Common Phytophthora sojae pathotypes occurring in South Dakota

Phytophthora root and stem rot, caused by Phytophthora sojae, is an important disease of soybean (Glycine max L.) in South Dakota. Because P. sojae populations are highly diverse and resistance genes deployed in commercial soybean varieties often fail to manage the disease, this study was initiated to determine P. sojae pathotype distribution in South Dakota. A total of 216 P. sojae isolates were baited from soil collected from 422 soybean fields in South Dakota in 2013-2015 and 2017. The pathotype of each isolate was determined by inoculating 10 seedlings of 13 standard soybean P. sojae differential lines using the hypocotyl inoculation technique. Of the 216 pathotyped isolates, 48 unique pathotypes were identified. The virulence complexity of isolates ranged from virulence on one Rps gene (Rps7) to virulence on 13 Rps genes and mean complexity was 5.2. Harosoy (Rps7), Harlon (Rps1a), Williams 79 (Rps 1c), William 82 (Rps1k), Harosoy 13XX (Rps1b), were susceptible to 98, 80, 78, 73, 72% of the isolates, respectively. These results highlight the highly diverse P. sojae pathotypes in South Dakota and the likely Rps genes to fail in commercial soybean varieties

On the through-process texture evolution assessment in grain oriented Fe-3 wt% Si steel produced by a novel directional inoculation technique

A novel directional inoculation technique has been designed to cast thin slab ingots containing Goss (or near Goss) oriented components in the as cast microstructure under the combined effect of oriented nucleation and oriented growth. The same has been targeted so as to retain Goss orientations and simultaneously develop γ fiber components (ranging from {111}<$$1\overline{1}0$$ 1 1 ¯ 0 > to {111}<112>) during hot rolling. The designed scheme of directional inoculation achieved oriented nucleation by the effect of exogenously added soft magnetic inoculants under magnetic field and oriented growth by the effect of fast cooling rates prevailing in the mould. The choice of 65Fe–35Co (wt%) system as soft magnetic inoculants was made taking into account the similarity in crystal structure and lattice parameter. The chemically synthesized inoculants under the effect of external magnetic field during solidification were able to exhibit directional inoculation. Variation in the cast microstructure and microtexture by varying the extent of inoculant addition was studied by EBSD technique. The ingots cast under different conditions were subjected to a designed hot rolling schedule and the through process microstructural and microtextural evolution was assessed. It was observed that fine equiaxed grains with initial cube orientations in the as cast structure could lead to the most desirable microstructural as well as microtextural gradient in the hot band.

Development of an inoculation technique for rapidly evaluating maize inbred lines for resistance to stalk rot caused by Fusarium spp. in the field

Maize (Zea mays L.) stalk rot, caused primarily by the soil-borne fungal pathogen Fusarium spp., reduces maize quality and yield worldwide. This study was undertaken to develop and utilize a rapid continuous injection inoculation technique to evaluate maize inbred lines for resistance to Fusarium spp. under field conditions, which could facilitate the identification and development of new sources of host resistance to manage the disease. Continuous injection inoculation is a rapid, stable, and simple method that can evaluate the resistance of maize inbred lines to Fusarium stalk rot (FSR) within 20 days. To verify the feasibility and reliability of inoculation method, Fusarium graminearum, F. proliferatum, and F. subglutinans were isolated, identified, and inoculated into maize at the six-leaf stage (V6) by a veterinary adjustable bottle continuous vaccination syringe. Our results showed that out of a total of 97 inbred maize lines, six (6.2%) showed high resistance to maize stalk rot, 20 showed resistance (20.6%), 32 were susceptible (33.0%), and 39 were very susceptible (40.2%). Based on simple sequence repeat (SSR) markers, an analysis of molecular variance indicated a significant correlation between population of the inbred maize line and resistance to FSR (P = 0.001). Overall, this study provided a systematic, rapid, stable, and simple identification method for maize inbred lines resistant to FSR in the field. At the same time, this method was also suitable for genetic diversity analysis of maize inbred lines resistant to FSR.

The Best Inoculation Technique Applied on Gyrinops versteegii Tree Trunk

Agarwood is a non-timber forest product having high economic value, however, its population in nature is getting decrease. Gyrinops versteegii, an agarwood-producing plant, has been listed in Appendix II CITES, therefore, exploitation of the agarwood in nature must be reduced. An effort to reduce the agarwood exploitation the nature is by agarwood cultivation including cultivation of agarwood-producing plant and agarwood inoculation. Some of agarwood inoculation methods are simpori and implant techniques. Simpori is a modified inoculation method using porous nail and Fusarium solani, meanwhile implant technique uses drill and pieces of wood that is soaked in F. solani spores. The present study aimed to determine the best inoculation technique applied to G. versteegii tree trunk at 4 to 5m height, comparing simpori and implant techniques. This study used completely randomizes design with two treatments (simpori and implant techniques). The result showed that the averages yield of production agarwood produced by simpori and implant techniques are 0.66 and 0.64%, respectively. Based on SNI 7631:2011, the visual quality of the produced agarwood belongs to kemedangan TG.C. In conclusion, both simpori and implant technique produced agarwood in similar quality and quantity at six months inoculation, however, simpori is more practical for application in the field. This study provides additional data about agarwood produced by simpori and implant technique and give the alternative methods for agarwood farmers producing their agarwood themselves.

Soybean inoculation techniques for the region of Tangará da Serra - MT, Brazil

The use of inoculated microorganisms on seeds has increased in Brazil, as they help on the fixation and use of nutrients by plants, promoting increasing yields, mainly due to the reduction in the application of nitrogen fertilizers. The aim of this study was to evaluate the influence of single inoculation and co-inoculation of Azospirillum brasilense and Bradyrhizobium japonicum bacteria on seeds and foliar inoculation on soybean, in the region of Tangará da Serra – MT, Brazil. The experimental design used was a randomized block with 9 treatments and 4 replicates. The treatments were composed by using B. japonicum and A. brasilense bacteria in different combinations and times of application on seeds and sprayed on the leaves. The use of A. brasilense together with B. japonicum significantly improved the agronomic characteristics of the evaluated soybean cultivar. There was an increase in yield with the use of A. brasilense through the co-inoculation technique when compared to the single use of Bradyrhizobium. The use of co-inoculation at V3 soybean stage promoted higher nodulation and yield than the standard inoculation performed in the seeds, ensuring better results of nodulation and yield besides increasing the size of the soybean root system, when there and co-inoculation techniques were implemented.