سکینه فرجی

In order to study the effects of drought stress on polyphenolic compounds of pomegranate juice (Punica granatum L.) (total phenol, total flavonoid and cyanidin 3-glocoside content) as well as  fruit yield, an experiment was carried out as split plot based on a randomized complete block design with three replications (irrigation levels in main plots and pomegranate genotypes in subplots). Results showed that drought stress increased the content of juice polyphenolic compounds (P <0.05) and decreased fruit yield (P <0.05) in comparison with non-stress conditions (75±5% FC). However, mild stress (55±5% FC) caused a lower yield loss (P <0.05) compared to severe stress (35±5% FC). The results also showed that the genotypes studied could be considered as a rich source of phenolic compounds; however, the highest difference among the genotypes was found for cyanidin 3-glocoside content at different irrigation levels. On the other hand, based on the principal component analysis, under non-stress and mild stress conditions, genotypes Agha Mohamad Ali (AMA), Pust Sefid Torsh (PST), Malas Torshe Saveh (MTS), and Malas Shirine Saveh (MSS) could be recommended in food and pharmaceutical industries as superior and natural antioxidant-rich genotypes due to the high fruit yield and polyphenolic compounds. Generally, because of the importance of yield potential under drought stress, the mild drought stress treatment (55±5% FC) could be introduced as the optimum condition to obtain acceptable level of secondary metabolites, particularly cyanidin 3-glocoside, and fruit yield in Saveh region.

In order to evaluate the freezing tolerance of olive cultivars (native and foreign), a factorial experiment based on completely randomized design with three replications was carried out under controlled conditions. The investigated factors included cultivar (Zard, Roghani, Koroneiki, Mission), temperature (-18, -20 °C) and frost duration (24 and 48 hours). In addition, the effects of double and triple interactions among cultivar were significant for these two physiological traits. By applying freezing temperatures for 24 and 48 hours, the results showed that the electrolyte leakage percentage and the amount of free proline increased and decreased respectively with decreasing temperature in all studied cultivars; however, the changes of proline were more regular than the electrolyte leakage. So that at -18 °C, the highest and lowest percentage of electrolyte leakage was related to Koroneiki and Roghani cultivars, respectively and at -20 °C, the following descending order was obtained for the percentage of electrolyte leakage: Koroneiki > Mission- Roghani> Zard. However, in similar conditions, the highest and lowest amount of proline belonged to Zard and Koroneiki cultivars respectively. The proline capability to discriminate the studied cultivars was higher. So, based on the results obtained, cultivar Zard may be suggested as the preferable and superior cultivar for cultivation in areas under freezing stress.

In order to compare yield and agronomic characteristics of 38 new winter rapessed (Brassica napus L.) cultivars along with Okapi as check, a field experiment was carried out based on randomized complete block design during 2009-10 cropping season with three. Rapeseed cultivars showed significant differences for all traits at 1 percent probability level. In this research, ES Betty, NK Karibik, NK Aviator, Champlain and RNX 3621 cultivars showed the highest grain yield. In order to evaluate qualitative characteristics of superior rapeseed (Brassica napus L.) varieties, another field experiment was performed in 2010-11 cropping season. Five superior rapeseed varieties, selected of first experiment along with Okapi, Modena and and Licord as check comprised the experimental factors. Results showed that ES Betty variety had the highest seed yield and linolenic acid. NK Aviator and Champlain varieties showed superiority for linoleic acid. ES Betty and NK Aviator had the lowest oleic acid. Also, Modena and Champlain varieties showed the highest seed content of both Iron (Fe) and Zinc (Zn). Licord had the greatest seed content of Copper (Cu) and Manganese (Mn). There was positive and significant correlation between seed yield, linolenic acid and glucosinolate content. Rapeseed cultivars had significant differences for seed yield, glucosinolate content, fatty acids combination and seed content of micro nutrients elements. Also, there was inverse relationship between quantitative and qualitative yield in rapeseed.

In order to evaluate of growth stages، physiologic traits and seed qualitative characteristics of advanced winter rapeseed (Brassica napus L.) varieties in Arak a field experiment was performed in 2010-2011 cropping seasons in randomized complete block design with three replications at experimental field of Agricultural and Natural Resources Research Center of Markazi Province، in Arak (34º 5´ N; 49º 42´ E، and 1775 m above sea level)، Iran. Seven advanced rapeseed varieties such as NK Aviator، RNX 6321، ES Betty، Modena، NK Karibic، Champlain and Licord and Okapi as check comprised the experimental factors. Each plot was including of four rows with 6 meter length and 30 centimeter distance. Important agronomic traits such as days number to initiation and end of flowering، length of flowering، days number to ripening، length of ripening، plant height، second branch number per plant، seed number per pod، pod number per plant، 1000 - seed weight، seed yield، seed oil and protein content، biological yield، harvest index and oil yield per unit area were estimated during growth season. The results of varianc analysis showed that rapeseed cultivars had significant differences for all measured traits. In this research، ES Betty cultivar had the highest grain yield (5699 kg/ha)، pod number per plant، 1000 - seed weight، harvest index، seed oil content and oil yield per unit area. In this research، Okapi variety had the least seed yield (3144 kg/ha)، pod number per plant and 1000 - seed weight. Also، there were positive and significant correlations between seed yield and some traits such as pod number per plant، 1000 - seed weight، biological yield and harvest index.