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Genetic Architecture of Spotted Stem Borer Resistance in Sorghum As Inferred From Qtl Mapping and Synteny with the Maize Genome

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Relation http://oar.icrisat.org/6046/
 
Title Genetic Architecture of Spotted Stem Borer Resistance in Sorghum As Inferred From Qtl Mapping and Synteny with the Maize Genome
 
Creator Vinayan, M T
 
Subject Sorghum
Genetics and Genomics
 
Description The present investigation was carried out to characterize the genetic architecture of
spotted stem borer resistance and related agronomic and morphological traits in
sorghum. The experimental material for this study consisted of 266 RILs derived from
a cross between susceptible parent ICSV 745 and resistant parent PB 15520. These
RILs were evaluated for phenotypic traits during the 2007 and 2008 rainy seasons
under artificial infestation of stem borer, and were genotyped with 90 polymorphic
SSR markers for linkage map construction and QTL analysis.
The RILs exhibited wide variation for the observed traits across both of the
screening environments. The mean performance of RILs for most of the spotted stem
borer resistance except stem tunneling, neared the mid-parental value. Among the
observed agronomic and morphological traits, except for testa (presence vs absence)
and agronomic performance score, the means of RIL population were skewed towards
that of one of the parents. High G×E interaction effects was observed in the RIL
population progenies for all the resistance component, agronomic and morphological
traits except plant color score and seedling basal pigmentation score, which are
largely controlled by single major genes. Across-environment, heritability estimates
for the resistance component traits were low to moderate, while for most of the
agronomic and morphological traits they were high. From the frequency distributions
polygenic inheritance was inferred for most of the observed spotted stem borer
resistance and agronomic traits. Presence of transgressive segregation for all the
observed resistance component traits except recovery resistance score and all
observed agronomic traits — seedling vigor, plant height, time to 50% flowering and
number of nodes suggesting that favorable and unfavorable alleles for these traits are
dispersed between the two RIL parental lines. A significant and positive association
was observed among all the observed resistance component traits, except stem
tunneling. Significant association was also observed between various agronomic and
morphological traits with resistance component traits such as plant height with stem
tunneling, deadheart incidence with time to 50% flowering, plant color with leaf
damage score and overall resistance score and recovery resistance score with both
plant height and number of nodes.
 
Date 2010
 
Type Thesis
NonPeerReviewed
 
Format application/pdf
 
Language en
 
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Identifier http://oar.icrisat.org/6046/1/MT_VinayanPhD_Thesis_2010.pdf
Vinayan, M T (2010) Genetic Architecture of Spotted Stem Borer Resistance in Sorghum As Inferred From Qtl Mapping and Synteny with the Maize Genome. PhD thesis, Tamil Nadu Agricultural University.