Pre-Harvest Sprouting Resistance in Bread Wheat: A Speed Breeding Approach to Assess Dormancy QTL in Backcross Lines

In this study, BC1F3:4 generation plants derived from the hybrid crosses of Rio Blanco × Nevzatbey, Rio Blanco × Adana99, and Rio Blanco × line 127 were used as experimental material. These hybrids incorporated QTLs associated with pre-harvest sprouting (PHS) resistance through molecular techniques. Key agronomic traits, including plant height, spike length, the number of grains per spike, grain weight, and physiological maturity, were evaluated in both greenhouse and growth room settings under accelerated growth (speed breeding) conditions. Results indicated that plants grown in the fully controlled greenhouse conditions exhibited superior agronomic performance compared with those cultivated in the growth room. Additionally, germination tests were conducted on each hybrid cross to identify genotypes exhibiting dormancy. The analysis revealed that 11 lines from the Rio Blanco × Nevzatbey combination, eight lines from Rio Blanco × Adana99, and six lines from Rio Blanco × Line 127 had notably low germination indices. Among the three hybrid families, the Rio Blanco × Nevzatbey BC1F3:4 hybrids demonstrated the lowest germination index (0.44). Furthermore, Rio Blanco itself recorded the lowest germination index under both greenhouse (0.02) and growth room (0.24) conditions. These findings suggest that environmental conditions exert a significant influence on the expression of dormancy in these genotypes, even when dormancy genes are present. The lines developed in this research have the potential to serve as elite material in breeding programs aimed at enhancing pre-harvest sprouting resistance.