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This study aimed to examine the reaction of several wheat species with different ploidy levels to foliar application of zinc (Zn) and iron (Fe) under different water regimes. Thirty-five wheat genotypes, including nineteen tetraploids from ten different species, ten hexaploids from five species, and six diploids from three species, were evaluated in the field over two moisture regimes with the following four treatments: control, foliar Zn application, foliar Fe application, and foliar Zn + Fe application. The experiments were conducted according to a split-plot scheme in a randomized complete block design with two replications in each moisture regime. Water stress negatively affected all measured traits, except grain Zn and Fe content. Combined foliar application of Zn + Fe significantly increased yield and alleviated yield reduction caused by water stress. Applying Zn and Fe significantly increased both micronutrient content in grains under both moisture conditions. Tetra and hexaploid species yielded nearly four times as much grain as unimproved diploid species and were less affected by water stress. All ploidy levels responded almost similarly to Zn and Fe treatments, with the combined application being as effective as each element separately. The highest yield increase in response to combined application of Zn + Fe under the two moisture conditions and the highest grain Zn content in response to Zn application under water stress was observed in hexaploid wheat. Combined foliar application of Zn and Fe increases grain Zn and Fe and alleviates water stress's adverse effects on all wheat ploidy levels, making biofortification cost-effective. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of yellow and brown seed coat color of flax on lignan content, seed yield, and yield components under two contrasting environments of non-stress and water stress conditions. The water stress environment intensified the discrimination between the two seed color groups as the yellow seeded families had lower values for seed yield components under the water stress. Heritability and the genetic advance for seed yield were significantly higher in brown-seeded families than those of yellow-seeded ones at water stress conditions. Secoisolariciresinol diglucoside (SDG) as the chief lignan in flaxseed was more abundant in yellow-seeded families under the non-stress environment but under water stress conditions, it increased in brown seeded families and exceeded from yellow ones. Considering that the brown and yellow seed color families were full sibs and shared a similar genetic background but differed in seed color, it is concluded that a considerable interaction exists between the flax seed color and moisture stress concerning its effect on seed yield and yield components and also the seed SDG content. Brown-seeded genotypes are probably preferred for cultivation under water stress conditions for better exploitation of flax agronomic and nutritional potentials. [ABSTRACT FROM AUTHOR]

In the present research, inter and intra genetic variability of 77 accessions belonging to 11 Thymus species were assessed using eight SRAP primer combinations. High polymorphism (98.3%) was observed in the studied species. The cluster analysis classified Thymus species into five main groups. According to molecular variance (AMOVA) analysis, 63.14% of total genetic variation was obtained within the species, while 36.86% of variation was observed among species. STRUCTURE analysis was also performed to estimate the admixture of species. For instance, T. carmanicus and T. transcaspicus revealed high admixtures. HPLC analysis also demonstrated the presence of rosmarinic acid (32.3–150.7 mg/100 g DW), salvianolic acid (8–90 mg/100 g DW), and cinnamic acid (1.7–32.3 mg/100 g DW) as major phenolic acids, as well as apigenin, epicatechin, and naringenin as the major flavonoids. The highest phenolic and flavonoid contents were detected in T. transcaspicus (37.62 mg gallic acid equivalents (GAE) g−1 DW) and T. vulgaris (8.72 mg quercetin equivalents (QE) g−1 DW), respectively. The antioxidant properties and total phenolic of Thymus species were examined using DPPH and β-carotene-linoleic acid model systems and consequently T. vulgaris and T. pubescens were detected with the highest and the lowest antioxidant activities respectively. Cluster and principal Components Analysis (PCA) of the components classified the species in to three groups. Finally, similarity within some species was observed comparing molecular and phytochemical markers. For instance, T. vulgaris separated from other species according to major polyphenolic profiles and molecular analyses, as well as T. transcaspicus, T. carmanicus, and T. fedtschenkoi that were clustered in the same groups. [ABSTRACT FROM AUTHOR]

In the present study, the diversity of 11 Thymus species was assessed using molecular and morphological markers. Essential oil content and morphological traits were also investigated during two agronomic years. The result of the analysis of variance showed considerable differences among morphological traits. In the first and second years, the essential oil content of the species varied from 0.63 to 1.94% and 0.86 to 2.34%, respectively. T. vulgaris and T. migricus showed the highest essential oil content in two agronomic years. In this research, nine ISSR primers were also used to amplify 151 polymorphic bands in 77 accessions belonging to 11 Thymus species. Cluster and principal component (PCA) analyses classified the species in three major groups. Among the species, T. vulgaris and T. fedtschenkoi presented relatively higher genetic distance in comparison with other species. Analysis of molecular variance (AMOVA) revealed that 72.34% of the total variation was belonged to within-species variation, while 27.66% was associated among the species. High gene flow (Nm = 1.11) and genetic differentiation (Gst = 0.31) were also observed among the species. T. transcaspicus exhibited the highest genetic variation (0.19), polymorphism % (57.69%), and Shannon index (0.29). The STRUCTURE analysis also showed a high admixture of Thymus species that might be originated from a high rate of natural hybridization. Finally, based on molecular and morphological information, T. vulgaris and T. carmanicus can be suggested as good candidate species for further breeding programs in Thymus species. [ABSTRACT FROM AUTHOR]

