Search

Emmer wheat (Triticum turgidum ssp. dicoccum) is an important gene source for wheat improvement but less studied in crosses with its descendant species durum (Triticum turgidum ssp. durum), especially in respect to the type of genetic components, intergenic interactions and the genetic mechanisms governing responses to drought. In this study, generation means analysis was performed using F1, F2, BC1P1 and BC1P2 from two different crosses of emmer × durum. Seeds were planted in a RCBD design with three replications under two water regimes. Results showed that there was a highly considerable difference between generations for all studied traits. The presence of significant mean parameter for all the traits, indicated the quantitative inheritance of the traits. Estimating the number of effective genes, polygenic control of the traits were confirmed. In moisture stress condition, epistatic effect for grain yield and yield-related traits illustrated the importance of epistasis in plant adaptation and performance stability. The additive × additive effect, which is fixable, was remarkable in both crosses. Under both water regimes, narrow-sense heritability was relatively high and estimates of gain from selection were positive for most of the traits. Among generations studied, the backcrosses were superior for drought tolerant indices. Based on the results, emmer wheat seems to have genetic potential for durum improvement.

Glycinebetaine (GB) accumulation in many halophytic plants, animals, and microorganisms confers abiotic stress tolerance to salinity, drought, and extreme temperatures. Although there are a few genetic and biochemical pathways to synthesize GB, but isolation of a single geneThe effects of overexpressedSeed-derived embryogenic calli of 'Tarom Molaie' cultivar were targeted with two plasmids pChlCOD and pCytCOD both harboring theThe seed germination experiment results showed that the transformed seeds had a higher germination rate than the controls under all salinity treatments. But also, the leaf growth dynamics showed that the control plants had a more favorable leaf growth dynamic in all of the treatments. Although, the transgenic lines (TIn a salinity sensitive crop such as rice, GB may not significantly contribute to the plant protection against salt stress. Also, insufficiency of choline resources as GB precursor might have affected the overall growth ability of the transgenic line and resulted in decreased leaf growth dynamics.

Emmer wheat (Triticum turgidum ssp. dicoccum) is one of the most promising gene sources for drought tolerance improvement of durum wheat (Triticum turgidum ssp. durum). Achieving desired results requires a conscious choice of crossing parents based on general and specific combining ability (GCA and SCA) and also understanding the genes action involved in controlling the desired traits. In this study a 12 × 12 full diallel cross was performed using four emmer and eight durum wheats. The 132 hybrid progenies along with their parental lines were field evaluated under water-stressed and non-stressed conditions. Based on the Griffing diallel analysis both GCA and SCA effects were highly significant for all measured traits under both water treatments indicating possibility of improvement for drought tolerance. In this respect, the amount of additive effect was higher than the non-additive suggesting the chance for genetic advancement through selection. Based on Hayman's graphical analyses under the two water conditions it was revealed that several grain yield component traits were under the control of partial dominance. In contrary, grain yield and most morphological traits showed either dominance or over-dominance gene action. Grain yield had a significant positive correlation with the number of kernels per spike, kernel diameter, grain weight per spike and harvest index. These traits also had greater share of additive effects, relatively high narrow-sense heritability and high Baker ratio suggesting effective indirect selection for grain yield. Most durum × emmer hybrids had grain yield and drought tolerance indices better than the parents indicating that Iranian emmer wheats have a great genetic potential for drought tolerance improvement of durum wheat.

Information on the nature and amount of genotype × environment (GE) interaction for economic traits and persistence is extremely rare in smooth bromegrass (Bromus inermis Leyss.), especially under drought stress. In this study, 25 half-sib (HS) families of smooth bromegrass were evaluated in the field during five consecutive years under normal and water deficit conditions. The effect of water deficit on dry forage yield was increased from the first year to the fifth, and manifested as a decline in persistence of HS families. Based on narrow-sense heritability estimates, additive gene action was found to be an effective factor in the control of yield components, whereas forage yield is controlled by both additive and non-additive gene actions. Considering the three parameters of stability of combining ability, mean performance and drought tolerance simultaneously, it was inferred that four parental genotypes were superior and stable with high values of general combining ability. This indicates that when developing synthetic varieties from these genotypes, both stability and plant productivity are transmitted to their progenies.

