Fine mapping of stay-green QTLs on sorghum chromosome SBI-10L ‒ An approach from genome to phenome

Sorghum is the fifth most important C4 cereal crop grown globally in arid and semi-arid climatic conditions. Drought is the major cause for loss of productivity worldwide. Delayed senescence of plants leads to adaptation to drought stress conditions by staying-green and giving high yields. In order to identify and dissect the stay-green genomic regions we have developed a high resolution fine mapping population from introgression line cross RSG04008-6 (stay-green) × J2614-11 (shoot fly resistant). Nearly 1894 F2 genotypes were screened with 8 SSR in order to identify double recombinants for both the parents in the sorghum chromosome-10 long arm (SBI-10L). The selected F2:4 recombinants were GBSed to increase the marker density between flanking markers Xgap001- Xtxp141 for stay-green QTLs on SBI-10L and a high resolution linkage map was developed using GBS SNPs. Out of 182 only 152 recombinants were replicated thrice in field for staygreen screening for two seasons (Summer 2013 and 2014). Fine mapping of the per cent Green Leaf Area (%GLA) traits identified 33 QTLs and 19QTLs were clustered into 7groups where 8 genes were identified. These were AP2/ERF transcription factor family (Sb10g025053), Ankyrin-repeat protein (Sb10g025310), WD40 repeat protein (Sb10g025320), NBSLRR Protein (Sb10g025283), Calcium dependant protein kinase (Sb10g030150), LEA2 protein (Sb10g029570), a putative uncharacterized protein (Sb10g024920) and senescence associated protein (Sb10g030520). With this study SBI-10L staygreen genomic regions were delimited from 15Mb to 8 genes co-localized with GWAS MTAs. Further cloning and expression level studies of the identified candidate genes will improve the development of drought tolerant genotypes

Fine genetic mapping of combined shoot fly resistance (SFR) and stay green (STG) traits on sorghum chromosome SBI-10

Sorghum is fifth most important C4 cereal crop used as food, feed, fodder, fuel and a “fail safe” source in semi-arid tropics of the world..