Evaluation of saltol introgressed back cross inbred lines for salinity tolerance in rice (Oryza sativa L.)

Abstract

Fifty one backcross inbred lines (BC3F3 population) of ADT 37 introgressed with saltol loci from FL478 controlling salinity 
tolerance in rice and 17 lines of CR 1009 Sub1 introgressed with saltol loci from FL478 were evaluated for their salinity 
tolerance along with respective recurrent parents.  All 68 backcross inbred lines (BIL) were subjected to genotyping using 
RM3412 which led to the identification of 20 lines in the genetic background of ADT 37 and 12 lines in the genetic background 
of CR 1009 harboring saltol loci from FL478. Seedlings of all 32 positive progenies were subjected to phenotypic evaluation 
under hydroponic conditions (EC levels of 6 dSm-1 and EC 12 dSm-1) by following IRRI’s standard protocol (1 - 9 scale scoring). 
Out of 32 selected BILs, 14 lines were found to be tolerant and remaining 18 lines were identified to be moderately tolerant. 
Tolerant lines exhibited very less reduction in their root growth with increased salinity level. Among the tolerant lines, minimum 
root and shoot length reduction was observed in BIL 1102, BIL 1079 and BIL 1091 at EC 6 dSm-1 level. At EC 12 dSm-1, 
minimum root and shoot length reduction was observed in BIL 33, BIL 44, BIL 772, BIL 1079, BIL 1091, BIL 1096, BIL 1101 
and BIL 1102. Saline tolerant lines viz., BIL 33, BIL 1094, BIL 1096 and BIL 1101 have recorded maximum uptake of K+ in 
both root and shoot which resulted in low Na+/ K+ ratio. The salt tolerant lines identified in this study will be further evaluated in 
saline soil under different locations to develop salt tolerant varieties.