نشریه نهال و بذر
سال بیست و هشتم شماره 1 (بهار 1391)

Based on the previous investigation results, fifteen Iranian cucumber landraces, eight as male and seven as female, were crossed with each with each other in an 8×7 factorial design, North Carolina Design II (NCD II). Eight quantitative and qualitative components including flesh texture firmness, skin texture firmness, aroma, taste, crunchy, fruit dry matter content, fruit flesh size and placental diameter/fruit diameter ratio were evaluated in F1 hybrids. In factorial design, male and female were not significant for most of the traits. indicating that the additive genetic variance did not contribute on controlling the traits. Male × female interaction was significant for all of the traits. Therefore, F1 hydrids can be used for getting hetrosis in all of the characters. High broad-sense heritability of hybrids showed high genetic variations of the traits in the germplams. The genetic correlations showed that decreasing placental diameter/fruit diameter ratio increased fruit crunchy and more crunchy fruits had the better taste. The 97 × 39 hybrid was the best hybrid via aroma, taste traits related to mid-parents and superior parent. The best selection criteria for breeding of the flavor was aroma, taste and crunchy selection. Ratio of gain from selection index related to that from aroma, taste and crunchy selection, separately were about 1.009, 1.004 and 1.001 percent more, respectively.

To evaluate response of rapeseed genotypes to drought stress, an experiment was performed in germination and later growth stages in laboratory and field conditions at Razi University, Kermanshah, Iran during 2005-2006 cropping season. Germination test under controlled conditions was done using a completely randomized design with factorial arrangement of four drought levels in three replications and field study was conducted based on a randomized complete block design in stress and non-stress conditions in three replications. In laboratory, the results indicated that with decline of water potential (from zero to -12 bar), most of germination traits were significantly reduced and shootlet length was the most affected trait from water stress. According to GSI there was a significantly different between genotypes and levels of drought stress, thus the highest GSI, was related to genotype Licord. In general, based on all germination characteristics Dante and Licord were tolerant genotypes in early stage of growth. In field, the result of ANOVA showed that there were significant differences among genotypes for all drought tolerance indices and yield in both conditions. Analysis of correlation between yields (in stress and non-stress conditions) and drought tolerance indices showed that STI, GMP and MP were suitable indices for screening rapeseed genotypes to drought stress and genotype Zarfam had the highest yield and highest counts for STI, GMP and MP. Thus it was selected as a tolerant genotype with high yield.

To study the effect of Bean common mosaic virus (BCMV) on seed yield, yield components and some morphological and phenological traits of bean genotypes, an experiment was conducted in research farm of the Islamic Azad University, Shiraz Branch in 2007. Twenty five common bean genotypes were sown in two separate randomized complete block design with three replications under BCMV infection and non-infection conditions. The virus was provided from a research farm in Yasuj. The characterization of the virus was confirmed by PTA-ELISA method. After proliferation of virus on susceptible cultivar, seedlings were inoculated by the leaf rub method. The leaves were dusted with carborundum powder before inoculation. Founded stress by this virus did not affect the reproduction period, but vegetative period decreased a little. The results indicated that virus stress has severely increased the empty pods(88.4%) and decreased seed yield by 46.76 percent, but no significant differences were observed for phenological phases. Pod length, number of seed per plant, number of seed per pod, number of empty pods, seed yield and harvest index were mostly affected by virus. On the basis of the results obtained, for breeding of resistant cultivar to BCMV, in addition to yield, special attention should be paid to these traits.

In the present study propagation of three clonal rootstocks of stone fruits including of VPK1, St-Julien A and GF677 were evaluated with in vitro culture. Explants of apical and lateral buds of rootstocks were disinfected and cultured in modified MS, WPM and Knop media. VPK1 rootstock produced the highest plantlet number and length in WPM and modified MS media. Two other rootstocks produced the highest of plantlet number and length in modified MS medium. VPK1 rootstock in WPM and Knop media and St-Julien A in Knop medium showed chlorosis symptoms, thus combination of plant growth regulators were evaluated in modified MS medium. St-Julien A had the highest proliferation in MS3 medium (containing 1 mgl-1 BAP and 0.5 mgl-1 NAA). Optimum proliferation in GF677 and VPK1 rootstocks were obtained in MS1 medium (containing 0.6 mgl-1 BAP and 0.01 mgl-1 NAA). Evaluating three rootstocks, the highest plantlet length were produced in MS1 medium. VPK1 produced callus in MS2 (containing 0.8 mgl-1 BAP and 0.1 mgl-1 NAA) and MS3 media. Increasing concentration of plant growth regulators led to vitrification and callus production of shoots in GF677 rootstock. St-Julien A and VPK1 rootstocks in medium containing 1 mgl-1 NAA and GF677 rootstock in medium containing 1 mgl-1 IBA produced the highest root length. In rooting medium proliferation of rootstocks were observed. Effect of clonal rootstocks on mean root number was not significant. Rooty rootstocks were transferred to peat and perlite medium in acclimization room.

