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CANDIDATE GENE BASED ASSOCIATION MAPPING FOR FUSARIUM WILT RESISTANCE IN CASTOR (Ricinus Communis L.)

KrishiKosh

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Title CANDIDATE GENE BASED ASSOCIATION MAPPING FOR FUSARIUM WILT RESISTANCE IN CASTOR (Ricinus Communis L.)
 
Creator AJAY KUMAR, CHANDRA
 
Contributor SENAPATHY, SENTHILVEL
 
Subject diseases, genes, castor (genus), fungi, planting, genotypes, germplasm, electrophoresis, oils, biological phenomena
 
Description Castor (Ricinus communis L.), a monotypic species in the spurge family
(Euphorbiaceae, 2n = 20), is an industrially important, non-edible oilseed crop widely
cultivated in tropical, sub-tropical and temperate countries for its high economic value.
Vascular wilt is an important disease of castor. Wilt in castor is caused by xylem
inhabiting fungus Fusarium oxysporum f. sp. ricini, which is a severe threat for castor
cultivation across India. As the pathogen is soil-borne and systemic in nature, chemical
and physical control is not much effective and economically viable. Cultivation of wilt
resistant cultivars proved to be an effective strategy to manage wilt in castor. However,
breeding for wilt resistance has been challenging due to complex inheritance of the trait
and pathogen variability. As the conventional screening procedures (sick plot screening)
for evaluating wilt resistance are cumbersome and often misleading, DNA markers
linked to the trait of interest can be used in selecting the desired plants in the breeding
populations through laboratory assays. Hence, this study was undertaken to identify
markers/genes associated with wilt resistance through candidate gene based association
analysis.
A set of 96 germplasm accessions (cultivated and wild forms) along with
standard checks viz., JI35 (susceptible) and 48-1 (resistant) was evaluated for reaction to
artificial inoculation of F. oxysporum f.sp. ricini using pot culture. The number of days
taken by each genotype to wilt was scored as a measure of resistance. Among 96
genotypes tested, 61 genotypes were categorized as ‘susceptible’ (reaction similar to
JI35) and 24 were ‘resistant’ (reaction similar to 48-1) and 11 were ‘highly resistant’
(reaction better than 48-1).
Based on literature search, three relevant candidate genes: (i) Immunity2 gene
(I2) of tomato (ii) Lipoxygenase5 gene of (LOX5) castor and (iii) alpha-dioxygenase1
gene (DOX1) of castor were chosen to ascertain their association with wilt resistance in
castor. The primer pair targeting DOX1 gene did not work. The partial regions of the
other two genes (LOX5 and I2) were amplified and sequenced. The association between
ii
the SNPs observed in the candidate gene regions and the phenotypic data (days to wilt)
was analyzed using general linear model as implemented in TASSEL 2.0.1. None of the
SNP/In-Del showed significant association with the phenotype suggesting that these
genes may not have a role in wilt resistance in castor. Therefore, there is a need to
explore the role of other candidate genes in Fusarium resistance in castor.
 
Date 2017-01-03T10:40:13Z
2017-01-03T10:40:13Z
2016
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/94082
 
Language en
 
Relation D10014;
 
Format application/pdf
 
Publisher PROFESSOR JAYASHANKAR TELANGANA STATE AGRICULTURAL UNIVERSITY RAJENDRANAGAR, HYDERABAD