Crop Biotechnology
Year:2015 | Volume:4 | Issue:10|Papers Count:6

In order to study the effect of salinity on yield and physiological traits of sunflower and genetic analysis of these traits under salinity conditions, a factorial experiment based on completely randomized design with three replications were performed outside the greenhouse in an open air area under natural environmental conditions. The studied factors were included 2 salinity stress levels (normal and 6 dS/m) and sunflower recombinant inbred lines (102 lines derived from the cross PAC2×RHA266 together with parental lines). Traits such as grain yield per plant, chlorophyll content, net photosynthetic rate, leaf relative water content, Na+ and K+ concentrations were measured after flowering. The effect of salinity was significant on grain yield, leaf relative water content, Na+ and K+ concentrations as well as on Na+/K+ and K+/ Na+ ratios. For all traits, significant differences were observed between the genotypes studied. Genetic analysis of studied traits was done using a linkage map comprising 221 molecular markers (210 SSR/11 SNP) with an average distance of 7.44 cM between markers via composite interval mapping (CIM) procedure. Totally, 10 and 8 QTLs were detected for studied traits under normal and salt stress conditions, respectively. The phenotypic variance explained by QTLs (R2) ranged from 10.4%- 34.4%. The results showed the existence of co-localized QTLs for some of the studied traits under normal and salt stress conditions including Na+.S.4.1 with Na+/K+.S.4.1, Chl.NS.6.1 with K+.S.6.1. Using co-localized QTLs in different environmental conditions and different years could enhance the efficiency of marker-assisted selection in plant breeding programs.

In this study, the effect of cold treatment (4oC for 1 to 5 days) in combination with heat shock (30oC for 1 to 10 days) and also colchicine treatment (25 to 100 mg/l for 24 to 72 h) were assessed on induction of sporophytical divisions in isolated microspore culture in two hybrid tomato cultivars (‘Berlina’ and ‘Petoperide’). Microspore-derived structures with more than 10 nuclei were only observed in cv. ‘Berlina’ and in the cultures incubated for 1 or 2 days at 4oC and then for 2 days at 30oC. In addition, cold treatment for 1 or 2 days and then 2 days at 30oC could efficiently induce formation of microsporederived structures with 9-10 nuclei in both cultivars tested. No microspore-derived structure with more than 5 nuclei was observed in the cultures treated at 30oC for 10 days. In the cv. ‘Berlina’, microspore-derived structures with 9-10 nuclei were detected when 25 mg/l colchicine was used for 48 h, while in cv. ‘Petoperide’, microspore-derived structures with more than 8 nuclei were not observed in all treatments tested. Globular embryos were only produced in two-layer culture medium when treated at 4oC for 2 and 5 days and then subjected to 30oC for 2 days. Microspore embryogenesis could be induced in tomato if appropriate duration of cold and heat treatment was selected.

DNA barcoding is a simple way to identify species using a very short genetic sequence from a standard part of the genome. This technique used to identify eight medicinal plants collected from the Ardabil province. DNA extraction was performed by modified CTAB method and PCR was performed with primers designed based on rbcL, trnH-psbA, matKChloroplast barcodes and ITS nuclear barcode. Then, PCR products purified and sequenced. The percentage of amplification and sequencing success were assumed in samples respectively, 87 and 62, 75 and 37, 62 and 12, 75 and 37. The sequences were blasted with samples existed in NCBI database and Bioinformatics analyses were performed. In phylogenetic tree, the species belonging to the same genus were separated from other genus based on rbcL and trnH-psbA barcode sequences. Also, in ITS barcode only G. glabra organized with plants from same genus. In this study, barcoding of L. ledebourii with rbcL was done for the first time. SNPs were counted for barcodes of rbcL (less than 30), trnH-psbA(less than100), ITS (more than 200) and matK (less than 20). Thus, rbcL barcode due to high separation ability, low number of SNPs and universality in most species, was introduced as the best barcode. However, trnH-psbA and ITS barcodes due to related problem with direct sequencing of PCR products and lack of access to high quality sequences were identified as complementary barcodes. MatK barcode is not recommended for these samples because of the low ability of amplification and sequencing.

