پژوهشنامه اصلاح گیاهان زراعی
پیاپی 14 (پاییر و زمستان 1393)

Appropriate selection of donor parent for breeding purposes needs sufficient knowledge about genetic diversity and germplasm classification. In order to investigation and classification of genetic diversity in 35 wheat (Triticum aestivum L.) genotypes، an experiment was conducted in University of Shahed based on randomized complete block design with 2 replications in 2009. In persent study 15 morphological characteristics such as days to 50% of flowering، plant height، number of stems per plant، number of productive tiller، number of internode، length of flag leaf، width of flag leaf، leaves angle، peduncle length، flag leaf distance to spike، spike length، number of grain per spike، awn length، 1000 grain weight and grain yield per plant were evaluated. The analysis of variance for all the traits indicated significant difference between studied genotypes (P<0. 01). Range and correlation analysis between traits، showed considerable genetic variation among studied genotypes. Cluster analysis via Ward method for field data، classified all genotypes in four groups. The ANOVA analysis showed significant difference among the clusters for leaves angle. Factors analysis، extract 5 factors that be able to describe nearly %75 of total variance.

Generating pyramid lines via multiple crosses is one of the most important strategies for rice breeding. 126 F3 lines generated from Ghaem as a female line and Shastak, Fajr, Domsiyah and Nemat as male lines including Neda and Sangetarom as check varieties studied in the form of augmented design at the experimental field of GABIT. Variance analysis indicated significant differences of agromorphological traits between check and others lines. Cluster analysis of check varieties based on ward method was conducted and Pearson correlation coefficient indicated possitive and significant correlation (P=0.1) between fertile tillers (r=0.91) and 1000 grain weight (r=0.97) with yield. Although 28 lines indicated significant differences with Ghaem check variety but only GF//GD-03-3 and GD//GS-03-1-23 lines have shown higher yield regarding to high yield Neda check variety. Three GD//GS-03-1-23, GD//GS-03-1-25 and GF//GN-03-2-18 lines have had excellent ideotype and seven clusters obtained from cluster analysis in which superior lines belonged to cluster 4 and 5.

Quantitative traits and the response of 20 genotypes of soybean to water deficit stress were evaluated at Agricultural Research Station of Gorgan in 2010 and 2011. Therefore, 3 separate experiments were conducted, each experiment as randomized complete block design, in 3 replications. In the first experiment, all soybean genotypes were irrigated based on 50 mm evaporation from evaporation pan, but in second and third experiments, the irrigations were applied based on 100 and 150 mm evaporation from evaporation pan. In all 3 stress levels, effects of genotype were significant on most of studied traits. Decreasing soil moisture and inducing drought conditions decreased grain yield in studied genotypes, however, the amount of yield reduction were different in genotypes. The mean grain yield of soybean genotypes in non-stress and stress conditions was 1989 and 1242 kg ha-1, respectively. Genotype HT2 in non-stress conditions (2569 kg ha-1), PE10 in medium stress conditions (2222 kg ha-1) and WE6 in high stress conditions (1688 kg ha-1) had the highest grain yield, respectively, which can be used in research programs.

This experiment was conducted to study the effects of water deficit stress on morphological traits, yield and yield components of 60 maize single cross hybrids at Torough Agricultural and Natural Resources Research C enter located in Mashhad, Iran on 2013. This experiment was laid out in randomized complete block design with three replications. The irrigation treatments were consisted of two irrigation levels (50 and 80 percent allowed water depletion as normal and drought stress, respectively). The result of ANOVA showed significant differences among single cross hybrids for all of measured traits in both conditions. In non-stress or normal condition, hybrids No.4 and in stress condition, hybrids No.9 were the best hybrids for grain yield with 13.30 and 9.02 ton/ha, respectively. According to the indices MP, GMP, STI and HARM among the studied hybrids the promising hybrids No.1 and No.1,4 and9 were recommended for water stress condition in Mashhad regions. During periods of lower growth in hybrid and non-treated with high temperatures during pollination can cause lead to the compounds than others. The correlation results showed the positive and significant relation between potential for performance (no stress) indices MP, GMP, STI, TOL and HARM. Most significant and positive correlation between the indices was related to GMP and STI (0.99). In general, hybrids L1×k1263/1, L5×k1263/1, L10×k1263/1 and 14×k1263/1 due to the high level of tolerance can be used in breeding programs.

In attention to wheat importance in human nutrition and its production limitations due to salt stress, this study was conducted to evaluate and grouping 52 different wheat varieties for activities of antioxidant enzymes. Seedlings in 4-5 leaf stage, which were grown in aeroponic way, were exposed to salt stress using 200 mM NaCl for 10 days. After that, activities of enzymes of catalase, glutathione peroxidase, ascorbat dehydrogenase, superoxide dismutase isozymes along to amounts of malon dialdehyde and hydrogen peroxide, Na, K and Cl were measured. Cluster analysis categorized the varieties into three distinct groups. The varieties such as Karkheh, Arta and Alborz as a distinct group had the lowest values of catalase, hydrogen peroxide and malon dialdehyde, in addition to high values of antioxidant enzymes. However, accumulation of Na and Cl under salt stress was high in the varieties but damage severity decreased because of increase in antioxidant enzymes activity that led to stop oxidative stress. Also, it is very probable that they have a special ability in leaves to detoxification Na and Cl. These genotypes were known as tolerant varieties which those may be applied in wheat breeding programs for salt tolerance. Totally, each of the varieties had some appropriate tolerance mechanisms to defense with salinity and the results clarified genetic variation in this regard.