Improving seed yield and oil quality of oilseed crops can aid in provision of a nutritious diet for humans. A worldwide collection of linseed was evaluated for seed yield (YLD), seed oil (OIL) and protein content (PRO), oil fatty acid composition, omega-3 to omega-6 ratio (ω3/ω6), total tocopherol content (TTC), and total phenolic content (TPC). At 2 years, higher temperature (~7%) and lower relative humidity (~16.6%) during the seed filling and maturity period (dryer condition) were correlated with significant decreases in YLD (~18%) and OIL (~4.5%), lower contents of linolenic acid (~13%) and TTC (9.8%), and lower ω3/ω6 ratio (~31%); oleic (~9%) and linoleic acid contents (~23%) and TPC (14.4%) increased. Correlation results demonstrated some significant associations among quantitative traits such as YLD, OIL, and thousand seed weight (TSW); however, the association of these traits with qualitative indices was mostly negative. Genotypes were classified irrespective of their geographical origin and independent of seed or flower colour. In this classification, a yellow-seeded Canadian group had the lowest ω3/ω6 ratio (~0.05), the highest seed yield and high TTC, whereas groups with the highest ω3/ω6 ratio (>3.0) had the lowest oil TTC and low to average seed yield. Results suggested that some brown-seeded Asian genotypes with high grain yield and oil potential, higher ω3/ω6 ratio, and other more stable oil quality indices are suitable to develop broadly adaptive varieties under the possible fluctuation of climatic factors. Other genetic groups could also be used for breeding programs with specific objectives.

Regarding the insufficient water resources, developing of cultivars with high tolerance to water deficit can be very effective to optimize water consumption. To identify maize hybrids with higher tolerance to water deficit, 52 single cross hybrids were field evaluated according to a randomized complete block design with three replications in each irrigation regime. The hybrids were produced through crossing of 13 inbred lines from CIMMYT germplasms with four testers of A679, K166B, K18 and MO17. Two check hybrid varieties (KSC704 and KSC705) were included for comparison. Two irrigation regimes including a normal and a deficit irrigation based on 65% water requirement of plants were applied during two growing seasons of 2014 and 2015 at the Research Station of the Agriculture and Natural Resources of Kermanshah Province. The drought tolerance and sensitive indices were calculated based on grain yield (t/ha) of hybrids at two irrigation regimes. The results of analysis of variance showed significant differences among the hybrids for grain yield and all the indices. The seed yield of hybrids in normal irrigation condition varied from 8.7 to 15.2 t/ha. This range was 4.9 to 10 t/ha in deficit irrigation condition. The cluster analysis classified the hybrids in three distinctive groups. It was recognized that hybrids number 51, 18, 45, 48, 21, 27, 23, 19, 20, 28, 38, 14 and 26 were superior than the others in terms of water deficit tolerance and grain yield. The PCA analysis showed that hybrids number 48, 45, 18 and 51 with high yield potential can be introduced as more promising ones for maize production in normal irrigation condition. However, hybrids 19, 23, 27, 25, 21, and particularly 9 were recognized more suitable for maize production in water deficit condition.

The diversity of 11 fatty acid desaturase (fad2) genes has not been investigated between cultivated and wild species in the Carthamus genus. In this study, 17 C. tinctorius accessions and 28 accessions from other Carthamus species were subjected to sequence analyses of this fad2 gene family. Results showed that among these genes, fad2-1 had a major role in the conversion of oleic acid to linoleic acid. Grouping of all studied wild polyploid species and the wild diploid C. leucocaulos suggested that C. lanatus transferred its fad2-1 gene to C. turkestanicus and C. lanatus. A phylogenetic tree based on fad2-1 gene sequences also showed that C. palaestinus and C. oxyacanthus grouped with C. tinctorius individuals, suggesting that C. tinctorius is closely related to both wild species. A one base pair deletion at position 604 in the fad2-1 gene coding region correlated with high levels of oleic acid content in five mutant phenotypes of the evaluated C. tinctorius accessions. Grouping of fad2-1 and fad2-8 (Ctfad2-10) indicated that both of these genes are involved in oleate desaturases activity. The fad2-3 (Ctfad2-3) and Ctfad2-4 had the highest sequence similarity among the other fad2 genes, indicating the conservative nature of these two genes among all the studied species. Our results suggest that C. lanatus is the likely progenitor of C. turkestanicus and C. creticus (Synonym C. baeticus). Also, C. palaestinus is genetically closer to C. tinctorius but the involvement of C. oxyacanthus cannot be excluded and, this requires further investigation.

