Comparison of responses to drought stress of 100 wheat accessions and landraces to identify opportunities for improving wheat drought resistance

Landraces of wheat (Triticum aestivum L.), collected from the Western Balkans, were considered as a potential genetic resource of drought resistance for wheat breeding. A group of 20 landraces with 80 wheat accessions of worldwide origin were tested in 4-year field trials under two watering regimes: fully irrigated and under a rain-out plot shelter. Fourteen agronomic traits were evaluated for their responses to drought stress, and four selection indices were calculated: mean productivity (MP), stress tolerance (TOL), stress susceptibility index (SSI) and stress tolerance index (STI). The average yield of landraces was significantly lower than that of accessions under both regimes, and there was no evidence that yield stability of landraces was better than that of accessions. However, TOL was better in landraces than in accessions, and several traits related to yield were shown to suffer less under water deficit (i.e. kernels per spike). Amongst landraces, relatively wide diversity (CV 10.2–18.9%) was found for most of the traits that can be exploited for improving drought tolerance of new varieties for the variable rainfed conditions of south-eastern Europe.