Shoot and Root Traits Contribute to Drought Resistance in Recombinant Inbred Lines of MD 23–24 × SEA 5 of Common Bean

Abstract

Drought is the major abiotic stress factor limiting yield of common bean (Phaseolus vulgaris L.) in smallholder systems in Latin America and eastern and southern Africa; where it is a main source of protein in the daily diet. Identification of shoot and root traits associated with drought resistance contributes to improving the process of designing bean genotypes adapted to drought. Field and greenhouse studies were conducted at the International Center for Tropical Agriculture (CIAT), Palmira, Colombia to determine the relationship between grain yield and different shoot and root traits using a recombinant inbred lines (RILs) population (MD23–24 × SEA 5) of common bean. The main objectives of this study were to identify: (i) specific shoot and root morpho-physiological traits that contribute to improved resistance to drought and that could be useful as selection criteria in breeding beans for drought resistance; and (ii) superior genotypes with desirable shoot and root traits that could serve as parents in breeding programs that are aimed at improving drought resistance. A set of 121 bean genotypes (111 RILs, 2 parents, 8 checks) belonging to the Mesoamerican gene pool and one cowpea variety were evaluated under field conditions with two levels of water supply (irrigated and rainfed) over three seasons. To complement field studies, a greenhouse study was conducted using plastic cylinders with soil inserted into PVC pipes, to determine the relationship between grain yield obtained under field conditions with different root traits measured under greenhouse conditions. Resistance to drought stress was positively associated with a deeper and vigorous root system, better shoot growth, and superior mobilization of photosynthates to pod and seed production. The drought resistant lines differed in their root characteristics, some of them with a vigorous and deeper root system while others with a moderate to shallow root system. Among the shoot traits measured, pod harvest index, and seed number per area could serve as useful selection criteria for assessing sink strength and for genetic improvement of drought resistance in common bean.

Root distribution patterns of peanut genotypes with different drought resistance levels under early‐season drought stress

“…(, ). Similar results have been reported in rice (Kano‐Nakata et al., ), Arabidopsis thaliana (van der Weele, Spollen, Sharp, & Baskin, ), chickpea (Benjamin & Nielsen, ), lupin (Rodrigues, Pacheco, & Chaves, ), common bean (Polania et al., ) and cowpea (Matsui & Singh, ). Thus, we conclude that selection of peanut genotypes which increase root length in deep soil layers when a drought is imposed is a worthy approach for plant breeding programmes.…”

“…() who noted ICGV 98305 could maintain dry matter during drought stress period. In previous studies, drought at pre‐flowering drought sharply reduced leaf area and biomass production when compared to a well‐watered treatment (Puangbut et al., ) and it also reduced biomass production (Polania et al., ). The results in this study were in agreement of those in the previous reports.…”

“…The balanced growth hypothesis proposed by Bloom, Chapin, and Mooney (), Kulkarni and Phalke () and Polania et al. () suggests that plants respond to drought by physiological adaptations that tend to equalize the exchange root: shoot ratio (Bloom et al., ; Kulkarni & Phalke, ; Polania et al., ). The concept that plants stimulate or maintain root growth at the expense of shoot growth in response to drought has also been mentioned by Adams and Erickson () and Anyia and Herzog ().…”

“…The selection of drought‐tolerant varieties is a preferred method for maintaining yield under drought (Polania et al., ), and therefore many peanut breeding programmes are screening for better productivity under drought. The plant mechanisms that help plants better survive during stress periods are usually classified into one of three types, escape, avoidance and tolerance (Fang & Xiong, ; Farooq, Hussain, Wahid, & Siddique, ).…”

Root responses in chromosome segment substitution lines of rice 'KDML105' under early drought stress

“…Not only physiological adaptation can improve drought tolerance, but also greater water extraction by deep rooting can contribute drought tolerance in several plants such as peanut (Junjittakarn et al, 2014), common bean (Polania et al, 2017) and rice (Nakata et al, 2011). Increasing the depth and density of roots are considered to be the main mechanisms for improving water uptake (Gowda et al, 2011).…”