Few prior efforts have been made to investigate the genetic potential of different subspecies of Triticum turgidum for drought tolerance and their quality-related traits compared with common wheat (Triticum aestivum) and to identify the association among agronomic, micronutrients, and quality-related traits, especially under climate change conditions. In this research, grain quality, technological properties of flour, and some agronomic traits were studied in 33 wheat genotypes from six different subspecies of Triticum turgidum along with three cultivars of Triticum aestivum in the field, applying a well-watering (WW) and a water stress (WS) environment during two growing seasons. A high degree of variation was observed among genotypes for all evaluated traits, demonstrating that selection for these traits would be successful. Consequences of water stress were manifested as declined DM, GY, and LASRC; and significantly increased GPC, K+/Na+, WAF, WSRC, SuSRC, and SCSRC compared to the well-watering condition. The reductions in the unextractable polymeric protein fraction and glutenin-to-gliadin ratio indicated a poorer grain yield quality, despite higher protein content. This study showed that the early-maturing genotypes had higher water absorption and pentosan, and therefore were more suitable for bread baking. In contrast, late-maturing genotypes are ideal for cookie and cracker production. Two subspecies of T. turgidum ssp. durum and T. turgidum ssp. dicoccum with high micronutrient densities and quality-related traits, and T. turgidum ssp. oriental due to having high values of grain protein content can be used to improve the quality of T. aestivum through cross-breeding programs. Based on the association of different traits with SRC values and other quality-related traits and PCA results, contrasting genotypes can be used to develop mapping populations for genome studies of grain quality and functional properties of flour in future studies.

Association analysis has been proved as a powerful tool for genetic dissection of complex traits. This study was conducted to identify marker–trait associations for recovery, persistence, and as well as finding stable associations. In this study, a diverse panel of polycross derived progenies of smooth bromegrass was phenotyped under normal and water stress, during three consecutive years. Association analysis was performed between nine important agronomic traits along with three seasonal growth activity indices based on 535 SRAP markers. Population structure analysis identified five main subpopulations possessing significant genetic differences. Association analysis using mixed linear mode1 identified 339 and 233 marker-trait associations under normal and water stress environments, respectively. Some of these markers were associated with more than one trait; which can be attributed to pleiotropic effects or to a number of tightly linked genes affecting several traits. If the effectiveness of these markers in genetic control of these traits is validated, they could be potentially used for initiation of marker-assisted selection and targeted trait introgression of smooth bromegrass under normal and water stress environments.

Wild relatives of safflower (Carthamus tinctorius L.) may contribute genes to improve cultivated species under water stress conditions. This study was conducted to increase genetic diversity of safflower for agromorphological traits and fatty acid profiles using interspecific hybridization. Three species—C. tinctorius, C. palaestinus Eig., and C. oxyacanthus M. Bieb.—were used to develop three segregating populations of C. tinctorius × C. palaestinus (TP), C. oxyacanthus × C. palaestinus (OP), and C. oxyacanthus × C. palaestinus (TO). Seventy-three lines, along with the three parental species, were evaluated for agromorphological traits under water stress and nonstress conditions in F₃ and F₄ generations during 2 yr. Fatty acid analysis of interspecific progenies showed occurrence of transgressive segregation. The results showed that mean values of seed yield for TP and TO progenies, where C. tinctorius was one of their parents, were higher than mean value of seed yield for OP that derived from the two wild species. High genetic variation was observed for seed yield, capitulum diameter, and phenological traits in interspecific populations under both moisture conditions. Indirect selection for flowering and seed yield components under water deficit conditions was most efficient to improve seed yield. Results indicated that gene introgression from wild relatives of safflower into the cultivated gene pool increased genetic variation for the measured traits and allowed identifying superior genotypes for future breeding programs.

