مجله پژوهش های ژنتیک گیاهی
سال سوم شماره 1 (بهار و تابستان 1395)

Plants are capable of responding to environmental stresses by activating their adaptation mechanisms and their response to environmental factors by changing their gene expression. Drought stress is considered as the most important abiotic stress in agriculture. In this regard, in present research, proteomics techniques used to detect proteins were responding to drought stress. To select drought susceptible genotype, 64 chickpea genotypes were assessed by simple lattice design 8×8 at the Sararood station (Iran) and then in the greenhouse of College of Agriculture and Natural Resources of Kermanshah Razi University (Iran) in three levels of stress including normal, medium and intensive stress conditions at poding stage. Finally, SAR 80 JI 09 K12-8 genotype was selected as susceptible to drought stress. Then, the evaluations consisted of a leaf proteome induced under drought stress conditions were performed. To study and identify the proteins associated with drought, total protein was extracted from the leaves by TCA- acetone method and isolated in the first dimension by IPG gels with pH gradient 7-4 and in second dimension after by 12.5% concentration polyacrylamide gels. Therefore, in the drought susceptible genotype the value of each spot was used as a standard amount. Protein spots on the gel were scanned and identified by using Image Master 2D Platinum of Melanie 6.0 software. The results of two-dimensional gel analysis and protein identification of drought susceptible genotypes showed that leaf proteome pattern has been widely changed in drought stress condition. In susceptible genotype, 212 protein spots repeatable were identified. 10 spots were detected by using MALDI-TOF-TOF mass spectrometry which were divided in different groups based on response to drought stress in biological cycles.

In order to genetic analysis of spike characteristics in barley, an experiment was conducted with 100 F3 and F4 barley families derived from Badia × Komino cross at Research Farm college of Agricultural University of Gonbad Kavous (Iran) based on randomized complete block design with three replications. Agronomic traits such as spike length, number of seeds per spike, total of spike, total weight of spike, grain length and grain diameter were measured. Linkage map with 7 SSR and 69 polymorphic alleles of iPBS markers were prepared which covered 632.2 cM of barley genome. QTL analysis was performed based on the method of composite interval mapping (CIM). Ten QTLs (with additive effect ranged from 127.07 for spike number to -0.625 mm for grain length) were detected. Phenotypic variance explained by QTLs ranged from 10.9 to 12.9 percent, which the highest related to spike length in F3 generation and the lowest related to the total number of spikes in F3 generation and the total weight of spike in F4 generation. All detected QTL were major effects and after validation can be used in breeding programs and marker-assisted selection.

Estimation of genetic variation in crops, a very important role in the development of breeding programs and preservation of genetic resources through morphological characteristics, is possible. To identifying genetic variation and double haploid barley lines classification in relation to germination traits, 72 lines derived from the cross of Steptoe and Morex were evaluated in randomized complete block design (RCBD) with two replications, at three conditions including normal and two salinity levels of NaCl (100 and 200 mM NaCl). Investigated traits in this study were coefficient of velocity of germination, final germination percentage, mean germination daily, germination rate index and average germination speed. The results indicated that considerable genetic variation among genotypes in all traits. Genetical correlation based on average of the three environments indicated that high significant correlation exist (r= 0.85**) between the daily germination and final germination percentage. In this study, the highest value of phenotypic and genotypic variation coefficient, broad and narrow sense heritability and genetic gain were calculated for final germination percentag. Based on cluster analysis, barley genotypes were grouped into three categories and genotypes of the third cluster, were superior coefficient of variation of germination, germination percentage, germination rate and mean daily germination index, but had low a mount of germination rate. Therefore, the genotype of this group can be used in breeding for high germination percentage. Using principle component analysis; five traits were grouped in the form of two new variables that explained 99.061 percent of the total variance. Analysis biplot indicated that the genotypes of first group have a high percentage of germination index and germination index coefficients.

Oilseed rape (Brassica nupus L), a member of Brassicaceae family, is an important crop regarding oil production worldwide. Brassicaceae is an economically important family of flowering plants with about 350 genera and more than 3000 species. Eleven pairs of single sequence repeat (SSR) primers were used to identify the genetic diversity among 21 oilseed rape genotypes. Results of SSR molecular marker analysis revealed that SSR primers produced a total number of 76 scorable bands of which 46 (60.5%) bands were polymorphics. The average number of bands for each primer and genotype was 6.9 and 3.6, respectively. Both CB10036B and Na10A09 primers produced 10 and Cb10403 primer produced 4 polymorphic bands, respectively. UPGMA cluster analysis based on Dice similarity matrix showed that Zarfam and Gerinimo genotypes had the highest (0.99%) and Licord and KS-11 genotypes had the lowest (0.72%) similarity. Both Iranian and foreign genotypes were grouped together in one major cluster, indicating presumably they may have the same origin and/or common pedigree. Results of AMOVA analysis within and between groups (spring – Autumn) revealed that almost 97% of total genetic diversity belonged to within group genotypes.

In order to estimate the components of genetic variance and general and specific combining abilities of maize lines, an experiment was done using 8 S6 inbred lines as female parents and 2 male inbred lines as testers consisted of K1264/5-1 (early mature) and K3615/1 (late mature) using line by tester mating design based on randomized complete block design with three replications in two different conditions (Salt stress with Ec=5 dsm-1 and non-salt conditions) in research field of graduate university of advanced technology (Kerman, Iran) in 2014. Analysis of variance results showed significant differences among inbred lines for some of measured traits in both salt and non-salt conditions. Significant differences observed for line × tester mean-squares in non-salty condition for all measured traits except days to silking and physiological maturity. In salt stress condition, just for leaves number per plant and days to silking, line × tester effects were not significant. Additive variance for days to silking and physiological maturity in non-salt condition was more than dominant variance, therefore the additive to non-additive variance ratio was more than 1 and indicating emphasis on this matter too. Inbred line L6 had a significant positive GCA and the highest grain yield with 1455.785 and 789.107 kg/ha in non-salt and salt stress condition, respectively. The crosses (L4×T1=428.460 and L7×T1= 438,345) in non-salt condition and (L3×T1=438.345) in salt stress conditions had a positive significant specific combining ability. Finally, from all existed variation, the lines and line × tester effects were more important than tester effects that indicates transmission of diversity from lines to hybrids.

In order to study genetic diversity, heritability and relation of some important traits with grain yield in bread wheat, 20 bread wheat irrigated lines evaluated using a randomized complete block design with three replications during two cropping cycles/years. Based on combined analysis results, there were a significant difference between genotypes. Also, in all traits, coefficient of phenotypic variation was greater than coefficient of genetical variation, indicating the effect of environment on investigated traits. The significant correlation between grain yield and number of days to maturity, spikes per m2 and the grains per spike. number of days to heading and number of days to maturity had highest heritability among traits, with 87 and 69%, respectively. Results of this showed that selection of early heading or shorter no. of days to heading and early maturing or shorter number of days to maturity is recommended to breeders for selection materials favorable for terminal warm condition and water shortage, preventing grain yield reduction. Results of cluster analysis showed that genotypes are divided in six groups. Totally, six superior genotypes from the fourth cluster were selected as superior lines. Based on bi-plot analysis, genotypes 14 and 5 showed the lowest genotype × trait interaction, but genotypes 16 and 8 showed the highest genotype × trait interaction.