Seed and Plant
Year:2008 | Volume:24 | Issue:1|Papers Count:15

This research was carried out to find genetic markers linked to drought tolerance in a barley doubled haploid population. In two separate experiments, 158 doubled haploid lines together with their drought tolerant parents (Wi2291 and Tadmor) were evaluated in Tel Hadya and Breda (Syria) with 100 millimeter difference in rainfall. They were planted in each environment using an alpha-lattice design with two replications. Linkage map was constructed using 50 SSR and 93 AFLP markers that included 8 linkage groups for the seven chromosomes. QTL analysis was performed using composite interval mapping. Number of QTLs, their genomic location and additive effects were identified between 0.5 and 2.5 gram in Tel Hadya and Breda, respectively. Seven QTLs were determined for grain yield, one of them was common in two environments, and two separate QTLs in mean of environments in each environment. Susceptible stress index (SSI) had three QTLs which two of them were common in controlling grain yield. Bmag13 marker, which is located on third chromosome, had simultaneous linkage with QTLs which control 1000KW, grain yield.

In order to study the genetic control of common smut in maize, eight inbred lines (two resistant, K1264/1 and K47/2-2-1-21-2, two moderately-resistant K74/1 and K47/2-2-1-4-1, two susceptible K19/1 and K19, and two very susceptibles K3304/1-2 and K47/2-2-1-3-3-1-1, were crossed in diallel in 2005 and evaluated in 2006 under artificial inoculation. All diallel crosses and parents were inoculated with a suspension of 106 sporidia per ml, 7-10 days after silking using tip injection method. At physiological maturity, disease severity was evaluated in each ear. Diallel analysis revealed the role of genes with additive and non-additive effects in genetic control of resistance. Lines K1264/1 and K74/1 with the highest negative GCA, had the least disease severity, while, K3304/1-2 with the highest positive GCA, had the highest infection. Cytoplasmic effect was also revealed for heritance of resistance to common smut. Ressesive alleles revealed to act as increasing and dominant alleles as decreasing factors of the disease severity. Wr/Vr graph showed K47/2-2-1-3-3-1-1 as holding the highest number of ressecive alleles, while, K1264/1 and K74/1 holding the highest dominant alleles.

To investigate the influence of chemical mutagenic compounds, semi woody cuttings of olive cultivars Roghani-Mahalli, Zard, Leccino and Manzanillo were treated with different concentrations of di-ethyle sulfate (DES) and di- methyl sulfate (DMS). Both rooted and control cuttings were studied in each treatment for each cultivar. The observations showed significant differences in morphological traits such as dwarfness, leaf form, annual shoot growth, rooting ease, root system and other characters. Application of di- methyl sulfate 0.1% had significantly more influence on the manzanillo cuttings compared to the other cultivars. Application of di-ethyl sulfate 0.03% caused more changes in morphological characters especially in production of dwarf plants in Roghani-Mahalli cultivar. In addition, the mutagenic chemical compounds influenced other morphological characters such as leaf color, leaf size, leaf number, stem color and bud color. Generally, the results showed the possibility of mutant production in olive by mutagenic chemical compounds, but for undrestanding of their effects, more investigation should be carried out.

Investigation of stomatal and nonstomatal parameters limiting photosynthesis (pn) under water stress condition may provide information to understand physiological bases of drought resistance. To investigation of the leaf gas exchange in different advances and old wheat genotypes, a filed experiment was carried out during 2003-04 growing season, at Ghamloo Research Station in Kurdistan province. A split plot designe with two main plots (rainfed and irrigation), and 20 lines and cultivars of rainfed bread wheat (19 advance lines with Sardari as a check)as sub plots with three replications was applied. Using IRGA device and leaf area meter, gas parameters (internal CO2 concentration, stomatal conductance, photosynthesis rate, transpiration, water use effeciency and mesophyl conductance) and leaf surface in both dryland and irrigation plots were measured. According to stress susceptiblity index (SSI), genotypes were divided into three groups of resistant, intermediate and susceptible. Except water use effeciency all parameters were reduced under dryland conditions, but this reduction was less in resistant lines than in susceptible ones. For example Pn reduction in susceptible group was 60% while in resistant group was 11%. Under dryland conditions, reduction in mesophile conductance was higher than stomatal conductance (20% more than stomatal conductance). It was concluded that decrease of Pn under dryland was mainly due to reduced mesophyl conductance (nonstomatal factor) rather than stomatal factors.

