ABSTRACT Climate change and global warming have significantly reduced the availability of irrigation water supplied to sugar beet crops in semi‐arid environments. Identifying and recommending drought‐tolerant sugar beet cultivars in water‐limited regions is essential for helping growers maintain stable and sustainable yields. Twenty‐nine sugar beet genotypes, including 25 germplasm accessions and four commercial hybrids, were examined under moderate and severe drought stress conditions in a 2‐year experiment to determine the most drought‐tolerant genotypes and the stress indices that could be used to screen drought tolerance. Twelve drought tolerance indices were estimated for each genotype based on white sugar yield under non‐stress (Yp), moderate (Ys1), and severe drought stress (Ys2) conditions. A significant drought stress response variation was observed in the tested genotype under both stress conditions. Based on drought tolerance indices, namely mean productivity (MP), geometric mean productivity (GMP), stress tolerance index (STI), yield index (YI), yield stability index (YSI), drought index (DI), relative drought index (RDI), harmonic mean (HM), stress susceptibility index (SSI), and tolerance index (TOL) as well as principal component analysis, the most drought‐tolerant genotypes were identified. Sugar beet genotypes PI590861, PI590855, PI590851, PI590799, PI578081, and PI590775 were determined to be the most drought tolerant. The significant and positive correlation of white sugar yield under Ys1 and Ys2 conditions with MP, GMP, STI, YI, YSI, HM, DI, and RDI showed that they could be used as the most suitable indices to screen drought‐tolerant genotypes. The selected individual genotypes with drought tolerance can be used to develop higher‐yielding cultivars for drought‐prone environments.
Arslan et al. (Thu,) studied this question.