In order to study the effects of salt stress on yield and yield components, 21 rice genotypes, in a factorial experiment were conducted based on Randomized Complete Block Design with 3 replicates on pots in greenhouse at Sari Agricultural Science and Natural Resources, during 2009. Salt stress was applied on reproductive stage in rice at 3 levels 0, 6 and 10 ds m-1 NaCl. Results showed that there were significant differences between rice genotypes for all measured traits. Shastak mohammadi and Tarom-Danesh in 6 ds m-1 NaCl and Hassani in 10 ds m-1 NaCl showed lowest reduction in grain yield in comparison with normal condition. Thus tolerant cultivars, in this experiment. Salinity increased sterility in rice genotypes. Significant correlation was observed between grain yield and number of panicle per plant in 6 and 10 ds m-1 NaCl. Finally, Shastak mohammadi, Hassani, Tarom-Danesh, Line 109 and Line 75 were the highest tolerant cultivar in response to salinity.

Molecular markers are considered as useful tools for breeding, screening and genetic characterization of genotypes. In crop plants, using of marker assisted selection (MAS) for traits such as product quality and resistance to pests and diseases is being widely adopted by numerous breeding programs worldwide. In current study effects of high molecular glutenin subunit loci Glu1, a lleles 2*, 17+18 and 5+10 were shown to be the most effective alleles for increasing gluten quality, respectively. In present study, we have screened F2 progenies of a composite cross (M-83-17/3/Dove”S”/Buc”S”//2*Darab/4/Pishtaz/3/Ww33/Vee”S”//Niknejad) belonging to breeding program for temperate climate regions of Iran for presence of 2*, 17+18 and 5+10 alleles. Forty individuals from F2 generation were tagged in the field. Sequence tagged site (STS) primers Were used as specific markers to test for the presence of 2*, 17 +18 and 5+10 in progenies. Our genotyping tests have revealed that out of 40 progenies, 12 individuals possessed the three alleles. Six out of 12 F3 progenies with 10 samples were selected and have been transferred to F4 generation. Results obtained from molecular markers experiment were in agreement with the results from SDS sedimentation test. It is indicated that 2*, 17+18 and 5+10 alleles have positive correlation with SDS-sedimentation volume. Cluster analysis based on between-group variances recognized five different clusters for high quality alleles with different combinations of the three alleles mentioned and three clusters for SDS-sedimentation volume with high, medium and low SDS-sedimentation volume, respectively.

Study of genetic relationships is a prerequisite for plant breeding activities as well as for conservation of genetic resources. Since the hybrid canola have more yield than inbred lines, determine the genetic diversity of this have particular importance. In the present study, genetic diversity among 36 genotype of Brassica sp. were determined using inter simple sequence repeat (ISSR) markers. Thirteen selected primers produced 267 discernible bands, with 257 (96.38%) being polymorphic, indicating considerable genetic diversity among genotypes. Average PIC and MI of all primers were 0.34 and 6.48, respectively. The results showed that average of marker index including Nei’s gene diversity, Shannon’s information index, the effective number of alleles were 0.34, 0.51, 1.58 respectively in genotypes of Brassica. Based on an un-weighted pair-group method using arithmetic average (UPGMA) clustering algorithm, three distinct groups were established. Genetic diversity shown by the marker ISSR, indicates that these markers can be used to identify differences between species and within species, In studies of phylogenetic. In order to evaluate the relationships and genetic structure of genotype canola using morphological characteristics is proposed.

In order to analyze genetic diversity and determine the most effective characteristics on seed yield, 49 alfalfa genotypes including foreign and Iranian germplasms, were evaluated using a simple lattice design with two replications in researches station of Natural Resources and Agricultural Research Center of East Azerbaijan province. Analysis of variance revealed significant genetic diversity among genotypes with respect to some of the traits. Coefficient of variation (C.V.) was smallest for days to end of seeding and highest for seed yield. Grouping of genotypes using Ward's algorithms and all the traits assigned 49 genotypes into three groups. Assignment of some landraces and foreign genotypes in one group indicated incongruity of genetic variation and geographical origins of genotypes. In grouping based on seed yield and related traits identified using path analysis, genotypes analyzed were classified into two groups. In this classification all of the landraces from East Azerbaijan province were located in one group. In factor analysis, five factor with eigenvalues greater than one explained 77.02 percent of total variance.

Rice is a second important crop at Iran and its cooking and eating quality plays important role for consumers. In order to improve yield and quality, a set of crosses among Amol3 and Sepidrood made with Dom­­­Siah Mashhad and Sange Jo. The F1 was back crossed with local varieties as donor parents for two successive generations (BC2) and then selfed upto five generations (BC2F5). 13 promising lines with higher yield and quality were selected. The selected lines including three checks Neda, Sepidrood and Sang Tarom planted in Randomized Complete Block Design with three replications and their yield quality test were done. Some of important characteristics of qualitative and quantitative were measurement. Line DN-33-18 accompand with quality check Sang Tarom and located in the fourth class. This Line regarding to the yield and early maturity indicated better performance than Sange Tarom (check variety). This line with 119cm height, 123 days to maturity and good physicochemical properties almost similar to the local good quality varieties, but 6.65 tons/hectare, while the average yield of local varieties is shown around 3.5-4 tons/hectare.