الفهرس 
Effect of different nitrogen fertilization levels on the yieldOnly 14 pages are availabe for public view
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Abstract
Sugarcane is the main crop for sugar production in Egypt. Sugarcane plants are subject to infestation with a variety of insect pests among which dominants, the lesser sugarcane borer, Chilo agamemnon Bles., and corn borer Sesamia cretica Led. which causes serious damage to sugarcane plants and considerable loss of sugar yield. The present investigation aimed at throwing light on the population density of two sugarcane borer S. cretica and C. agamemnon, effect of sugarcane varieties and rates of (N) fertilization on the main insect pests attacking sugarcane plants, Effect of sugarcane varieties and rates of (N) fertilization on the physical, chemical parameters and yield components, the relation between the rates of infestation by C. agamemnon and juice quality -#99;-#104;-#97;-#114;acteristics of certain sugarcane varieties and expected values (increase or decrease) in juice quality -#99;-#104;-#97;-#114;acteristics with increase the rates of infestation by C. agamemnon. The results of these studies could be summarized as follows: br 5.1- Seasonal abundance of two sugarcane stem borers, S. cretica Led. and C. agamemnon Bles., on five sugarcane varieties. br 5.1.1- population density of S. cretica Led. br Results revealed that the population density for the pink corn borer, S. cretica was the highest monthly number of dead hearts during July followed by June and the least number of dead hearts was recorded in May during two successive seasons of 2011/2012 and 2012/2013. br Population density of S. cretica on five sugarcane varieties of the three observation revealed that sugarcane varieties G.84-47 and G.98-28 recorded less infestation and the moderate ones were recorded in case of G.T.54-9 variety, while the highest infestation of S. cretica were recorded on varieties of G.2003-47 and G.2003-49. br 5.1.2- Population density of the C. agamemnon Bles. br Results revealed that number of bored stalks of C. agamemnon increased gradually -#102;-#114;-#111;-#109; Aug. up to Mar. during two successive seasons of 2011/2012 and 2012/2013. br Population density of C. agamemnon on five sugarcane varieties of the eight observation showed the highest infestation was recorded in case of G.2003-47 and G.T.54-9 varieties. Meanwhile G.98-28 variety recorded the lowest infestation. While, G.84-47 and G.2003-49 varieties were moderate infestation. br 5.2- Effect of sugarcane varieties and rates of (N) fertilization on the main insect pests attacking sugarcane plants. br 5.2.1- Sugarcane varieties: br It is evident that sugarcane varieties significantly differed in their susceptibility to pink corn borers, Sesamia cretica and Chilo agamemnon infestation. br 5.2.1.1- S. cretica Led. br In 2011/2012 season, sugarcane varieties G.2003-47 and G.2003-49 were the highest infestation. Meanwhile, sugarcane varieties G.T.54-9, G.98-28 and G.84-47 were intermediate infestation by the S. cretica. br In 2012/2013 season, G.2003-47 variety was the most susceptible. On the contrary, G.98-28 variety was the least susceptible one. An intermediate infestation was observed in G.2003-49, G.84-47 and G.T.54-9 varieties. br 5.2.1.2- C. agamemnon Bles. br 5.2.1.2.1- Number of bored stalks. br 1n 2011/2012 season, G.98-28 variety was the least infested one. Meanwhile, the G.T.54-9 variety was the most susceptibility. An intermediate infestation was recorded in the varieties G.2003-47, G.2003-49 and G.84-47. br In 2012/2013 season, G.2003-47 and G.2003-49 varieties were the most susceptible. On the contrary G.98-28 variety was the least susceptible one. Meanwhile, the intermediate infestation was observed in stems of the varieties G.84-47 and G.T.54-9. br 5.2.1.2.2- Number of girdled stalks: br In 2011/2012 season, G.2003-49 variety was the most susceptible, meanwhile G.98-28 variety was the lowest susceptible. Whereas, an intermediate infestation were recorded in G.T.54-9, G.2003-47 