Influence of the nitrogen level on root growth and morphology of two potato varieties differing in nitrogen acquisition

Nitrogen (N) loss is a worldwide problem in crop production. Apart from reasonable N fertilizer application, breeding N efficient cultivars provides an alternative way. Root architecture is an important factor determining N acquisition. However, little is known about the molecular genetic basis for root growth in relation to N supply. In the present study, an F 8 maize (Zea may L.) recombinant inbred (RI) population consisting of 94 lines was used to identify the QTLs for root traits under different nitrate levels. The lateral root length (LRL), axial root length (ARL), maximal axial root length (MARL), axial root number (ARN) and average axial root length (AARL) were evaluated under low N (LN) and high N (HN) conditions in a hydroponics system. A total of 17 QTLs were detected among which 14 loci are located on the same chromosome region as published QTLs for root traits. A major QTL on chromosome 1 (between bnlg1025 and umc2029) for the AARL under LN could explain 43.7% of the phenotypic variation. This QTL co-localizes with previously reported QTLs that associate with root traits, grain yield, and N uptake. Our results indicate that longer axial roots are important for efficient N acquisition and the major QTL for AARL may be used as a marker in breeding N efficient maize genotypes.

Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

Mapping QTLs for root traits under different nitrate levels at the seedling stage in maize (Zea mays L.)

Liu

Chen

et al. 2008

“…The way the roots fill the soil matrix is shown to be important for acquiring nutrients (Sattelmacher et al, 1990). Therefore, measuring the root branching pattern (Bernston, 1992) and incorporating an appropriate parameter describing it into a nutrient uptake model may increase its predictive abilities.…”

Section: Future Directions In Modelling Nutrient Uptakementioning

confidence: 99%

Mechanistic simulation models of nutrient uptake: A review

Rengel

1993

Mechanistic models of nutrient uptake consider diffusion and mass flow acting simultaneously to supply nutrients to the sorbing root surface. Plant parameters that determine nutrient uptake include those describing changes in root geometry and size due to root growth and others describing kinetics of the nutrient uptake process. Mechanistic models generally assume that nutrient uptake occurs evenly along the roots that are uniformly distributed in homogeneous and isotropic soil having no temporal and spatial gradients in volumetric moisture content. Uptake of immobile nutrients (like P and K) is mainly determined by the soil-supply parameters and is well predicted by the simulation models. In contrast, uptake of mobile nutrients (e.g. Ca and Mg) that usually accumulate at the root surface is determined mainly by the plant-uptake parameters; prediction of uptake of those nutrients is subject to a much wider error due to uncertainties of applying kinetic parameters measured on hydroponically-grown plants to soil-grown plants. Comparison of model-predicted and experimentally-observed uptake values should be done by calculating the mean squares of deviates instead of performing regression analysis, especially if data that encompass a relatively wide range in root length are considered. Complementaryion effects occurring at the soil-root interface raise the need for developing a multi-nutrient uptake model that will simultaneously calculate uptake of several essential nutrients taking into account interactions among them.

“…Genotypic variability in utilization efficiency has been reported as being positively correlated with soil fertility Moll et al, 1982). Thus, under conditions of low soil fertility uptake efficiency appears to be of special importance for improved crop performance (Sattelmacher, 1987;Sattelmacher et al, 1989). Uptake efficiency may be due to physiological (i.e.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of tuber bearing Solanum species belonging to different ploidy levels for its yielding potential at low soil fertility

Sattelmacher

Kuene²,

Malagamba

et al. 1990

Self Cite

Virus free tubers from thirty-six clones of tuber bearing Solanum species belonging to different ploidy levels, from the world gene bank at the International Potato Center, were cultivated under field conditions at low and high fertilizer rates. Nine of the clones were chosen for their high yielding potential (advanced group) and twenty-seven for their extensiveness (native group). The tuber yields of the thirty-six clones at the two fertilizer levels were positively correlated and the advanced group yielded more than the native group, even under conditions of low soil fertility.A broad genetic variation in root size at both fertilizer levels was apparent. Although some native clones showed rather large root systems as a group, the advanced clones had a similar root dry weight to the native clones.Tuber dry weight was significantly correlated with root dry weight but the advanced clones had a higher tuber yield per unit of root dry matter produced.