The resistance response of sunflower genotypes to black stem disease under controlled conditions

Phoma black stem, caused by Phoma macdonaldii, is one of the most important diseases of sunflower in the world. The sources of resistance to Phoma black stem were investigated. A total of 184 genotypes, including some recombinant inbred lines (RILs), several M6 mutant lines obtained by gamma irradiation of seed of the genotype AS 613, and other genotypes from different countries, were evaluated against an aggressive French isolate (MP6) in controlled conditions. The study was carried out in a randomized complete block design with three replicates. Each replicate consisted of 10–12 seedlings. Twenty μL of spore suspension (106 pycnidiospores mL-1) were deposited on the intersection of the cotyledon petiole and the hypocotyl of sunflower plantlets at the two-leaf stage. The percentage of the area exhibiting disease symptoms was scored on the two cotyledon petioles of each of the plantlets three, five and seven days after inoculation. The disease progress rate (rd), as the slope of the regression line for disease severity against time, was also calculated. Analysis of variance detected significant differences among sunflower genotypes for disease severity 7 days after inoculation,as well as for the disease progress rate. A strong correlation (r=0.96, P<0.01) was found between disease severity 7 days after inoculation and the disease progress rate. The inbred lines F1250/03 (origin: Hungary), M5-54-1, M6-862-1 (mutant lines), SDR 18 (origin: USA) and two wild Helianthus accessions, 1012 Nebraska and 211 Illinois, (wild type) were highly resistant to Phoma black stem. These findings will assist breeders in choosing parent plants for breeding durable resistance to Phoma black stem

Potential of indigenous microbes as helping agents for phyto-restoration of a Pb-contaminated soil

The aim of this study was to assess the effects of heavy metal tolerant soil microbes inoculation on growth and metal uptake of pearl millet, Pennisetum glaucum, couch grass,Triticum repens and alfalfa,Medicago sativa in a soil spiked (and subsequently aged) with increasing concentrations of Pb. A soil sample (soil 1) was spiked with increasing (0 to 1500 mg/kg) concentrations of Pb and incubated for a seven months period. Another soil sample with a historical background of metal contamination (soil 2), having heavy metals-resistant microbial communities, also was taken and used as inocula. The plants were grown in pots containing contaminated soils. At the end of growth period, plants shoots were harvested, washed, oven-dried, ground and analyzed for Pb. The results showed a significant reduction (p < 0.05) in plants yield by increasing soil Pb concentration and inoculation of stress-adapted microbes further increased this reduction. This could be attributed to the increased access of plants to the relatively immobile Pb existed in the studied calcareous soil as well as to more metal contaminant absorption caused by soil microbial activity. In general, introduction of the microbes also resulted in lower Pb uptake by the studied plants

Fungi as Bioremediators

XI, 489 p. 32 illus., 6 illus. in color.online re

Genetic analysis of partial resistance to basal stem rot (Sclerotinia sclerotiorum) in sunflower

Basal stem rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is one of the major diseases of sunflower (Helianthus annuus L.) in the world. Quantitative trait loci (QTLs) implicated in partial resistance to basal stem rot disease were identified using 99 recombinant inbred lines (RILs) from the cross between sunflower parental lines PAC2 and RHA266. The study was undertaken in a completely randomized design with three replications under controlled conditions. The RILs and their parental lines were inoculated with a moderately aggressive isolate of S. sclerotiorum (SSKH41). Resistance to disease was evaluated by measuring the percentage of necrosis area three days after inoculation. QTLs were mapped using an updated high-density SSR and SNP linkage map. ANOVA showed significant differences among sunflower lines for resistance to basal stem rot (P <= 0.05). The frequency distribution of lines for susceptibility to disease showed a continuous pattern. Composite interval mapping analysis revealed 5 QTLs for percentage of necrotic area, localized on linkage groups 1, 3, 8, 10 and 17. The sign of additive effect was positive in 5 QTLs, suggesting that the additive allele for partial resistance to basal stem rot came from the paternal line (RHA266). The phenotypic variance explained by QTLs (R 2) ranged from 0.5 to 3.16%. Identified genes (HUCL02246_1, GST and POD), and SSR markers (ORS338, and SSL3) encompassing the QTLs for partial resistance to basal stem rot could be good candidates for marker assisted selection

Efectiveness of fungal bacterial biofertilizers on agrobiochemical attributes of quinoa (Chenopodium quinoa willd.) under salinity stress

The efects of fungi and bacteria biofertilizers under salinity stress were studied on some morphological and physiological traits of quinoa. The experiment was conducted as a factorial based on a completely randomized design with three replications. The factors included NaCl (no salinity-150 mM NaCl and 300 mM NaCl), Trichoderma (no Trichoderma and Trichoderma), and bacterial biofertilizers (no biofertilizer-N biofertilizer and P biofertilizer). The highest shoot and root length and dry weight were observed in the treatment of no salinity+no Trichoderma+N biofertilizer. Salinity increased Na+and K+content and decreased K+/Na+ratio, whereas the application of Trichoderma alleviated the efect of salinity on these factors. Ca2+/Na+ and Mg2+/Na+ ratios were signifcantly decreased in high salinity level compared to the zero salinity level. The highest and lowest phenol content was observed in the treatments of 300 mM NaCl+Trichoderma+P biofertilizer and no salinity+no Trichoderma+N biofertilizer, respectively. Flavonoid content was higher in the treatments of no salinity+Trichoderma+N biofertilizer and no salinity+Trichoderma+P biofertilizer than in the other treatments, also The high-performance liquid chromatography analysis revealed that all phenolic and favonoid compounds exhibited the greatest increase in treatments of no salinity+Trichoderma+N biofertilizer and no salinity+Trichoderma+P biofertilizer, which is consistent with the signifcant increase in total favonoid content in these treatments. The results showed that using N biofertilizer can improve the growth and development of quinoa in saline soils

