نشریه نهال و بذر
سال هفدهم شماره 2 (تابستان 1380)

This experiment was carried out to determine the desirable hormone treatment for increasing the number of roots in greenhouse cucumber (c.v. Ruba) cuttings. A factorial experiment based on Randomized Complete Design with 6 replications was used in this study. Treatments were 1) cutting type (nodal and non-nodal), 2) duration of hormonal treatment (30 sec and 60 sec) and 3) type of hormone (lndolebuteric Acid at concentrations of 500, 1000 and 1500 mglit-1, Naphtaleneacetic Acid at 50, 100 and 150 mglit-1, the mixture of low concentrations of the two hormones and control). At the end of the experiment, number of roots, length of the longest root and percentage of rooted cuttings were measured. Results indicated that nodalcuttings produced more and longer roots (p < 0.01). Roots number was also affected by duration of treatment (more roots were produced with 60 sec compared with 30 sec). Both hormones increased the number of roots significantly, though the lenght was not affected. Maximum roots number was obtained with 1500 mg-1 lndolebuteric acid.

This research was conducted to estimate the late spring cold and early autumn freezing for some crops in Charmahal and Bakhtiari province. Data on time occurrence of daily temperature in different ranges including (0-1), (-1-3) and less than -3° C, absolute minimum temperature and the first and last temperature lower than zero in autumn and spring respectively, were obtained from several metheorological stations in Shahre Kord, Pole Zamankhan, Boroujen, Lordegan and Koohrang. Then, data were modeled by using different distribution functions like normal, 2-parameter lognormal, 3-parameter lognormal, Pearson type III, logpearson type III, Gumbel and Gamma. The best distribution function was selected based on the residual sum of squares. Knowing the proper distribution function, the probability of occurrence of spring cold and autumn freezing was estimated for different locations.

In order to evaluate heritability and gene action for resistance to barley powdery mildew, two resistant cultivars were crossed with a susceptible one. P1, P2, F1, F2 and F3 generations were planted in a Randomized Complete Block Design. At seedling and booting stages, susceptible cultivar was inoculated with a isolate of the pathogen. Infection type and disease severity were recorded and generation mean analysis was performed. The results showed that additive, dominance and epistasis effects were important for the two examined traits. Analysis of generation indicated that dominant variance was more important than additive variance in both traits. The approximate number of genes were estimated to be between one and two.

This experiment was conducted during 1999 and 2000 growing seasonin order to increase success in growth and further establishment of grape cuttings under Maryvan dryland conditions. Six different planting types were used based on Randomized Complete Block Design (RCBD) with four replications. Results indicated that there was a significant difference at 1% level between planting types in autumn and spring as well as planting of rooted and un-rooted cuttings. The highest percentage of established grape was achieved by autumn planting of rooted cutting with and without covering of cutting buds by soil with 73.26 and 64.52 percent budbreak respectively. Although, the regional traditional planting method (planting of non-rooted cuttings in spring) resulted in 32.51 percent budbreak.

The present investigation was carried out in Olive Research Station of Roodbar during three consecutive years (1997-1999) in a randomized complete blok design with 6 treatments and 4 replications to determine the best pollinizer for olive cv. Zard. The t10wers of cv. Zard were pollinated artificially by pollens of cultivars Beleidy, Mari, Roughani, Leccino, Manzanilla and Zard (self-pollination) after emasculation. Percentage of initial fruit sets, percentage of final fruit set, index of fertility, index of compatibility and number of flowers in each inflorescence were measured and compared with the results of open pollination. The results indicated significant differences among the pollen genitor cultivars at 1% probability level. The olive cultivar Zard had a partial self incompatibility, which varied by the years. Cultivars Leccino, Zard, Mari, Manzanilla, Beleidy and Roughani were found to be the best pollinizers, respectively, considering their means of final fruit set and index of compatibility in various cultivars.

This study was conducted to determine the effect of water salinity in sprinkler irrigation on yield of different wheat cultivars, using different mixtures of saline and fresh water. The experiment was conducted in a Randomized Complete Block with split plot arrangement with four replications in 1998-1999 growing season at Roodasht Agricultural Research Station in Isfahan. The main plots were four water quality treatments (average 5, 7, 9 and 11 ds/m) and the sub plots were four cultivars of wheat (Mahdavi, Cross Sorkhtokhm, Ghods and Niknezhad). Each replication was 15x30 meters. The sprinkler effective radius was 15 meters and spraying angle was 360. The comparison of treatment means with LSD method at P=0.05 revealed that different water qualities affected grain yields of cultivars significantly. The grain yield in 11 ds/m water quality treatment decreased by 50 percent, compared with that of the 5 ds/m water quality treatment. Effects of different cultivars on grain yield were not significant, although Mahdavi and Niknezhad had the highest and the lowest grain yields, respectively. The mean dry weight in earing and physiological maturity stages were significantly different. Mahdavi produced the highest and Niknezhad the lowest dry weight. The mean 1000-grainweight of the varieties had significant difference. Mahdavi and Ghods had the highest and the lowest 1000-grain weight, respectively. The mean Na+ and K+ ions concentrations in flag leaf at flowering (GS=65) had significant difference. Mahdavi had the highest K+ and the lowest Na+ concentrations in its nag leaf.

