نشریه نهال و بذر
سال بیست و ششم شماره 3 (تابستان 1389)

An experiment was conducted to evaluate relative resistance to P. cactorum, the casual agent of apple crown rot, in eleven apple rootstocks. The experiment was in factorial (with apple rootstocks and year factors) on the basis of completely randomized design with three replications. Each plot consisted of four young plants. All rootstocks excluding Morabbaei, were propagated vegetatively. One year old rootstocks were evaluated in pots containing soil inoculated artificially with inoculum of P. cactorum. Disease response of the rootstocks was assessed three months after inoculation based on canker length (cm), crown girdling (%), mortality (%) and mean canker area (cm2). The analysis of variance on pooled data showed that effect of rootstock on measured characterestics was significant at 1% probability level. MM106 rootstock was highly susceptible (mean canker area: 4.72 cm2, crown girdling: 89.33%, canker length: 5.28cm and mortality (%): 83.33%). M9, Azayesh and CK1 rootstocks were resistant and Morabbaei and MM111 rootstocks were moderately susceptible compared to the highly susceptible rootstock.. Gami almasi and CK2 rootstocks were moderately resistant and M26, M27 and B9 rootstocks showed relatively tolerance responces to P. cactorum. Interaction between year and rootstock was not significant.

An experiment was conducted under normal and post-anthesis drought stress conditions using RCBD with three replications at Karaj, Arak, Mashhad and Miandoab Agricultural Research Stations in 2004-05 and 2005-06 cropping seasons to evaluate the tolerance of 18 facultative and winter wheat genotypes to drought stress. Combined analysis of variance was done on grain yield. Tolerance and susceptibility of the genotypes to drought stress were calculated using Stress Tolerance Index (STI), Stress Susceptibility Index (SSI), Tolerance (TOL), Mean Productivity (MP), Geometric Mean Productivity (GMP), and SDR. Interaction of year × location in normal condition and effect of genotype and interaction of year × location and genotype × year × location were significant in stress condition. Correlation coefficients of indices with grain yield in normal and stress conditions showed MP and STI as the most appropriate indices for selection of tolerant genotypes. Using biplot,, SDR and drought tolerance and susceptibility indices, determined genotypes C-83-6, C-83-7 and C-83-8 as the most tolerant genotypes and genotype C-83-14 as the most susceptible genotype.

Fifty nine durum wheat genotypes obtained from the National Plant Gene Bank of Iran along with two bread wheat checks (Vee/Nac and Soissons) and two durum checks (Dena and Zardak) were evaluated for quantitative and qualitative traits in an observational experiment in 2008-2009 at Seed and Plant Improvement Institute, Karaj, Iran. Each genotype was planted in two lines 2.5 m long. The checks were repeated 14 times among the rows. Descriptive data analysis showed presence of a vast genetic variability among the genotypes for the recorded traits. For example grain yield varied between 300.5-868.5 gm-2. Correlation analysis among agronomic and grain quality traits revealed positive correlation between protein percentage and plant heigh t, length of peduncle, lodging susceptibility, Zeleny, hardness and had negative significant correlation with length of spike, thousand-kernel weight, number and weight of grains per spike. Principal component analysis reduced 13 variables to four components by 72.1% cumulative proportional variance. Results showed genotypes no. 15 (Wc-45704) and 52(P.S.No3) with good quantitative and qualitative traits such as high grain yield, low lodging susceptibility, early maturity, low number of shriveled seeds, higher protein percentage, high gluten index and SDS sedimentation, were the best genotypes among the experimental genotypes.

The seed and oil yields stability of seven spring safflower advanced lines were evaluated in four different environmental conditions of Karaj, Isfahan, Islamabad and Zarghan in a randomized complete block design with four replications for two years (2002 -2004). The results showed significant differences among the genotypes in different locations and years. After homogeneity test for error variances, combined analysis of variance was performed. F test of different sources of variation revealed that the effect of genotype × year × location interaction was significant (P < 1%). Stability of genotypes were evaluated using Eberhart and Russell and Francis and Kannenberg methods. The results showed significant differences for the main effects of genotype and environment × genotypes and deviation from regression. According to the classification of genotypes based on the mean of seed and oil yields, coefficient of regression equal to unity and less deviation from regression and coefficient of variability (CV%), lines I.L.111 and Isfahan-14 with the highest seed yield (1660 and 1611 kgha-1, respectively) and stability were selected as desirable genotypes.

Pollen grain viability of five hazelnut cultivar Gerche, Negret, Pashmineh, Gerdoii and Gerd-e-Eshkevarat was evaluated to investigate the storage time and select the best pollinizer among them. In the first experiment, half of pollen grains were stored at room temperature (25 ± 1°C) and the rest in refrigerator (4°C). After 24 hours, 5, 10 and 20 days, pollen grains were cultured on medium culture containing 10, 15 and 20% sucrose and 10 gl-1 agar (pH=6.5). The highest percentage of pollen germination was observed in medium containing 15% sucrose. After 20 days the mean pollen germination of Gerde-e-Eshkevarat, Pashmineh, Gercheh, Gerdoii and Negret cultivars was 54.48, 42.67, 42.21, 35.59 and 31.41% respectively at 4°C. In the second experiment, Kasford, Dubase and Secorp cultivars were pollinated with five male parents. Open pollination was considered as control. Open pollination and pollination with Gercheh and Gerdoii as male parents (means 51.37, 49.83 and 45.51, respectively) and Secorp and Dubase cultivars as female parents (means 55.03 and 52.92) had the highest mean of fruit set. Open pollination of Dubase and Secorp and cross pollination between Gercheh with Dubase and Secorp had also the highest mean of fruit set. Kasford cultivar with mean 19.75 produced the highest mean of blank fruit percentage.

