Potential root depth development and nitrogen uptake by tetraploid bahiagrass hybrids

Abstract

The objectives were to develop a screening technique to evaluate the tetraploid germplasm of Paspalum notatum Flüggé (bahiagrass) for potential rate of root depth development (RRDD), estimate the variability for RRDD among hybrids, and analyze the association between RRDD and nitrogen (N) uptake. First, a screening technique was developed based on the evaluation of two clones grown in clear acrylic columns of different sizes, filled with mineral or organic substrates. The RRDD response was determined to be constant across substrates, and tube sizes. Second, differences in RRDD among thirteen clones were compared by growing plants in acrylic columns filled with mineral substrate. Genetic variability was identified among the bahiagrass germplasm for RRDD. Greater RRDD values resulted in greater root and shoot mass, indicating that RRDD was related to early vigor. Finally, to evaluate the relation between RRDD and N uptake, labeled N ( 15 N) was injected either at the depth of the deepest root of each clone or at the maximum depth of all clones. Rapid root depth development was a determining factor for rapid access and uptake of nitrogen present in deep soil layers. This relationship might explain why clones exhibiting rapid root penetration also showed greater early vigor.

Classification of Zoysiagrass Genotypes on Rooting Capacity and Associated Performance during Drought

“…Characterization of rooting capacity in greenhouse settings is a routine screening procedure in turfgrass breeding for assessing a plant's ability to cope with drought stress (Huang et al, 1997b; Qian et al, 1997; Bonos et al, 2004; Acuña et al, 2010; Fuentealba et al, 2015). Rooting results gathered from greenhouse screenings can be used to explain drought responses observed in the field if the proper root variables are chosen (Lehman and Engelke, 1991; Marcum et al, 1995).…”

“…The two experiments were initiated on 6 Aug. and 14 Nov. 2011, respectively. Procedures used for the root study were similar to those described by Acuña et al (2010) and Fuentealba et al (2015). Plugs (5‐cm diam.)…”

“…Root depth measurements, based on the single deepest visible root, were initiated 1 wk after planting and subsequently recorded three times per week. Rate of root depth development (RRDD, cm d −1 ) was determined from the linear increase in the depth of the deepest root as a function of time in the first 30 d (Acuña et al, 2010). Sixty days after planting, the maximum root depth (MRD) was recorded and the root and soil cores were harvested from the tubes.…”

“…Fisher's protected LSDs were estimated and used to separate the significant genotype means at the α ≤ 0.05 level. In the greenhouse study, RRDD was defined as the slope of the linear regression between days after planting and root depth over the first 30 d using SAS Proc Reg (Acuña et al, 2010). No significant experiment × genotype interaction was detected for root characteristics, except for RRDD.…”

“…For Depth B, RDW ranged from 9.7 mg for BA 189 to 97 mg for TAES 5335-3. Genotypes not different 30 d (Acuña et al, 2010). Sixty days after planting, the maximum root depth (MRD) was recorded and the root and soil cores were harvested from the tubes.…”