Abstract
Abstract: The objective of this work was to identify the genetic variation of foxtail millet (Setaria italica) cultivars, from three ecogeographic origins in China, regarding the uptake and utilization of N by the genotypes at the seedling stage, aiming at the genetic improvement of this crop. Seedlings of 79 cultivars were fertilized with a nutrient solution, on a sand substrate, and evaluated under low-N (LN, 0.2 mmol L-1) and high-N (HN, 6.0 mmol L-1) concentrations. A large variation was observed between cultivars, among the three ecogeographic regions, for shoot biomass, shoot N content and concentration, and N use efficiency (NUE), uptake efficiency (NupE), and utilization efficiency (NutE), especially under HN conditions. Cultivars of Northwest China showed the highest variation for shoot biomass, N content, NUE, and NupE. A strong positive correlation was observed between NUE and NupE, and NUE and NutE, but there was no correlation between NupE and NutE. NupE accounted for 77.6% of the total variation of NUE, and NutE for the rest. The uptake and utilization of N show a large variation among the foxtail millet cultivars at the seedling stage, and the variation of N uptake contributes more than that of N utilization to the variation of N use efficiency.
Highlights
Foxtail millet, Setaria italica (L.) Beauv. – a self pollinating C4 plant and one of the ten small-grained cereals – is an important grain crop used as staple food in some regions of China, India, and Japan, and is grown for animal feed in the USA and Europe (Austin et al, 2006; Upadhyaya et al, 2011)
The cultivars varied significantly for nitrogen uptake efficiency (NupE), nitrogen utilization efficiency (NutE), and N use efficiency (NUE), which showed that there had a significant variation of shoot biomass and nitrogen use among the different foxtail millet cultivars
Shoot biomass showed the highest coefficient of variation (CV), followed by shoot-N content, NUE, NupE, and NutE
Summary
Setaria italica (L.) Beauv. – a self pollinating C4 plant and one of the ten small-grained cereals (small millets) – is an important grain crop used as staple food in some regions of China, India, and Japan, and is grown for animal feed in the USA and Europe (Austin et al, 2006; Upadhyaya et al, 2011). – a self pollinating C4 plant and one of the ten small-grained cereals (small millets) – is an important grain crop used as staple food in some regions of China, India, and Japan, and is grown for animal feed in the USA and Europe (Austin et al, 2006; Upadhyaya et al, 2011). Foxtail millet shows a small diploid genome, and has become a model plant for biofuel crops and genomic study for C4 carboxylase pathway and short growing duration (Jia et al, 2013). The planting area of foxtail millet has declined seriously because of its low-grain yield (in comparison with other staple cereals) that can not meet the food demand by people (Vetriventhan et al, 2012). In recent years, grain yields of foxtail millet have raised substantially under breeders’ effort (Diao, 2007). Cereal crops are inefficient in the use of N fertilizer, as about 33% only of the N fertilizer applied to the crop is recovered in aboveground plant biomass, at the end of the cropping season (Garnett et al, 2009)
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