نشریه نهال و بذر
سال بیست و پنجم شماره 4 (زمستان 1388)

The reaction of sixteen potato-promising clones to PVX, PVA and PVY was evaluated in greenhouse condition. At first, viral infection of each clone was examined using DAS-ELISA. Infected clones were treated by electrotherapy technique to achieve virus free clones. Single nodes of healthy plants were cultured on MS medium. After growing, plantlets were transferred to greenhouse and minitubers harvested about two months later were used as experimental materials. Three week old potato plants were inoculated mechanically with tobacco plants extracts infected to PVX, PVY and PVA. After 30 days, the result of DAS-ELISA of each plant was scored. Data analysis showed that the reaction of clones to the three viruses were significantly different at 1% level. However, the difference among plantlets in each replicate was insignificant. Mean comparison of clones, ELISA absorbance values test indicated that clones 397015-1 and 397015-13 were resistant to all the three viruses and clone 397008-2 was susceptible to three viruses. Other clones were resistant or susceptible to one or two viruses.

Hordeum spontaneum has been considered as the ancestor of cultivated barley (Hordeum spontaneum) and there is no biological crossing barrier between the two species. Genetic base of cultivated barley has been narrowed the modern plant breeding, causing trouble in confrontation to unfavorable environmental conditions. Hence, wild barley has become an important germplasm source for introducing new genes into cultivated barley. This research was performed in order to identify drought tolerant genotypes of Hordeum spontaneum. Genotypes were studied under stress and non-stress conditions in randomized complete block designs with three replications. STI, MP, GMP and HM were identified as the most favorable indices based on correlations with grain yield in stress and non-stress conditions. Investigation on 3D graphs using selected indices placed genotypes 02TN555, 02TN374, 02TN494 in group A (having higher yield in both stress and non-stress conditions) and genotype 02TN220 in group B (higher yield in non-stress condition and lower yield in the stress conditions). The remaining genotypes were located in group C (low yield in both conditions). All genotypes were grouped in three categories of tolerant, moderately susceptible using cluster analysis.

Water deficit is the most important restrictive factor agricultural productions in arid and semi arid zones. To study the effects of water deficit on vegetative growth of five almond cultivars, an experiment was conducted in 2003-04 growing season, using a split plot based on completely randomized block design. Four irrigation regimes based on 20, 40, 60 and 80 mm evaporation from surface of class A pan were considered as main plots and seedling of five almond cultivars Mamaei, Rabie, Sefid, Shahroud 12 and Shahroud 21 as sub plots. Seeds of these cultivars were sown in nylon bags during autum to receive enough natural chilling. Two month after germination and growth, the seedlings with uniform stem diameter and plant height were selected and planted in plastic pots (30×40 cm) and were treated with different irrigation periods for 120 days. The results showed that increasing irrigation period had significant effect on reduction of plant height, stem diameter, number of internodes, branches, leaf area and shoot and root dry weight, but internodes length and shoot to root dry weight ratio were not significantly decreased. Seedlings had significant differences in plant height, stem diameter, shoot and root dry weight, leaf area, number of internodes and shoot to root dry weight ratio. With increasing irrigation period shoot dry weight decreased in Shahroud 12, rabbie, Sefid, Mamaei and Shahroud 21 cultivars respectively. The amount of leaf nitrogen and potassium and root nitrogen was increased with water deficit. According to the results, with increasing of irrigation period, vegetative traits decreas in seedlings of Shahrood 21, Mamaei, Sefid, Rabie and Shahrood 12 cultivars, respectively.

In the present study resistance of some elite lines of wheat at seedling stage were evaluated in cereal rusts greenhouse at Seed and Plant Improvement Institute in Karaj and at adult plant stage in Ahvaz under artificial inoculation with an isolate of leaf rust from Ahvaz. For seedling resistance, different components of resistance were measured. The results showed that lines M-85-1, M-86-1 and C-85-10 had lower infection types, latent period and smaller pustules size and number. In field experiment some lines showed resistance at adult plant stage. In general, 18 out of 62 lines were resistant at seedling and adult plant stages and 13 lines were susceptible at both stages. Lines C-85-15, C-86-7, C-86-9, M-85-11, M-86-6, M-86-5 and M-86-10 were susceptible at seedling stage and resistant at adult plant stage.

