PHENOTYPIC AND MOLECULAR SCREENING OF ADVANCED BACK CROSS POPULATION FOR NECK BLAST RESISTANCE IN RICE

Publication Date : 30/05/2015


Author(s) :

M Girija Rani , Ravi Kumar, B.N.V.S.R , Bhuvaneswari V , Krishnam Raju S.


Volume/Issue :
Volume 1
,
Issue 5
(05 - 2015)



Abstract :

Rice blast is the most devastating disease causing severe yield loss due to prevalence of neck blast at reproductive stage. Location specific and wide variation in physiological races of blast pathogen results in identification of less stable resistant lines by phenotypic screening. Molecular markers are powerful tools to detect presence of blast resistant genes besides screening in blast nurseries. Present study was undertaken with an objective to detect neck blast resistant lines in advanced back cross ( BC2F3 and BC2F4) population of Samba mahsuri/ WGL 167 and samba mahsuri/OR 2309-19 in neck blast nurseries and using molecular markers. Polymorphic marker RM 224 linked to pi-1 blast resistant gene identified between Samba mahsuri and WGL 167 where as RM 206 a pik-h gene linked marker between Samba mahsuri and OR 2309-19 were used to screen advanced back cross lines. Thirty three lines were found to be resistant (score 0 or 1) in Samba mahsuri/WGL 167 population and 136 lines in Samba mahsuri/OR 2309-19 under disease pressure of 9 as per SES of IRRI in BC2F3 population during rabi 2010. Among the resistant lines, twenty six lines co segregated with resistant allele of RM 224 in Samba mahsuri/WGL 167 mapping population where as seventeen lines co segregated with resistant allele of RM 206. These selected resistant lines advanced to BC2F4 generation subjected to neck blast screening in rabi 2011 and identified 19 resistant lines in Samba Mahsuri/WGL 167 mapping population and 22 resistant lines in Samba Mahsuri /OR 2309 showing disparity in disease reactions in the two seasons. But fourteen lines co segregated for resistant allele of RM 224 in samba mahsuri/ WGL 167 and seven lines cosegregated with resistant allele of RM 206 showing stable disease reaction in both the seasons. These results indicated that molecular markers are powerful in identification of resistant lines as phenotypic screening is influenced by environment in expression of virulence of pathogen against resistant genes.


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