Genetic analysis and marker association of physiological traits under rainfed and heat stress conditions in spring wheat (Triticum aestivum L.)

Identifying gene interactions and markers associated with physiological traits, especially at later stages of grain filling, can help develop effective breeding methodology in wheat crop. Six generations (P1, P2, F1, F2, BC1P1 BC1P2) four different spring crosses (drought-responsive x drought susceptible) F3 generation a single cross, i.e., MACS6272 UP2828 were phenotyped genotyped to decipher action markers. Ample variation canopy temperature depression (CTD - 2.6 5.6?C), chlorophyll content by SPAD (39.6 51.3), relative water (RWC 51.5 75.4 %), filling period (GFP 61.1 80.1 days), 100 seed weight (3.7 5.5 grams), harvest index (HI 25.8 46.2 biological yield (BY 35.5 89.8 grams) (GY 13.4 36.5 per plant observed six generations. GY positively correlated CTD, SPAD, 100SW, BY HI (0.08* 0.85**). had the maximum direct (0.82) indirect effect via other traits on GY. Significant non-additive epistatic (j & l) duplicate found for most except GFP 100SW. Seven SSR NDVI, RWC, explained phenotypic (PVE) ranging from 10.1% 18.4%, marker Xcfd35 explaining highest PVE RWC. The identified candidate genes (in silico) belonged transmembrane proteins (Xcfd32, Xcfd50), nucleic acid binding domains (Xbarc124, Xgwm484) having enzymatic activity (Xcfd35, Xwmc47, Xwmc728) important abiotic stress tolerance. Complex inheritance deciphered indicated delaying selection segregation so that useful transgressive segregants be selected improving yields wheat.