This research was carried out to find genetic markers linked to drought tolerance in a barley doubled haploid population. In two separate experiments, 158 doubled haploid lines together with their drought tolerant parents (Wi2291 and Tadmor) were evaluated in Tel Hadya and Breda (syria) with 100 millimeter difference in rainfall. They were planted in each environment using an alpha-lattice design with two replications. Linkage map was constructed using 50 SSR and 93 AFLP markers that included 8 linkage groups for the seven chromosomes. QTL analysis was performed using composite interval mapping. Number of QTLs, their genomic location and additive effects were identified between 0.5 and 2.5 gram in Tel Hadya and Breda, respectively. Seven QTLs were determined for grain yield, one of them was common in two environments, and two separate QTLs in mean of environments in each environment. Susceptible stress index (SSI) had three QTLs which two in controlling common in controlling grain yield. Bmag13 marker, which is located on third chromosome, had simultaneous linkage with QTLs which control 1000KW, grain yield.

In order to produce new hybrids and evaluate the general and specific combining ability of sunflower inbred lines and restorers, four inbred lines and six restorers were selected in 2004. Twenty-four F1 hybrids were derived in 2004 and evaluated on a RCBD design with three replications in 2005. The results of variance analysis showed that treatments were significantly different for all traits except grain yield. RHa107F81-127/2×Aha107F81-240, Azargol and RHa107F81-127/2×AHa107F81-30 had the highest grain yield with 4471, 4274 and 4131 kgha-1, respectively.  Variance analysis of combining ability by design II of Comstock and Robinson showed that general combining ability of restorers and inbred lines for grain yield was not significant. Rha107F81-127/2 restorer and AhaF81-120 inbred had the greatest general combining ability for grain yield.  The results generally showed that male parents or restorers play important role to produce hybrid cultivars and Rha107F81-127/2 has a good potential to be applied in breeding programs.

Drought stress is one of the most important environmental stresses that reduces grain yield dramatically. Grain yield results as a complex trait from contribution of many traits in plant, and evaluation of morphological traits with less complicated inheritance under different environmental conditions and related to grain yield could be used as selection criteria. To study the genetics of traits related to plant stature and flag leaf area, a cross was made between durum wheat cultivars Oste-Gata (drought tolerant) and Massara-1 (susceptible). Their F1, F2 and F3 progenies were evaluated under normal and late-season drought stress using a randomized complete block design. Generation mean analysis was performed by scaling test which essays all generations simultaneously. Analysis of variance of generations showed that all traits except of width of flag leaf, differed significantly between generations. Three parametric models contain m, d and h had the best fit. Although both additive and dominance components were involved in the expression of all the traits under both environments, yet the dominance component suffered more than the additive component. Dominance variance was contributed in plant height, peduncle length and length of flag leaf more than additive variance. Therefore, these traits can not be used as selection criteria. There was no epistatic effect for the studied traits, indicating the lack of gene interactions for the traits in the segregating populations.

In order to study the genetic control of different traits in maize, a diallel mating was used with 14 inbred lines. Parents and their F1 generations were evaluated in a RCB design with three replications at research farm of Seed and Plant Improvement Institute in Karaj in 2006. Hayman and Jinks method was used for data analysis. The results indicated over dominance genes effect for plant height, ear height, number of kernel per row, number of kernel per ear, 100-seed weight, and kernel moisture percent and for yield Gene effects for ear length, ear diameter, number of row per ear, corn cob percent and kernel weight per ear were partial dominance. The increasing alleles for 100-seed weight, corn cob percent and kernel moisture percent were ressecive and for other traits were dominant. The parents which had the highest number of dominant and ressecive genes for different traits were as follow: For yield lines no. 12 and 14, for plant height lines no. 12 and 9, for ear height lines no. 7 and 13, for ear length lines no. 3 and 6, for ear diameter lines no. 8 and 14, for number kernel per row lines no. 7 and 6, for number of row per ear lines no. 13 and 1, for number kernel per ear lines no. 8 and 1, for 100-seed weight lines no. 8 and 2, for cob percent lines no. 10 and 9, for kernel weight per ear lines no. 12 and 2 and for moisture percent lines no. 12 and 11.

To evaluate drought tolerance of tobacco cultivars by quantitative indices, a research was conducted using factorial experiment on the basis of completely randomized design, with six cultivars of Virginia tobacco in four replications in the potty conditions during 2005. Cultivars including K326F, C176, C347, C258, C319 and MN944F were compared in two levels of irrigation including irrigation at the level of field capacity (75% available water) and stress condition in the fast growth stage (irrigation at 25% available water). To evaluate drought tolerance of cultivars, some related indices such as mean productivity (MP), tolerance (TOL), stress susceptibility index (SSI), geometric mean productivity (GMP) and stress tolerance index (STI) were used. On the basis of their correlation with yield under stress and non-stress conditions, MP, GMP, STI were selected as the best indices to separate tolerant cultivars. In respect of these indices, among the cultivars of tobacco, K326F with high yield and drought tolerance characteristics was selected. Using biplot method and comparison of best indices measures for each cultivar, C347 was identified as the most sensitive cultivar to drought stress.

