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STUDIES ON ANTHRACNOSE OF HORSEGRAM (Macrotyloma uniflorum[Lam.] Verdc.)

KrishiKosh

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Title STUDIES ON ANTHRACNOSE OF HORSEGRAM (Macrotyloma uniflorum[Lam.] Verdc.)
 
Creator UDAYA SANKAR, A
 
Contributor MEENA KUMARI, K.V.S.
 
Subject dna, biological development, vegetables, meat, plant extracts, physical control, yews, organic compounds, retting, diseases
 
Description Horsegram (Macrotyloma uniflorum (Lam.) Verdc. Syn. Dolichos biflorus) is a hardy, drought resistant, under exploited annual legume, grown extensively in peninsular India as poor man’s pulse crop. Sporadic reports of occurrence of anthracnose disease in horsegram have been reported from India and it can cause infection to an extent of 68% in horsegram. Although anthracnose is considered as a minor disease of horsegram, it may attain the status of major disease in future due to the effect of climate change at global level. As there is meagre information available on etiology and sources of resistance against anthracnose of horsegram in Andhra Pradesh, the present studies were undertaken to understand the seed borne nature of the pathogen along with its preventive management.
Colletotrichum dematium was isolated from horsegram leaves suspected with anthracnose symptoms and pure culture of it was maintained for conducting further studies. The pathogenicity of C. dematium was proved by following seed inoculation, detached leaf technique and pot culture studies.
C. dematium infection was noticed in all parts of the horsegram seed, i.e., seed coat, endosperm (cotyledons) and embryo in Component plating technique with varied levels of intensity. Seed coat infection was the highest, ranged from 62-100%, followed by cotyledonary infection (36-72%) and embryo infection (30%). This indicates that the pathogen is both externally and internally seed borne. Seed to seedling transmission of the fungus, C. dematium was successfully proved using paper towel method, sand method and grow-out test methods. Paper towel method resulted in higher seed rot (34%) followed by sand method (12%) and grow-out test (10%). The Seedling decay symptoms were observed to a range of up to 20%.
Horsegram accessions (21 genotypes and 4 released varieties) were screened in the laboratory by seed inoculation using standard blotter method using AK-21 as resistant check. Three accessions (AK-21, IC 470275 and IC 470259) were found resistant by recording < 10% seed surface area infected. Four accessions (IC 343900, IC 343830, IC 526968 and Palem-2) were found highly susceptible with >50% of percent seed area infected with the fungus. Among the 25 accessions tested, 12% of the accessions fall under resistant category, 36% each under susceptible and moderately resistant categories and the remaining 16% under highly susceptible category.
Greenhouse studies of germplasm screening yielded one Immune accession, IC 470275 (NS/05-113) with zero Percent disease index (PDI). None of the accessions was found Resistant. Eleven accessions (IC 470259, IC 470255, IC 470272, IC 470311, IC 526968, IC 470171, IC 470263, IC 470278, IC 470176, IC 261287 and PALEM-1) were grouped under Moderately Resistant category and eight accessions under
susceptible category. The remaining five (AK-21, AK-26, IC 343830, IC 343900 and IC 257875) were Highly Susceptible with > 50 PDI. It was observed that 4, 44, 32 and 20% of the accessions were grouped under immune, moderately resistant, susceptible and highly susceptible categories, respectively based on their PDI values.
The present investigation resulted in identifying an immune horsegram genotype, IC 470275 (NS/05-113), which can be used in the future crop improvement programmes to develop a suitable variety for growing in Andhra Pradesh region.
 
Date 2016-06-13T10:20:59Z
2016-06-13T10:20:59Z
2013
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/67231
 
Language en
 
Relation ;D9266
 
Format application/pdf
 
Publisher ACHARYA N. G. RANGA AGRICULTURAL UNIVERSITY