Iranian Journal of Genetics and Plant Breeding
Volume:9 Issue: 2, Oct 2020

Ten rice genotypes were evaluated in a randomized complete block design with four replications in three regions of Iran during three cropping seasons. Likelihood ratio test (LRT) was shown the significant effects of genotype and genotype by environment interaction (GEI). Scree plot indicated the first three components explained 81.24% of GEI variation. Mosaic plot partitioned total sum of squares (TSS) and indicated genotype and GEI effects illustrated 52.72% and 47.28% of TSS, respectively. Heatmap plot also exhibited variations in the grain yield of genotypes across environments. The best linear unbiased predictors (BLUPs) of grain yield showed that G2, G5, G4, G10 and G6 had a higher prediction than the overall grain yield. The nominal yield plot indicated G4, G5, G6 and G10 had a small contribution in GEI and were more stable genotypes. In the fourth quarter of grain yield vs the weighted average of absolute scores (WAASB) biplot, G2, G5 and G10 were highly productive and stable. Based on a weight of 50:50 for grain yield and stability, G5, G6, G2, and G3 had the highest WAASBY values and were determined as stable genotypes. In WAASB/GY ratio plot, it is observed that G5, G6, G2, and G3 had the highest WAASBY values and were deyermined as stable genotypes. Factor analysis based on WAASBY values of all of the traits identified three factors with a cumulative variance of 79.35. Based on the multi-trait stability index (MTSI), G6 and G3 were selected. In conclusion, G5 was superior to all genotypes and can be used to determine the best cropping manangement in agronomic research experiments and for the introduction of new cultivars.

Mapping QTLs with molecular markers can be very useful for plant breeders in agricultural genomics. The identification and introgression of QTLs for grain yield and drought tolerance indicesis an efficient approach to improve the drought tolerance of rice varieties. In this study, QTLs controlling some traits associated with grain yield and drought tolerance indiceswere identified using 150 F8 lines derived from a cross between Sepidroud and Gharib, under non-stress and stress conditions. The genetic linkage map containing 12 ISSR polymorphic markers, 103 SSR, 1 IRAP marker, 11 REMAP markers and 16 combinations of ISSR markers covered 1005.2 cM of the rice genome and a mean distance between adjacent markers was 4.43 cM. In this experiment, two QTLs with main effects were mapped for SSI and YSI indices, three QTLs with main effects for grain yield under non-stress and stress conditions, TOL, STI, GMP, and YI, four QTLs with main effects for MP and HM. One epistatic QTL was mapped for grain yield under non-stress condition and STI index. The phenotypic variation explained by each main effect QTLs and epistatic QTLs ranged from 3.99 to 25.41% and 6.51 to 18.81%, respectively. Fifteen main effect QTLs, including, qGY9, qGY12a, qTOL4,qTOL5, qSSI5, qSSI6, qSTI9, qSTII2, qMP9, qGMP9, qGMP12, qHM12a, qYSI5, qYSI6, and qYI12a as the major QTLs controlling these traits can be considered in rice breeding programs for improving grain yield and drought tolerance after validation. The markers UBC816-2, (Tos2+UBC827)-4, (UBC826+HB12)-6, RM215 and RM5371 located near major QTLs could be used in MAS programs.

