Seed and Plant
Year:2004 | Volume:20 | Issue:1|Papers Count:13

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.

In order to study effects of plant density and mother bulb size on onion seed yield, a split-factorial experiment with a randomized complete block design with three replications was conducted in Kabootar Abad Research Station of Isfahan during two cropping seasons (1998-1999 and 1999-2000).Main plot was different row spaces (50, 60 and 70cm) and sub plot formed from factorial combination of two mother bullb sizes (3-6 and 6.5-9.5cm) with three plant spaces on rows (15,25 and 35cm). The results showed that 50 and 60cm row spaces had not significant differences in the seed yield and yield components (umbels/m2, capsules/umbel, seeds/capsule and 1000 seeds weight) but seed yield and umbels/m2in 70cm row space was significantly lower than the those of other two row spaces. The treatments of 15 cm plant space and 6.5-9.5cm mother bulb size had the highest seed yield and umbls/m2.Seeds/capsule in 15cmplant space was significantly higher than that of 35 cm plant space.1000 seeds weight and capsules/umbel decreased as plant space increased from 15 to 35cm. Among yield components, umbels/m2 had the most contribution in the seed yield and this yield component explained about 0.67 of seed yield variations. Plant density and mother bulb size had not significant effects on seed  germination.

In order to evaluate selected corn lines to common smut (Ustilago maydis), an experiment was conducted in a complete randomized block design, with 30 treatments (lines) in four replications, in Kabutar Abad Experimental Station. For artificial inoculation, fungal inoculum consisting of a mixture of sporidia was applied to ears, 2 to 3 days after silk stage after removing the cobs with pruning shears by injection of 3 ml of inoculum (106 spore/m!) into the cut cobs. At harvesting time, the disease incidence (D.I.), based on infection rate in each line, and disease severity (D.s), based on disease progress in each ear, were evaluated. The results showed that by the cut cob injection method, high percentages of infected ears were obtained (more than 90%). Based on disease severity (scale 0-7) on ears, lines were grouped in four categories consisted of three lines without infection (Immune), two lines with high tolerance, 15 lines moderately resistant to moderately susceptible and 10 lines susceptible or highly susceptible.

In order to study the response of different winter and facultative wheat (T. aestivum L.) genotypes to terminal drought stress, this experiment was conducted in the Experimental Field of Cereal Research Department, Seed and Plant Improvement Institute at Karaj in 1999/2000 and 2000/2001 cropping seasons. Twenty winter and facultative wheat genotypes were evaluated in two separate experiments, one with non-stress and in the other one, stress was applied from anthesis to physiological maturity. A randomized complete block design with three replications was used. Results of combined analysis of variance of grain yield showed significant difference between genotypes. Genotype x year and genotype x irrigation interactions were significant at 5% probability level, however, genotype x irrigation x year was not significant. Stress tolerance index (STI), stress susceptibility index (SSI), geometric mean productivity (GMP), mean productivity (MP) and tolerance (Tol) were calculated based on the grain yield of the genotypes in both conditions. Among the genotypes number 8 (Pck/Vee) was outstanding. Grain yield of this genotype in non-stressed and stressed conditions was 9320 and 7079 kgha-1, respectively. MP, GMP, STI and SSI for this genotype were 8200 kgha-1, 8123 kgha-1, 0.85 and 0.98, respectively. Results showed that correlation coefficients between STI, GMP and MP indices and grain yield (under both conditions) were positive and highly significant, therefore, these indices can be used to identify high yielding and tolerant genotypes under non-stressed and stressed conditions. Finally, using cluster analysis based on indices and grain yield (in both conditions), genotypes were classified in five groups.

Four advanced lines of wheat which had appeared to be resistant to yellow rust in past years, along with the susceptible cultivar Bolani were intercrossed in one-way diallel cross. Seedlings were grown in greenhouse until the first leaves fully expanded and then inoculated with two pathotypes (race) 6E130A+and 166E42A+of yellow rust, separately. Infection types were scored 18 days after inoculation. Diallel analysis was done by two methods of Griffing, and links and Hayman. Results of analysis of variance of Wr + Vr and Wr - Vr, regression analysis of Vr and Wr and estimates of genetic parameters indicated the importance of additive and dominance effects with pathotype 6E130A+ and importance of additive, dominance and epistatic effects with pathotype 166E42A+. Broad-sense and narrow-sense heritability of infection type were estimated 97% and 58% for pathotype 6E130A+and 99% and 81% for pathotype 166E42A+, respectively. Line M-78-16 possessed the greatest general combining ability to decrease infection type and therefore was suggested to be included in breeding programs for resistance to yellow rust.

Work on cold tolerance in chickpea has been initiated since the advantages of fall sown crop over traditional spring sown crop were realized. In order to evaluate cold tolerance and yield potential in high altitude and cold regions, genetic variation in forty entries of chickpea together with one susceptible control (ILC 533) was studied in a RCB design with two replications in fall sowing under rainfed conditions ip Kurdistan province during 2000-02 cropping seasons. In this nursery the susceptible control (ILC 533) was sown after every two entries. Different characteristics e.g. seed yield, days from sowing to flowering, 100 seeds weight, plant height, number of pods per plant, number of seeds per pod, number of primary branches, and number of secondary branches were recorded. Annual and combined analysis of variance showed that there were significant differences among genotypes for seed yield, Number of secondary branches,100 seeds weight and cold tolerance (P<0.05). Sixteen entries showed a desirable level of tolerance 3, based on 1 to 9 scale (1 = healthy and 9 = killed due to frost). By investigation into the pedigrees of entries, it was revealed that cold tolerant entries (FLIP 95-255C, FLIP 93-260C and Sel95 TH1716) are derived from crosses between cultivated chickpea with C. reticulatum (ILWC 182), a wild relative of cultivated chickpea (c. arietinum L.).

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.

Determination of ploidy level is requird for studying interspecific relationship, genetics of transgenic plants and developing interspecific hybrids in breeding programs. Genus Medicago is the most important forage crop of Fabaceae family. There are almost 85 annual and perennial species under this genus. Species of this genus have small chromosomes with different ploidy levels, requiring extensive ploidy analysis in its breeding program. Therefore, an efficient technique is needed for determination of the ploidy level. The relationship between ploidallevel and the number of chloroplasts in stomatal guard cells was studied in order to examine the ! possibility of using cloroplast count as an alternative to chromosome count. Three randomly selected middle leaves of greenhouse grown plants were used for chloroplast counting in twenty pairs of stomatal guard cells per each leaf. Chromosome numbers were also determined in root tip squashes of studied plants. The ploidy level was highly correlated with the number of chloroplast in stomatal guard cells of lower surface of the leaf. Number of chloroplasts in tetraploid species M sativa L., M scutellat (L.) Mill. Gard. And M rugosa Desr. was approximately twice as many as the number of chloroplasts in diploid speciesM coronata (L.) Bartalini, M radiate L., M rigidula (L.) All., M polymorpha L., M constricta Durieu., M noeana Boiss., M minima (L.) Bartalini., M truncatula Gaetn., M littoralis Rhode., M orbicularis (L.) Bartalini., M laciniata (L.) Mill. Gard., M arabica (L.) Huds., M ciliaris (L.) Krocker. And M lupulina (L.). Our results suggest that this method can successfully be used for determination of ploidy level in Medicago species.

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.