Root and shoot traits of bread wheat (Triticum aestivum L.) landraces and cultivars

In order to break the current grain yield barriers, breeders require genetic variation. Breeding for resistance to abiotic stresses may lead to better plant survival and improved grain yield. Exploring landraces may expand the genetic diversity of modern wheats. Five Turkish bread wheat landraces and 14 modern durum and bread wheat cultivars were evaluated for root and shoot biomass as well as grain yield for 2 years in three experiments. Root and shoot traits were measured in plants grown in 1 and 1.5 m PVC tubes in a glasshouse. Significant genotypic differences were found within and between landraces and modern wheats. Shoot biomass, total root biomass, shallow root weight, deep root weight, number of tillers per plant, and plant height were significantly greater in landraces compared to modern wheats. Correlation coefficients were positive between root biomass and shoot biomass (0.78), and number of fertile tillers (0.76). Plant height, shallow and deep root weights, as well as the total root biomass were positively correlated. Semi-dwarf and mid-height cultivars had greater grain yield than tall lines: winter wheats had greater harvest index, whereas intermediate (facultative) wheats had greater shallow root weights and total root biomass. Results highlight the mode of adaptation in landraces to water stress and suggest that landraces may be a valuable resource in breeding for altered root architecture.