Thinopyrum intermedium was identified previously as resistant to Tapesia yallundae, cause of eyespot of wheat. Using GUS-transformed isolates of T. yallundae as inoculum, we determined that wheat lines carrying Th. intermedium chromosome 4 Ai#2 or the short arm of chromosome 4 Ai#2 were as resistant to the pathogen as the eyespot-resistant wheat- Th. ponticum chromosome substitution line SS 767 (PI 611939) and winter wheat cultivar Madsen, which carries gene Pch 1 for eyespot resistance. Chromosome 4 E from Th. elongatum and chromosome 4 J from Th. bessarabicum did not confer resistance to T. yallundae. Genome-specific PCR primers confirmed the presence of Thinopyrum chromatin in these wheat- Thinopyrum lines. Genomic in situ hybridization using an St genomic probe from Pseudoroegneria strigosa demonstrated that chromosome 4 Ai#2 belongs to the J(s) genome of Thinopyrum. The eyespot resistance in the wheat- Th. intermedium lines is thus controlled by the short arm of this J(s) chromosome. This is the first report of resistance to T. yallundae controlled by a J(s) genome chromosome of Th. intermedium.

Chinese leymus [Leymus chinensis (Trin.) Tzvel.] is a perennial grass (tribe Gramineae) that is widely distributed throughout northern China and Mongolia where it is produced as a forage product. Severe production losses due to weed growth have serious economic consequences, and as non-selective herbicides not only kill the weeds but are also harmful to this forage grass, the introduction of a foreign gene for resistance to the herbicide Basta is necessary since this species lacks herbicide resistance. We have investigated the transformation of a gene for phosphinothricin acetyltransferase (PAT) through microprojectile bombardment in Chinese leymus. Calli from immature inflorescences cultured on N6 medium supplemented with 2.0 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) and 5.0 mg/l of glutamine were bombarded. The bombarded calli survived on selection medium with 1.0 mg/l of phosphinothricin (PPT). Twenty-three plantlets regenerated from resistant calli on differentiation medium supplemented with 1.0 mg/l 6-benzylaminopurine, 1.0 mg/l kinetin, and 1.0 mg/l PPT, and five of these regenerated plantlets survived on rooting medium with 1.0 mg/l of PPT. PCR and Southern blotting analyses indicated that the PAT gene had been integrated into the genomes of two Chinese leymus plantlets and that the gene was stably transferred to its clonal offsprings. There were no other phenotypic effects associated with transgene expression during vegetative growth except tolerance to the herbicide Basta.

An efficient micropropagation technique by axillary bud multiplication was established for cloning tetraploid black locust tree (Robinia pseudoacacia L.). The result showed that the optimal medium for shoot multiplication and elongation was Murashige and Skoog (MS) medium supplemented with 0.5 mg/l 6-benzylaminopurine in combination with 0.5 mg/l kinetin and 0.1 mg/l 1-naphthaleneacetic acid. The best medium for rooting was half-strength MS medium with 0.25 mg/l indole-3-butyric acid. In the present report, we examined the genetic fidelity of the micropropagated plants by the randomly amplified polymorphic DNA (RAPD) method with 25 primers. The cloned plants of tetraploid black locust showed complete stability.

Mungbean (Vigna radiata L.), an important leguminous food crop in China, is popularly grown in arid regions. The total area of mungbean production is 8.0 × 105 ha. In August and September 2010, wilted symptoms were observed in mungbean plants in Yulin, Shaanxi Province and Datong, Shanxi Province. Infected plants had silvery gray coloration of stems and lateral branching with senesced leaves still attached to the plant. Dark brown necrotic areas were observed on the exterior of the taproot underneath the epidermis and in the pith of the lower stems of wilted plants. Black spherical microsclerotia, 43.9 μm, were present in infected plant tissues. Six fungal isolates were cultured on potato dextrose agar at 25°C and the mycelium was initially hyaline but later became gray. Black microsclerotia, 60 to 80 × 75 to 123 μm, were observed in culture after 2 to 7 days of incubation. On the basis of field symptoms, colony color, and the size of microsclerotia, the fungus was identified as Macrophomina phaseolina (Tassi) Goid (3). To confirm the morphological identification, the rDNA internal transcribed spacer (ITS) regions of the six isolates were amplified with universal primers ITS1 and ITS4. The resulting ITS sequences of the six isolates (GenBank Accession Nos. HQ660589, HQ660590, HQ660591, HQ660592, HQ660593, and HQ660594) were aligned in GenBank, which showed 97 to 99% identity with 60 M. phaseolina isolates (e.g., Accession Nos. GU046867, FJ415067, and FJ960441). Using the PCR primers MpKF1 (5′-CCGCCAGAGGACTATCAAAC-3′) and MaKR1 (5′-CGTCCGAAGCGAGGTGTATT-3′) specific for M. phaseolina (1), a 350-bp PCR fragment was obtained, indicating that these isolates were M. phaseolina. Pathogenicity tests of six isolates were performed by inoculation of 3-week-old seedlings of cv. Zhonglv 8 using the hypocotyl inoculation technique, respectively (2). Each isolate was transferred to petri dishes containing PDA 2 days prior to inoculation. On the day of inoculation, an inoculum slurry was prepared by cutting agar with the pathogen into small strips and passing the strips through a 5-syringe until uniform. A small quantity of inoculum extruded into the vertical cut in each hypocotyl of at least eight seedlings in each pot, and the PDA was used as the control to extrude into the vertical cut in each hypocotyl of at least eight seedlings in another pot. The inoculated and control plants were incubated in the mist chamber at 25°C and 90 to 100% relative humidity for 48 h before growing in a greenhouse at 30°C. Six days after inoculation, all inoculated plants, wilted or dead, showed dark brown-toblack lesions. No symptoms were observed on the control plants. For each isolate tested, M. phaseolina was reisolated from inoculated plants, but was not isolated from the control plants. The fungus has been detected in 29 plant species of 23 genera in China, including the major crops Arachis hypogaea, Helianthus annuus, and Glycine max. Although M. phaseolina has caused great yield reduction of mungbean in many areas of Asia, to our knowledge, this fungus as a causal agent of mungbean charcoal rot has not previously been reported in China. Reference: (1) B. K. Babu et al. Mycologia 99:797, 2007. (2) D. L. Pazdernik et al. Plant Dis. 81:1112, 1997. (3) G. S. Smith and T. D.Wyllie. Charcoal rot. Page 29 in: Compendium of Soybean Diseases. 4th ed. G. L. Hartmann et al., eds. The American Phytopathological Society, St. Paul, MN, 1999.