The vast genetic resources of wild barley (Hordeum vulgare ssp. spontaneum, hereafter WB) may hold unique assets for improving barley (H. vulgare ssp. vulgare) cultivars for drought stress. To evaluate genetic potential and characterization of variation among a diverse collection of barley and WB genotypes, mostly originated from Iran, a field experiment was performed under three moisture environments (control, mild and intense drought stress) during two years (2012–2014). Considerable variation was observed among the wild and cultivated genotypes for drought tolerance and agronomic traits. Principal component analysis (PCA) grouped genotypes studied into three groups (WB, two-row barley and six-row barley groups). However, Iranian and foreign WB genotypes were not completely separated, showing a high variation within both gene pools. The high significance of genotype by environment interaction, confirms importance of using accurate target environments for drought stress breeding. A number of WB genotypes with the highest values of the number of tillers, number of seed per spike, seed weight, grain yield and yield stability index under stressed environments were identified as superior genotypes. Most of these genotypes originate from Iran, highlighting the importance of this germplasm in barley breeding.

Association analysis has been proved as a powerful tool for genetic dissection of complex traits. This study was conducted to identify marker – trait associations for recovery, persistence, and as well as finding stable associations. In this study, a diverse panel of polycross derived progenies of smooth bromegrass was phenotyped under normal and water stress, during three consecutive years. Association analysis was performed between nine important agronomic traits along with three seasonal growth activity indices based on 535 SRAP markers. Population structure analysis identified five main subpopulations possessing significant genetic differences. Association analysis using mixed linear mode1 identified 339 and 233 marker-trait associations under normal and water stress environments, respectively. Some of these markers were associated with more than one trait; which can be attributed to pleiotropic effects or to a number of tightly linked genes affecting several traits. If the effectiveness of these markers in genetic control of these traits is validated, they could be potentially used for initiation of marker-assisted selection and targeted trait introgression of smooth bromegrass under normal and water stress environments.

Lodging is one of the most important factors that affect wheat final yield. Emmer is a likely gene source to improve durum wheat; however, it is highly susceptible to lodging. The genetic studies of traits related to lodging in crosses of durum×emmer remains largely understudied. Here, we used progenies (six generations) derived from two crosses of durum×emmer in a generation means analysis (GMA) to determine gene action, inheritance, and genetic gain from selection in respect to plant height and its related traits. The results indicated that lodging resistance was significantly and negatively correlated with plant height and positively correlated with grain yield and mainly influenced by stem diameter. GMA results indicated that epistasis did not play an essential role in the genetic control of lodging related traits and almost the major portion of the genetic variation in these crosses resulted from additive gene actions. Also for all of the studied traits, the additive variance was higher than the dominance one. Narrow sense heritability was higher than 0.60 for most of the traits, and the genetic gain after one cycle of selection was positive for plant height and its components in both crosses. It was found that, selection in early generations may result in simultaneous reduction of plant height and increased stem diameter to improve lodging resistance in durum×emmer crossings.

Emmer wheat (Triticum. turgidum ssp. dicoccum) as an ancestor of bread and durum wheats, can be a potential resource to restore genetic diversity in modern durum wheats. In order to estimate the combining ability, the type of gene action, heritability, and other genetic parameters of agronomic traits, a full diallel cross (12 × 12) was made between eight durum cultivars and four emmer wheat accessions. The F1 hybrids (132 combinations) and their parents were evaluated for important traits that account for productivity during two cropping seasons. Considerable genetic diversity among the parents and the hybrids was evident, with most of the hybrids showing higher grain yields than their respective durum parent. High general combining ability for all of the measured traits, and higher Baker ratios for most of the traits indicated that additive gene action was involved. Based on the Griffing diallel method, the specific combining ability was significant for most of the measured traits. The Hayman analysis revealed the presence of partial dominance gene action for traits such as the number of tillers per plant (NT), grain weight per spike (GWS), harvest index (HI), days to heading (DH), and number of kernels per spike (NKS). However, plant height (PH), days to maturity (DM), peduncle length (PL), and grain yield (GY) were under the influence of the over-dominance gene action. The narrow-sense heritability for GWS, NKS, kernel diameter (KD), and HI was relatively high and these four were positively correlated with grain yield. Therefore, selection for these four traits in early generations may indirectly improve yield. The results indicate that Iranian emmer wheats are a good source of wild type alleles and valuable QTLs to improve the elite durum wheat cultivars.

