نشریه نهال و بذر
سال بیستم شماره 1 (بهار 1383)

Evaluation and identification of local cultivars of grapevine can provide a good gene bank, useful for breeding of this tree. A high diversity in local grapevine cultivars exists m West Azarbaijan province, therefore, a comprehensive study on different characteristics and collection of these cultivars was necessary. The present investigation was carried out during a period of six years (1993-1999), in which forty five morphological characteristics of forty seven local cultivars of grapevine at different growth stages before flowering, during flowering, berry set and ripening were determined according to the IBPGR's decriptors. General characteristics of cultivars indicated that all cultivars belonged to Vitis vinifera L. species. Six cultivars Sachakh, Lalbideneh Ghermez, Gezel Ozum, Khalili Ghermez, Ghara Gandomeh and Gazandahi having inverse flay were also determined. These cultivar can be used in breeding program.

Winter sown lentil compared with spring sowing, will enhance yield, provide better rotational and soil conservation system and consequently increase lentil area and production in Iran. Cold susceptibility in winter sown lentil is one of the abiotic stresses which affect its production. Hence, in order to evaluate the cold hardiness of 39 lentil genotypes, obtained from the lentil germplasm collection of College of Agriculture Karaj, (Iran) and ICARDA (Syria), a randomized block design experiment with three replications was performed over the years 2000 and 2001 in Karaj conditions (NL 35o). The level of cold hardiness among the lentil genotypes were measured by examining the alive and dead seedlings after being exposed to natural winter and spring cold weather and expressed in percentage. The absolute minimum temperatures during the two growing seasons were -10oC and -9.8°c, respectively. Phenological traits (such as days to 50% flowering, seed filling period, maturity), seed yield and 1000 seed weight were recorded in each year. Pooled analysis of variance for genotypes response to winter sowing were statistically significant among various traits. The histogram for cold hardiness percentage showed that the tolerant lentil genotypes (91-95% winter hardiness) comprised only 4% frequency percentage and the tolerant genotypes (71-90% winter hardiness) was 28 percent. The coefficient of variation for winter hardiness among the genotypes were about 17.5%. This variation is due to environment since no genotypic heredity for cold hardiness in lentils has yet been reported. The lentil seed yield had a relatively higher variation (about 28.6%) compared to other traits. Nevertheless, the seed yield had a significant and positive correlation (r=%20**) with cold hardiness percentage, and the high yielding genotypes also showed very high or high cold hardiness percentage. Between cold hardiness percentage and duration from sowing to harvest, a quadratic relation (R2= %19) existed and very high and high tolerant genotypes had shorter duration to maturity. On the whole, the lentil genotypes in this study were grouped into four clusters based on cold hardiness percentage, seed yield and maturity traits. The high tolerant accessions 2, 36, 7, 13 and 32 along with relatively high tolerant accessions 16, 12 and 26 had the lowest euclidean distance and all were grouped in one cluster.

Cucurbit wilt caused by Phytophthora drechsleri is one of the most important diseases in Varamin and Garmsar areas. Reduction of yield of cucurbit by this disease has been reported about 25%. Soil salinity which can cause the important damage to the plant metabolism and nutrition, is common in these regions. Cucumber is susceptible to salinity stress. Therefore salinity stress may increase the susceptibility of cucumber to Phytophthora drechsleri. Different levels of salinity (control, 0, 10, 25 and 50 mM NaCl) on three current cultivars (Tezier, Super 2000 and U. S. A.) of cucumber were investigated at the presence of P. drechsleri in greenhouse conditions. A factorial analysis for completely randomized design with 3 replications, was used for these experiments. Significant differences were observed among the different levels of salinity. Increasing stress due to salinity increased the susceptibility to the disease. Cucumber cultivars had different responses to salinity. The effects of different levels of salinity (0, 10, 25, 50 and 75 mM NaCl/l) were also investigated on growth of P. drechsleri on CMA culture at a completely randomized design with 3 replications. Variance analysis of growth area of fungus on CMA culture showed significant differences among different levels of salinity. Growth area of fungus was 6359 mm2 for control and 4725 and 4797 mm2 for 50 and 75mM NaCl, respectively.

Qualitative and quantitative aspects of Iranian raisin, as a significant exporting material, has been declined because of several reasons in recent years. There are many factors affecting quality of raisin. Fruit harvesting date is one of these factors which is highly effective on quantitative and qualitative traits of raisin through alterating fruit characteristics and even plant yield. Therefore, this investigation was carried out to determine the best time of white seedless grape harvesting in Qazvin for obtaining a raisin uniform in color and size with suitable taste and tissue and highest in yield. For this purpose, harvesting dates with 10-day intervals including 22nd August, 1, 11, 21st September and 2nd October were used in a RCBD with four replications in one of the orchards of Takestan region. In each treatment, four plants were considered and harvesting was done form two middle plants. In each harvesting date, traits such as content of soluble solid materials(TSS), bunch length, bunch weight, volume and weight of berry, grape yield, and after production of raisin, traits such as color, size, 50-seed weight, marketing value and amount of recoverable raisin were measured. Results showed that late harvests (21st September and 2nd October) having about 23% TSS, weight of 18 grams for 50-seed of raisins and the best ratio of grape to raisin (3.5 kg grape for production of one kg golden yellow raisin) are the most suitable harvesting date for raisin production in Takestan region. Also higher TSS% lead to significant increase in quality, color, and 50-seed weight and raisin production efficiency.

The present study was carried out in 1995and 1996to determine the most suitable carrot cultivar for Sistan region. The experiment was conducted in a randomized complete block with three replications at Zahak Research Station in Zabol. Nine carrot cultivars including a local cultivar (Zardak), were planted in plots with 5 rows, 5 m length. Row space was 35 cm and plant space on the rows was 5-7 cm. Mean yields of cultivars in two years were compared statistically with local check cultivar through L. S. D. The combined analysis of variance showed a significant difference among the cultivars. Cultivar Nantes Tip Top with 16.806 tons per hectare, produced significantly higher yield than the local check and other cultivars, therefore, this cultivar can be recommended as a suitable cultivar for cultivation in Sistan region.