الفهرس 
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Abstract
Experiments were carried out at Agronomy Seeds lab and Crop Physiology lab Agronomy Dept., faculty of Agriculture, Ain shams university. The present investigation was proposed to evaluate the effects of different storage methods at several storage periods on quality and nutrient value of yellow grain maize (Zea mays L.). In Egypt, maximum storage periods for yellow grain maize is a whole year before the release of new maize production in the market, therefore, this investigation was proposed to store grains at maximum period of a whole year for monitoring changes on grain quality and fodder nutritional value at fixed intervals through the year as kept by different methods.
In the present study yellow maize (three -way hybrid 368) grains were stored via four storage methods (M1 -Treated threshed grains with CaCo3, M2- Threshed grains, M3- Grains on de -husk ears and M4- Covered grains with husk) and were evaluated at four storage periods (3, 6, 9 and 12 months).
The obtained results could be summarized as follows:
1- Weight of 100 grain, insect%, hectoliters and moisture content:
The data shows that the weight of the grain, the percentage of insects, the hectoliters, and the moisture percentage had significantly changed over time and depending on the storage method. Concerning the storage periods; it has been found that P1 and P2 had given the highest values with non-significant difference for weight of 100-grains and hectoliters. Also the same period gave the lowest values for insect percentage and moisture percentage. About storage methods, the TTG followed the TG had shown the maximum values for weight of 100-grains and hectoliters, also had revealed the minimum values for insect percentage and moisture percentage. Overall, the grain weight had decreased over time, the insects % had increased over time, the hectoliters had decreased over time, and the moisture % had increased over time. The storage method also had a significant effect on the abovementioned traits, and the TTG followed the TG were the best storage methods. The interaction between storage periods and storage methods also influenced the quality of maize grains. Data aslo revealed that P1M1, P2M1, P4M1, P3M1 and P4M2 had given the highest values of weight of 100-grains. Regarding insects %, it is found that P1M1, P2M1, P4M1, P3M1 and P4M2 had given the minimum values. The P1M1 followed by P1M2, P4M2 and P4M1had shown the maximum values of hectoliters. Finally, the interaction between P1M1, P1M2 and P2M1had resulted the minimum values for moisture percentage. At few words, The TTG followed by TG method were the most effective storage treatments.
2- Germination and seedling traits:
The results revealed that the storage period and method had a significant effect on the germination, plumule length, radical length, seedling fresh weight, and seedling dry weight of yellow maize grains. Regarding storage periods, germination percentage decreased with increasing storage periods but was highest for 3 months; and the length of the plumule and radical length were decreased as the storage period increased but were highest values for 6 and 3 months, respectively. Also, the fresh and dry weight of seedlings decreased as the storage period increased, then grains stored for 6 and 3 months were recorded the highest values respectively. It was shown that germination after storage decreased with length of storage, this occurred because most of the stored seed were infected with fungi although seeds were stored at acceptable temperature (10°c) there were lowered germination percentage. Concerning the storage methods, the results showed that germination %, plumule length (cm), radical length (cm), seedling fresh weight (g), and seedling dry weight (g) were highest for treated threshed grains with CaCO3 (TTG) and lowest for covered grains with husk (CGWH) and grains on de-husk ears (GDH), respectively. This result may be due to calcium carbonate absorbs moisture from the surrounding atmosphere, which preserves the integrity of the grain, as well as reducing the chances of infection with store pests, which leads to preserving the grain for a longer period. The interaction between storage period and storage method had a significant impact on all abovementioned traits. Germination percentage was highest for grains stored for 3 months (P1) under four different storage methods (TTG, TG, GDH and CGWH) with non-significant difference. However, storage period for P2, P3 and P4 had the highest values with non-significant differences under TTG treatment. plumule length (cm) had the highest values with non-significant difference under P3M1, P2M1, P4M2, P2M2 and P4M1. Radical length was highest for grains stored for P1 under four different storage methods (TTG, TG, GDH and CGWH) with non-significant difference. Seedling fresh weight had the highest values with non-significant difference under P3M1, P2M2 and P4M2. seedling dry weight had the highest values with non-significant difference under P1M1, P4M1, P1M2 and P1M4. In brief, maize grains were stored for 3, 6, 9 and 12 months under two storage methods i.e., Treated threshed grains with CaCo3 (TTG) followed by Threshed grains (TG). TTG method is the most effective way to store maize grains to reserve its quality. The TG method is also effective, but not as effective as the TTG method. The GDH and CGWH methods are less effective than the TG method.
3- Chemical composition of grains
Results showed a significant effect of storage periods and methods and their interaction on yellow maize grain chemical composition. Data also obtained that the storage treatment for 3 months recorded the highest values for the following studied traits i.e., protein%, ethereal extract %, fiber % and ash%. On the other hand the highest value of NEF percentage was recorded at storage period 12 months. Results also cleared that by prolonging the storage period from 3 months to 6, 9 and 12 months, this led to a significant decrease in all the previous characteristics except NEF percentage. In addition, the percentage of decrease was estimated when storing for a period of 12 months compared to storage for a period of 3 months as follows protein 26.26%, ethereal extract 31 %, fiber 26.79% and ash 14.96%. In respect of the effect of storage methods on quality of yellow maize grains there was a significant effect and the grains were treated with calcium carbonate recorded the highest values of protein%, ethereal extract %, fiber % and ash% thus, it is considered the most appropriate storage method that preserves the value of grains. In the same time this treatment (TTG) recorded the lowest value of NEF percentage. On the other hand, covered grains with husk (CGWH) gave the lowest main values of protein%, ethereal extract %, fiber % and ash% it means that there was an inverse relationship between NEF and the other grain measured components.
The interaction between storage period and storage method had a significant impact on abovementioned traits as well as P1M1, P1M2, P1M3, P1M4, P2M1 and P2M2 interaction treatments recorded the highest values of protein % and fiber % followed by P2M3 and P3M1 for protein only. Concerning the effect of interaction between periods and storage methods on ethereal extract and ash % data revealed that P1M1 and P1M4 treatments gave the highest mean values respectively. The results also showed that covered grains with husk (CGWH) were stored for 12 months, while achieving the lowest values of protein%, ethereal extract %, fiber % and ash% also gave the highest value for NEF percentage.
4- Grain nutritional value
The data shows that the nutritional value of yellow grains maize traits (gross energy (GE), digestible energy (DE) and total digestible nutrients (TDN) %) had significantly changed and decreased by prolonging the storage periods as well as the highest and the lowest values of GE, DE and TDN were recorded with storage periods of 3 and 12 months, respectively. Results also clarified that treated threshed grains with CaCo3 (TTG) was the most suitable storage method to save the nutritional value of grain and recorded the highest values of gross energy (GE), digestible energy (DE) and total digestible nutrients (TDN) %. While storage covered grains with husk (CGWH) gave the lowest values of the pervious traits. In respect to the impact of interaction between periods and method of storage on gross energy (GE), digestible energy (DE) and total digestible nutrients (TDN) % of yellow maize grains, data cleared that P1M1 gave the highest values followed by P1M2 for the abovementioned traits, while storage covered grains with husk (CGWH) for 12 months (p4M4) recorded the lowest nutritional value of grains. It is noting that treatment 1 recorded the lowest rates of deterioration in the nutritional value of grains with prolonged storage period.