Breeding new seedless table grapes requires application of embryo rescue technique. For successful application of this technique, it would be necessary to get enough information about anatomical and cytological phenomena occurs in certain time inside ovule after fertilization. To do so, this research work was conducted in 1998 in Horticultural Research Station in Karaj. Samples were collected at 2, 21, 35 and 45 days after flowering from 20 years old grapevines of five seedless cvs, i.e. White seedless, Red Seedless, Askary, Yaghooti and Green Keshmeshi. Samples were fixed in FPA50 and later ovules were dissected out, dehydrated, embedded and eventually serially sectioned longitudinaly at 5f.Lmthickness by ultra-microtome, stained with PAS method and were observed by field optics. Results showed that in all cvs, fertilization had been taken place in more than 50% of ovules, but not in all, due to their abnormal development. Zygote and free nuclear endosperm were formed. However, in some cvs e.g. Red seedless, zygote never get divided and degenerated before 21 days. In White seedless and Yaghooti few percent of zygotes could divide several times and produced few cells pro-embryo. In cv. Yaghooti, pro-embryo could develop by five weeks while in White seedless, pro-embryo could develop even by six weeks and then were degenerated. In cultivars such as Askary and Green Keshmeshi, higher number of pro-embryo could develop by 45 days. According to the results, embryo resuce should have been done before three weeks in cv. Red seedless, before five weeks in cv. Yaghooti and about six weeks in cvs White seedless, Askary and Green Keshmeshi.

The presesnt study was conducted for 3 years in Maragheh Agricultural Research Station to determine the effect of fertilizer placement in different depths of soil on wheat grain yield in dryland. For this purpose a modified cereal drill for dryland condition, Kesht Gostar, was selected and used to find out the effect of separating seed and fertilizer on wheat yield. This trial was carried out by 7 methods of fertilizer application in a Randomized Complete Block Design with 4 replications. According to the results, placement of fertilizer 9 cm below the seed gave significantly higher yield (1.9 tha-1) as compared with 1.3 tha-1 of the check, where seeds and fertiiizer were placed together. Also number of spike per square meter at fertilizer placement of 9 cm below seed was more than others, and correlation between number of spike and grain yield was significant (r= 0.76), low output of mixture application of seed and fertillizer, might be due to low moisture contents in the seed bed, where high osmotic pressure effect could damage seeds germination.

Considering the importance of citrus breeding programmers for releasing new cultivars to the citrus industry, the present research was carried out in order to explore the best method of pollen preservation and storage. Long-term pollen storage was sudied on pollens from matured citrus cultivars including Shell-Mahalleh, Yuzu, Troyer and Citromelo. Experimental design used, was a factorial design with two factors based on Randomized Complets Block Design with 3 replications. Factor one was 3 methods of storage (room temperature, refrigerator and freezing) and the second factor was 4 mentioned cultivars. In vitro viability test was performed on pollens after 7, 15,30,60 and 140 days storage at room temperature (+25 °c), refrigerator (+4 °c) and freezer (-18°C). Results based on analysis of variance of data showed significant differences at 1% level between the effects of treatments of storage methods, cultivars and interactions between two factors. Control treatment (fresh pollen) and 7 days storage treatment at freezer showed highest germination percentage (38.77% and 26.93% respectively) and classified in groups a and b respectively. In addition, among studied cultivars Shell-Mahalleh and Yuzu showed 18.94% and 15.49% germination and grouped in classes a and b respectively. Interaction effects of control x Shell-Mahalleh, control x Yuzu, 15 days storage in freezer x Yuzu and 7 days storage in freezer x Shell-Mahalleh showed 50%, 46%, 42% and 36% germination and located in groups, a, b, c and d respectively. Also results from 140 days pollen storage of Shell-Mahalleh cultivars showed 22.2%, germination in the viability test assay. Considering the amount of pollen germination decreased with prolonging of pollen storage period, this finding is very important in citrus breeding programs.

Kohdasht is a new improved spring bread wheat (Triticum aestivum L.) cultivar suitable for warm and semi arid areas of Iran. In 1990-91 cropping season, line Tr 801020029 R-1R-6R-0R was received from ICARDA under 9th Semi Arid Area Screening Nursery. Based on agronomic characteristics, resistance to diseases and abiotic stresses under field conditions, Tr 8010200-29R-1R-1R-6R-0R was selected for further evaluations. It was included in yield trials in main Research Stations in warm and semi arid areas of the country, together with other 24 wheat lines, as well as the widely grown improved cheek cultivar Zagros. Results revealed that this line is more tolerant to drought, yellow rust, leaf rust and produces significantly higher and stable yield. This line is earlier in spike emergence and maturity than Zagros, with mean grain yield of 3.77 tha-1. Its plant height and thousand kernel weight are about 90 cm and 37g, respectively. Its grain color is white and its grain protein content is 10.5%. Based on these superiorities and good performance, the new line was released in 2000, under the name of Kohdasht.