Water deficit is the most limiting factor for seed yield of crop species in the arid and semi-arid regions. Due to increasing limitation of fresh water resources and importance of safflower (Carthamus tinctorius L.) as a significant oilseed crop in Iran, it is necessary to evaluate physiological responses of drought tolerance and its association with seed yield of this crop in water stress condition. In this study, 21 safflower genotypes were planted by hand in the field under water stress and non-stress conditions in a randomized complete block design with two replications during 2 years (2016–17). The results indicated that water deficit stress significantly reduced relative water content (RWC), chlorophyll a (Chl-a) and chlorophyll b (Chl-b) concentrations and seed yield, but increased ascorbate peroxidase (APX) and peroxidase (POX) activities and leaf proline concentration. Significant differences were observed among the genotypes for all studied traits except Chl-b concentration. Genotypes were discriminated according to their response to drought using stress tolerance index (STI). Drought tolerant genotypes displayed a higher capability for accumulation of proline in association with maintaining RWC, antioxidant enzymes activity and higher seed yield, compared to the drought sensitive genotypes. Presented results suggested that safflower genotypes with higher levels of antioxidant enzymes activity, RWC and proline accumulation are characterized by a higher STI. Therefore, these physiological traits can be employed as effective criteria for selecting safflower genotypes with more tolerance to water deficit stress. [ABSTRACT FROM AUTHOR]

Climate change models predict more frequent and severe droughts in the world. For the future adaptation of perennial forage grasses, identification and selection of genotypes with enhanced recovery and persistence under repeated drought is crucial. The aim of the present study was to investigate traits related to persistence, recovery, and root adaptation in three sets of tall fescue genotypes with different flowering date, after successive drought stress. A total of 72 genotypes of tall fescue (24 medium, 24 late, 24 early flowering) were assessed for agro-morphological traits and persistence during 2010–2014 under two levels of soil moisture. In 2015, irrigation was withheld and all genotypes were evaluated for drought recovery in the field. Then 18 genotypes were chosen based on field results to evaluate their root traits at two irrigation levels (control and intense drought stress) in pots. In the field, plant persistence decreased from year 2 to 5 under both control and intense drought stress conditions in all three sets of genotypes, although persistence of late flowering genotypes was higher. The results also indicated that most of the genotypes with greatest persistence had higher recovery after the final severe drought. Persistence and recovery were positively correlated with root length (RL), root area (RA), root volume (RV), root weight (RW) and root to shoot ratio (R/S) under both soil moisture. Moreover, genotypes with higher recovery after drought had more RL, RA, RV and R/S than others. Application of principle component analysis to identify genotypes of interest for future breeding programs is discussed. [ABSTRACT FROM AUTHOR]

Genetic analysis of root and physiological traits and selection of genotypes with higher drought tolerance through these traits is generally limited in tall fescue. In this study, some parental genotypes of tall fescue first were assessed for field drought tolerance in 2014-2015 and then the polycross seeds were harvested to provide half-sib families. Sixteen half-sib families along with their corresponding parental genotypes were assessed in a pot experiment for root and physiological characteristics under three irrigation levels (control, mild and intense) in 2016. The results showed that drought stress decreased dry forage yield (DFY), relative water content and total chlorophyll and increased carotenoid and proline in both parental genotypes and half-sib families. Intense drought stress decreased most of the root traits at 0-30 cm soil depth while at 30-60 cm depth length, area, volume and dry weight of roots were increased. A broad range of general combining ability (GCA) was observed for DFY (21M and 9E), root (21M, 12L and 20L) and physiological characteristics (12L and 9E) at three irrigation levels. Moderate to high estimates of narrow sense heritability (0.40-0.72) as well as genetic variation for root and physiological traits, indicated that phenotypic selection can be successful to attain genetic progress. Indirect selection to improve DFY was more effective through selection for root and some physiological traits. Significant associations of root and some physiological traits with drought tolerance demonstrated that these traits could be used as appropriate selection criteria to elevate forage yield and identify superior genotypes for arid and semi-arid regions. [ABSTRACT FROM AUTHOR]

