Screening and Repeatability of Quantitative Indicators of Drought Tolerance in Wheat-Barley Disomic Addition Lines

摘要

To locate the genes controlling drought tolerance in barley (Hordeum vulgare cv. 'Betzes'), a set of complete wheat-barley disomic addition lines (DALs) along with two donor (barley) and recipient (wheat) parents were evaluated under drought stress and non-stress conditions for three cropping seasons. Several drought tolerance indices based on the grain yield of DALs in the stress and non-stress conditions were used to study the genetic variation in barley and to investigate relationship between theindices within and over the years. Differences in ranking of genotypes based on each index were observed from year to year, indicating that the drought tolerance of genotypes is influenced by year effect. The relationships among the indices and their association with mean yield based on Spearman's rank correlation were determined in each of the three cropping seasons. Principal component analysis (PCA) based on the Spearman's rank correlation matrix revealed that the screening methods were significantlyinter-correlated with each other indicating that several of the statistics probably measure similar aspects of drought tolerance. The stress tolerance index (STI), geometric mean productivity (GMP), harmonic mean (HM) and mean productivity (MP) were consistently and highly correlated with each other over there cropping seasons, and, therefore, could be used to select drought tolerant genotypes with high yield performance in both stress and non-stress conditions. The stress susceptibility index (SSI), yield stability index (YSI), tolerance (TOL) and sensitivity drought index (SDI) showed consistent relationships with each other over years and can be used to screen the drought resistant and stable genotypes. According to multiple year data, most of thegenes controlling drought tolerance are located on chromosome 7H in barley.