Mapping of the QTLs governing grain nutrients in wheat (Triticum aestivum L.) under nitrogen treatment by using high density SNP markers

Animireddy China Malakondaiah ¹ Sudhir Kumar ^1* Hari Krishna ¹ Biswabiplab Singh ¹ Sukumar Taria ¹ Monika Dalal ² LEKSHMY Sathee ¹ Renu Pandey ¹ Ranjeet Ranjan Kumar ¹ Viswanathan Chinnusamy ¹

• ¹ Indian Agricultural Research Institute (ICAR), New Delhi, India
• ² National Institute for Plant Biotechnology, Indian Council of Agricultural Research, New Delhi, Delhi, India

This study is to identifiy superior wheat recombinant inbred lines (RILs) of RAJ 3765 X HD 2329 with high nutrients in grain through multi-trait genotype ideotypes distance index (MGIDI). Moreover, to identify QTLs/genes associated with grain nutrient content by using SNP based genetic linkage map. The parents and their RILs population were grown under control and nitrogen-deficient (NT) conditions and nutrient content was determined using ICP-OES. Analysis of variance and descriptive statistics showed a significant difference among all the nutrients. The highest mean values of grain iron concentration (GFeC) and grain zinc concentration (GZnC) were 52.729 (mg/kg) and 35.137 (mg/kg) respectively, under control condition, while lowest mean of 41.016 (mg/kg) and 33.117 (mg/kg) respectively, recorded under NT, a similar trend was observed in all the elements. Genotyping was carried out using the 35K Axiom R Wheat Breeder’s Array. A genetic linkage map was constructed using 2,499 polymorphic markers identified for parents across 21 wheat chromosomes. Genetic linkage mapping identified a total of 26 QTLs on 17 different chromosomes. We identified 18 QTLs under control conditions and 8 QTLs under nitrogen stress conditions. QTLs for each nutrient was selected based on high percentage of phenotypic variation explained (PVE%) and Logarithm of Odds (LOD) score value more than 3. LOD score for studied nutrients varies from 3.04 to 13.42 explaining about 1.1% to 27.83% of PVE. One QTLs was mapped for grain calcium concentration (GCaC), whereas two QTLs each for grain potassium concentration (GKC), GFeC, grain copper concentration (GCuC) and grain nickel concentration (GNiC) were mapped on different chromosomes. We mapped four QTLs each for GZnC, grain manganese concentration (GMnC) and grain molybdenum concentration (GMoC), while highest of five were linked to grain barium concentration (GBaC). In silico analysis of these chromosomal regions identified putative candidate genes that code for 30 different types of proteins, which play role in many important biochemical or physiological process. Putative candidate gene magnesium transporter MRS2-G linked to GFeC and probable histone-arginine methyltransferase CARM1 and ABC transporter C family, were found to be linked to GZnC.