This research aimed to estimate the nucleotide polymorphism and point mutation/substitutions for ITS2 region in 12 different Triticum and Aegilops species, and to demonstrate their phylogenetic relationships. The aligned ITS2 dataset showed a total of 67 SNPs and transitions (75%) predominant over transversions (25%). The C/T transitions were observed at highest level in the studied species. The highest nucleotide substitutions occurred in ITS2 sequences of T. aestivum, T. turgidum, and A. speltoides that showed similar substitutions on the base sites 76, 193, 215, 230 and 241 (TCCAG changed to ATTTA). T. boeticum and T. urartu showed similar substitutions on the base sites 85, 201, 231, 234 and 252 (GTGCC changed to AGATA). Remarkably, the nucleotide of base site 146 was C in all Triticum species, but T in all Aegilops species. The substitution rate in A. neglecta, and A. umbellulata was zero, it was concluded that their ITS2 is conserved. The secondary structures of ITS2 in the studied species was similar to that of the other flowering plants with four helices and the variation in helices length. The helix III had the longest length compared to the other helices. The length ranges of helices I, II, IV varied from 9 (T. turgidum, and T. urartu) to 10, 11 (A. cylindrica) 13 and 6 (A. speltoides) and 10 (T. boeticum) paired bases, respectively. Using pairwise ITS2 nucleotide comparisons, the closeness of A. caudata with A. cylindrica, T. boeticum with T. urartu, A. neglecta with A. umbellulata was observed. Phylogeny trees classified 12 species into four main clades. The highest point mutations occurred in ITS2 sequences related to the species grouped in the first clade.

Germplasm evaluation of crop plants as a repository of useful genes to cope with biological and abiotic stresses has always been the focus of plant breeders. The fungus causing Ascochyta blight is one of the most important biological factors limiting chickpea cultivation and production in most parts of the world, including Iran.The present study was conducted to identify the genetic sources of resistance of 20 chickpea genotypes in seedling, flowering, and podding stages in greenhouse conditions. Damages caused by the disease was recorded using a 9-degree scale after observing complete death in the sensitive control genotypes. Analysis of variance of the studied traits of chickpea genotypes was conducted via factorial experiment in a completely randomized design at two levels for factor A (disease-free and disease-contaminated conditions) and 18 levels (genotypes) for factor B (genotypes 13 and 15 were lost due to high susceptibility to the disease in the first stage of growth, samples were taken from 18 genotypes).The results showed that the resistant and susceptible genotypes were more accurately distinguished from each other in the podding stage. At this stage, 9 genotypes with a degree of damage 1, 2, and 3 (less than five) showed high resistance to the causative agent of Ascochyta blight. Physiological and biochemical traits involved in disease resistance were measured. The results showed that all traits except chlorophyll a, chlorophyll b and polyphenol oxidase had significant differences at 1% probability level in terms of disease stress. Chlorophyll a, chlorophyll b contents and polyphenol oxidase activity were significantly different at 5% probability level. In interaction of disease×genotype, only catalase was significantly different among all studied traits. The amount of peroxidase and polyphenol oxidase were affected by the disease and their rates increased. A positive relationship was observed between the level of polyphenol oxidase enzyme and pathogen resistance. Generally speaking, crops’ reactions to harsh environmental conditions seems impossible to predict without the analysis of the relevant mechanisms.

Aegilops tauschii is one of the ancestors of bread wheat and is the main source of genes for resistance to biotic and abiotic stresses. The present research was performed as a factorial experiment based on a completely randomized design to determine the effect of drought stress on some morphological traits in 23 A. tauschii genotypes. Some important morphological and physiological traits were evaluated in the greenhouse conditions. The results showed that root length, the number of leaves and tillers, chlorophyll content, shoot and root fresh weight, shoot and root dry weight, percentage of yellow and rolled leaves at seedling stage and shoot and root dry weight, flag leaf, peduncle and spike length and the number of spikes at maturity stage increased in drought stress. Instead, RWC and shoot length were reduced at the seedling stage in the drought stress condition. In the seedling stage, the highest values obtained for root length, number of leaves, root fresh and dry weight, percentage of yellow and rolled leaves were 44.67 cm, 24.00, 3.35 g/plant, 0.40 g/plant, 50% and 80.79% under drought condition, respectively. In the maturity stage, the highest values obtained for shoot and root dry weights were 26.58 and 41.77 g/plant obtained in genotypes KC-55 and KC-2122 under drought condition. The highest values for flag leaf length, peduncle length, spike length and the number of spike were 12.30 cm, 15.65 cm, 9.08 cm and 30 observed in genotypes KC-2123, KC-2225, KC-2115 and KC-621 at control, respectively. Based on the ward’s cluster analysis, A. tauschii genotypes were divided into four different groups. The results of this study showed genotypes KC-621, KC-1772 and KC-2225 were tolerant to drought stress and therefore, they are recommended for use in wheat breeding programs.

