In spite of the development observed in the area and production of potatoes crop in Yemen for the period of (1990-2010) to the level of self-sufficiency, the exported quantity, however, still very limited, It even decreased sharply in 2010 by 84.5%, compared to it's level exported in 2006. Stagnant productivity of potatoes in Yemen at around 13 ton only per-hectare, in front of (35- 45) ton/h globally, is believed to be the main obstacle standing behind the failure of exportation the Yemeni potatoes to the abroad. According to field study, several results have been obtained, the most important of which: The variables, such as, chemical fertilizer, equipment, manure and seeds are found to be the most effective factors on the output of potatoes. It is proved statistically significant at (0.01) level and responsible for the change occurred in the production of sampled individuals by 77% (R2), however, the result show that the quantity used in the production process of potatoes by mentioned above factors fill short to meat the level of optimal quantity required to maximize the profit.  The size of optimal level of production was estimated at (19.9) ton and the price of potatoes accepted by producers was estimated at 121390 YR/Ton. According to percentage of importance, seeds came first at the total variable cost by 31%, then, irrigation by 17.6%, fertilizers and pesticides 14.6%. Net revenue was estimated at (493640) YR, and the benefit /cost ratio was estimated at 1.40. The most important recommendation reached by this study is directed toward more using inputs in process of production by producers of potatoes, to maximize profit and increase productivity of area cultivated.

Study was conducted during 2008 - 2009 on five local grape cultivars: Gubery, Assemy, Aswed, Razeqi  and Bayadh at the faculty of Agriculture–ThamarUniversity . Cultivars were collected from Rawdha and Bany Husheish area – Sana'a Governorate. Morphological and physical characters of berry were determined and the chemical analysis for juice was also assessed. Finally, cuttings were taken from all cultivars and cultivated at the nurs- ery. Data were collected and analyzed by SAS system according to the least significant difference at the probability level of 0.05 and the results showed that: Assemy cultivar gave the maximum value of berry weight of 8.5 g, whereas the lowest rate was for Razeqi cv. of 1.2 g. According to berry dimensions, berry length ranged between 1.6 - 2.6 cm and berry width 1.35-2.43 cm. Razeqi cv. gave the highest content of T.S.S (24.5%), whereas Gubery cv. contained the lowest value  of  20.37%. pH value  was  between 3.98–4.77 and organic acids  were between 0.35 -0.80%. Aswed cv.  gave the highest rate of rooting percentage of 58%  meanwhile, the lowest rate was found in the Razeqi cv. (6.75%).