IDENTIFICATION OF FAVOURABLE ALLELES FOR MULTIPLE TRAITS AND NUTRIENT MANAGEMENT IN SALT TOLERANT RICE VARIETIES TO ENHANCE PRODUCTIVITY IN COASTALSALINE ECOSYSTEMM. GIRIJA RANI, V. SAILAJA, J. PADMAVATHI AND SANJAY K. KATIYARAbstract Rice crop is most sensitive to salinity at seedling and reproductive stages causing huge yield loss. Cultivation of salt tolerant rice varieties along with management practices will minimize the yield loss in saline soils. Four salt tolerant rice varieties MCM 100, MCM 103, MCM 109 and MCM 125 developed by pedigree breeding in typical coastal saline soils of Andhra Pradesh at Agricultural Research Station, Machilipatnam with moderate tolerance to BLB, BPH. The present study aimed to identify favourable alleles and suitable best nutrient management practices for four salt tolerant rice varieties developed at Agricultural Research Station(ARS), Machilipatnam of Acharya NG Ranaga Agricultural University (ANGRAU). Variation in haplotype of saltol region was found among the four varieties using 11 SSR markers and none of the variety showed complete positive alleles of Saltol region. Maximum number of favourable alleles of 7 was noticed in MCM 109 followed by MCM 103, MCM 125 with 5 alleles and minimum number of 3 alleles was observed in MCM 100. Diagnostic markers for saltol i.e., RM 3412 and RM 8094 expressed in all varieties except MCM 100 which conferred positive allele for RM 8094. This indicates that there is variation in salt tolerance at genetic level and there might be other minor genes contributing for salt tolerance are to be traced out by using metabolomic studies. Molecular profiling using 1K RICA (Rice Custom Amplicon) genotyping with 217 SNPs revealed that all the four rice varieties possess favorable alleles for anaerobic germination (qAG3), Heading date (DTH8, ehd1), reproductive stage drought tolerance (DTY 12.2), BLB resistant alleles for Xa21, eating quality (SBElib), Grain Size (GS3). MCM 103 and MCM 109 have nitrogen use efficient alleles (NGR5), MCM 109 has additional resistant allele for BLB (Xa4, qXa26), MCM125 has resistant alleles for BPH (Bph32), blast (pi54, pita, pitr). More number of favourable alleles for heading date genes was identified in MCM 109 followed by MCM 100. The results of best management practices under coastal saline soils implied that MCM 103 and MCM 109 can respond to RDF (recommended dose of fertilizer) (90:60:60 kg/ha) with foliar application of Zinc sulphate. Salt tolerant rice varieties MCM 100 and MCM 125 can give potential yield under 25 % extra over RDF and application of N,K in 3 splits+ Application of 0.2% Zinc sulphate at 15DAT, 20DAT. |