Agrobacterium tumefaciens-based plant transformation is a natural and ideal way of introducing genes into plant genomes. The system is based primarily on tissue culture techniques, including cell differentiation and plant regeneration, which might produce somatic cell mutations. In the present research, wheat plants were transformed by a non-tissue culture approach. Accordingly, mature embryos were inoculated with A. tumefaciens at an early stage of germination. A variety of different treatments, such as Agrobacterium strains (EHA105 and LBA4404 harboring pCAMBIAl105.1R), levels of glucose, concentrations of acetosyringone (0, 50, 100 and 200 µM), and types of wheat cultivars (Azar2, Alvand, and Sardari) were studied. The transformation efficiency was determined by using the number of resistant leaves to hygromycin, histochemical GUS analysis of leaf tissues, as well as PCR analysis of three transgenes located within the T-DNA region. The results showed that the maximum efficiency was obtained when 200 µM acetosyringone was used in combination with 15% glucose in the induction medium. In addition, the relative expression analysis of virulence genes by qRT-PCR revealed that VirB2 and VirD2 were significantly up-regulated when 200 µM acetosyringone and 15% glucose were used as inducers and carbon source, respectively. Therefore, Vir genes inducing factors as well as a three-step culture of Agrobacterium should be considered as major elements for any wheat transformation protocol. The putative transgenic T1 seeds were soaked and germinated in hygromycin solution, and the seedlings were further analyzed with the aforementioned methods. Based on the results, a modified Agrobacterium-mediated transformation protocol is presented. The current results suggest an inexpensive, quick and efficient approach for wheat genome transformation.

For evaluating the effects of TaMOR, TaNAC69-1 and TaExpb23 expression on root system architecture and drought tolerance of wheat, 10 bread wheat varieties were compared through germination test, pot experiment and field trial. In germination test, genotypes were evaluated under 0, -3 and -6 bar osmotic potentials. In the pot experiment genotypes were compared at 50%, 75% and 100% field capacity (FC) irrigation regime. In the field trial, genotypes were grown under well-watered and rain fed conditions. Based on the results of this experiment, it was concluded that water deficit had a significant effect on all traits except for seminal root numbers. Significant genotypic differences were observed for all traits indicating the presence of genetic variability among the genotypes. Correlation coefficients showed that TaMOR gene expression had a positive correlation with plant yield under 75% FC stress (r=0.733*). TaNAC69-1 gene expression had positive correlations with plant yield and plant biomass under 50% FC (r=0.634* and r=0.711*). TaNAC69-1 gene expression also showed a positive correlation with root numbers under 50% FC condition (r=0.622*). TaNAC69-1 gene expression also showed a positive correlation with seminal root angle (r=0.648*) under severe stress. TaExpb23 expression showed positive correlation with plant yield and biomass under 75% FC (r=0.663* and r=0.723*). Based on the results of this experiment, it was concluded that under different stress levels, TaMOR, TaNAC69-1 and TaExpb23 gene expressions had significant correlations with traits. Due to significant G×E interactions, it was also concluded that the effect of expression of TaMOR, TaNAC69-1 and TaExpb23 genes on traits is different under distinct stress levels.

