Phenotyping for drought tolerance of crops in the genomics era

Abstract

Improving crops yield under water-limited conditions is the most daunting challenge faced by breeders. To this end, accurate, relevant phenotyping plays an increasingly pivotal role for the selection of drought-resilient genotypes and, more in general, for a meaningful dissection of the quantitative genetic landscape that underscores the adaptive response of crops to drought. A major and universally recognized obstacle to a more effective translation of the results produced by drought-related studies into improved cultivars is the difficulty in properly phenotyping in a high-throughput fashion in order to identify the quantitative trait loci that govern yield and related traits across different water regimes. This review provides basic principles and a broad set of references useful for the management of phenotyping practices for the study and genetic dissection of drought tolerance and, ultimately, for the release of drought-tolerant cultivars.

Genomics-assisted breeding for drought tolerance in chickpea

“…Morphophysiological traits related to drought are generally categorised either as constitutive traits (affecting yield at low and intermediate drought conditions) or drought-responsive traits (affecting yield only under severe drought conditions) (see Blum 2006;Tuberosa 2012). However, progress achieved thus far in breeding for drought tolerance has mostly been attributed to changes in constitutive traits that affect dehydration avoidance rather than drought-responsive traits (Blum 2005(Blum , 2006(Blum , 2011.…”

Emerging tools, concepts and ideas to track the modulator genes underlying plant drought adaptive traits: An overview

“…15 Therefore, an important morpho-physiological feature (dehydration avoidance mechanism), the deposition of epicuticular waxes, can enable the plant to maintain hydration under the conditions of low VPD. 8 However, reduction in transpiration can affect the evaporative cooling which makes it essential for a tradeoff between water conservation and stomatal regulation to bestow a cooler canopy. The genomic regions for canopy temperature in wheat have been identified recently and their genetic associations with stomatal conductance and grain yield have also been evaluated.…”

“…Similarly, numerous traits including primary, secondary, and integrative drought-resistance traits exist, whose significance needs to be identified through precise phenotyping and be validated for intervention towards crop improvement for attainment of drought tolerance. 3,5,8 The molecular scrutiny of some of these traits is highly recommended. Hence the deployment of Figure 1.…”

“…[6][7] Since drought tolerance is a complex trait, for targeted crop improvement, an understanding of the traits linked to plant water relations and cell tolerance to drought assumes significance and integrative traits are being used in high throughput phenotyping. 5,8 A few critical traits related to water relations such as water mining and water conservation determining water use efficiency (WUE) and cellular tolerance (CT) to desiccation are considered to be decisive for drought adaptation. The efficiency of the system to combat stress effects relies on how best the water relations are maintained either by mining more available soil water or by conserving water or both, along with various CT mechanisms.…”

Performance of Solanum aethiopicum Shum group accessions under repetitive drought stress

“…Drought stress often affects plant morphological traits (Tuberosa, 2012). The studied growth response parameters were number of leaves, plant height, plant canopy, leaf area and plant branching among accessions and the different water levels in the above mentioned traits.…”