The consequences of recurrent drought events compared with a single drought and its interaction with deliberate selfing, compared with open-pollination on post-stress recovery, persistence, and drought memory, are not understood in orchardgrass (Dactylis glomerata L.). A long term study was started by creating 25 selfed (S1) and 25 open-pollinated progeny of orchardgrass in 2012. Populations were studied in the field, applying a normal and a recurrent drought stress environment for 4 years (2013–2016). In 2016, after the first harvest (June), watering was withheld in both moisture environments for 2 months and then plants were re-watered and evaluated for post-drought recovery and drought memory. On average, open pollination caused higher forage yield in the second and third years; while, in the first and fourth years, there was no significant difference. Obligate selfing reduced persistence of genotypes but did not affect recovery after prolonged drought. The early flowering genotypes had more plant productivity, yield stability, persistence, and drought tolerance, and were also capable of more regrowth and recovery. The results showed that genotypes of orchardgrass constantly performed differently under periodic drought as compared to prolonged drought stress. Moreover, there were significant genetic variations between genotypes in terms of stress memory.

Background Little information is available on the application of marker-trait association (MTA) analysis for traits related to drought tolerance in smooth bromegrass. The objectives of this study were to identify marker loci associated with important agronomic traits and drought tolerance indices as well as fining stable associations in a diverse panel of polycross derived genotypes of smooth bromegrass. Phenotypic evaluations were performed at two irrigation regimes (normal and deficit irrigation) during 2 years; and association analysis was done with 626 SRAP markers. Results The results of population structure analysis identified three main subpopulations possessing significant genetic differences. Under normal irrigation, 68 and 57 marker-trait associations were identified using general linear model (GLM) and mixed linear mode1 (MLM), respectively. While under deficit irrigation, 61 and 54 markers were associated with the genes controlling the studied traits, based on these two models, respectively. Some of the markers were associated with more than one trait. It was revealed that markers Me1/Em5–11, Me1/Em3–15, and Me5/Em4–7 were consistently linked with drought-tolerance indices. Conclusion Following marker validation, the MTAs reported in this panel could be useful tools to initiate marker-assisted selection (MAS) and targeted trait introgression of smooth bromegrass under normal and deficit irrigation regimes, and possibly fine mapping and cloning of the underlying genes and QTLs.

Mentha is one of the most important genera of the Lamiaceae with a wide geographical distribution and considerable commercial importance. The general aim of this work was to group 34 accessions from four species of mint using ISSR molecular markers to select some accessions to estimate the potential cross-ability of mints valuable in breeding and phytochemical research. The reproductive characteristics including the type of flower, petal color, sepal and petal lengths, length of stamen and pistil as well as the number of free and living pollen grains in the anther were also studied to find out cross-ability patterns and the possible reproductive barriers. Analysis of molecular variance (AMOVA) among and within species showed more intra-specific variation (92.24%) in comparison with inter-species variation (7.76%). Results of cluster analysis based on ISSR data grouped the mint genotypes into five clusters. By this, the greatest genetic similarity was found between Ms12 from M. spicata and Ml29 from M. longifolia. The genotype Ms12 along with Ms22, the other genotype from M. spicata, were found to be male sterile due to stopped stamen development. These two had higher combining ability (seed set) when used as the female parent in intra-specific crosses and when crossed with M. longifolia compared to the other genotypes in diallel crosses. The highest number of hybrid seeds was obtained where Ml29 was crossed as the male parent with male sterile Ms12 as the female one. This high success rate of seed set in interspecific crosses between M. spicata and M. longifolia could be related to their genomic similarity confirmed by ISSR molecular data. Therefore, producing hybrid seeds and subsequent generations from crosses between these species, utilizing male sterility mechanism, can be a source of new genetic variation for mint.

