Molecular and Morpho-Agronomical Characterization of Root Architecture at Seedling and Reproductive Stages for Drought Tolerance in Wheat

Abstract

Water availability is a major limiting factor for wheat (Triticum aestivum L.) production in rain-fed agricultural systems worldwide. Root architecture is important for water and nutrition acquisition for all crops, including wheat. A set of 158 diverse wheat genotypes of Australian (72) and Indian (86) origin were studied for morpho-agronomical traits in field under irrigated and drought stress conditions during 2010–11 and 2011-12.Out of these 31 Indian wheat genotypes comprising 28 hexaploid (Triticum aestivum L.) and 3 tetraploid (T. durum) were characterized for root traits at reproductive stage in polyvinyl chloride (PVC) pipes. Roots of drought tolerant genotypes grew upto137cm (C306) as compared to sensitive one of 63cm with a mean value of 94.8cm. Root architecture traits of four drought tolerant (C306, HW2004, HD2888 and NI5439) and drought sensitive (HD2877, HD2012, HD2851 and MACS2496) genotypes were also observed at 6 and 9 days old seedling stage. The genotypes did not show any significant variation for root traits except for longer coleoptiles and shoot and higher absorptive surface area in drought tolerant genotypes. The visible evaluation of root images using WinRhizo Tron root scanner of drought tolerant genotype HW2004 indicated compact root system with longer depth while drought sensitive genotype HD2877 exhibited higher horizontal root spread and less depth at reproductive stage. Thirty SSR markers were used to study genetic variation which ranged from 0.12 to 0.77 with an average value of 0.57. The genotypes were categorized into three subgroups as highly tolerant, sensitive, moderately sensitive and tolerant as intermediate group based on UPGMA cluster, STRUCTURE and principal coordinate analyses. The genotypic clustering was positively correlated to grouping based on root and morpho-agronomical traits. The genetic variability identified in current study demonstrated these traits can be used to improve drought tolerance and association mapping.

Identification of promising sources for drought tolerance in cultivated and wild species germplasm of barley based on root architecture

“…Hence, divergent parents selected from these clusters can be utilized in breeding program for barley improvement under rain-fed conditions, which is the main breeding target in India. Present results are in congruence with Tomar et al (2016) and Huang et al (2017), who also categorized genotypes into highly tolerant, sensitive, moderately sensitive and tolerant while studying molecular and agro-morphological characterisation of root architecture for drought tolerance in wheat and Eruca, respectively.…”

Investigation on Various Aboveground Traits to Identify Drought Tolerance in Cowpea Seedlings

“…Information on cowpea drought tolerance at the seedling stage would be substantial in efforts toward developing drought-tolerant cultivars. Tomar et al (2016) showed that plants with good tolerance at early vegetative growth were able to withstand drought stress at a later stage of plant development. Another study demonstrated that plant genotypes with some degree of drought tolerance at the seedling stage were likely to be drought tolerant at later stages (Rzepka-Plevne s et al, 2009).…”

Root System Architecture and Its Association with Yield under Different Water Regimes in Durum Wheat

“…However, incorporating selection for root traits directly in a breeding program has been met with many challenges, foremost the difficulty of phenotyping large numbers of genotypes in a cost-and time-efficient manner (Mace et al, 2012). Several wheat studies have evaluated roots using different phenotyping methods including rhizotrons (Nagel et al, 2012;Lobet and Draye, 2013;Clarke et al, 2017), soil coring (Trachsel et al, 2011;Wasson et al, 2012;Wasson et al, 2014), lysimeters (Ehdaie et al, 2014;Elazab et al, 2016), hydroponics (Liu et al, 2015), paper roll culture and Petri dishes for seedling (Tomar et al, 2016), rhizoboxes (Fang et al, 2017, and X-ray-computed tomography (Gregory et al, 2003;Mairhofer et al, 2013;Colombi and Walter, 2017;Flavel et al, 2017). However, most of these techniques are either expensive or not precise enough and reproducible.…”