Characterization of a Soybean Germplasm for Root Traits.

Root traits are critical for water and nutrient absorption, which plays an integral role in crop yield. The objectives of this study were to evaluate a soybean germplasm for root penetrability of hardpan, root length, surface area, volume, average diameter, dry weight, and root-shoot ratio, and determine whether root traits have any relation with plant height, shoot dry weight, and seed size. The soybean germplasm had 49 genotypes including slow- and fast- wilting genotypes, elite cultivars, perennials, lines with exotic pedigree, forage soybean, fast- and slow- canopy producing lines, and lines that sustain nitrogen fixation under drought conditions. Plants were maintained under optimal growth conditions in a greenhouse. Single plants were grown in mesocosms, which were constructed of two stacked PVC pipes (top and bottom pipes of 25 and 46 cm length, respectively, and 15 cm diameter) with a 2 cm wax layer (artificial hardpan; penetration resistance, 2.07 mPa at 27°C) in between. Plants were harvested when half of the population reached flowering stage. The experiment was conducted twice (two runs). Significant genetic variability was observed for all root and shoot traits in the soybean germplasm. Fourteen genotypes penetrated the hardpan in at least one run; a slow wilting line NTCPR94-5157 had the largest penetrability. Genotypes NTCPR94-5157, NMS4-1-83 (exotic pedigree), N07-14182 (exotic pedigree), and N09-13128 (exotic pedigree) were ranked high, and genotypes PI 424007 (perennial), R01-581F (sustained nitrogen fixation under drought conditions), N09-12854 (exotic pedigree), and Boggs (intermediate in wilting) were ranked low for most root traits. Plant height and shoot dry weight had positive relationships (R² > 0.5) with root length, surface area, and volume. No correlations were found between seed size and most root traits. The results of this study offer soybean breeders important information when developing new soybean cultivars to improve yield in stressful and optimum environments.

---

See more from this Division: C02 Crop Physiology and Metabolism
See more from this Session: Crop Physiology and Metabolism Poster II

<< Previous Abstract | Next Abstract >>