Iranian Journal of Genetics and Plant Breeding
Volume:8 Issue: 1, Apr 2019

Rice fragrance is one of the most important and determining factors in rice quality. Aromatic rice is a special group considered to be of the best quality. It is important to know the physiological behavior and genetic source of aromatic rice in order to improve breeding programs. In this research, thirteen rice cultivars were used for molecular and biochemical evaluations. The research population included three aromatic cultivars and ten cultivars from Khuzestan province in Iran. Thirteen SSR and four MAS markers related to grain aroma were used for genotyping the rice cultivars. The highest PIC for SSR markers was 0.75 Cluster analysis using the UPGMA method classified all cultivars into three groups. The results of MAS for EAP and INSP primers showed a molecular band of 355 bp in the non-aromatic rice cultivars. In this study, four non-aromatic cultivars (Hamar (Sorkheh), Danial, Garde Ramhormoz, and Hoveizeh) were detected. The results of IFAP and ESP primers further revealed a band of 257 bp, identified in Tarom, Domsiah, Basmati, Anbarbo Najafi, Anbarbo Red, Anbarbo Yellow, Kadoos, Champa, and Shafagh, all aromatic cultivars. Moreover, the volatile components of rice seed samples were extracted and identified using the sensitive and efficient solid phase extraction method, GC-MS. Eight compounds (aldehyde, pentane, hexanal, heptane, tetradecane, ketone, acetic acid, and 2-acetyl-1-pyrroline) were identified from the studied cultivars as the most important chemical compositions of aroma in rice. The 2-AP compound was recognized in Tarom, Domsiah, and Anbarbo Najafi cultivars. Finally, four MAS primers identified all aromatic rice cultivars as well as thirteen SSR markers related to rice fragrance.

In bread wheat (Triticum aestivum L.), crop height is an important determinant of agronomic performance. To map QTLs with additive effects and additive×additive epistatic interactions, 148 recombinant inbred lines and their parents, (‘YecoraRojo’ and Iranian landrace (No. #49)) were evaluated under normal and water deficit conditions. The experiments were carried out on research farms of Mahabad University and Miyandoab Agricultural Research Center in 2014-2015. The experimental design was an alpha lattice design with two replications. Quantitative trait loci (QTL) for the studied traits were carried out for additive effects and additive×additive epistatic interactions using the QTL Network 2.0 software based on the mixed-linear model. A number of 177 microsatellite and 51 retrotransposon markers were used to construct the linkage map. In the present study stem length, plant weight, peduncle length, and peduncle weight were measured. Results showed that under both normal and water deficit conditions, both positive and negative transgressive segregations were significant, also the highest and lowest broad and narrow sense heritability were estimated for stem length (73.69 and 36.74 percent) and peduncle length (40.51 and 20.25 percent), respectably. The results showed that under the normal condition, seven QTLs (R2A=5 to 11%), and eight additive×additive epistatic interactions (R2AA=1.66 to 10.92%) were significant. Under the water deficit condition seven QTLs (R2A=4.27 to 9%), and five additive×additive epistatic interactions (R2AA=3.8 to 14.58%) were significant. Five QTLs from the 14 QTLs identified in this study were located in chromosome 5A, indicating the importance of this chromosome in controlling the plant architecture characteristics and possibly using it for marker-assisted selection and genetic engineering.

Wheat powdery mildew caused by fungal pathogen Blumeria graminis f.sp. tritici is a destructive wheat disease, occurring in regions with cool and humid climates. In order to investigate the changes in pathogenicity of the disease and to identify the effective genetic source of resistance, a total of 29 wheat genotypes with different resistance major genes (Pm) were studied in two hotspots of Gorgan and Sari under natural incidence of the disease over 2015-2018. Resistance reaction of the genotypes was evaluated by disease development, disease severity and coefficient of infection. The results indicated that mean of coefficient of infection for Gorgan was larger than that for Sari in all three years of the study. The reaction of some genotypes showed apparent differences between the two regions during the years of study. The highest genetic distance was observed between Ralle (Pm3d) and Holger (Pm6). NK-747 (Pm6) and Maris Huntsman (Pm2+Pm6) as well as Amigo (Pm17) and Maris Huntsman (Pm2+Pm6) showed the highest genetic similarities to each other. A total of 65.78% of the data variation was justified by principal component analysis on the basis of the coefficient of infection. The genotypes Maris Dove (Mld+Pm2), Shamrock (with unknown Pm), Broom (Pm3d) and Axona (Pm2+Pm3d+Mld) expressed effective resistance over the years and locations. The total results of this research indicated variations in the virulence of wheat powdery mildew population during the years of the experiment. This finding emphasizes on the necessity of constant monitoring of the disease in the infected areas. The genes with effective resistance identified in this study could be used in resistance breeding to powdery mildew especially for Gorgan and Sari.