Single sequence repeat markers associated with partial resistance in sunflower to Phoma macdonaldii

Phoma black stem of sunflower, caused by Phoma macdonaldii, occurs in many countries. The objective of the present study was to estimate the number of markers and genomic regions in sunflower associating with Phoma black stem resistance. Genetic variability among 32 sunflower genotypes, including recombinant inbred lines and their parents, M7 mutant lines developed by gamma irradiation, and some genotypes from different countries of origin, was evaluated using simple sequence repeat (SSR) markers. Eighty-eight markers were generated at 38 SSR loci, with a mean number of alleles per locus of 2.32. Using susceptibility data of 32 sunflower genotypes against seven P. macdonaldii isolates (Darvishzadeh et al., 2007), one to four markers were associated with each of seven different P. macdonaldii isolates. To reduce the probability of false positives, a sequential Bonferroni-experiment-wise P-value was used for each marker trait association tested. The identified markers showed a promising trend, although they did not pass the more stringent bar of statistical significance, and should be studied further

Foliar Applications of ZnO and Its Nanoparticles Increase Safflower (<i>Carthamus tinctorius</i> L.) Growth and Yield under Water Stress

Foliar application or minerals is a methodology to promote growth and/or yield and to protect plants against different kinds of stresses. Currently there is a great interest in evaluating the effect of nanoparticles for enhancing the effect of these treatments. This study was performed to evaluate and compare the effect of foliar application of zinc oxide (ZnO) and zinc oxide nanoparticles (ZnO-NPs) on the growth and yield of safflower under different irrigation regimes. Foliar applications of ZnO in all concentrations (4, 6, 8, 10, 12, and 14 g L−1) led to an increase in biomass yield, number of capitula per plant, number of seeds per capitulum, and grain yield of plants compared with control plants. The maximum increase in the studied traits was obtained with a ZnO concentration of 6, 8, and 10 g L−1. In a second round of experiments, we observed the effect of nanoparticles and found that spraying with ZnO and ZnO-NPs at a concentration of 10 g L−1 may ameliorate the deleterious effects of water deficit. The results of the present study support the idea that foliar application of ZnO improves safflower yield, especially under drought stress, and showed that using of nanoparticles increases the efficiency of the application

Genetic Diversity of <i>Trichoderma harzianum</i> Isolates in Sunflower Rhizosphere: The Application of the URP Molecular Marker

The genetic diversity of 77 Trichoderma harzianum isolates collected from sunflower rhizosphere soils in Urmia, Khoy, and Salmas in West Azerbaijan province, Iran, was evaluated by using the Universal Rice Primer (URP) molecular marker. The DNA band pattern of the isolates was developed using seven primers of this marker. These primers produced 186 gene loci, out of which 182 loci were polymorphic. Accordingly, the genetic diversity of the isolates was calculated, and their kinship relations were determined by cluster analysis using the NTSYS software package. URP-6R had the highest marker index among the studied primers, followed by URP-1F, URP-4R, and URP-25F, implying their higher efficiency in discriminating between the isolates. The results showed that the URP marker could discriminate between isolates using macroscopic morphological characteristics, such as color and colony type, potential of pigment production in the culture medium, and colony growth rate. Furthermore, there was no significant relationship between the geographical distribution of the isolates and the band patterns generated by the primers except for a few cases. The results generally revealed that the URP marker was an efficient tool for determining the genetic diversity of T. harzianum

Genetic Diversity of Trichoderma harzianum Isolates in Sunflower Rhizosphere: The Application of the URP Molecular Marker

The genetic diversity of 77 Trichoderma harzianum isolates collected from sunflower rhizosphere soils in Urmia, Khoy, and Salmas in West Azerbaijan province, Iran, was evaluated by using the Universal Rice Primer (URP) molecular marker. The DNA band pattern of the isolates was developed using seven primers of this marker. These primers produced 186 gene loci, out of which 182 loci were polymorphic. Accordingly, the genetic diversity of the isolates was calculated, and their kinship relations were determined by cluster analysis using the NTSYS software package. URP-6R had the highest marker index among the studied primers, followed by URP-1F, URP-4R, and URP-25F, implying their higher efficiency in discriminating between the isolates. The results showed that the URP marker could discriminate between isolates using macroscopic morphological characteristics, such as color and colony type, potential of pigment production in the culture medium, and colony growth rate. Furthermore, there was no significant relationship between the geographical distribution of the isolates and the band patterns generated by the primers except for a few cases. The results generally revealed that the URP marker was an efficient tool for determining the genetic diversity of T. harzianum