Abstract
Drought is a prominent limiting factor that impacts negatively durum wheat grain yield. Ten durum wheat breeding lines were evaluated under rainfall conditions at the Field Crop Institute Agricultural Experimental Station of Setif, Algeria, during the 2016/2017 cropping season. The investigation aimed to study the ability of flag leaf water status to discriminate among varieties for drought tolerance trait. Significant variability was observed among the tested varieties for leaf dry, wilted and turgid weights, leaf relative water content, water saturation deficit and excised water loss, after three wilting periods of 30, 60 and 90 minutes dehydration at 40°C. The assessed breeding lines were differentially categorized as drought tolerant and drought sensitive based on either relative water content or water saturation deficit or excised leaf water loss genotypic mean values. Correlation, principal components and cluster analyses indicated an unwanted significant association between excised leaf water loss and relative water content and water saturation deficit and classified the assessed entries into three clusters (CI, C2 and C3). Cluster C1 had high relative water content, low water saturation deficit but high excised water loss, while C3 had low relative water content, low excised leaf water but high-water saturation deficit, C2 being intermediate. Crosses between distant clusters (C1 vs C3) are proposed to generate more variability of the targeted traits in progeny population and to break undesirable linkage between alleles controlling leaf water status, allowing to select efficiently drought tolerant genotypes.
Highlights
Drought is the most important abiotic stress factor affecting crop production worldwide, causing large economic losses
This study aimed to investigate variation in leaf water status of a set of durum wheat (Triticum durum Desf.) advanced breeding lines under field conditions
Compared to the results of [18, 23, 24] who reported Relative water content (RWC) mean values above 90.0% for varieties tested under irrigation conditions and below 85.0% for varieties tested under stressed conditions, the mean values reported in the present study are representative of drought stress conditions
Summary
Drought is the most important abiotic stress factor affecting crop production worldwide, causing large economic losses. With a projected increase in drought events due to climate change, yield improvement under drought conditions is becoming a major goal of many plant breeding programs [2]. To develop drought-tolerant genotypes, it is essential to primarily understand mechanisms underlying this stress, and to identify their trait-markers. Three basic mechanisms are involved in drought stress resistance: escape, avoidance or tolerance, and resistance [2]. Plants, showing escaping mechanism, complete their life cycle before the onset of drought, during the brief period of favorable conditions. In the drought-resistance mechanism, plants adapt themselves to survive drought in two distinct strategies leading to drought avoidance and to drought tolerance. Several physiological traits have been advocated as indicators of drought resistance and proposed to be used as tools for the development of drought resistant genotypes [4]. Efficient screening techniques applicable in early growth stage are Corresponding author: Hamenna Bouzerzour Ecology and Plant Biology Department, Natural and Life Sciences Faculty, Setif-1 Ferhat Abbas University, Setif, 19000, Algeria
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