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Two field experiments were conducted out during 2012 and 2013 seasons to estimate combining ability, heterosis for six inbred lines (Three American inbreds: P97, B73and Oh.43 and three Egyptian inbred lines: R39, Inb.1021 and Inb.1004) and its F1 crosses. The most important results obtained from this investigation can be summarized as follows:  The differences among means of parental inbreds and also among means of crosses were significant or highly significant for all studied traits.  Mean squares of crosses were highly significant for all studied traits, indicating wide range of genetic variability among the studied crosses and this is primary requirement for further computation.  Both general and specific combining abilities mean squares were found to be highly significant for all studied traits.  GCA/SCA variances ratios were found to be lower than unity for six traits i.e. time to tassel emergency, time to silk emergency, number of rows/ear, number of kernels/row, grain yield/plant and shelling percentage and higher than unity for plant height and 100-Kernel weigh.  Significant positive general combining ability (GCA) effects were found for most studied traits. The best combiners were P2 (P79) and P4 (Inb.1021) for earliness traits; P5 (Inb.1004) and P6 (Oh.43) for plant height; P5 (Inb.1004) for number of rows/ear; P1 (R39) for number of grains/row; P2 (P97), P3 (B73) and P4 (Inb.1021) for 100-grain weight; P1 (R39) for grain yield/plant; P1 (R39) and P2 (P97) for shelling percentage.  Significant positive specific combining ability (SCA) effects were found for most studied traits. The best cross combinations P3×P4 for number of rows/ear; P1×P5 for number of grains/row; P1×P3, P1×P6, P2×P3, P2×P5, P3×P5 and P4×P6 for 100-Grain weight; P1×P2, P1×P5, P2×P5, P3×P6 and P4×P5 for grain yield/plant; P1×P5, P3×P6 and P4×P5 for shelling percentage.  Results showed significant or highly significant heterosis over mid-parents and better parents for all studied traits. The best crosses over mid and better parents were (P1×P5) for number of rows/ear; (P1×P6) for number of grains/row; (P2×P5) for100-grain weight;(P1×P6)for grain yield and (P1×P4) for shelling percentage.  The study recommends using inbred line P3 (B73) and crosses P1×P2, P1×P3 and P3×P6 in breeding program of maize to improve the yield and its components where they recorded the highest value of the grain yield/plant and gave a better combining ability.

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Two field experiments were conducted at Farm of Sids Agricultural Research Station, Egypt, during 2013 and 2014 seasons to study the effect of different irrigation regimes (I 1 = 100 %, I 2 = 85 % and I 3 = 70 % from irrigation requirements) and nitrogen levels (90, 120 and 150 kg N fed-1) on maize growth, yield and its yield attributes and some crop-water relationships. The most important results could be summarized as follows:Irrigated maize plants with full irrigation produced higher values of plant height, ear diameter, 100-grain weight, weight of grains ear-1 and grain yield as well as total amount of irrigation water applied, seasonal consumptive use and the net income. Irrigated maize plants with 80 % from irrigation requirements gave the highest values of water use efficiency and utilization efficiency.Supplied maize plants with 150 kg N fed-1 induced highest values of the abovementioned growth, yield and its attributes and net income as well as improve seasonal consumptive use, water use efficiency and utilization efficiency.Irrigated maize plants with full irrigation requirements and supplied with 150 kg N fed-1 produced highest yield and net income of maize plants.

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Two field experiments were conducted at the Experimental Station, Faculty of Agriculture, Mansoura University, during the two successive winter seasons of 2009/2010 and 2010/2011. The main objectives of this study were determining the effect of sowing dates (1 st Sept., 1 st Oct. and 1 st Nov.), nitrogen fertilizer levels (40, 60 and 80 kg N/fed) and time of foliar application with "Melagrow" as natural growth promoter (without, one and two times) on growth and petal yield of safflower (Carthamus tinctorius, L.) cv. Giza 1. The obtained results could be summarized as follows: 1. Intermediate sowing date of safflower (1 st October) significantly surpassed other sowing dates (1 st September and 1 st November) in all studied growth and petal yield characters, except Crop growth rate "CGR", Relative growth rate "RGR" and Net assimilation rate "NAR" which produced from sowing on 1 st September in both seasons. 2. Fertilizing safflower plants with 80 kg N/fed significantly increased all studied growth and petal yield and markedly recorded the highest values of these characters in both seasons. However, application of 40 kg N/fed produced the lowest values of all studied characters in the two growing seasons. 3. Foliar application with Melagrow(as a natural growth promoter) twice after 30 and 70 days from sowing significantly recorded the highest values of studied growth and petal yield characters, exclusion leaves/stem and branches ratio, CRG, RGR and NAR in both seasons. While, application of Melagrow one time after 30 days from sowing came in the second rank in this respect in both seasons. On the other hand, the lowest values of all growth and petal yield characters were resulted from the control treatment (without foliar application) in both seasons. From the obtained data in this study, it can be concluded that sowing safflower on 1 st October and mineral fertilizing with 80 kg N/fed beside twice foliar application with Melagrow as a natural growth promoter in order to maximizing its growth and petal yield under the environmental conditions of Dakahlia Governorate, Egypt.

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