Powdery resistance putatively derived from Thinopyrum intermedium in the wheat line L962 is controlled by a single dominant gene designated PmL962 and mapped to chromosome arm 2BS. Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a destructive disease affecting the production of wheat (Triticum aestivum). Powdery mildew resistance was putatively transferred from Thinopyrum intermedium to the common wheat line L962, which conferred resistance to multiple Chinese Bgt isolates. Genetic analysis of the powdery mildew response was conducted by crossing the resistant line L962 with the susceptible line L983. Disease assessments of the F1, F2, and F2:3 populations from the cross L983/L962 indicated that resistance was controlled by a single dominant gene. A total of 373 F2:3 lines and 781 pairs of genomic simple sequence repeat (SSR) primers were employed to determine the chromosomal location of the resistance gene. The gene was linked to four publicly available and recently developed wheat genomic SSR markers and seven EST-STS markers. The resistance gene was mapped to chromosome arm 2BS based on the locations of the linked markers. Pedigree, molecular marker and resistance response data indicated that the powdery mildew resistance gene in L962 is novel. It was temporarily designated PmL962. It is flanked by Xwmc314 and BE443737at genetic distances of 2.09 and 3.74 cM, respectively, and located in a 20.77 cM interval that is co-linear with a 269.4 kb genomic region on chromosome 5 in Brachypodium distachyon and a 223.5 kb genomic region on rice (Oryza sativa) chromosome 4. The markers that are closely linked to this gene have potential applications in marker-assisted breeding.

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Lodging can be an important factor in limiting yield and quality of summer foxtail millet [Setaria italica (L.) P. Beauv.]. Although lodging resistance varies among different genotypes, direct selection for lodging resistance is difficult because of its sporadic occurrence in the field and inconsistency between years. A 2-year-field study was conducted with 35 summer foxtail millet cultivars or advanced breeding lines to determine the association between lodging resistance and culm morphology, anatomy and chemical composition. Path analyses indicated that stem-breaking strength had the most important effect on the lodging coefficient. The breaking strength of stem was associated with specific morphological properties of the culm, such as greater culm diameter and most importantly culm wall thickness. Width of sclerenchyma tissue, and the number and sheath width of the large vascular bundles were the major anatomical properties that influenced stem-breaking strength. The cellulose and lignin compositions of the culm had different effects on stem-breaking strength. Cultivars with smaller lodging coefficients contained higher levels of cellulose, but lower levels of lignin than the cultivars that were more prone to lodging. The findings from the present study provide useful information on lodging-associated traits in the culm that can be used as indicators for the improvement of lodging resistance in foxtail millet.

Extreme climatic oscillation has been the subject of global attention. The purpose of this study is to explore the response of extreme precipitation to solar activity and El Nino events in typical regions of the Loess Plateau-a case study in the Yan'an area. The precipitation data was from nine weather stations in Yan'an and the sunspot number and the Southern Oscillation Index (SOI) were from 1951 to 2015. The results show that maximum precipitation occurred mainly at the peak sunspot number or 2a near it and the sunspot number minimum and valley values were not significantly correlated. The results of Morlet wavelet showed that a 41-year period of precipitation was the most obvious within the 64-year scale. Similarly, sunspot number showed a 16-year periodic variability. Correlation analyses of the 16-year and 41-year scales demonstrated that the relationships between precipitation and sunspot number were close. In addition, extreme precipitation often occurred in the year following El Nino events. According to 10-year moving average curves, precipitation generally showed a downward trend when SOI was negative. The results indicate that solar activity and El Nino events had significant impacts on precipitation in typical regions of the Loess Plateau.