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Sorghum stalk rot complex in Mindanao : occurrence, etiology and development as affected by various cultural management practices and weather factors / by Naomi G. Tañgonan

By:

Tañgonan, Naomi G [author]

Contributor(s):

Quimio, Tricita H [adviser]

Material type: Text

TextLanguage: English Publication details: Los Baños, Laguna : 1984. Cavite State University- Main Campus,Description: 149 pages : illustrations ; 28 cmContent type:

text

Media type:

unmediated

Carrier type:

volume

Subject(s):

DDC classification:

633.174 T15 1984

Online resources:

Click here to view thesis abstract and table of contents

Abstract: TANGONAN, NAOMI GAAC. University of the Philippines at Los Banos, July 1984. Sorghum Stalk Rot Complex in Mindanao: Occurrence, Etiology and Nevelopment_as Affected by Various Cultural Management Practices and Weather Factors. Major Professor: Dr. Tricita H. Quimio Two sorghum croppings, a main crop and a ratoon, were conducted to determine the pathogens causing the stalk rot complex in Mindanao and to determine the effects of various cultural management practices and prevailing weather conditions on its occurrence and development. Results show that three fungal pathogens were consistently associated with each other and with the stalk rot complex. These were Colletotrichum graminicola (Cesati) Wilson, commonly causing a “red rot" symptom in sorghum stalks, Fusarium moniliforme Sheldon and Macrophomina phaseolina (Tassi) Goid. (Rhizoctonia bataticola (Taub.) Butler) better known as responsible for causing "charcoal rot'' of sorghum. Because of their synergistic relationship to one another, their combined effect resulted in an etiological phenomenon - the sorghum stalk rot complex. Larger lesions were developed when two or three were associated together. Pathogenicity tests conducted both in the field and greenhouse revealed that significantly bigger lesions developed when the plants were inoculated in the field. Except for lesion length, no other disease parameter was significantly influenced by tillage practice, Deep plowing the field and weeding apparently limited the size of lesions or severity of infection on sorghum plants regardless of NPK levels applied and population density maintained. Conversely, minimum tillage without weeding resulted 4o much larger lesion size. Grain yield of sorghum in both croppings was higher where a maximum tillage supplemented with hand weeding was employed. NPK fertilizers applied at higher rates resulted in a significantly higher percentage infection of stalk rot in both main crop and ratoon sorghum, However, no significant effect on the rate of infection was noted. Significantly higher yield was obtained with increasing NPK application. Population density did not have any significant effect on both percentage and rate of infection of stalk rot. Lesion length, on the other hand, was significantly influenced by higher population density, Closer planting of sorghum promoted the increase in lesion size. Grain yield was significantly higher with increasing population density. The number of days to flowering and tillering capacity of the ratoon sorghum were significantly influenced by all treatments of tillage practice, NPK fertilizer and population density. Plant height, however, was not affected by NPK fertilizers nor increasing population density, Only the main crop showed significantly taller plants when treated with maximum tillage and supplemented with weeding. The effects of weather factors showed that high temperature slows down infection rate; high relative humidity increases infection rate but not beyond an optimum level; high rainfall exerts a depressive effect on infection rate while longer sunshine duration accelerates it.

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Holdings ( 1 )
Title notes ( 4 )

Holdings
Item type	Current library	Collection	Call number	Materials specified	URL	Status	Notes	Date due	Barcode
Theses / Manuscripts	Ladislao N. Diwa Memorial Library Theses Section	Non-fiction	633.174 T15 1984 (Browse shelf(Opens below))		Link to resource	Room use only	T-1414		00002300

Thesis (Ph.D. - - Plant Pathology) University of the Philippines, College, Laguna.

Includes bibliographical references.

TANGONAN, NAOMI GAAC. University of the Philippines at Los Banos, July 1984. Sorghum Stalk Rot Complex in Mindanao: Occurrence, Etiology and Nevelopment_as Affected by Various Cultural Management Practices and Weather Factors. Major Professor: Dr. Tricita H. Quimio

Two sorghum croppings, a main crop and a ratoon, were conducted to determine the pathogens causing the stalk rot complex in Mindanao and to determine the effects of various cultural management practices and prevailing weather conditions on its occurrence and development.

Results show that three fungal pathogens were consistently associated with each other and with the stalk rot complex. These were Colletotrichum graminicola (Cesati) Wilson, commonly causing a “red rot" symptom in sorghum stalks, Fusarium moniliforme Sheldon and Macrophomina phaseolina (Tassi) Goid. (Rhizoctonia bataticola (Taub.) Butler) better known as responsible for causing "charcoal rot'' of sorghum. Because of their synergistic relationship to one another, their combined effect resulted in an etiological phenomenon - the sorghum stalk rot complex. Larger lesions were developed when two or three were associated together. Pathogenicity tests conducted both in the field and greenhouse revealed that significantly bigger lesions developed when the plants were inoculated in the field.

Except for lesion length, no other disease parameter was significantly influenced by tillage practice, Deep plowing the field and weeding apparently limited the size of lesions or severity of infection on sorghum plants regardless of NPK levels applied and population density maintained. Conversely, minimum tillage without weeding resulted 4o much larger lesion size. Grain yield of sorghum in both croppings was higher where a maximum tillage supplemented with hand weeding was employed.

NPK fertilizers applied at higher rates resulted in a significantly higher percentage infection of stalk rot in both main crop and ratoon sorghum, However, no significant effect on the rate of infection was noted. Significantly higher yield was obtained with increasing NPK application.

Population density did not have any significant effect on both percentage and rate of infection of stalk rot. Lesion length, on the other hand, was significantly influenced by
higher population density, Closer planting of sorghum promoted the increase in lesion size. Grain yield was significantly higher with increasing population density.
The number of days to flowering and tillering capacity of the ratoon sorghum were significantly influenced by all treatments of tillage practice, NPK fertilizer and population density. Plant height, however, was not affected by NPK fertilizers nor increasing population density, Only the main crop showed significantly taller plants when treated with maximum tillage and supplemented with weeding.

The effects of weather factors showed that high temperature slows down infection rate; high relative humidity increases infection rate but not beyond an optimum level; high rainfall exerts a depressive effect on infection rate while longer sunshine duration accelerates it.

Submitted to the University Library 01/07/1944 T-1414