Stevia rebaudiana Bert. is a medicinal plant with anti-oxidant, antimicrobial, antifungal and antiviral drug properties which contains two valuable secondary metabolites, stevioside and rebadioside A, with very high sweetness capacity. In this research hairy roots were produced from S. rebaudiana leaf disks using two strains of 15834 and A4 A. rhizogenes. Then, the best hairy root line was selected and propagated. The effect titanium dioxide nanoparticles at 20, 40 and 60 mg/l after 0, 24, 48 and 72 h of elicitation and cobalt chloride and cadmium chloride each at 100 and 200 μmol after 2 and 8 h of elicitation were studied on the production and accumulation of stevioside and rebadioside A. The results demonstrated that most treatments of elicitors at different times had significant effects on the production and accumulation of target metabolites, but titanium dioxide nanoparticles caused the highest production and accumulation of stevioside (96.88 mg/l and 24.28 mg/g DW), respectively at 40 mg/l after 24 h. However, at 60 mg/l and 48 h it had the highest effect on production and accumulation of rebadioside A after 48 h (89.39 mg/l and 21.28 mg/g DW), respectively. Also the results demonstrated that treatment of cobalt chloride and cadmium chloride both at 100 μmol after 8 h had a strong effect on the production (114.19 and 183.98 mg/l) and accumulation (29.54 and 42.87 mg/g DW ) of stevioside, respectively. Cadmium chloride at 200 μmol had the highest effect on the production and accumulation of rebadioside A after 2 h (105.51 mg/l and 25.42 mg/g DW), respectively. Meanwhile, no production of readioside A was observed at 100 and 200 μmol in 8 h treatment.

Wheat (Triticum aestivum L.) is the most important food crop. It offers a great wealth of material for genetic studies due to its wide ecological distribution. The effects of GCA and SCA of morpho-phenological traits i.e. days to emergence, days to flowering, days to maturity, flag leaf length, grain filling duration, spike weight per plant, stem weight and grain yield were studied utilizing an 8×8 half diallel cross according to Griffing’s method II of Fixed model (I). Kouhdasht, Mehregan, Karim, Line 17, N-80-19, Atrak, N-92-9 and Ehsan cultivars were evaluated based on a randomized complete block design (RCBD) with two replications at the research farm of Gonbad Kavous University during fall 2017-2018. The analysis of variance and effect of SCA were significant for all the characters which showed a significant variability among their parents for all studied traits. The analysis of variance indicated that the effect of GCA was significant for all traits except for days to maturity and grain filling duration (p≤0.05). The obtained results from the mean square ratio of GCA to SCA showed that non-additive genetic variance played a predominant role in the inheritance of most traits. Based on GCA and SCA effects obtained from biplot analysis on 8 parents, N-92-9×Ehsan, N-92-9×Kouhdasht, Mehregan×Atrak, Ehsan×Line 17, N-80-19×Mehregan and Karim×Karim were detected as the best hybrids for grain yield. Further studies in relation to the agronomic traits, can improve our knowledge about the wheat cultivars used in the present study and can direct future breeding programs.

Vitamin E is one of the lipid soluble vitamins consisting of several isoforms, including tocopherols and tocotrienols amongst which the alpha tocopherol is the most active one. The conversion of γ tocophrol to α tocopherol takes place by the activity of γ-tmt enzyme. Many plants including canola lack the γ-tmt gene to enable them to convert γ tocophrol into α tocopherol. The aim of this study was to transfer γ-tmt gene into canola plants to enable them to produce α tocopherol and increase their vitamin E content. γ-tmt gene was isolated from tomato (Lycopersicum esculentum L.), Memory1 cultivar. Then, it was amplified using PCR, digested by XbaΙ enzyme, cloned into the pBluescriptΙΙ cloning vector and subcloned into E. coli. The gene was then transferred into pBI121 vector and subsequently the vector containing the γ-tmt gene was transferred into Agrobactearium tumefaciens. Two canola cultivars Zafam and Hayola 401 were used. The cotyledons of canola seeds were inoculated by Agrobactearium tumefaciens. Seven putative transformants from each cultivar (Zarfam 2 to 8 and Hayola 2 to 8) were chosen for further investigations. After the emergence of shoots and roots, the seedlings were assayed for the presence of γ-tmt gene, by PCR. Vitamin E content of the transformed plants was assayed by FTIR spectrophotometer. Results showed several fold increases in vitamin E contents of the transgenic plants compared to the control. The increases in α-tocopherol content were 2.61 and 2.71 times in Zarfam 6 and Hayola 8, respectively. This approach could be considered as a useful method for fortifying oil seed crops with vitamin E.