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Theses

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19863
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Subject: Plant Pathology × Author: KAU × End date: 1986 × Start date: 1986 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Studies on the seed borne diseases of rice in Kuttanadu
    (Department of Plant Pathology, College of Agriculture, Vellayani, 1986) Jose Joseph; KAU; Susamma Philip
    Several fungi were isolated from the seeds of twelve varieties/cultivars of rice collected from different localities of Kuttanadu, the major rice growing tract of Kerala. Fungi were encountered extrenally as well as internally. Among the externally seed borne fungi, Aspergillus flavus was the most common with its occurrence on nine varieties followed by Bipolaris oryzae and Curvuleria lunata. Other fungi included Rhizopus stolonifer, Chaetomium gracile, Syncephalestrum racemosum, Fusarium moniliforms, Trichoderma virde, Sarocladium oryzae. Aspergillus niger, Alternaria padwickii, Fusarium gramineazum, Piricularia oryzae, A. fumigatus, A. quadrilineatus, Nigrospora oryzae and Penicillium spp. Among the varieties Jaya was found to harbour the maximum fungal population. The germination percentage was not found to be affected due to seed inoculationwith the predominant fungi viz. A. flavus, A. padwickii, B. oryzae, C. lunata and S. oryzae.
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    ThesisItemOpen Access
    Epidemiology and control of sheath rot disease of rice
    (Department of Plant Pathology, College of Agriculture, Vellayani, 1986) Krishnakumaran Nair, B; KAU; Chandrasekharan Nair, M
    Studies on symptomatology, epidemiology and control aspects of sheath rot disease of rice caused by Serocladium oryzae Cams & Hawksworth (= Acrocylindrium oryzae Saw.) were done in detail. The disease initiated as purplish-brown oblong lesions on the sheath of the flag leaf. At maturity lesions enlarged in size with grey -white centres and often covered the entire flag leaf sheath. Panicle often did not emerge but choked inside the affected sheaf itself. Artificial inoculation studies showed that under sufficient humid conditions the pathogen took an average five to eight days for initiation and 15 to 20 days for the complete development of the disease in rice plants. The pathogen was isolated from four naturally infected rice varieties, collected from three different culture (isolates viz., S1, S2, S3, S4, S5, S6 & S7) were selected based mainly on symptomatological variations and their comperative morphological characters were studied in detail. No appreciable differences were noticed in the morphological characters between isolates.
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    Effect of root-knot nematode Meloidogyne incognita on nodulation in cowpea
    (Department of Plant Pathology, College of Agriculture, Vellayani, 1986) Nirmala Moni, D; KAU; Sasikumar Nair
    An investigation was carried out at Colloge of Agriculture , Vellayani, Kerala, to study the effect of Infeatation with Meloidogyne incognita on nodulation and 1 1 formation in cowpea. Ten varieties of cowpea, New Era Pathenettumaniyan, HG-22, PTB-1 PTB-2, 0-152, Sundari, V-16, V-37 and V-240 were initially screened for resistance to this nematode. She plants were inoculated with 1000 second stage larvae of H.incognita on 14th day and various observations on gall number, gall fresh weight, nodule number, nodule fresh weight leaf number plant height, root length# fresh and dry weight of shoot and nematode population in infested root and soil were taken on 50th day of plant growth. Eight varieties namely Pathinettumaniyan HG-22 PSB-1 0152 Sundari V-16 V-37 and V-240 were found resistant while two varieties new Era and PTB-2 were highly susceptible to this nematode.