Sorghum is one of the most important crops grown for human diet and bio-energy. An understanding of genotypes efficiency by evaluating multivariate methods like genotype by traits (GT) and genotype by yield×trait (GYT) biplot is essential to detect suitable genotypes of sorghum. Therefore, traits interrelationship of eighteen sorghum genotypes were investigated based on a randomized complete block design with three replications during 2016-2017. The data of various characters were subjected to ANOVA, Pearson correlation, the GT and the GYT biplot analysis via SAS and GGE biplot software. The analysis of variance depicted that there were significant differences among Genetype×Year interaction based on evaluated variables (P>0.01). The evaluation of traits and their association by GT and GYT biplot indicated that there were significant (P>0.001) differences among traits and yield-trait combination which was strongly approved by numerical Pearson correlation. Also, the GT biplot indicated that the best-ranked genotypes included G4>G15>G6>G17>G18>G16>G13>G3 and the GYT biplot superiority-ranked genotypes compris-ed of G4>G6>G17>G3>G15>G10>G2>G7>G11. Both the GT and GYT biplot confirmed that FGCSI04 (G4) was the most suitable and ideal genotype strongly suitable to sorghum production according to prominent performances on plant height, panicle length, panicle width, grain yield and biological yield. This genotype evaluation showed that there were existed a high genetic diversity among genotypes for the studied variables in which GT and GYT approach simultaneously can help breeders to select prominent genotypes and reduce genetic load in the breeding programs.

This study was carried out to investigate the influence of drought stress during the flowering stage, on the content of water soluble carbohydrates and the expression of genes related to carbohydrate metabolic enzymes (FBPA, FBPase, PGM, PRK, RBCL, RBCS, SBPase, TK, TPI, and GAPDH) in bean (Phaseolus vulgaris L.) leaves. A factorial experiment was conducted based on a randomized complete block design with four replications. Factors included different bean cultivars, Taylor and COS16 (as tolerant cultivars), Khomein and Akhtar (as sensitive cultivars), drought stress included normal irrigation (100% FC) (available water), moderate stress conditions (60% FC), and high stress conditions (30% FC) and stress duration. Significant differences were observed among cultivars and levels of drought stress in carbohydrates content and gene expression. Drought stress caused a decrease in sucrose and an increase in water soluble carbohydrate concentration, glucose, and fructose. These analyses revealed that expression levels of most genes encoding chloroplast enzymes involved in carbon fixation (Calvin cycle) were reduced in the leaves during prolonged drought stress. The expression levels of most genes were higher in tolerant cultivars compared to susceptible ones under drought conditions. Calvin cycle related genes expression showed significant negative correlations with water soluble carbohydrates concentration, glucose, and fructose. In deficient water condition, tolerant cultivars (Taylor and COS16) accumulated more soluble sugars, and Khomein and Akhtar as susceptible cultivars had the lowest soluble sugar in both conditions. The soluble sugar content of different bean cultivars was typically increased, showing that sugar metabolism was influenced greatly by soil water stress.

Safflower (Carthamus tinctorius L.) is one of the important oilseed crops grown commercially in Iran. The production of cultivars with high seed yield and oil content is the most important purpose of safflower breeding. Study of genes action to improve morphological traits especially under drought stress condition is very important. For this purpose, an experiment was conducted in 2013-2015 in the researching farm in Isfahan, Iran using the generations of the crosses between two pure lines (KIR1015×Ac-Sunset) under drought stress and non-stress conditions based on randomized complete block design with three replications. The results of generation mean analysis showed that for plant biomass in both stress and control conditions and for plant seed yield, number of head per plant in control condition m and [a] were the best fitted. For number of head per plant and number of branches in stress condition and for 100 seed weight in control condition, m, [a] and [d] were shown to be the best fit of generation means. The dominant variance of plant seed yield, 100 seed weight and number of branch in stress condition and plant height, plant seed yield, 100 seed weight and number of branch in control condition were higher than additive variance. Broad sense and narrow sense heritabilities of oil content were 59.82 and 89.47 in control and drought stress conditions, respectively. Yield traits such as plant seed yield, number of head per plant and oil content were controlled by additive effects, which suggest scope for breeding and selection for improved drought tolerance in safflower.

