Among cereal crops, wheat being indispensable staple crop globally, plays an important role in combating challenges related to food and nutritional security. It has been reported that every 1°C rise in average global surface temperature will lead to wheat yield reduction from 4.1 to 6.4% world-wide and 8.0% in India.

Enhanced tolerance to heat stress, increase in yield potential and gene discovery using wild genepool should remain priorities for the genetic improvement of wheat. Emmer wheat (Triticum turgidum subsp. dicoccum) is getting attention due to its nutritional benefits and adaptability to varying climates. Recent advancements in genomic research are being used to unravel the genetic architecture of target traits in different species of wheat including tetraploid wheat.

In this study, we have evaluated ~ 200 diverse set of tetraploid emmer wheat germplasm from the national genebank (NGB) of India for terminal heat stress tolerance and grain quality traits. Evaluation for terminal heat tolerance was conducted using multi-environmental phenotyping of 192 accessions using 15 agro-physiological traits at two locations (Delhi and Pune) for two consecutive years in alpha lattice design (ALD).

Grain quality traits were estimated from grain harvest of multi-environmental trial conducted at Delhi, Karnal, Pune, Ludhiana. Analysis of variance (ANOVA), Correlation, Principal Component Analysis, Clustering, Population Structure was performed. GWAS analysis was done using phenotyping data and 35 K SNP genotyping data to identify Marker Trait Association (MTA) for the studied traits. All the traits were significantly different across the environment.

Regarding terminal heat tolerance, five most tolerant genotypes were identified namely, IC535302, IC47037, EC06912, IC535082 and IC534587 based on heat susceptibility index for grain yield. Similarly, multi trait accessions EC577932, IC35119, EC06910 and IC535301 having high zinc and protein content and, accession IC535079 with high iron, zinc and protein were identified. For terminal heat stress, a total of 180 significant MTAs were identified under different environment for all the traits using multi-locus GWAS model, out of that 24 were identified as stable MTAs for DSE, DF, NDVI, FLL, PH, PDL.

For grain quality traits, 125 genomic regions were identified using three multi-locus models, 68 for TGW followed by 25 for GPC. Marker Affx-92926240, PDL_LP2022 codes for pentatricopeptide repeat-containing protein, has role of high temperature tolerance. Thus, we can conclude that NGB emmer wheat germplasm possesses huge genetic diversity for the studied traits and the promising germplasm and trait linked markers identified could be deployed in wheat improvement program.