The present research aimed to characterize physical and morphological features of thirteen varieties of mandarin as one of the National Gene Bank and Genetic Resources (NGBGR) objectives in Egypt which include also, collection, conserva-tion, characterization, and evaluation of agricul-tural genetic resources. The present study investi-gates the morphological characterization, pollen grain fertility and sterility as well as fruit chemical characterization (vitamin C, PH, T.S.S and acidi-ty) of 13 mandarin varieties (Citrus sp.).Including Balady, Malawy, Chine mandarin, Clementine, Celiopatra, Centra, Satsuma, Tangerine Dancy, El-Shorbagee, Sonbol, Sayed Marri, Abd El-Razik and Aswan. The Physical and morphological char-acterization descriptors revealed differences among varieties. Characterization of tree shape resulted in eight obloid varieties and five were spheroids. Leaf lamina shape morphological char-acteristic studies showed one elliptic variety, three ovate and 9 lanceolate. Fruit shape studies indicat-ed that five varieties were pyriforum, five obloid and three were spheroid. Fruit apex shape demon-strated that seven varieties were depressed, while six were truncate. Differences in flavedo (skin) color among varieties revealed that seven were orange; two were dark orange and one variety for each of (light orange, green yellow, dark yellow and yellow). As to the color of the pulp (flesh), results indicated that two varieties were yellow, 10 were orange and one was orange-red. The average number of carples per fruit ranged 10-14 carple in 9 varieties and from 5-9 carple in four varieties. The average number of seeds per fruit revealed that five varieties had ten to nineteen seeds; three varieties hold 20-50 seeds and two varieties con-tained five to nine seeds, one variety included one to four seeds, while two varieties had no seeds. Other morphological studies are investigated and will be presented. Fruit chemical characterization disclosed that Malawy had the highest vitamin C concentration (44.82 mg/100 ml) whereas both of Celiopatra and Satsuma showed the lowest con-centration (15.0 and 14.0 mg/100 ml, respective-ly).The greatest pH was determined in Abd El-Razik (pH 3.91) variety in contrast to the more acidity (pH 3.12-3.77) found in El-Shorbagee and Chine mandarin juice, respectively. The best total soluble solids were determined in the Abd El-Razik (15.1%), whereas the least ones were found in Satsuma (9.13%). Chine mandarin recorded the highest titratable acidity of 3.88% in contrast to 0.67 % for Sonbol. Studies of pollen grain fertility showed that Celiopatra and Sayed Marri varieties gave the highest pollen fertility (99.84%and 99.44% respectively). Contrarily, the highest pol-len sterility was found in Clementine variety (8.41%).

The potato plants (Solanum tuberosum L.) vs. valor were exposed to different levels of nitrogen fertilizer (60, 100, 140, 180 kg N/feddan (4200 m2)) and in-row plant spacing (12.5, 25 and 50 cm) for maximizing the yield production to match food security needs under climate change impacts on Delta region,  Egypt. The experiment was carried out during two growing seasons (2010/2011 and 2011/2012) in split plot design at El-Bossily Farm, Agricultural Research Center, El-Behira Governorate, Egypt. The vegetative growth characteristics and yield parameters were measured. The result of this study verified that increasing nitrogen level up to 180 kg N/feddan significantly increased the vegetative growth, total and marketable yields than the other N treatments. The in-row plant spacing 50 cm was significantly increased vegetative growth and yield (kg/plant), but the total yield (kg/m2) had different trend. The highest total yield /m2 was obtained by 12.5 cm treatment. The interaction effect of 180 kg/feddan of N and 12.5cm in-row plant spacing were increased the total tuber yield (kg/m2) significantly. In contrary, the best marketable yield (tubers > 35 mm) /m2 was obtained by 25 and 50 cm in-row plants.  This study was concluded that the best agronomic practices for potato production obtained by application 180 kg N/feddan of with in-row plant spacing 25 cm treatment. The economical consideration of the different treatments showed that the best total net income was obtained by 180 kg/feddan N with 50 cm in-row plant spacing.