Evaluation of yield performance and its stability is essential for yield trials conducted in different environments. We determined the forage yield stability of 24 tall fescue ( Festuca arundinacea Schreb.) genotypes using different parametric and non-parametric stability measures and compared those stability statistics across 14 test environments (combination of year, location and moisture conditions) during 2008-2013 growing seasons. The results of parametric measures totally indicated that genotypes G21 and G3 were the most stable ones. However, the non-parametric measures identified G15 followed by G11, G3 and G13 as the most stable genotypes. These genotypes may be recommended for genetic improvement of tall fescue with high degree of adaptation. Principal component analysis based on the rank correlation matrix indicated that most of the non-parametric measures were significantly inter-correlated with parametric measures and therefore seem to be useful alternatives to complement parametric measures. Based on the static and dynamic concepts, the results revealed that stability measures can be classified into three groups. [ABSTRACT FROM AUTHOR]

The changes in total phenolic content (TPC), total flavonoid content (TFC), proline, malondialdehyde (MDA), HO, and antioxidant activity were assessed based on three model systems in three Achillea species ( Achillea millefolium, A. nobilis, and A. filipendulina) growing under four irrigation regimes, including 100 % FC (field capacity as normal irrigation) 75 % FC (low stress), 50 % FC (moderate stress), and 25 % FC (severe stress) conditions. The highest TPC (47.13 mg tannic acid/g DW) and TFC (20.86 mg quercetin/g W) were obtained in A. filipendulina under moderate and severe stress conditions. In 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the highest and the lowest antioxidant activity was obtained for A. millefolium (70.28 %) and A. filipendulina (53.21 %), respectively, while in the FTC model system A. nobilis revealed the highest antioxidant activity (1.934) in severe drought condition. In the linoleic model system, the highest antioxidant activity was observed under low drought stress condition in A. nobilis. MDA and HO content were increased due to both low (75 % FC) and moderate (50 % FC) drought stress, but they were decreased under severe stress condition (25 % FC). Furthermore, A. millefolium revealed the lowest HO (4.96 nm/g FW) and MDA content (176.32 μmol/g). Investigation of the relationship among different metabolites showed a strong positive correlation with TPC and TFC. Finally, the moderate drought stress treatment (50 % FC) was introduced as the optimum condition to obtain appreciable TPC and TFC,, while the highest antioxidant activity was obtained in severe stress condition (25%FC). [ABSTRACT FROM AUTHOR]

Half-sib (HS) mating is the most important breeding method of open-pollinated sexual forage grasses such as tall fescue. Progeny testing procedures of half-sib families can only measure general combining ability (GCA) due to the unknown pollen donor. In tall fescue, genetic studies using HS mating and application of molecular markers for paternity identification in polycross progenies are so far limited. In this study, 960 genotypes from sixteen half-sib families of tall fescue derived from polycrosses, along with their corresponding parental genotypes were evaluated for agro-morphological traits in the field during 2016 and 2017. Genetic diversity of the parental genotypes was assessed using twenty EST-SSR markers and then a minimal set of primers was used to identify the most likely male parent in the polycross progenies. Considerable genetic variation was observed among the parental genotypes based on both morphological and molecular assessments. Moderate to high estimates of narrow sense heritability (0.53–0.84) for morphological traits indicated that phenotypic selection can be successful to achieve genetic progress. The EST-SSR markers allowed to identify a unique paternal parent in 177 of the offspring which were divided into 66 full-sib families. The number of genotypes per full-sib family varied from 1 to 11. Marker data used to identify full-sib families, estimate specific combining ability (SCA), and select siblings based on the genetic value of both parents. No clear association was found between GCA of parents and the corresponding SCA for forage yield, indicating that both additive and dominant gene actions may play a role in the genetic control of this trait. The obtained results highlighted the importance of marker-based paternity identification to increase gain from selection in polycross breeding programs of tall fescue. [ABSTRACT FROM AUTHOR]

Wild introgression may play an important role to improve drought tolerance of safflower (Carthamus tinctorius L.). Response of populations derived from inter-specific hybridization to drought stress in terms of physiological traits and the possibility of selection of superior lines are poorly understood in safflower. Inter-specific hybridizations were performed to produce three populations of TP (C. tinctorius × C. palaestinus), PO (C. palaestinus × C. oxyacanthus), and TO (C. tinctorius × C. oxyacanthus). In total, a number of 189 lines derived from hybridization along with their parents were evaluated in the field in F3 (2015), F4 (2016) and F5 (2017) generations under normal and drought stress conditions. The results indicated that under drought stress condition, C. tinctorius and C. palaestinus had higher malondialdehyde and proline content, while the highest relative water content was belonged to C. oxyacanthus. Consequently, various inter-specific populations behaved differently to decrease the effect of drought stress. TP and TO with C. tinctorius as their common parent, had higher seed yield and seed yield component than PO population. TP population was the most tolerant population due to its highest stress tolerance index, while TO population showed the highest seed yield stability under deficit irrigation. The results indicated that gene introgression from wild relatives into cultivated safflower gene pool increased genetic variation and provided the chance of selection of superior drought tolerant genotypes for future breeding programs. [ABSTRACT FROM AUTHOR]