and G.84-47 varieties. br In 2012/2013 season, the highest infestation occurred in G.2003-47 variety. Meanwhile, the least infestation was recorded in G.98-28 variety followed by G.84-47 variety. An intermediate occurred in G.2003-49 and G.T.54-9 varieties. br 5.2.1.2.3- Number of bored joints: br In 2011/2012 season, G.T.54-9 variety was the most susceptible, Whereas G.98-28 variety was the least susceptible one. An intermediate infestation were recorded in varieties, G.2003-47, G.2003-49 and G.84-47. br In 2012/2013 season, G.2003-47 variety was the most susceptible, Whereas G.98-28 variety was the least susceptible one. An intermediate infestation were recorded in varieties, G.2003-49, G.T.54-9 and G.84-47. br 5.2.1.2.4- Number of joints: br In 2011/2012 season, G.84-47 variety was the highest number of joints, meanwhile the lowest number of joints occurred in variety G.98-28. An intermediate number of joints occurred in varieties G.T.54-9, G.2003-49 and G.2003-47. br In 2012/2013 season, the highest number of joints occurred in G.T.54-9 variety, meanwhile the lowest number of joints was happened in G.98-28 variety. An intermediate number of joints occurred in varieties, G.84-47, G.2003-47 and G.2003-49. br 5.2.1.2.5- Number of holes: br In 2011/2012 season, G.T.54-9 variety was the highest number of holes of infestation, meanwhile the least infestation was observed in G.98-28 variety. An intermediate infestation were recorded in sugarcane varieties G.2003-47, G.2003-49 and G.84-47. br In 2012/2013 season, the highest number of holes occurred in G.2003-49 variety followed by G.T.54-9 variety, meanwhile the least number of holes was recorded in G.98-28 variety. br 5.2.1.2.6- Percentage of bored stalks: br In 2011/2012 season, G.98-28 variety was the least susceptible as percentage of infestation, whereas G.T.54-9 variety was the most susceptible one followed by G.2003-47. An intermediate infestation were recorded in sugarcane varieties G.2003-49 and G.84-47. br In 2012/2013 season, G.2003-47 variety was the highest susceptible, whereas G.98-28 variety was the least susceptible. br 5.2.1.2.7- Percentage of girdled stalks: br In 2011/2012 season, G.T.54-9 variety was the highest infested one. Meanwhile, G.98-28 variety was the least infestation. An intermediate as percentage were recorded in varieties G.2003-49, G.2003-47 and G.84-47. br In 2012/2013 season, G.2003-47 was the most susceptible variety. On the contrary G.98-28 variety was the least susceptible one. Remaining varieties were moderate susceptible infestation to C. agamemnon. br 5.2.1.2.8- Percentage of bored joints: br In 2011/2012 season, the highest percentage of infestation was recorded in G.T.54-9 variety, meanwhile, the lowest infestation was occurred in G.98-28 variety. br In 2012/2013 season, G.2003-47 and G.2003-49 varieties were the highest infestation. Meanwhile, the least infestation occurred in G.98-28 variety. Remaining varieties were intermediate susceptible infestation to C. agamemnon. br 5.2.1.2.9- Mean of holes / joints: br In 2011/2012 season, G.T.54-9 and G.2003-47 varieties were the highest infestation. Meanwhile, the least infestation was recorded in variety G.98-28 followed by G.84-47 and G.2003-49 varieties. br In 2012/2013 season, the least susceptible were occurred in sugarcane varieties by G.84-47 and G.98-28. Whereas, G.T.54-9, G.2003-47 and G.2003-49 varieties were the highest susceptible. br 5.2.1.2.10- Mean of holes / bored joints: br In 2011/2012 season, G.98-28 variety was the least susceptible one. Meanwhile, G.84-47 variety was the most susceptible. An intermediate were recorded in the varieties G.2003-47, G.T.54-9 and G.2003-49. br In 2012/2013 season, G.84-47 variety was the least susceptible, meanwhile G.2003-49 and G.T.54-9 varieties were the most susceptible. Other sugarcane varieties were moderate infestation. br 5.2.1.2.11- Mean of holes / stalk: br In 2011/2012 season, G.T.54-9 variety was the most susceptible, meanwhile G.98-28 variety was the least susceptible with C. agamemnon infestation. br