Sugarcane (Saccharum officinarum L.) is one of the most important sugar crops that provides the major part of consumed sugar of the people worldwide. Because of the excessive demand for sugar and its byproducts, cultivation of sugarcane is expanding rapidly in subtropical arid and semi-arid regions such as south-west of Iran. Salinity is an important abiotic stress that causes reduction in sugarcane yield under saline and sodic conditions of soil and water in Khuzestan province. This study was conducted to evaluate seven commercial and promising sugarcane cultivars at formative stage for different stress tolerance indices and distribution of genotypes and indices in 3-D plots and biplots by using a complete randomized design with three replicates and four salinity treatments (0, 0.25, 0.5, 0.75% NaCl) in a hydroponics system at research greenhouse of Isfahan University of Technology (IUT). Different tolerance and sensitivity indices for dry weight yield of sugarcane cultivars showed that NCO-310 genotype had high dry matter yielding potential in all stress levels. Also CP82-1592 genotype in medium and high level stress intensities had potential to yield relatively high dry matter and low sensitivity to salinity stress. Based on stress tolerance index (STI) revealed that NCO-310 (a commercial cultivar) and CP82-1592 (a promising line) at all salinity levels were the most tolerant cultivars.

Wheat powdery mildew is an important disease of wheat especially in humid areas. The disease which is caused by Blumeria graminis f.sp. tritici, has recently become serious in different provinces of Iran.The present study was carried out to investigate virulence factors and pathotypes of the pathogen in different provinces of  Iran. Infected samples of wheat were collected from different provinces in 2005 and transferred to the greenhouse at Seed and Plant Improvement Institute in Karaj. After purification and multiplication of spores on susceptible cultivar Bolani, 18 isolates were evaluated for their virulence genes. Pure spores of each isolate were inoculated separately on the first leaves of 17 near isogenic lines (differentials) in the greenhouse. Infection types were assessed based on 0 to 9 scale, 12 and 16 days after inoculation. From the total of 18 isolates of Blumeria graminis f.sp. tritici, 14 pathotypes were identified. This indicated the high genetic variability in the population of the pathogen and presence of different pathotypes. Pathotypes No. 6 and 12 from Varamin with 87.8% pathogenicity, were the most virulent pathotypes. Only one of the pathotypes was isolated from more than one region. High frequencies of virulence for genes Pm3b, Pm5 and Pm3d were found. Frequencies of virulence for Pm1,2,9 and Pm 2,4b,8 were low. Comparing the results of virulence surveys in different provinces during 2000 to 2006 showed an increase in frequencies of virulence for some resistance genes while virulence for some of genes had been decreased. It shows frequently variable pathotypes in every region.

Responses of ten pomegranate cultivars Malas Torsh Saveh, Malas Shirin Saveh, Agha Mohammad Ali Shirin, Alk Torsh Saveh, Alk Shirin Saveh, Poost Sefid Shirin, Poost  Sefid Torsh, Poost Siyah Shirin, Tabestani Torsh Saveh and Poost Sefid Bihasteh Shomal to population density of Tenuipalpus punicae were evaluated during 2001-2002 in Saveh region. A Randomized Complete block design in three replications was used for analysing the data collected from forthnightly sampling of mites onset from mid. May up to mid. November. Maximum number of mites on both sides of leaves was recorded 67.66 and 24.33 at the middle and end of August on Poost Sefid Shirin cultivar during two years of sampling, respectively. Maximum (13.47) and minimum (0.4) mites densities were recorded on Poost Sefid Shirin and Malas Torsh cultivars in the first year and rather similar densities in the second year determined them as susceptible and resistance cultivars to the mite density respectively, but in general no significant difference was observed among the cultivars with population density of mite. Analysis of data from eleven sampling intervals indicated only peak of mite population during September which can be related to the high temperature occurred during this period. Population of mite was highly affected by color and taste of pomegranate cultivars. Cultivar Poost Sefid and local cultivars with white color and sweet taste attracted higher populations of mite. Maximum mite-days (225 days) was also observed on Poost sefid Torsh cultivar. These findings indicate that white colored pomegranate cultivars accepting higher populations of mites and longer time of activity, seems to be more sensitive to the mite.