To study the genetic diversity among barley genotypes, 64 genotypes provided by the Seed and Plant Improvement Institue, Karaj, Iran were assessed for their 22 agronomic characteristics and seed storage proteins. Polypeptide-patterens of storage proteins were determined using SDS-PAGE, and three hordeins (B, C and D-hordeins) were analysed by Photo Capture software. Ca lculated Polypeptide bands based on the molecular weight ranged from 30 to 120 KDa. High genetic polymorphism observed in agronomic traits and polypeptide bands, producted 51 polymorphism bands the greatest belonging to B-Hordein with 22 bands. Clustering analysis using UPGMA method based on Euclidean, agronomic traits were divided to 6 groups, and polypeptides bands based on Jaccard coefficient to 11 groups. The high polymorphism between agronomic traits and polypeptides bands indicated high heterogenousity in these genotypes. Histogram of B-hordein was the most frequent hordein with highest impact on protein-wise polymorphism.

Thrips tabaci is one of the most important pests causing serioues damages on onion s in Iran despite several chemical sprayings. To assess the population density and damage of the thips on onion, Improved Sefid-e-Khomein genotype along with seven other Iranian cultivars of onoin were planted in a RCB design with four replications in two separate experiments (sprayed and non-spray ed) in Arak for three years (2001-2003). The control field was also planted by ten meters distance and sprayed with current insecticide in order to reduce thrips damages. The highest number of thrips were counted on Ghermez-e-Azarshar, Sefid-e-Shahroud and Ghermez-e-Shahroud cultivars (27.6, 25.7 and 25.3 thrips per plant, respectively) and the lowest on numbers were recorded on Sefid-e-Qom and Sefid-e-Kordestan (16.01 and 15.8, respectively). Amount of damage was highest on Ghermez-e-Azarshahr and the lowest Sefid-e-Kordestan and Sefid-e-Qom cultivars. In non-sprayed plots, the highest yield was recorded for Sefid-e-Kashan and Sefid-e-Qom cultivars (79.2 and 75.1 tha-1, respectively) and the lowest yield for Sefid-e-Kordestan cultivar (61.0 tha-1). Based on the average density of thrips, average damages and curling scores and average yield in sprayed and non-sprayed plots, the Improved Sefid-e-Khomein genotype was found to be tolerant to the thrips.

Infected safflower seedlings were collected from different parts of Isfahan province and reactions of twenty one genotypes of safflower to six isolates were then evaluated in laboratory and greenhouse. A factorial experiment based on complete randomized block with three replications was used. Safflower seeds were germinated in the Lab. and after 48 hours, they were inoculated with one week old culture of F. solani isolates. Seven days after inoculation, lesion length on roots was measured. In greenhouse, safflower seeds were planted in 15 cm pots, five seedlings per each. Autoclaved wheat seeds inoculated with F. solani isolates were applied as inocula after seven days. Percentage of alived seedlings was assessed 7 and 45 days after inoculation. Statistically analyzed data showed significant difference among genotypes in laboratory and greenhouse tests. The results showed a negative correlation between lesion length on root and number of alive seedlings (r= -0.72). The most resistant genotype was pure line KW11 with 9.31 mm lesion length on roots and alive seedlings of 80% and 62.8% after 7 and 45 days, respectively. The most susceptible genotypes were Koseh cultivar and pure lines KW2 and KW3 with 13.29, 12.72 and 12.13 mm lesion length on roots and alive seedlings of 58%, 61.8% and 65.6% after 7 days and 25.6%, 28.4% and 28.4% after 45 days, respectively. Moreover, 7 days after inoculation, 14 genotypes had over 70% and 7 genotypes between 30 and 70% alive seedlings, and 40 days after inoculation, 18 genotypes had between 30 and 70% and only 3 genotypes had less than 30% alive seedlings.