In 2012/2013 season, Again G.98-28 variety was the least susceptible ones, meanwhile G.2003-49 variety was the highest susceptible to C. agamemnon followed by G.2003-47 and G.T.54-9 varieties. br 5.2.1.2.12- Number of bored stalks at harvest: br In 2011/2012 season, G.T.54-9 variety was the highest susceptible. Whereas, G.98-28 variety was the least susceptible one. On the other hand sugarcane varieties G.84-47, G.2003-47 and G.2003-49 were suffered an intermediate infestation. br In 2012/2013 season, Again G.T.54-9 variety was the most susceptible to infestation with C. agamemnon. Meanwhile, the lowest infestation was recorded in variety G.98-28. Remaining sugarcane varieties were moderate infestation. br 5.2.2- Nitrogen fertilization: br Susceptibility of sugarcane varieties with Sesamia cretica and Chilo agamemnon increased by increasing the rate of N fertilization. The highest levels of infestation were recorded in the case of sugarcane varieties received 280 kg N fertilizer per feddan. br In general trends of the present results showed that increasing level of nitrogen fertilization significantly increased levels of infestation by two main insects, S. cretica and C. agamemnon. br 5.3- Effect of sugarcane varieties and rates of (N) fertilization on the physical parameters: br 5.3.1-Sugarcane varieties: br 5.3.1.1- Stalk diameter (cm): br In general the tested sugarcane varieties varied significantly in stalk diameter. br In 2011/2012 season, G.98-28 and G.T.54-9 varieties were the most a thickness stalk. Meanwhile, G.84-47 variety was the slightly thinner as comprising with other varieties. br In 2012/2013 season, G.84-47 variety was the least slightly thinner, Meanwhile G.T.54-9 was the most thickness stalk. Remaining varieties were moderate stalk diameter. br 5.3.1.2- Stalk length (cm): br In 2011/2012 season, G.84-47 variety was the most stalks length, meanwhile the G.2003-49 variety was the least stalks length. An intermediate were occurred in varieties G.T.54-9, G.2003-47 and G.98-28. br In 2012/2013 season, G.T.54-9 and G.84-47 varieties were the taller than remaining varieties, whereas the G.98-28 variety was the shortest varieties. Meanwhile, G.2003-47 and G.2003-49 varieties were intermediate stalks length. br 5.3.1.3- Number of millable cane / fed.: br In general there were significant differences between the sugarcane varieties. br In 2011/2012 season, the sugarcane varieties can be arranged in ascending -#111;-#114;-#100;-#101;-#114; as follows G.2003-47, G.2003-49, G.98-28, G.T.54-9 and G.84-47. br In 2012/2013 season, the lowest number of millable cane occurred in G.2003-49 variety. Meanwhile, the highest number of millable cane occurred in varieties G.84-47 and G.T.54-9. br 5.3.2- Nitrogen fertilization: br Physical parameters of sugarcane varieties with stalks diameter (cm), stalks length (cm) and number of millable cane / fed. increased by increasing rate of fertilization. br 5.4- Effect of sugarcane varieties and rates of (N) fertilization on the chemical parameters and yield components at harvest. br 5.4.1- Sugarcane varieties: br 5.4.1.1- Brix percentage: br In general sugarcane varieties varied significantly in the brix percentage. In 2011/2012 season, G.98-28 variety was the least brix percentage. Meanwhile, G.84-47 variety was the highest brix percentage. Remaining varieties were intermediate. br In 2012/2013 season, G.T.54-9 variety was the least brix percentage, Meanwhile G.84-47 variety was the highest brix percentage. br 5.4.1.2- Sucrose percentage: br In 2011/2012 season, G.98-28 variety was the least as the percentage of sucrose. Meanwhile, remaining varieties were moderate. br In 2012/2013 season, all sugarcane varieties were nearly similar as percentage of sucrose. br 5.4.1.3- Purity percentage: br In 2011/2012 season, in general sugarcane varieties varied insignificantly in the purity percentage. br In 2012/2013 season, G.98-28 variety was the least purity percentage, meanwhile G.2003-47 was the highest purity percentage. br 5.4.1.4- Sugar recovery percentage: br