Phenotypic evaluation of interspecific recombinant inbred lines (RILs) of Phaseolus species for aluminium resistance and shoot and root growth response to aluminium–toxic acid soil

Abstract

Aluminium (Al) toxicity limits common bean productivity in acid soil regions of the tropics. To improve Al resistance of common bean, Al-sensitive Phaseolus vulgaris (SER16) was crossed to Alresistant P. coccineus (G35346-3Q) to create 94 F 5:6 recombinant inbred lines (RILs) of the pedigree SER16 9 (SER16 9 G35346-3Q). RILs were characterized for resistance to Al in a hydroponic system with 0 and 20 lM Al in solution, and for shoot and root growth response to Al-toxic infertile acid soil in 75 cm long soil cylinder system using an oxisol of low Al-(12.5%; pH 4.6; fertilized) and high Al-saturation (77%; pH 4.1; unfertilized). G35346-3Q increased its taproot elongation rate by 3.5% between 24 and 48 h under 20 lM Al in solution, while the best RIL, Andean genotype ICA Quimbaya, and sensitive genotype VAX1 expressed reductions of 2.6, 12.5, and 69.5%, respectively. In the acid soil treatment the

Root traits and their potential links to plant ideotypes to improve drought resistance in common bean

“…The root traits were evaluated at this time since the greatest phenotypic differences between the genotypes were observed (Polania et al 2009;Butare et al 2012). Visual rooting depth (VRD) was measured during the experiment at 7 day intervals using a ruler with cm scale, registering the total depth reached by the roots that were visible through the plastic cylinder.…”

“…However the phenotypic evaluation of root traits under field conditions is labor intensive and expensive. Keeping this in mind, some rapid and cost effective methodology has been used to carry out root phenotypic evaluations, such as small soil cylinders under greenhouse conditions, which allow to evaluate several root traits under different types of abiotic stress (Polania et al 2009;Butare et al 2011Butare et al ,2012. Phenotypic evaluations of root traits in common bean under drought stress have shown the importance of different rooting patterns, including deep rooting which allows access to water from deeper soil layers (Sponchiado et al 1989;White and Castillo 1992;Lynch and Ho 2005;Polania et al 2009Polania et al , 2012Beebe et al 2013Beebe et al , 2014Rao 2014;Burridge et al 2016).…”

Soil Compaction Induced Changes in Morpho-physiological Characteristics of Common Bean

“…The six genotypes used from CIAT's breeding program were: A774, ALB 91, BAT 477, CALIMA, DAB 295, and SMC 140. ALB 91 is an interspecific line developed with introgression of Phaseolus coccineus genes into Phaseolus vulgaris (Butare et al 2012). Three soil compaction treatments were imposed for each genotype under each level of water supply.…”

“…The soil was sieved and mixed with washed river sand in 2:1 w/w proportions. Plants were cultivated in cylindrical polyethylene soil tubes (0.80 m long, 0.10 m internal diameter, and 6.3 L capacity) that were inserted into thin walled PVC tubes (Butare et al 2012) to assess the development and distribution of roots in soil cylinders. We used a hydraulic press to establish different pressures with predetermined soil quantities to a fixed volume to create three different soil bulk densities.…”

“…Total biomass was measured at harvest by separating different plant components and drying them at 60°C for 48 h to determine dry weight. Plant roots collected from each soil cylinder were washed manually and scanned (Epson Expression 10000XL), and total root length (m plant −1 ), mean root diameter (mm), and root volume (g cm −3 ) were determined using a WinRHIZO image analysis system (Butare et al 2012). The length and density of root hairs were measured using a scanner.…”