25 % before 2nd irrigation), as well as when splitting N application into two equal doses before the first and second irrigation with planting Twc Nefertety hybrid.
3- Exposing plants to skipping 3rd irrigation during elongation stage significantly decreased plant height. The highest value was obtained from normal irrigation (without skipping), while the lowest one was obtained from skipping 3rd irrigation at elongation stage. Time of N application had no significant effect on this trait in both seasons.
Sc-10 maize hybrid recorded the tallest plant, while Sc-2010 was the shortest one in the first season. The effect of interaction between the different combinations for the three studied factors on this trait had no significant effect in both seasons.
4- Ear height was significantly increased with normal irrigation (without skipping) in both seasons, while ear height significantly decreased by exposing plants to skipping 3rd irrigation at elongation stage. In 2003 season, Sc-10 hybrid gave the highest value on this trait, while Twc ”Nefertety” gave the lowest one. Time of N application as well as all types of interactions had no significant effect on this trait in two seasons.
5- Effect of irrigation treatments on ear position % was significant in both seasons, while hybrids showed a significant effect on this trait in the second season only. Time of N application as well as the effect of interaction between the different combinations for the three studied factors on this trait had no significant effect in both seasons except, irrigation treatments x time of N application, time of N application x hybrids as well as the interactions between three factors studies in the second season only.
6- Stem diameter significantly increased when applied normal irrigation (without skipping), while the thinner one was obtained due to skipping 3rd irrigation at elongation stage in both seasons. The highest value of stem diameter when splitting N application into three equal doses (at planting and before first and second irrigation), while the lowest value was recorded with splitting N application into two equal doses (before the first and second irrigation) in the first season. Sc 10 maize hybrid gave the thickest stem, while Sc-2010 gave the thinnest in 2003 season. The effect of interaction between the different combinations for the three studied factors on this trait had no significant effect in both seasons except, irrigation treatments x time of N application, irrigation treatments x hybrids and time of N application x hybrids in the first season.
7- Number of green leaves/ plant was significantly affected by irrigation treatments and hybrids in both seasons, as well as time of nitrogen application in the first season. The effect of interaction between the different combinations for the three studied factors on this trait had significant effect in both seasons except, irrigation treatments x time of N application in both seasons, as well as the interaction among the three studied factors in the first season. The highest number of green leaves/ plant was obtained by planting Sc-2010 hybrid with normal irrigation (without skipping) when splitting N application into two doses (50 % before 1st irrigation + 50 % before 2nd irrigation) in the second season.
8- Leaf area/ plant was significantly increased with normal irrigation (without skipping), while skipping 5th irrigation at milk ripe stage significantly decreased leaf area/ plant in both seasons. The highest leaf area/ plant was obtained when applying nitrogen fertilization into three doses (20 % at planting + 40 % before 1st irrigation + 40 % before 2nd irrigation) in 2003 seasons. Hybrids Sc-10 and Sc-2010 gave the highest value of leaf area/ plant in the first and second seasons, respectively. The effect of interaction between the different combinations for the three studied factors on this trait had significant effect in both seasons. The highest leaf area/ plant was obtained by planting hybrid Sc-10 with normal irrigation when splitting N application into three equal doses (at planting, before first irrigation and before second irrigation), while the lowest one was obtained from skipping 5th irrigation when splitting N application into three equal doses with planting hybrid Sc-2010 in the first season. In the second season, the highest value was obtained from normal irrigation by splitting nitrogen application into three doses, 25 % at planting + 50 % before 1st irrigation + 25 % before 2nd irrigation (TN2) with planting hybrid Sc-2010, while the lowest one was obtained from skipping 5th irrigation (I4) when splitting nitrogen application in two equal doses (before first and second irrigation) (TN4) with planting hybrid Sc-10 .
II: Yield and its components :
1- Ear length was significantly affected by irrigation treatments and hybrids in both seasons, as well as time of nitrogen application in the second season only. The effect of interaction between the different combinations for the three studied factors on this trait had no significant effect in both seasons except, time of N application x hybrids and the interaction among the three factors studied in the second season. Sc-10 maize hybrid gave the longer ears when received normal irrigation (without skipping) when splitting N application into three doses (20 % at planting + 40 % before 1st irrigation + 40 % before 2nd irrigation) in the second season.
2- Ear diameter was significantly decreased due to skipping 3rd irrigation at flowering stage (I3), while normal irrigation (without skipping) gave the highest value in the two seasons. The highest value of ear diameter was obtained when splitting N application into three doses (20 % at planting + 40 % before 1st irrigation + 40 % before 2nd irrigation) in both seasons. Maize hybrid Sc-10 gave the highest value of ear diameter, while Twc ”Nefertey” gave the lowest one in two seasons. In 2003 season, the interaction between irrigation treatments x time of N application, irrigation treatments x hybrids as well as the interaction among the three factors studied had significant effect on ear diameter. The highest ear diameter was recorded by normal irrigation when splitting N application into three doses (20 % at planting + 40 % before 1st irrigation + 40 % before 2nd irrigation) with planting Sc-10, while the lowest one was obtained by planting maize hybrid Sc-2010 when skipping 4th irrigation with splitting N application into two equal doses.
3- Normal irrigation (without skipping) gave the highest number of rows/ ear in both seasons. Time of N application had significant effect on this trait in 2003 season only. Hybrids Sc-10 gave the highest value of number of rows/ ear in the two seasons. The effect of interaction between the different combinations for the three studied factors on this trait had significant effect in both seasons except, the interaction effect between irrigation treatments x time of N application in 2003 season as well as time of nitrogen x hybrids in both seasons.