Generally, sugarcane varieties varied significantly in the sugar recovery percentage, meanwhile the varieties G.84-47, G.T.54-9, G.2003-49 and G.2003-47 were the highest sugar recovery percentage. br 5.4.1.5- Pol %: br In 2011/2012 season, G.98-28 variety was the least as percentage of pol %. Meanwhile, remaining varieties were nearly similar as percentage of pol%. br In 2012/2013 season, G.T.54-9 and G.98-28 varieties were the least as percentage of pol%. br 5.4.1.6- Reducing sugar percentage: br In 2011/2012 season, G.2003-47 and G.2003-49 varieties were the lowest reducing sugar percentage. Meanwhile, the insignificant differences were found between sugarcane varieties G.T.54-9, G.98-28 and G.84-47 on the reducing sugar percentage. br In 2012/2013 season, results revealed that insignificant differences were found between sugarcane varieties in reducing sugar percentage. br 5.4.1.7- Weight of juice /20 stalks (kg): br In 2011/2012 season, G.84-47 variety was the least weight of juice /20 stalks. Meanwhile, the sugarcane varieties G.98-28 and G.T.54-9 were the highest weight of juice / 20 stalks. br In 2012/2013 season, G.T.54-9 variety was the highest weight of juice, meanwhile the least weight of juice occurred in G.84-47 variety. br 5.4.1.8- Mean of stalk weight (kg): br In 2011/2012 season, G.84-47 variety was the least mean of stalk weight /kg. Meanwhile, G.T.54-9 variety was the highest mean of stalk weight. br In 2012/2013 season, G.T.54-9 and G.2003-47 varieties were the highest mean of stalk weight. Meanwhile, G.84-47 and G.98-28 varieties were the least mean of stalk weight. br 5.4.1.9- Sugar yield (ton/fed.): br In 2011/2012 season, G.98-28 variety was the least sugar yield, meanwhile the G.T.54-9 variety was the highest sugar yield (ton/fed.). br In 2012/2013 season, generally, there are significant difference between sugarcane varieties in sugar yield (ton/fed.). G.2003-47 variety was the highest sugar yield. Meanwhile, the least sugar yield occurred in variety G.98-28. br 5.4.1.10- Cane yield (ton/fed.): br In 2011/2012 season, G.98-28 and G.2003-49 varieties were the least cane yield (ton/fed.). Meanwhile, the variety G.T.54-9 was the highest cane yield. br In 2012/2013 season, results revealed that there are insignificant difference between sugarcane varieties in cane yield (ton/fed.). br 5.4.2- Nitrogen fertilization: br - Effect of rates of (N) fertilization on chemical parameters and yield component: br Results revealed that brix, sucrose, purity, sugar recovery and pol percentages showed a reverse relationship due to nitrogen fertilization rates. Also, results revealed that reducing sugar percentage, weight of juice (kg), mean of stalk weight (kg), sugar yield (ton/fed.) and cane yield (ton/fed.). showed a positive relationship due to increasing rates of nitrogen fertilization. br 5.5-The relationship between the rate of infestation by C. agamemnon and juice quality -#99;-#104;-#97;-#114;acteristics: br 5.5.1 – G.T.54-9 sugarcane variety: br Results revealed that negative significant correlation and insignificant between the rate of infestation by C. agamemnon on the pol % in bored stalks during the two seasons, respectively. In contrast, simple correlations between C. agamemnon infestation and the percentages of the sucrose %, brix %, purity % and sugar recovery % were insignificant negative during the first and the second seasons of 2011/2012 and 2012/2013. br 5.5.2- G.98-28 sugarcane variety: br Statistical analysis revealed that highly significant negative correlations between the rate of infestation of C. agamemnon and the percentages of sucrose, brix, sugar recovery and pol during the first season, 2011/2012. Whereas, insignificant negative correlation was recorded during the second season, 2012/2013. br 5.5.3- G.84-47 sugarcane variety: br Results revealed that insignificant negative correlation between the rate of infestation of C. agamemnon and percentages of sucrose, brix, sugar recovery and pol, meanwhile insignificant positive in the percentages of purity and glucose