This research was conducted to evaluate the susceptibility of some recently selected quince genotypes to the fire blight disease on hawthorn rootstock. Seven quince genotypes from Guilan and nine genotypes from Khorasan Razavi provinces together with the quince cultivar Isfahan as control were evaluated using four bacterial isolates encoded as 2, 36, K1 and Z1. The bacterial isolates initially were selected by biochemical, physiological, and virulence tests, as well as nested fragment amplification on pEA29 plasmid by Aj external and PEANT internal primers. Generally, all selected quince genotypes showed more disease resistance compared to the "Isfahan" cultivar. Genotypes M4 with 47.3% and ASM1 with 13.1% final disease progress showed the highest and lowest symptoms, respectively. Based on the results, 3 quince genotypes were classified as moderately susceptible, 11 genotypes were moderately resistant and 2 genotypes were resistant and none of the genotypes were susceptible. According to the results of necrosis progress rate, the beginning period of disease establishment did not have correlation with final resistance of genotypes.

Two experiments were conducted to evaluate 40 barley genotypes for crown freezing tolerance and some physiological traits under controlled conditions. In the first experiment, seeds were planted in pots in the greenhouse and the treatments were arranged as randomized complete block design with three replications. After acclimation, percent of tissue fresh and dry weight, water content and relative water loss were measured in each experimental unit. The second experiment was conducted as split plot design based on randomized complete blocks with three replications. Freezing temperatures were considered as main plots and the genotypes as subplots. After acclimation of the genotypes in the growth chamber, seedling’s crowns were transferred to a freezer and were treated with different freezing temperatures. Then, percent survival of the crowns and consequently LT50 were determined. Analysis of variance of data showed significant differences among genotypes for percent water content of the crown, leaf and seedling and relative water loss. Mean LT50 of the genotypes was -10.140C. Genotypes Ec79-18, A1C84-9, A1C84-14 and Schulyer were more suitable than others in terms of physiological characters. Genotypes EC83-15, EC80-11, EC82-11, A1C84-15, Schulyer and EC79-18 and 3 had the highest crown survival rate and the lowest LT50. The correlation coefficient of percent dry weight of different tissues with percent crown survival were positive and significant. Furthermore, negative significant correlation of percent crown survival with percent leaf and seedling water content and with relative water loss were observed. However, the correlations were not strong.

Genetic diversity of 35 barley genotypes was evaluated by microsatellite markers and the association of these markers with several characters related to freezing tolerance were studied. DNA was extracted from young barley leaves using the CTAB method and then multiplied with 44 microsatellite primer pairs from which 36 primers produced clear banding pattern. Amplified products were separated using 6% polyacrylamide denaturing gel electrophoresis. Zero-one binary data were recorded for the presence (one) or absence (zero) of the bands. Furthermore, for each marker alleles were named alphabetically as a, b, c, etc. From the data obtained, polymorphic information content (PIC) and average gene diversity were calculated for each microsatellite primer pair. Then, the barley genotypes were grouped based on neighbor-joining algorithm and the distance coefficient of Kimura 2-parameters. Furthermore, the fresh and dry weight of leaves, crowns and seedlings, percent of tissue water content, amount of tissue water loss, frost survival rate at -6, -10, -14, -16 and -18 oC and LT50 of the barley genotypes were measured and association analysis of the microsatellite markers with the phenotypic values of these traits was carried out. Numbers of polymorphic alleles were 268, with an average of 7.44 alleles per locus. Marker Hvm74 with 21 alleles and Hvm2a with three alleles had the maximum and minimum number of alleles, respectively. The lowest and highest major allele frequency of 0.13 and 0.53 belonged to Hvm20 and Hvm14 markers, respectively. Average major allele frequency was 0.31. PIC ranged from 0.42 (for Hvm2) to 0.94 (for Hvm74) with an average of 0.74. The gene diversity ranged from 0.53 to 0.93 with an average of 0.78. Highest amount of heterozygosity (0.25) was related to Hvm74 markers. The results of cluster analysis showed that microsatellite markers were highly capable of identifying genetic differences among barley genotypes. Association analysis revealed significant association of 62 alleles belonging to 38 microsatellite markers with 12 out of 13 characters evaluated on the barely genotypes under study. Maximum and minimum number of alleles were observed in relation to crown moisture (with 10 alleles) and relative water loss (with one alleles), respectively. Five alleles were associated with LT50, which may be used in barley breeding programs if they contribute to freezing tolerance consistently in other experiments.