4- Exposing maize plants to skipping 4th irrigation at flowering stage (I3) decreased number of kernels/ row, while normal irrigation (without skipping) gave the highest value on this trait in the first season. Time of N application had significant effect on number of kernels/ row in two growing seasons, the highest value was obtained from splitting N application into three doses (20 % at planting + 40 % before 1st irrigation + 40 % before 2nd irrigation) in both seasons. Hybrid Sc-10 gave the highest number of kernels/ row in both seasons. The effect of interaction between the different combinations for the three studied factors on this trait had no significant effect in both seasons except, the interaction effect between time of N application x hybrids and the interaction among the three factors studied in the first season. The maximum value was recorded from planting Sc-10 hybrid with using normal irrigation and splitting N application into three equal doses (at planting, before first and second irrigations in 2003 season.
5- Grain yield/ plant was significantly increased when applied normal irrigation (without skipping) in both seasons. Time of N application had significant effect on this trait in the two seasons. The heaviest grain yield/ plant was recorded when splitting N into three doses (20 % at planting + 40 % before 1st irrigation + 40 % before 2nd irrigation). Maize hybrid Sc-10 gave the highest grain yield/ plant, while Twc ”Nefertey” gave the lowest one in both seasons. The interaction effect between irrigation treatments x time of N application, irrigation treatments x hybrids and the interaction between time of N application x hybrids had significant effect on this trait in 2003 seasons, as well as the interaction among three factors studied had significant effect on this trait in both seasons, the highest grain yield/ plant was recorded when planting hybrid Sc-10 and using normal irrigation with splitting N application into three doses (20 % at planting + 40 % before 1st irrigation + 40 % before 2nd irrigation) in both seasons.
6- Number of ears/ 100 plant was significantly increased by normal irrigation treatment (without skipping) compared with the other irrigation treatments in both seasons. The highest number of
ears/ 100 plant was obtained when splitting N application into three doses (20 % at planting + 40 % before 1st irrigation + 40 % before 2nd irrigation) in both seasons. Sc-10 hybrid gave the maximum number of ears/ 100 plant in the two growing seasons. The effect of interaction between the different combinations for the three studied factors on this trait had no significant effect in both seasons except, the interaction effect between irrigation treatments x time of N application and time of N application x hybrids in the second season as well as irrigation treatments x hybrids in both seasons. The highest number of ears/ 100 plant was recorded by applying N into three doses (20 % at planting + 40 % before 1st irrigation + 40 % before 2nd irrigation) with normal irrigation (without skipping) in the second season. Sc-10 hybrid gave the maximum number of ears/ 100 plant when applying it normal irrigation in both seasons.
7- Kernel depth was significantly affected by irrigation treatments and hybrids in both seasons while, time of N application had significant effect on this trait in the first season only. The effect of interaction between the different combinations for the three studied factors on this trait had no significant effect in both seasons except, the interaction effect between time of N application x hybrids in the first season. The highest value was obtained from planting Twc Nefertety with splitting N application into three doses (25 % at planting + 50 % before 1st irrigation + 25 % before 2nd irrigation)
8- Shelling percentage was significantly affected by irrigation treatments in both seasons. Normal irrigation treatment (without skipping) gave the higher shelling percentage, while skipping 5th irrigation at milk ripe stage (I4) gave the lowest value. Splitting N application into three doses (20 % at planting + 40 % before 1st irrigation + 40 % before 2nd irrigation) gave the highest value of shelling percentage in the two seasons. Sc-10 maize hybrid gave the maximum shelling percentage, while Twc ”Nefertey” gave the lowest ones in 2003 and 2004 seasons. The effect of interaction between the different combinations for the three studied factors on this trait had significant effect in both seasons. The highest value was recorded from Sc-10 plants with using normal irrigation, when splitting N application into three equal doses in first season or from the same hybrid with normal irrigation when splitting N application into two equal doses in the second season.
9- 100- kernels weight was significantly increased when applied normal irrigation (without skipping) compared with the other irrigation treatments in both seasons. Time of N application had significant effect on this trait in the two seasons. The highest value was obtained when splitting N application into three doses (20 % at planting + 40 % before 1st irrigation + 40 % before 2nd irrigation). This trait was significantly affected by hybrids in both seasons. Sc-10 hybrid gave the highest value, while the hybrid Twc ”Nefertey” gave the lowest one. The effect of interaction between the different combinations for the three studied factors on this trait had no significant effect in both seasons.
10- Grain yield/ fed was significantly increased by normal irrigation (without skipping). The highest value was obtained by normal irrigation, while the lowest one was recorded from skipping 4th irrigation at flowering stage in both seasons. Results revealed that, the highest value of grain yield/ fed. was obtained when splitting nitrogen application into three doses (20 % at planting + 40 % before 1st irrigation + 40 % before 2nd irrigation) in both seasons. Sc-10 hybrid gave the highest value, while the hybrid Twc ”Nefertety” gave the lowest one in both seasons. The effect of interaction between the different combinations for the three studied factors on this trait had no significant effect in both seasons except, the interaction effect between irrigation treatments x time of N application. The maximum grain yield/ fed. was recorded by normal irrigation (without skipping) when splitting N application into three doses (25 % at planting + 50 % before 1st irrigation + 25 % before 2nd irrigation) in the first season, while the maximum value on this trait in the second season was obtained when splitting nitrogen application into three doses (20 % at planting + 40 % before 1st irrigation + 40 % before 2nd irrigation) with the normal irrigation treatment. The interaction among three factors studied had significant effect in the first season only. The maximum grain yield/ fed was obtained by normal irrigation when splitting N application into three doses (20 % at planting + 40 % before 1st irrigation + 40 % before 2nd irrigation) with planting Sc-10 hybrid. While, the lowest one was obtained by skipping 4th irrigation (I3) when splitting N application into three equal doses (TN3) with planting hybrid Twc Nefertety.