Current study was designed to fine map the Ol-qtl1 area by evaluation of F2, BC2 and BC2S1 progenies, obtained by hybridizing the susceptible L. esculentum cv Money Maker with the resistant L. parviflorum G1.1601, for segregation of resistance to Oidium lycopersici. Two flanking markers, ct21 and ct184 were used to screen recombinant plants. To monitor the targeted area effectively, 24 out of 54 new designed primers have been identified as SCAR and CAPS markers. The results confirmed the presence of resistant controlling area flanked by ct21 and ct184. Resistant homozygote individuals were resistant, with average 0.5 disease index (DI) value, heterozygote plants had intermediate responses and susceptible homozygote individuals showed susceptible performance. Results of recombinant screening showed that the targeted area is located in the upstream of tg25. Based on the results of this research, targeted area was narrowed down to a region of approximately 15 cM. Newly developed SCAR and CAPS markers can be used in marker assisted selection based breeding programs.

Due to its wide adaptability, chickpea is considered as an important crop in arid, semi-arid and in marginal lands. Most important factors which limit yield of chickpea are short length of physiological growth period and susceptibility to cold and diseases, especially Ascochyta rabie. Releasing a chickpea cultivar with high yield and good characteristics such as cold tolerance, resistance to disease (Ascochyta rabie), erect growth habit and early maturity has been a most important goal in Agricultural and Natural Resources Research Center of Neishabour, Iran. Thus, in order to release a chickpea cultivar suitable for autumn-winter cultivation, more than 300 genotypes from ICARDA (including ILC3279), Italy and some Iranian landraces were examined during an eight year period starting from 1990. In different nurseries, preliminary and advanced yield trails, ILC3279 produced the highest yield and exhibited good agronomic characteristics, therefore this genotype and two other were selected as the superior genotypes. In adaptability and other agronomic and physiological trails, to find the best planting date, plant density and physiological characteristics, ILC3279 was found to be the most superior genotype for releasing. It was finally registered officially in Iran with the name of Binaloud as a new chickpea cultivar.

In order to develop a high yielding rice cultivar with optimum cooking quality, a cross was conducted between two rice cultivars Khazar, high yielding and resistant to blast disease and Daylamani Tarom, with good cooking quality in 1990. Forty pure lines were selected and compared for high grain yield in 1996. Ten selected lines together with two check cultivars Dasht and Onda were tested in advanced yield trails in Amol, Chalous and Tonekabon for three years. Overall, mean yield comparison suggested that line No. 5 produced the highest yield (6.5 to 7 tha-1) and showed a good stability over the years and locations. Based on the results on agronomic trails, row spacing of 10×30cm, 110 kg pure nitrogen and planting date of 25 May can be recommended for the new line. The new line is resistant to rice blast, tolerant to stem borer and moderately susceptible to sheath blight disease. This line, has some important characteristic such as moderate amylose content (23.5%), suitable plant height (106 cm), long panicle length (27cm), high weight of 1000 grains (26g), early maturity (124 days) and high yield (6.5-7t/ha). The new line was officially registered as a new rice cultivar in Iran with the name of Shiroudi in 2007.

Babol local lettuce as a landrace in Mazandaran, has cultivated for many years. Local lettuce is a mixture of different genotypic and phenotypic forms which affects its marketability. It was purified by individual selection method during a three year priod (1998-2000) based on the selection for characteristics such as shape of bush, closed pome high yield, good marketability and resistance to diseases. A pure sample was developed in 2000 covering several good characteristics of the local lettuce and after evaluation in several agronomic and yield trial experiments it was registered as a new cultivar named Varesh in 2008. Varesh is a high yielding lettuce cultivar with good shape of bush, closed pome, good marketability and moderately resistant to Bremia lactucae Based on the agronomic trials, the plant density of 100000 (50×20 sowing pattern), 200 kgha-1 urea fertilizer and planting date of 22 November were recommend for this cultivar. The average yield of the new cultivar in farmers condition was more than 40tha-1.