Wheat occupies the largest global harvested area of any crop, most of which has been affected by abiotic stress. Root features are challenging to enhance through conventional selection strategies, and therefore, molecular approaches such as genome-wide association studies (GWAS) may help overcome some of the limitations. In the current study, 170 elite spring wheat lines were studied for root and shoot characteristics under water-stress and non-stress environments in two replications of field soil tubes. Root and shoot phenotypes especially network root length, network root volume and plant highest showed significant decrease under water-stress in contrast with well-watered condition. Also, the studied factors revealed distinct aspects of the population, which are called “root development”, “deep rooting system”, “plant vigor”, and “spike properties” via principal component analysis (PCA). The population was genotyped using 90 K Illumina SNPs and a total of 14,968 markers used in GWAS. In total, 186 significant marker-trait associations were identified on 16 chromosomes, some of which confirmed previously reported loci for root length. Several new loci affecting root development in wheat were identified in the present study. Several MTAs on specific chromosomes were identified exclusively under well-watered condition as well as water-stress environment, particularly 58 significant ones related to the root development component. The most significant associations were found for the deep rooting component. Also, candidate loci were identified having significant effect on different aspects of the studied population particularly the deep rooting system and the root development under water-stress environment. The candidate SNPs identified in the current study were validated by the whole WAMI population's field data, emphasizing the reliability of performed GWAS for identifying loci affecting root quantitative-related traits. These results improve our understanding of the genetic basis of root system architecture under well-watered and water-stressed environments.

Plant genotypes with higher drought tolerance through improved root characteristics are poorly studied in orchardgrass. In the current research, 30 orchardgrass genotypes were polycrossed and the resulting half-sib families evaluated under both normal and water stress environments. Under water stress conditions, values for most root traits decreased at 0–30 cm soil depth, while at 30–60 cm depths, the root length (RL), root area (RA), root volume, percentage of root dry weight (RDW) and the ratio of root to shoot were increased. We identified drought-tolerant genotypes with a high combining ability for root characteristics and a high yield potential. High estimates of heritability as well as genetic variation for root traits indicated that phenotypic selection would be successful in order to achieve genetic progress. Indirect selection to improve dry matter yield was most efficient when selecting for RL and RDW under water stress conditions. Significant associations between a drought tolerance index and RL, RA and root volume confirmed the importance of these traits in conferring drought tolerance of orchardgrass.

In this study, agro-morphological and yield-related traits associated with drought tolerance in 80 barley genotypes belonging to 15 wild species together with the cultivated one, and their potential to improve adaptation to different levels of drought stress conditions (moisture environments) were studied. There was significant genetic variation among the genotypes and species for all of the measured traits, as well as differential responses of genotypes across environments. The results indicated high variation for grain yield (GY) under drought stress among the genotypes, and that some of the wild genotypes had consistently superior specific adaptation to the water stress conditions. The genotypes belong to wild barley species, especiallyHordeum murinumandHordeum marinumhad lower GY but relatively higher yield stability under different environments. Traits such as number of seed per plant and hundred kernel weight were positively correlated with GY in all of the environments. High negative correlation between GY and days to ripening was observed only under intense drought environment, showing drought escape as a strategy of wild plants under highly stressed conditions. Grouping of the genotypes by principal component analysis completely separated cultivated barley and its progenitor (Hordeum vulgaressp.spontaneum) from other wild genotypes; however, the other wild species were slightly separated from each other. In addition, the Iranian and foreign genotypes did not completely separate from each other. The identified wild barley genotypes with favourable characters and high drought tolerance could be used in genetic studies and barley improvement programmes especially for drought stress.

Safflower (Carthamus tinctorius L.) is one of the oldest domesticated crops, mainly grown as oilseed in the arid and semi arid regions of the world. Cross-ability of Carthamus species has made wild safflower species a suitable source for transferring drought tolerant genes to cultivated species. This study was conducted to investigate seed yield per plant, oil content and fatty acid composition of some Carthamus species and to identify the effects of drought stress on these measured traits. In this regard, 27 genotypes from C. tinctorius, C. palaestinus, C. oxyacanthus, C. lanatus and C. glaucus were planted in the field under normal and drought-stress conditions for two years. Results showed that some studied species differed in oil content, seed yield per plant and fatty acid profiles. As an example, the highest seed oil content (32%) was found in genotype number 22 from C. palaestinus, and the lowest (18%) was obtained for the genotype number 11 from C. lanatus. For all the species, oil content was not affected by moisture stress and did not change over different environments. Similar and stable responses of various Carthamus species for fatty acid composition indicated that hybridization between these species for genetic improvement of drought tolerance may have no adverse effects on oil quality. Considerable diversity within species for all measured traits, similarity in fatty acid profiles and almost the same pattern of changes under drought stress showed that the wild species especially the crossable ones, are good candidates to be used in breeding of cultivated safflower.