Multi-Environment Screening of Durum Wheat Genotypes for Drought Tolerance in Changing Climatic Events

Abstract

Durum wheat is the most widely grown cereal in Tunisia, but its production is threatened by drought, which is exacerbated by climate change. This study aimed to identify drought-tolerant durum wheat genotypes from five modern varieties and six landraces in a multi-environment trial at two sites (Kef and Siliana, Tunisia) during three growing seasons under rainfed and irrigated conditions. Six drought tolerance indices (mean productivity (MP), geometric mean productivity (GMP), stress susceptibility index (SSI), tolerance index (TOL), stress tolerance index (STI), and yield stability index (YSI)) were used to evaluate the 11 genotypes. The environment was the dominant source of variation for grain yield (GY; 94.27%), followed by the environment × genotype interaction (4.06%) and genotype (1.65%). Cluster analysis based on GY identified four environment-based groups with distinct water treatments, extreme minimum/maximum temperatures, and rainfall. Principal component analysis and a correlation matrix revealed that drought tolerance indices significantly correlated with GY in non-stressed and stressed conditions and could be separated into four groups. Based on STI, MP, and GMP, G6 and G8 (landraces) were the most drought-tolerant genotypes attaining high GY in both conditions. TOL was able to discriminate G1, G3, and G5 (modern varieties) as well as drought-susceptible genotypes, all of which were suitable for irrigation. Genotypes G7, G9, G10, and G11 (landraces), which had high SSI and lowest STI, MP, GMP, and YSI values, were susceptible to drought and were thus not suitable for cultivation in both conditions. Finally, G2 and G4 (modern varieties), which had an intermediate rank for different indices, were classified as semi-tolerant or sensitive genotypes. Drought tolerance indices and genotype ranks were helpful tools to screen drought-tolerant genotypes with a large adaptation to a range of environments, namely irrigated and rainfed conditions (landraces G6 and G8), or genotypes with the ability to adapt (modern varieties G1, G3, and G5) to irrigated conditions.

Association Mapping of Drought Tolerance Indices in Ethiopian Durum Wheat (Triticum turgidum ssp. durum)

“…This relation provides the basis for utilizing drought tolerance indices as a means to explain the phenotypic variation. It has been also reported that drought tolerance indices can be derived from GY and traits that are strongly and positively correlated with GY as a measure for selecting the best genotypes (Farshadfar et al, 2012 ; Patel et al, 2019 ; Ayed et al, 2021 ).…”

“…The strong and positive correlation of GY_FNS and GY_FDS: GMP ( r = 0.88 and 0.92) and STI ( r = 0.86 and 0.92), respectively, suggests that GMP and STI may be potential drought indices to select stable and relatively higher-yielding accessions under drought stress conditions. Respectively, GMP and STI were reported as convenient drought indices parameter to select stable and high-yielding durum wheat genotypes under drought stress and non-stress conditions (Patel et al, 2019 ; Ayed et al, 2021 ). Interestingly, in this study, three out of the top five accessions selected based on the combined rank of drought indices were from Ethiopian durum wheat landraces and could be recommended as parents for wheat drought-tolerant improvement breeding with other cultivars.…”

Genetic Potential and Inheritance Patterns of Physiological, Agronomic and Quality Traits in Bread Wheat under Normal and Water Deficit Conditions

“…Drought is one of the most significant abiotic stresses limiting wheat production, particularly in arid environments [ 80 ]. The results elucidated that water scarcity caused substantial reductions in all assessed traits compared to well-watered treatment, except proline content, antioxidant enzyme activities (CAT, POD, and SOD), grain protein content, wet gluten content, and dry gluten content which significantly increased.…”

A comprehensive meta-QTL analysis for yield-related traits of durum wheat (Triticum turgidum L. var. durum) grown under different water regimes

“…The main producers of durum wheat in the world are Spain, France, Italy, and Greece in southern Europe, Morocco, Algeria, and Tunisia in northern Africa, Turkey, and Syria in southwest Asia, and Canada, United States, and Mexico in North America ( Martínez-Moreno et al, 2020 ), and Argentina and Chile in South America ( Colasuonno et al, 2019 ). Durum wheat is commonly grown in arid and semi-arid regions under rainfed conditions, where the precipitations are scarce and irregular across years ( Ayed et al, 2021 ). The water scarcity combined with high temperatures during grain filling period significantly affects the quality and the yields of durum wheat, causing grain yield losses of up to 50% to farmers ( Dettori et al, 2017 ; Soriano et al, 2021 ).…”