The Experts below are selected from a list of 5481 Experts worldwide ranked by ideXlab platform
D. E. Groth - One of the best experts on this subject based on the ideXlab platform.
-
Commercial Potential of Microbial Inoculants for Sheath Blight Management and Yield Enhancement of Rice
Bacteria in Agrobiology: Crop Ecosystems, 2011Co-Authors: K. Vijay Krishna Kumar, D. E. Groth, M. S. Reddy, Joseph W. Kloepper, Kathy S. Lawrence, X. G. Zhou, Shouan Zhang, R. Sudhakara Rao, Qi Wang, M. R. B. RajuAbstract:Sheath Blight of rice is an economically significant disease worldwide. Use of plant growth-promoting rhizobacteria (PGPR), one type of microbial inoculants, for Sheath Blight management and yield enhancement of rice is gaining popularity in modern agriculture due to increasing concerns with the use of chemical fungicides. Among different microbial inoculants, PGPR are used for their growth-promoting activities and managing Sheath Blight in rice. However, the efficacy of experimental PGPR strains is typically not consistent under field conditions due to limited knowledge of their formulations, shelf life, delivery systems, compatibility with chemicals and agronomic practices, and the mode of action. In this chapter, a general review on scope and commercial potential of various PGPR for rice Sheath Blight management and yield enhancement is provided. Efficacy results obtained from tests with Integral®, a current commercial product, which contains the strain Bacillus subtilis MBI600, are presented as an example of the potential for PGPR in management strategies for Sheath Blight.
-
Effects of cultivar resistance and single fungicide application on rice Sheath Blight, yield, and quality
Crop Protection, 2008Co-Authors: D. E. GrothAbstract:Abstract The increased number of Sheath Blight ( Rhizoctonia solani )-resistant rice ( Oryza sativa ) cultivars available will allow producers to use less fungicide and avoid significant reductions in grain and milling yields. Among cultivars currently in cultivation in the southern United States, Sheath Blight resistance levels range from very susceptible to moderately resistant. A study was conducted to determine the response of cultivars, with different levels of susceptibility, to Sheath Blight inoculations and fungicide application and to determine the impact of Sheath Blight disease development on rice yield and quality. Sheath Blight epidemics in field plots were initiated by inoculation at the panicle differentiation growth stage in 2006 and 2007. Azoxystrobin at 0.17 kg a.i. ha −1 was applied at mid-boot. Inoculation significantly increased Sheath Blight severity and incidence and caused yield losses of 8% in moderately resistant cv. Jupiter to 40% in very susceptible cv. Trenasse. Milling yields were affected to a lesser extent. Fungicide treatments reduced Sheath Blight incidence and severity, regardless of cultivar except in Jupiter. Single azoxystrobin applications were effective in minimizing yield loss due to Sheath Blight in all cultivars.
-
Effects of Cultivars and Fungicides on Rice Sheath Blight, Yield, and Quality.
Plant disease, 2007Co-Authors: D. E. Groth, Jason A. BondAbstract:ABSTRACT The development of Sheath Blight (Rhizoctonia solani)-resistant rice (Oryza sativa) cultivars will allow producers to use less fungicide and to avoid significant reductions in grain and milling yields. Among cultivars currently in cultivation in the southern United States rice-producing region, Sheath Blight resistance levels range from very susceptible to moderately susceptible. A study was conducted to determine the response of cultivars with different levels of susceptibility to Sheath Blight inoculations and fungicide applications and to determine the impact of Sheath Blight disease development on rice yield and quality. Sheath Blight epidemics in field plots were initiated by inoculation at the panicle differentiation growth stage from 2003 through 2005. Azoxystrobin at 0.17 kg a.i. ha–1 and flutolanil at 0.56 kg a.i. ha–1 were applied in sequential applications at midboot and 50 to 70% heading. Inoculation significantly increased Sheath Blight severity and incidence and caused yield losses ...
Jason A. Bond - One of the best experts on this subject based on the ideXlab platform.
-
Effects of Cultivars and Fungicides on Rice Sheath Blight, Yield, and Quality.
Plant disease, 2007Co-Authors: D. E. Groth, Jason A. BondAbstract:ABSTRACT The development of Sheath Blight (Rhizoctonia solani)-resistant rice (Oryza sativa) cultivars will allow producers to use less fungicide and to avoid significant reductions in grain and milling yields. Among cultivars currently in cultivation in the southern United States rice-producing region, Sheath Blight resistance levels range from very susceptible to moderately susceptible. A study was conducted to determine the response of cultivars with different levels of susceptibility to Sheath Blight inoculations and fungicide applications and to determine the impact of Sheath Blight disease development on rice yield and quality. Sheath Blight epidemics in field plots were initiated by inoculation at the panicle differentiation growth stage from 2003 through 2005. Azoxystrobin at 0.17 kg a.i. ha–1 and flutolanil at 0.56 kg a.i. ha–1 were applied in sequential applications at midboot and 50 to 70% heading. Inoculation significantly increased Sheath Blight severity and incidence and caused yield losses ...