In this research, 150 wheat doubled haploid lines were produced using chromosome elimination method by crossing between wheat and maize. Resistance of doubled haploid lines, their parents and check cultivars against strip and stem rust was evaluated at seedling and adult plant stages. Accordingly, eight known molecular markers which are tightly linked to resistance genes including Yr 5, Sr 31/ Yr 9/ Lr 26, Yr 15, Sr38/ Yr 17/ Lr 37, Lr 34/ Yr 18/ Pm 38, Yr 27, Yr 36 and Yr 48 were screened in parents. Results showed that molecular markers for Yr 5, Yr 15, Yr 27 and Yr 36 couldn' t detect polymorphism between parents as well as positive and negative controls. For gene block Sr38/ Yr 17/ Lr 37 and locus Yr 48 allele sizes were not similar to those which were expected for these genes. Results also showed that MV17 and Flanders have gene block ofSr 31/ Yr 9/ Lr 26, and only 3 lines of population DH-26: Ghods*3/MV17 had this gene block from which two doubled haploid lines showed resistance reaction to TTSTK and TTKSK of Puccinia graminis pers. f.sp tritici races. Genetic test for the presence or absence of gene block Lr 34/ Yr 18/ Pm 38 on parents of doubled haploid lines showed that MV17 comprises this gene block. Evaluation of doubled haploid lines for this gene block showed that 6 doubled haploid lines of population DH-26: Ghods*3/MV17 have gene block Lr34/ Yr 18/ Pm 38 for which only one doubled haploid line showed resistance reaction to Puccinia striiformis Westend f.sp. tritici race of 7E158A+, Yr 27 at both seedling and adult plant stages.

The present study was conducted to validate microsatellite markers associated with drought tolerance in rice, in the natural population, including foreign varieties, aerobic rice and Iranian varieties. Plant material under normal and two levels of osmotic stress (-8 and -16 bar using of mannitol) were evaluated by standard germination test in terms of 14 traits. Genotyping was done using 26 pairs of microsatellite markers on 53 genotypes of rice. The results of the structure analysis showed the number of clusters that maximizes ΔK parameter is three. Then association analysis was conducted using the matrix structure of the population by GLM and MLM statistical models. Two MLM models identified, 75 and 30 markers for studied traits at 5% level, respectively. The markers RM11943, RM104, RM190, RM28166, RM231, RM510, RM270, RM19367 and RM431 were identified as markers associated with tolerance to osmotic stress with explain variation of several germination traits. Also the results indicated RM270 with 40.4% of the seed vigor, RM276 with explain variation of 33.9% of the percentage of water content of the seedling, and RM523 with explain variation of 40.6% and 30.7% of the speed of germination coefficient, had highest of coefficient of determination under stress relatively to other markers. That could be a reason for conformation of their relationship with germination traits under osmotic stress. Considering of the obtained results, after verification of results in the other genetic backgrounds we can use these markers in the breeding programs.

Since the economic value of cultivar depends on different characteristics, thus detailed knowledge on genetic behavior and identification of genomic loci linked to these traits will help to improve plant cultivars. In this investigation, relation and linkage between of 30 microsatellite markers with some of important agro morphological traits in 106 different sunflower lines was evaluated through GLM and MLM association models in Structure and TASSEL software. Based on the 30 microsatellite markers used in this study, population genetic structure subdivided into five subpopulations (K=5) that barplat results also confirmed it. In association analysis based on GLM and MLM models, 9 and 16 loci showed significant relation with assessed traits, respectively, and explained considerable variations of this studied traits. In this study, some co-localized QTLs were identified for studied traits. Common markers between of traits can be due to pleiotropic effects or linkage between of genomic regions involved in these traits. Results of the current study presented useful information about the genetic basis of the studied traits and can be used in different sunflower breeding programs including marker aided selection. In future studies, coding genes of important agronomical traits could be identified by sequencing of loci with highest R2 (ORS1209, ORS822 and ORS649). Markers with highest association to traits can be used for saturating linkage maps.