General and specific combining ability effects were partitioned according to a proposed model to estimate general and specific combining ability effects for each parent when it is used as a female or a male in its hybrid combinations. A working example includes a full-diallel among eight parents was used so that all possible hybrid combinations were included. The objectives of this study were: (1) to compare the GCA and SCA effects before and after partitioning, (2) to evaluate the relative contribution of each parent to its cross combination when it is used as a male or female parent, (3) to estimate maternal effects in the form of GCA and SCA effects, and (4) to estimate the relationship between maternal and reciprocal effects. Results revealed that estimated GCA effects according to Griffing’s method is equal to the average of GCA effects of each parent, after partitioning, when it is used as a male and a female in its hybrid combinations. In addition, the average of the difference between female and male GCA effects would provide precise estimation of the maternal effect. This would prove that maternal effect provides precise estimation to the favorable alleles, which is mainly additive. The SCA effects calculated according to Griffing’s method is the average of SCA effects of each cross and its reciprocal. The average of the difference between SCA effects of each cross and its reciprocal, according to the proposed model, is equal to the reciprocal effect. This would prove that reciprocal effect provides precise estimation to the interaction effect between nuclear and cytoplasmic genes given that the interaction between male and female alleles inside the nucleus of the cross is similar to its reciprocal hybrid.

Two field experiments were carried out at the Experimental Farm of Gemmeiza Agricultural Research Stations during 2007 and 2008 seasons to study the effect of row spacing, i.e. (60,70 and 80cm apart) and plant density, i.e. (20000, 25000 and 30000 plants/fed.) on growth, yield and yield components of two maize hybrids, i.e. (S.C125 and S.C162). A split-split plot design with four replicates was used in the two experiments.  Results showed that increasing ridge spacing significantly recorded No. of days two 50% tassling and silking , plant and ear heights were in the same direction planting on 80cm ridge was associated with a significant increase in ear length , No. of kernels/row, 1000 kernels weight and grain yield (ard/fed).  On the other side, plant density of 25000 plant/fed was associated with the highest grain yield and its component as soon as it is considered of the optimum environmental.  Single cross 125 was earlier than single cross 162 of days to 50% tassling and silking. S.C. 125 had the best effects of plant and ear height towards low ear position, 1000 kernels weight, S.C. 162 gave the highest values of No. of ear length kernels/row and grain yield. (Ridge spacing x plant density interaction was significant for No. of days to 50% tassling and silking, plant and ear heights, No. of kernels/row. Plant density x hybrid interaction was significant for plant height, ear length, 1000 kernels weight (g) and grain yield ard./fed).  This investigation showed that planting on 80-cm rows at plant density of 25000 plants/fed (25-cm between hills) in order to obtain the highest grain yield. This would also facilitate using the mechanization and saving costs, time, and effort.

Two field experiments were carried out at the Experimental Farm of Gemmeiza Agriculture Research Station, Agricultural Research Center, Egypt, during the two growing summer seasons of 2010 and 2011. The main objective of this study was to evaluate the effect of compost rates, humic acid treatments and nitrogen fertilizer rates on growth, grain yield and its components of maize cultivar yellow single cross 166. Each rate of compost was performed in separate experiment. Every experiment of compost rates was carried out in split plot design with four replications. The main plots were occupied with humic acid treatments. The sub-plots were assigned to nitrogen fertilizer rates. The obvious results of this investigation can be summarized as follows:Adding 30 m 3 compost/fed recorded the highest values of growth traits, grain yield and its attributes in both seasons and their combined. Moreover, applying 15 m 3 compost/fed came in the second rank in both seasons and their combined. The lowest values of these characters were obtained by control treatment (without compost) in both seasons and their combined Soaking seeds before planting in humic acid plus foliar spraying plants with humic acid enhanced maize growth, subsequently produced the highest means grain yield and its attributes in both seasons and their combined. It was followed by soaking seeds before planting in humic acid or foliar spraying plants with humic acid in both seasons and their combined.There were substantial differences in all studied characters among various studied nitrogen fertilizer rates in both seasons and their combined. Fertilizing maize plants with 120 kg N/fed produced the highest values of these characters in both seasons and their combined. However, using 60 kg N/fed was accompanied with the least values of grain yield and its attributes characters in both seasons and their combined, as well as there are many significant effect of the interactions among studied factors on studied characters.Generally, it can be concluded that organic fertilizing maize plants hybrid S.C. 166 with 30 m3 compost/fed and soaking seeds plus foliar spraying plants with humic acid at the rate of 1000 ppm in addition mineral fertilizing with 120 or 90 kg N/fed in order to maximizing its growth and productivity under the environmental conditions of Gemmeiza district, El-Gharbia Governorate.

