Expression analysis and characterization of morpho-physiological traits for reduced height and increased lodging resistance in barley (Hordeum vulgare L.) hybrids under different water regimes

Lodging, being the major problem in barley, affects both grain yield and quality and can be mediated through the exploitation of GA homeostatic genes, nonetheless. HvGA20ox, HvGA3ox and HvGA2ox genes play an important role in the Gibberellic Acid (GA) homeostasis that improves plant architecture especially plant height. In the current study, eight lines and five testers with different expression levels of HvGA20ox, HvGA3ox and HvGA2ox transcripts with lodging resistance and sensitivity were hybridized using Line × Tester mating design. Forty F₁ hybrids were generated and the next year all F₁ along with their parents were sown in filed under RCBD split plot in three replications and two treatments (normal and water deficit). Variance due to general combining ability (σ² gca) was lower than the variance due to specific combining ability (σ² sca) which indicates non-additive gene action. Line 3 was found with higher GCA estimates for the number of tillers/plant, grain yield, photosynthesis and water use efficiency. Cross 6, 11 and 21 were observed with twofold upregulation of HvGA2ox.2 transcript and downregulation of HvGA20ox.1 transcript at third node. These hybrids also showed a significant decrease in plant height (18–20%), lodging (< 10%) and increased grain yield (15–18%). The results proposed that the best-performing combinations may be utilized in breeding programs for the development of barley varieties with increased grain yield and lodging resistance.