Paul S. Teng - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Sheath Blight on yield in tropical, intensive rice production system
Plant Disease, 1996Co-Authors: Tom W. Mew, K. G. Cassman, Paul S. TengAbstract:Sheath Blight (Rhizoctonia solani) of rice (Oryza sativa) is associated with intensive and high-input production systems. The effect of Sheath Blight on yield, the effect of high nitrogen (N) rate on Sheath Blight incidence, and the stages of crop that are most susceptible to the disease and vulnerable to yield losses were investigated. Grain yield data from a long-term experiment showed a quadratic polynomial curve in response to N input. An initial increase in N supply corresponded to an increase in yield, but at the highest N level, a reduction in yield was observed. Sheath Blight incidence also increased with increasing N level. The estimated yield reduction from Sheath Blight in plots receiving the highest N rate ranged from 20 to 42% in artificially inoculated plots. The highest sclerotial population recorded was only 2.02 sclerotia per 500 g of oven-dried soil or about 1.23 sclerotia per liter of puddled paddy soil. This low sclerotial density in our studies suggested that sclerotia may not be the primary source of inoculum in a tropical lowland rice system. Crop residues colonized by the pathogen may play an important role in Sheath Blight epidemics in this intensive rice production system. Screenhouse and field experiments indicated significant yield losses when Sheath Blight infection started at panicle initiation, booting, or flowering. The effect of Sheath Blight on yield resulted primarily from a reduction in mean seed weight and a lower percentage of filled spikelets. No yield loss or decrease in yield components was observed when infection started at tillering or grain filling.
Tilak Raj Sharma - One of the best experts on this subject based on the ideXlab platform.
-
Identification of major quantitative trait loci qSBR11-1 for Sheath Blight resistance in rice
Molecular Breeding, 2009Co-Authors: V. Channamallikarjuna, Humira Sonah, M. Prasad, G. J. N. Rao, Suresh Chand, H. C. Upreti, Nagendra K. Singh, Tilak Raj SharmaAbstract:Sheath Blight caused by Rhizoctonia solani Kuhn is one of the important diseases of rice, resulting in heavy yield loss in rice every year. No rice line resistant to Sheath Blight has been identified till date. However, in some rice lines a high degree of resistance to R. solani has been observed. An indica rice line, Tetep, is a well documented source of durable and broad spectrum resistance to rice blast as well as quantitative resistance to Sheath Blight. The present study identified genetic loci for quantitative resistance to Sheath Blight in rice line Tetep. A mapping population consisting of 127 recombinant inbred lines derived from a cross between rice cultivars HP2216 (susceptible) and Tetep (resistant to Sheath Blight) was evaluated for Sheath Blight resistance and other agronomic traits for 4 years across three locations. Based on Sheath Blight phenotypes and genetic map with 126 evenly distributed molecular markers, a quantitative trait loci (QTLs) contributing to Sheath Blight resistance was identified on long arm of chromosome 11. Two QTL mapping approaches i.e., single marker analysis and composite interval mapping in multi environments were used to identify QTLs for Sheath Blight resistance and agronomical traits. The QTL qSBR11-1 for Sheath Blight resistance was identified between the marker interval RM1233 (26.45 Mb) to sbq33 (28.35 Mb) on chromosome 11. This region was further narrowed down to marker interval K39516 to sbq33 (~0.85 Mb) and a total of 154 genes were predicted including 11 tandem repeats of chitinase genes which may be responsible for Sheath Blight resistance in rice line Tetep. A set of 96 varieties and a F2 population were used for validation of markers linked to the QTL region. The results indicate that there is very high genetic variation among varieties at this locus, which can serve as a starting point for allele mining of Sheath Blight resistance.
Yinong Yang - One of the best experts on this subject based on the ideXlab platform.
-
A Method for Inoculation and Evaluation of Rice Sheath Blight Disease
Plant disease, 2008Co-Authors: Dong Soo Park, Ronald J. Sayler, Yeon Gyu Hong, Min Hee Nam, Yinong YangAbstract:Sheath Blight of rice, caused by Rhizoctonia solani, is one of the most important rice diseases worldwide; however, no rice cultivar has been found to be completely resistant to this fungus. To facilitate detailed analysis of Sheath Blight resistance at genetic, molecular, biochemical, and functional genomic levels, new methods were developed for effective and uniform infection and accurate evaluation of the disease. The efficiency of R. solani infection was tested on two resistant (Tetep and Jasmine 85) and two susceptible (Chucheongbyeo, Junambyeo) cultivars using three different inoculum types (agar block, liquid cultured mycelia ball, and mycelia suspension). By covering the inoculated Sheaths with aluminum foil to maintain humidity, 100% infection rate was achieved in this study. Liquid cultured mycelia balls caused significantly longer lesions (5.4 cm) than other types of inoculum, including agar block (2.4 cm) and mycelia suspension (1.6 cm). An improved method for evaluating Sheath Blight disease was selected by comparing two methods for evaluating disease severity among three partially resistant cultivars and five susceptible cultivars inoculated with liquid cultured mycelia balls. In addition, a new formula was developed to calculate the disease susceptibility index. Lesion length and the susceptibility index generally were correlated in each leaf, but there were discrepancies between the two evaluation methods due to differences in plant architecture among the cultivars. The susceptibility index calculated using the new formula was the most accurate method for evaluating Sheath Blight disease across all cultivars. The effect of heading date and panicle number also was evaluated in relation to Sheath Blight resistance. Cultivars with late heading dates generally were more resistant to Sheath Blight than those with early heading dates.