The present research was concerned with studying the physiological response of two sorghum cultivars to different rates and splitting of NPK. This study was carried out in the Experimental Agricultural Farm of Agriculture faculty in Assiut Univ, Assuit Governorate, Egypt; during the two growing seasons of 2012 and 2013. The field experiment was carried out in a randomized complete block design (RCBD) using split-split plot arrangement with three replications. The cultivars (Giza 15 and Dorado cultivar) were a signed in the main plot, while the NPK rates (75, 100 and 125% of the recommended NPK fertilizers/fed) were allotted in the sub plot and different Split doses (1, 2, 3 and 4 times) were allotted in the sub-sub plots. The experimental unit area was 12 m2. In general, the maximum meanvalues of grain yield (21.2 and 23.1 ard/fed in 2012 and 2013 seasons, respectively) were obtained from Giza 15 cultivar when received the highest NPK rate (125% of the recommended NPK fertilizers/fed) applied at three equal doses.

The present research was concerned with studying the physiological response of two sorghum cultivars to different rates and splitting of NPK. This study was carried out in the Experimental Agricultural Farm of Agriculture faculty in Assiut Univ, Assuit Governorate, Egypt; during the two growing seasons of 2012 and 2013. The field experiment was carried out in a randomized complete block design (RCBD) using split-split plot arrangement with three replications. The cultivars (Giza 15 and Dorado cultivar) were a signed in the main plot, while the NPK rates (75, 100 and 125% of the recommended NPK fertilizers/fed) were allotted in the sub plot and different Split doses (1, 2, 3 and 4 times) were allotted in the sub-sub plots. The experimental unit area was 12 m2. In general, the maximum meanvalues of grain yield (21.2 and 23.1 ard/fed in 2012 and 2013 seasons, respectively) were obtained from Giza 15 cultivar when received the highest NPK rate (125% of the recommended NPK fertilizers/fed) applied at three equal doses.

The present research was concerned with studying the physiological response of two sorghum cultivars to different rates and splitting of NPK. This study was carried out in the Experimental Agricultural Farm of Agriculture faculty in Assiut Univ, Assuit Governorate, Egypt; during the two growing seasons of 2012 and 2013. The field experiment was carried out in a randomized complete block design (RCBD) using split-split plot arrangement with three replications. The cultivars (Giza 15 and Dorado cultivar) were a signed in the main plot, while the NPK rates (75, 100 and 125% of the recommended NPK fertilizers/fed) were allotted in the sub plot and different Split doses (1, 2, 3 and 4 times) were allotted in the sub-sub plots. The experimental unit area was 12 m2. In general, the maximum meanvalues of grain yield (21.2 and 23.1 ard/fed in 2012 and 2013 seasons, respectively) were obtained from Giza 15 cultivar when received the highest NPK rate (125% of the recommended NPK fertilizers/fed) applied at three equal doses.

In order to study the effect of irrigation water rates and splitting nitrogen on productivity of wheat. Three field experiments were conducted at El-Wady Al-Assiuty experimental farm in new reclaimed soil during 2013/2014 and 2014/2015 seasons using cultivar Sids 12 using sprinkler irrigation system. Each experiment subjected to one level of irrigation water requirements (100%, 75% and 50%) and each experiment contains four treatments of splitting nitrogen fertilization. Results indicated that, irrigation levels had a high significant effect on yield and its components. As when 50% of the recommended irrigation requirements was applied, the reduction of grain yield reached 44.3 and 28.9% in the first and second seasons, respectively. Moreover, splitting nitrogen fertilization affected all studied traits. As splitting nitrogen fertilization to five splits recorded the highest mean value of grain and biological yields as compared with control (3 splits) in both seasons. The interaction between irrigation levels and splitting of the nitrogen fertilizer had a significant effect on grain yield. As the highest mean value of grain yield was obtained from 5 splits with 100% of irrigation requirement in the first season while in the second season the highest grain yield was obtained from 6 splits with 100% irrigation requirements. From this study, data clarify that in sandy soils about 25% of irrigation requirements could be saved without significant losses in grain yield by splitting the nitrogen fertilization. Thus we could have additional amount of water could be used for increase the cultivation area of wheat to minimize the production consumption gap of this crop.

Heterosis and combining ability for grain yield and some agronomic traits were studied among thirty F1 grain sorghum crosses and their elven parents under three NPK levels during 2014 and 2015 seasons. Significant differences among genotypes were found for all studied traits, indicating wide genetic diversity. The interaction of genotypes with each of years and NPK levels were significant in most studied traits. The analysis of variance for combining ability revealed that the mean square due to entries, parents, parents vs. crosses, crosses, lines, testers, lines × testers turned up significant for all studied characters and suggesting that the experimental materials possessed considerable variability that both general and specific combining ability were involved in the genetic expression of these characters. The female line ICSB610 showed significant and negative general combining ability (GCA) effects for days to 50% heading and panicle length and positive for grain yield and plant height. It may be used to develop high yielding, early flowering, and tall hybrids with short panicles. For specific combining ability (SCA), effects, the crosses ICSA613 × ICSR89028 and ICSA20 × ICSR53 gave positive and highly significant SCA effects which indicated that these crosses can be considered desirable combiners. These crosses had also high grain yield per se and one of the parents with highest GCA effects. The observations on portioning of combining ability variance into additive and dominance variances indicated the role of both additive and dominance gene action. The magnitude of non-additive variance was higher than the additive variance by many folds for all studied traits.

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