To study the effects of selection and selfing, on progeny lines of Behbahan landrace onion, a five year (1999-2004) experiment was conducted five year at farms of Behbahan region and Behbahan Agriculture Research Station. In the first year, 500 bulbs of two morphotypes (white and red) of Behbahan landrace onion were selected and stored in non controlled storage. In the seconed year, 100 bulbs of each morphotype were selected and planetd. The umbles of each buld were isolated by cloth bags at flowering time. In the third year, self pollinated seeds from each bulb were planted and 57 progeny lines were selected. Bulbs of selected progeny lines were planted for then second selfing in the fourth year. In the fifth year, seeds of the second self pollinated bulbs were planted and 28 progeny lines were selected. The results showed that the growth rate of progeny lines decreased as compared with the source line, due to inbreeding depression, and consequently seedlings emergence percent, seedlings survival percent, leaf hight, mean bulb weight, mean bulb diameter and bulb storability were also decreased. In the other hand duration of seedlings growth of progeny lines in nursery increased compared to the source line. However, the bolting and doubling bulb percent of progeny lines were considerably lower than source line. Bulb off color was not observed in the progeny lines after the second selfeing.

To study genotype × environment interaction and determine the stability and adaptability of grain yield of bread wheat under salinity stress conditions in temperate zone areas of Iran, field experiments were conducted with 17 new advanced bread wheat lines together with three salinity tolerant checks cultivars Roshan, Kavir and Bam, using randomized complete block design with three replications under salinity stress conditions(EcSoil =8-14 ds/m, EcWater =8-12 ds/m). Experiments were carried out in three experimental stations in Yazd, Birjand and Isfahan during 2005-06 and 2006-07 cropping seasons. Combined analysis of variance for grain yield showed significant differences among the genotypes (P<0.05). The location × year and genotype × year and genotype × location × year interactions were also significant (P<0.01). Analysis of different stability parameter revealed that lines MS-81-14, MS-81-4, MS-81-3 and MS-81-5 were more high yielding and stable genotypes with good adaptability to salinity stressed conditions, among them line MS-81-14 with average grain yield of 5.470 tha-1,YS=23, R=3.42, SDR=4.609, R2 =97.4%, non-significant stability variance (σ i2), low Wricke's ecovalance(Wi) and also with good adaptability and agronomic chacteristics was identified as the most high yielding and stable genotype.

In order to study drought tolerance in bread wheat, 142 recombinant inbred lines in F8 generation, derived from a cross between Azar 2 (winter type) and 87Zhong 291 (facultative type) was used. Experiment was conducted in a randomized block design with three replications under drought stress and supplementary irrigation during 2006-07 cropping season, at Maragheh Experimental Station of the Dryland Agricultural Research Institute. Analysis of variance revealed significant differences among genotypes for different agronomical and physiological traits in two experimental conditions. Average of grain yield under drought and irrigated conditions were 928 and 2547 kgha-1, respectively. Under drought and irrigated conditions, grain yields ranged from 272 to 1935 kgha-1 and 1086 to 3805.4 kgha-1, respectively. Accumulation of photosynthesis assimilates in grains were 10.64, 24.89, 52.61 and 11.86 percent in the first, second, third and fourth weeks after anthesis, respectively, under drought condition. More than 88 percent of photosynthesis assimilates, accumulated in the third week after anthesis. Correlation coefficients of grain weight with grain filling rate in the first and second weeks after anthesis were r=0.76** and r=0.048* respectively. In most of the lines, total photosynthesis assimilate accumulation finished in the third week after anthesis. The results indicated that traits such as date to heading, date to anthesis, 1000 kernel weight and grain filling relative were important selection criteria for drought tolerance in wheat breeding programs.

Research was conducted to develop and release new improved winter wheat (Triticum aestivum L.) cultivar suitable for cold and mild-cold rainfed areas of Iran. In 1988/89 cropping season Fenkang15/Sefid was created by crossing between Fenkang15 and Sardari (Sefid local cultivar)) in Karaj. Based on agronomic traits, and biotic stress tolerance under field conditions, a new line of Fenkang15/Sefid was selected. The new line was evaluated in main cold and mild-cold DARI research stations together with 16 other wheat lines, including the widely grown improved check cultivars Sardari and Azar 2. Results indicated that the new line had higher and stable grain yield at Maragheh and Ardebil areas. It was early-mild in maturity, with mean grain yield of 2420 kgh-1 (in seven years of evaluation in cold and mild cold research stations). The plant height of the new line is 81cm, 1000 kernel weight is 36 g, grain color is red and its protein content is 11-12.5%. Based on these results, the new line was officially released in 2007 through the Agricultural, Education and Extension Organization, under the name of Rasad.