Search Result of "Ram Narayan Chaudhary"

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ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effects of Plant Age on Symptom Development Produced by Pyricularia oryzae Toxin)

ผู้เขียน:Imgนายณรงค์ สิงห์บุระอุดม, รองศาสตราจารย์, ImgRam Narayan Chaudhary, Imgนายธรรมศักดิ์ สมมาตย์, ศาสตราจารย์, Imgดร.เอ็จ สโรบล, รองศาสตราจารย์

สื่อสิ่งพิมพ์:pdf

Abstract

The main objective of this experiment was to determine suitable plant age for toxin inoculation on detached leaves and whole plant conditions. For detached leaves inoculation, it was found that 20 day old plants were the most sensitive to both crude extract toxin (CET) derived from culture filtrate of P. oryzae and tenuazonic acid. The degree of sensitivity was manifested by yellowing produced around the lesions of inoculated leaves. Forty day old plants were found to be the most appropriate age for CET inoculation as they produced typical blast symptom while tenuazonic acid could produce similar typical blast symptoms on leaves at all plant ages. The reactions to CET were varied to the different plant ages while the reactions to tenuazonic acid were not significantly different among them. The experimental result indicated that the lesion sizes produced on blast susceptible and resistant varieties upon CET and tenuazonic acid were not significantly different. In general, leaves exhibited higher sensitivity to CET than tenuazonic acid. It probably might be due to the concentration of the former higher than the latter. CET at concentration of 25% was the most appropriate for spray inoculation on 2-3 week-old seedlings.

Article Info
Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 032, Issue 1, Jan 98 - Mar 98, Page 90 - 101 |  PDF |  Page 

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ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Inoculation Techniques of Crude Extract Toxin Produced by Pyricularia oryzae Cav)

ผู้เขียน:ImgRam Narayan Chaudhary, Imgนายณรงค์ สิงห์บุระอุดม, รองศาสตราจารย์, Imgนายธรรมศักดิ์ สมมาตย์, ศาสตราจารย์, Imgดร.เอ็จ สโรบล, รองศาสตราจารย์

สื่อสิ่งพิมพ์:pdf

Abstract

The mechanical wounding of leaves is necessary for symptom development when inoculated with crude extract toxin (CET) as well as the most suitable method of inoculation for detached leaf and whole plant conditions. The experimental results revealed that the CET could produce disease symptoms even without leaf wounding before inoculation. For detached leaf condition, inoculation by micropipette was found to be efficient and effective. While foliar spray method was the most suitable for whole plant inoculation, symptoms produced by crude extract toxin varied to methods of inoculation. A 30 microlitres drop of CET by micropipette inoculation produced the similar typical blast symptom whereas spray inoculation produced small brown necrosis spots. CET spraying on detached leaves and whole plants gave the same result indicating that CET could be applied for screening toxin resistance on the whole plant condition.

Article Info
Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 031, Issue 3, Jul 97 - Sep 97, Page 368 - 380 |  PDF |  Page 

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ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Pathogenicity Determination of Crude Extract Toxin Produced by the Fungus Pyricularia oryzae Cav. Causal Agent of Rice Blast)

ผู้เขียน:ImgRam Narayan Chaudhary, Imgนายณรงค์ สิงห์บุระอุดม, รองศาสตราจารย์, Imgนายธรรมศักดิ์ สมมาตย์, ศาสตราจารย์, Imgดร.เอ็จ สโรบล, รองศาสตราจารย์

สื่อสิ่งพิมพ์:pdf

Abstract

Series of experiments were carried out to determine the disease determinant factor of crude extract toxin produced by the rice blast fungus, Pyricularia oryzae, to determine an optimal concentration of crude extract toxin for screening against this toxin, and to obtain information on the phytotoxic effect of crude extract toxin on different varieties. The result indicated that crude extract toxin produced by P. oryzae was disease determinant factors. Leaf trated with this toxin produced spindle shaped to roundish lesion with gray centre and brown margin with or without halo and running lesion. The symptom was similar to those produced by the blast fungus infection. The capability of crude extract incited blast symptom increased when crude extract concentration increased. It was concluded that 25 percent concentration of the crude extract would be an appropriate concentration to inoculate rice plants. Genotypic variation was found among rice varieties against crude extract toxin inoculation. Varieties tested against crude extract toxin could be rated resistant, moderately resistant and susceptible to the toxin. The varieties produced small, roundish brown lesion with gray centre and without halo and running lesion were classified to be resistant whereas the varieties that produced larger round lesion with halo and running lesion were classified as susceptible. The result suggested that variety KTH-17 was considered to be susceptible whereas Usen was resistant.

Article Info
Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 029, Issue 4, Oct 95 - Dec 95, Page 498 - 507 |  PDF |  Page