A Field trial was conducted in Gemmeiza Agricultural Research Station (Middle Nile Delta, Egypt) in 2011and 2012 to study the effect of four irrigation patterns under two ridge spacing on maize growth, grain yield, yield components, saving of applied irrigation water, and water productivity(WP). The assessed irrigation patterns were: 1) Control where all of furrows were irrigated (ALL), 2) irrigating via every other furrow starting at the 3 rd irrigation (EOF3), 3) irrigation via every other furrow technique starting from the 4 th irrigation (EOF4), and 4) irrigating with every other furrow starting from the 5 th irrigation (EOF5). Irrigation patterns were evaluated under two ridge spacing (70 and 80 cm). The experimental design was randomized complete block arranged in incomplete block design, where replications were nested within ridge spacing and irrigation pattern treatments were randomly arranged within ridge spacing treatments. The most important findings could be as follows:-*Under 80-cm ridge spacing both days to 50% tasseling and 50% silking were significantly decreased, but 70-cm ridge spacing reduced ear height, and ear position (%). * Ridge spacing did not significantly affect plant height, grain yield, number of kernels per row, ear length, ear diameter, kernel depth, and 100-kernel weight. However, 80-cm ridge spacing was associated with higher ear length, ear diameter, kernel depth, and 100-kernel weight. *Irrigation pattern (EOF3) had significantly higher days to 50% tasseling than the control (ALL). Treatment EOF4 had the highest plant height. The lowest plant height was linked to EOF5 treatment but the highest ear height and ear position resulted from application of EOF3. *Grain yield was not significantly affected by irrigation patterns. Irrigation patterns EOF4 and EOF5 were associated with the lowest number of kernels per row. * Effect of ridge spacing x irrigation pattern Interaction was significant for plant height, ear height and kernel depth. *Applied irrigation water decreased, while water productivity increased under 80-cm comparing with 70-cm ridge spacing. The highest value of applied water was recorded for (ALL) irrigation pattern treatment with 70-cm ridge spacing. Application of EOF3, EOF4, and EOF5 patterns reduced applied irrigation water and improved water productivity. *The highest WP was recorded under the interaction of planting maize crop in 80-cm ridge spacing with EOF3 and EOF4 irrigation patterns. Saving irrigation water was higher at EOF3 followed by EOF4, then EOF5. This study strongly suggest applying every other furrow irrigation technique starting from the 3 rd irrigation (EOF3) with planting maize crop on 80-cm ridge spacing to save more irrigation water without concomitant reduction in grain yield.

Identification of specific physiological differences among maize genotypes (six inbred lines, four single crosses and four three-way crosses) to drought would be useful to plant breeders for improving selection criteria. Two field experiments were conducted in optimum and stress moisture conditions at Gemmeiza Agricultural Research Station in 2001 and 2003 growing seasons. The treatments were 14 genotypes, (six inbreds and eight hybrids), which were separately established under three irrigation treatments in split plot design with four replications. The genotypes were compared under water-deficit conditions on the basis of certain rapid techniques to determine leaf area index (LAI), photosynthetic efficiency (photo), canopy temperature depression (CTD), stomatal conductance (SC) and chlorophyll (CHL) content which were deleteriously affected by water stress in the sensitive genotypes. Results revealed that values of LAI, photosynthetic efficiency, canopy temperature depression, stomatal conductance and chlorophyll content of maize hybrids surpassed those of inbred lines. This was true at 30, 45 and 60 days after planting (DAP). Differences among maize hybrids and among inbred lines were significant at different growth stages for the same studied traits, except of the LAI for the inbreds, at 30 DAP and CTD for the hybrids at 30 as well as 60 DAP. Detecting certain physiological criteria, i.e. LAI, photosynthetic efficiency (photo), canopy temperature depression (CTD), stomatal conductance (SC) and chlorophyll content (Chl) could be used as reliable techniques to explore the physiological activity of maize genotypes at early stages of growth and may be recommended in screening different genotypes in maize breeding programs.