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

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.

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Supervisors NameSupervisors ID
Mohanasundaram, KUNSPECIFIED


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.

Item Type: Thesis (PHD)
Subjects: Mandate crops > Sorghum
Others > Genetics and Genomics
Depositing User: Mr Sanat Kumar Behera
Date Deposited: 20 Jul 2012 04:29
Last Modified: 05 Dec 2013 05:08
Acknowledgement: UNSPECIFIED
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