Selection- and conservation-based breeding programs require the study of genetic diversity. In this study, a collection of durum wheat consisting of 90 rainfed genotypes was subjected to the analysis of genetic diversity and population structure based on polymorphisms obtained from the Start Codon Targeted (SCoT) marker system. Out of 26 initial primers tested, 15 primers produced scorable polymorphism and were therefore, selected for further analyses. On average, 11.27 polymorphic fragments were observed for each primer per reaction. Polymorphism Information Content (PIC) ranged from 0.10 to 0.32 per locus with an average of 0.23 per primer. Resolving power (Rp) was varied from 0.98 to 5.80. The structure analysis classified the assessed population into 3 subpopulations. Besides, the Neighbor-Joining phylogenetic tree and Principal Coordinate Analysis separated genotypes into 3 and 5 distinct clusters. The Analysis of Molecular Variance (AMOVA) revealed high intra-population diversity. The gene flow index (Nm) indicated a relatively small probability of gene flow between the studied subsets. The Nei’s gene diversity (n), Shannon’s information index (I), and allele distribution statistics revealed that the individuals of subpopulation-2 had a significant capacity for genetic diversity. In conclusion, the studied SCoT primers had a high discriminating power and therefore, were efficient for evaluating genetic diversity in the durum wheat. The results of this study revealed the existence of a significant genetic diversity between the studied genotypes. Besides, the individuals of subpopulation-2 had a notable level of genetic diversity that can be used for various breeding purposes.

The synthetic seeds strategy is an effective method for conservation, germplasm exchange, and distribution of Rosmarinus officinalis. R. officinalis is one of the plants of the Lamiaceae family that originates from the Mediterranean region. According to our knowledge, there is no report on the production of synthetic seeds from somatic embryos obtained from shoots of R. officinalis. In this study, a method for synthetic seed production and regeneration was investigated from shoot explants of R. officinalis. Shoots of R. officinalis were cultured on the MS medium containing various concentrations of NAA and 2,4-D. The best callus induction (41.66%) was obtained on the MS medium fortified with 1 mg/L 2,4-D. The friable embryogenic calli were transferred to a half-strength MS medium with various concentrations of BAP and 2,4-D. Somatic embryos were obtained after 45 days. The highest somatic embryogenesis was obtained on the MS medium containing 1 mg/L 2,4-D and 0.5 mg/L BAP. Somatic embryos at the torpedo stage were encapsulated in sodium alginate and synthetic seeds were obtained. The highest growth ability of synthetic seeds (80.55%) was obtained in the MS medium supplemented with 1.5 mg/L kinetin and 0.5 mg/L BAP. Moreover, the germination percentage of synthetic seeds decreased with increasing storage period and temperature. However, a higher reduction in the synthetic seed germination was recorded at 20±2 °C. The highest germination percentage of the synthetic seeds (85%) was obtained 30 days after storage at 4±1 °C.

Analysis of the genotype×environment (GE) interaction of barley (Hordeum vulgare L.) can aid in detecting genotype performance better under diverse and harsh environments. Sixteen advanced breeding lines and two cultivars were tested across five locations at Gachsaran, Gonbad, Ilam, Lorestan and Mughan districts during three years of 2017 to 2019. Stability analysis was determined using 19 different variance and regression methods with 26 univariate statistics because each method explores stability from different aspects and all of them can reflect a comprehensive stability characteristic of genotypes. The result showed that environment, genotype and GE contributed 92, 2 and 8% of the total variation and there is no strongest genetic control. According to the GE sum squares-based parameters, genotypes G13, G12 and G15 were more stable. The coefficient of line slope and residual variance of common and adjusted linear regression, manifested G1, G2, G12 and G18 as the most stable and responsive genotypes. The selective value of genotype (SVG) identified G6, G10 and G11 as the most stable genotypes while G2, G5 and G13 were the most stable genotypes based on superiority measure (SM). According to H parameter, genotypes G2, G13 and G18 were identified as the most stable genotypes while the dynamic CV and dynamic regression introduced G3 and G15 as the most stable genotypes. The relative superiority (RS), proposed G1, G2 and G5 as the most stable genotypes. Finally, H statistic, RS and SM could be recommended for stability analysis in future breeding programs for the simultaneous selection of yield and stability.