during the first season. While, were significant negative of brix and pol% and insignificant correlations of sucrose, purity and sugar recovery percentages, while insignificant positive correlation of glucose % during the second season, 2012/2013. br 5.5.4- G.2003-47 sugarcane variety: br Results demonstrated that insignificant negative correlation between the rate of infestation of C. agamemnon and percentages of sucrose, brix, purity, sugar recovery and pol for the two successive seasons of 2011/2012 and 2012/2013. In contrast, it was insignificant positive correlation of glucose % for the first and second seasons. br 5.5.5- G.2003-49 sugarcane variety: br Statistical analysis revealed that significant negative correlation between the rate of infestation of C. agamemnon and percentages of sucrose, purity and sugar recovery. In contrast, there were insignificant negative of pol and glucose %. While, insignificant positive correlation with brix% during the first season, 2011/2012. Whereas, were insignificant negative correlations of sucrose, sugar recovery and pol percentages. While, insignificant positive correlation in the purity and glucose%. And it was significant negative correlation of brix % during the second season, 2012/2013. br 5.6- Expected values (increase or decrease) in juice quality -#99;-#104;-#97;-#114;acteristics with increase the rates of infestation by C. agamemnon infesting five sugarcane varieties at harvest: br 5.6.1- Brix percentage: br Statistical analysis revealed that the highest brix percentages were recorded with the lowest level of infestation by C. agamemnon in all different sugarcane varieties, except G.2003-49 variety during the two successive seasons. Meanwhile, G.98-28 variety was the least as the brix percentage. br 5.6.2- Sucrose percentage: br Results revealed that the maximum sucrose percentages were recorded with the lowest level of infestation by C. agamemnon in all sugarcane varieties. Meanwhile, G.2003-49 variety was the highest sucrose percentage during the first season, while in the second season, G.2003-47 variety was the highest sucrose percentage. However, G.98-28 variety was the least as the sucrose percentage during two successive seasons. br 5.6.3- Purity percentage: br Results revealed that the maximum purity percentages were recorded with the lowest level of infestation by C. agamemnon in all sugarcane varieties during two successive seasons. G.2003-49 variety was the highest purity percentage in the first season, while in the second season, the G.2003-47 variety was the highest purity percentage. However, the G.98-28 variety was the least as purity percentage during the first and the second seasons. br 5.6.4- Sugar recovery percentage: br Results indicated that the maximum sugar recovery percentages were recorded with the least level of infestation by C. agamemnon in all sugarcane varieties during the first and the second seasons. G.2003-49 variety was the highest sugar recovery percentage in the first season. While in the second season, the highest sugar recovery percentage was occurred in G.2003-47 variety. Meanwhile, the G.98-28 variety was the lowest as the sugar recovery percentage during the two successive seasons. br 5.6.5- Pol percentage: br Results indicated that the maximum pol percentages were recorded with the lowest level of infestation by C. agamemnon in all sugarcane varieties during the 1st and the 2nd seasons. Meanwhile, G.T.54-9 variety was the highest pol % in the first season, while the G.84-47 variety was the highest pol % in the second season. However, the G.98-28 variety was the least as the pol percentage during two successive seasons. br 5.6.6- Glucose percentage: br Results revealed that the highest glucose percentages were recorded with the highest level of infestation by C. agamemnon in all sugarcane varieties throughout two successive seasons. G.2003-49 and G.T.54-9 varieties were the least as the glucose percentage during the 1st season, while in the 2nd season, the G.2003-47 variety was the least as the glucose percentage.