Fruit and leaf characteristcs including leaf morphology and fruit physical and chemical characters of 22 edible fig and 11 caprifig genotypes grown in different regions of Fars Province including Estahban, Abesard-e-Khafr, Morvarid Darab, and Dost iran Kazerun were studied during 1998 to 2001. Data collected from three trees classified all genotypes as Izmir groups that need caprification for fruit formation. Five edible fig genotypes were suitable for dry fruit and the remainings were suitable for fresh fruit consumption. Results of cluster analysis showed maximum similarity (84%) between Kharfak and Payves cultivars and minimum similarity (42%) between Torshook and Alamee Siah cultivars. Sabz cultivar in Estahban and Payves cultivar in Dost iran Kazerun being pollinated, were the most the most important cultivars for dry fig.

Stem or black rust of wheat, caused by Puccinia graminis Pers. f. sp. tritici Eriks. and Henn (Pgt), was the most feared and devastating disease of wheat  at one time worldwide. The fear from stem rust was understandable because an apparently healthy looking crop about 3 weeks prior to harvest could reduce to a black tangle of broken stems and shriveled grain by harvest. The disease has been controlled by deploying resistance genes in commercial cultivars. Successful control of disease over forty years has significantly reduced the risk of crop losses and research activities as well. Almost 50 stem rust resistance (Sr) genes are now catalogued, several of which have been used in commercial wheat cultivars worldwide. With the exception of Sr2 that confers slow rusting race non-specific resistance at adult-plant stage, all other Sr- genes are race specific, and are expressed at both seedling and adult-plant stages. Resistance gene Sr2 in addition to other unknown minor genes known as 'Sr2-complex' provided the foundation for durable resistance to stem rust in germplasms developed in CIMMYT. In addition to Sr2 some other stem rust resistance genes derived from alien resistance genes sources such as Sr24, Sr26, and Sr31 and more recently Sr38 have been used widely. Deployment of stem rust resistance genes declined the importance of stem rust worldwide. All translocations except with Sr26, are also carrying additional resistance genes for other wheat diseases. Sr31 known to be located on 1B.1R translocation is completely linked with Yr9 and Lr26, genes conferring resistance to stripe and leaf rust. The 1B.1R translocation has been used widely in spring, facultative and winter wheat breeding programs in Europe, China, Russia, and USA and in several cultivars in developing countries derived from CIMMYT germplasms during mid 1980s. It was not until 1999 that the first virulent pathotype to Sr31 was detected in Uganda. This race is commonly known as Ug99 and also has been designated as TTKSK using North American nomenclature system. Following its first detection in Uganda, investigation in neighboring countries revealed that same race migrated to Kenya in 1999/2002, to Ethiopia in 2003, and finally it was reported in Yemen in 2006. The migration route of Ug99 matches with the migration route of Yr9 virulent race of Puccinia striiformis f. sp. tritici (Pst) during 1986/1991. The Yr9-viruelnt Pst pathotype migrated from Africa to Iran in 1992 and caused 1 and 1.5 million tones crop losses in 1992 and 1993 respectively. The pattern of airflows and wheat growing distribution in these areas supports the migration routes similar to that taken by Yr9-virulent Pst pathotype in 1990s. Similar genetic background of wheat cultivars growing in the possible migration route of Ug99 that are highly susceptible to this pathotype will also enhanced the potential risk of epidemics of stem rust in this epidemiological zone. Based on the historical events and predictions, Iran will be one of the frontline countries in the predicated migration route of Ug99. It tooks five years for Yr9-virulent Pst pathotype to reach this country. Conducive environmental conditions exist in Iran and if an epidemic occurs from Ug99 or any variant of Pgt carrying virulence for stem rust resistance gene Sr31 that is present in most of the Iranian wheat cultivars derived from CIMMYT germplasms, serious catastrophic crop losses would be expected.

Research was conducted to develop and release new improved winter safflower (Carthamus tinctorius L.) cultivar suitable for cold and semi cold areas of Iran. In 1995, 1996 and 1997, line L.R.V.51.51  was selected from Uromeieh landraces based on agronomic traits, resistance to diseases and abiotic stresses under field conditions. It was included in yield trials in main Research Stations Karaj, Isfahan and Darab, together with 9 safflower lines, as well as widely grown improved cheek cultivar Zrgan-279 Results showed that this line produces significantly higher and stable yield. Analysis of the grain and oil yields using Eberhart and Russel method showed significant difference for the main effects of genotype and genotype × environment (linear) interactions and non-significant difference for deviation from regression. According to the classification of genotypes based on the mean of grain and oil yields, coefficient of regression and deviation from regression, the new line L.R.V.51.51 with its high grain and oil yields and stability was selected as a desirable genotype while it has more tolerant to cold than Zargan-279, with mean grain and oil yields 2205 kgha-1 and 600 kgha-1 respectively. The new line was released in 2005, with the name of Paideh.