In a survey carried out during the years 2004 and 2005, some gardens and forests of hazelnut were selected in Guilan, Qazvin, East Azarbaijan, West Azarbaijan and Ardebil provinces of Iran and in each area superior genotypes were identified and marked. Quantitative and qualitative characteristics of selected genotypes were recorded by hazelnut descriptors in all growth stages. Totally one hurdred genotypes were identified, among them thirty were selected as superior genotypes having desirable characteristics particulary with regards to growth habit, fruiting rate, shape and length of nut, offsetting and suckering production, flowering mode, oil percentage, kernel and nut weight, % kernelled and harvest time. The highest yield and performance were assessed in Navan 1, Soorii, Gerd Shok, A1, A2, K1, K2, K3 and Tarom genotypes, the higest weight of kernel and nut belonged to Navan 7, Navan 20 and Navan 31 genotypes, the lowest suckering production was assessed in Uromia 5, Uromia 34 and Soorii and the earliest fruit in Soorii and Gerd genotypes.

To assess the reaction of bread wheat advanced genotyoes to septoria tritici leaf blotch (Mycosphaerella agraminicola), 33 genotypes with a susceptible cheack cultivar Tajan were evaluated in greenhouse and field during 2009-2010 cropping season. In greenhouse, seedlings were inoculated with spore suspension of Septoria tritici and maintained under plastic covers in saturated humidity at 20ºC. In field, wheat genotypes were inoculated with spore suspension under irrigation system at three growth stages. The reaction of genotypes were evaluated by assessing leaf necrosis area and pycnidial coverage percentage in both experiments. Area under disease progress curve (AUDPC) was also calculated for each genotype used in these experiment. Analysis of variance showed significant differences among genotypes for leaf necrosis area and pycnidial coverage at 1% and 5% probability levels, respectively. Lines N-87-18 and KST10 had the highest and lowest leaf necrosis area in greenhouse, respectively. The highest AUDPC was calculated for line N-87-17 and the lowest for KST10. In field, genotypes differed significantly for leaf necrosis aea at 1% level. Lines N-87-19 and N-85-10 had the highest and the lowest leaf necrosis area, respectively. Line KST9 had the highest and line N-85-10 the lowest AUDPC 0

The cytoplasmic male sterile (CMS) lines that are used in production of hybrid seeds in three-line system often get contaminated with their maintainer lines. Using such impure CMS lines in rice hybrid seed production lead to un-uniformity and yield loss in hybrid rice. Laborious and time consuming phenotypic evaluations are used for elimination of off-type plants in CMS multiplication farms. The other option for off-type elimination in CMS lines is application of molecular markers. In this study, PCR-based mitochondrial markers was used for distinguishing five male sterile lines from five maintainer lines. Results showed that marker cms had ability to differentiate male sterile lines Neda A and Nemat A from their maintainers. Also, marker drrcms differentiated male sterile lines Dasht A, Champa A and Amol 3 A from their respective maintainers. Results of the study demonstrate use of these two markers for off-type detection in CMS seed multiplication process. This is helpful in promotion of hybrid seed production technology in Iran.

Line G11867 was first introduced in Iran together with 206 other white, chitti and red beans lines through CIAT, and was tested in different breeding experiments from 1992 to 1999. It was selected as a superior line in all experiments. In 2001 this line was evaluated with other six lines for drought tolerance, and it was found to be more tolerant than cv. Daneshkadeh the check cultivar. Line G11867 was evaluated as a resistant line to CMV but susceptible to BCMV and BYMV. It was also resistant to two spotted mite in several experiments. In farmers farms its yield (2700 kgha-1) was more than the local check cultivar (1986 kgha-1). Its cooking quality was also evaluated good, compared to the newly introduced cultivars Pak and Shokofa. Due to high yield, drought tolerance and resistance to CMV and mite, line G11867 was officially introduced as a new cultivar for cultivation in cold regions of Iran in 2010.