Water uptake efficiency and above- and belowground biomass development of sweet sorghum and maize under different water regimes

Abstract

Background and aims Lately sweet sorghum (S) has attracted great interest as an alternative feedstock for biofuel production due to its high yielding potential and better adaptation to drought than maize (M). However, little is known about the response of newly developed sweet sorghum genotypes to water deficits, especially at the root level and its water uptake patterns. The objective of this study was to compare the water uptake capacity, growth and developmental characteristics at the root and canopy levels of a sweet sorghum hybrid (Sorghum bicolor cv. Sucro 506) with those of maize (Zea mays cv. PR32F73) at two water regimes. Methods The trial was setup in a total of 20 rhizotrons (1 m 3 ), where calibrated soil moisture probes were installed for monitoring and adjusting the soil moisture content to 25% (well-watered, W) and 12% (drought stress, D). Results DS was able to sustain its physiological activity close to that of WS plants, while maize was not. The biomass production potential of DS was reduced about 38%, while in maize the reduction was 47%. The water use efficiency (WUE), however, was increased by 20% in sweet sorghum and reduced in 5% in maize. Moreover, in contrast to maize the root length density and water uptake capacity of DS was enhanced. Root water uptake efficiency in DM was sustained close to its potential, but not in sweet sorghum. Conclusions In summary, the better adaptation to drought of sweet sorghum is explained by increased WUE, sustained physiological activity and enlarged root system. It is also associated with a reduced water uptake efficiency compared to its control but maintained compared to maize.

Biomass sorghum and maize have similar water-use-efficiency under non-drought conditions in the rain-fed Midwest U.S.

“…There is evidence to suggest that sorghum and maize have differing biomass production and water dynamics; however, results vary based on environment, management, and species subtype (Steduto et al, 1997;Farré & Faci 2006;Zegada-Lizarazu et al, 2012;Oikawa et al, 2014). Some studies have shown greater biomass production for biomass sorghum than other C4 species, including maize and switchgrass (Hallam et al, 2001).…”

“…Some studies have shown greater biomass production for biomass sorghum than other C4 species, including maize and switchgrass (Hallam et al, 2001). Sweet sorghum, a variety with sugar-rich stems (Rooney et al, 2007), and grain sorghum, both with deep, extensive roots (Rooney et al, 2007;Zegada-Lizarazu et al, 2012), produced comparable biomass to maize when water was not a limiting factor, and more biomass than maize in water limited environments (Farré & Faci, 2006;Schittenhelm & Schroetter, 2014). Sweet sorghum was found to be less sensitive to drought than maize (Zegada-Lizarazu et al, 2012), and more water-useefficient than maize and other major grain crops (Steduto et al,1997;Katerji & Mastrorilli, 2014).…”

“…Sweet sorghum, a variety with sugar-rich stems (Rooney et al, 2007), and grain sorghum, both with deep, extensive roots (Rooney et al, 2007;Zegada-Lizarazu et al, 2012), produced comparable biomass to maize when water was not a limiting factor, and more biomass than maize in water limited environments (Farré & Faci, 2006;Schittenhelm & Schroetter, 2014). Sweet sorghum was found to be less sensitive to drought than maize (Zegada-Lizarazu et al, 2012), and more water-useefficient than maize and other major grain crops (Steduto et al,1997;Katerji & Mastrorilli, 2014). However, previous studies on sorghum water dynamics have largely focused on grainyielding varieties (Steduto & Albrizio, 2005;Farré & Faci, 2006) and biomass sorghum in irrigated systems (Steduto et al, 1997;Farré & Faci, 2006;Rinaldi & Garofalo, 2013;Narayanan et al, 2013;Mullet et al, 2014;Hao et al, 2014Oikawa et al, 2014Yimam et al, 2015).…”

Stress-Tolerant Feedstocks for Sustainable Bioenergy Production on Marginal Land

“…Several of the most tolerant taxa were C4 perennial grasses, including Andropogon gerardii, Pennisetum purpurem, and Sorghum bicolor. For example, Sorghum bicolor is highly productive in dry African climates [109], likely due to the high WUE and large root systems found in many cultivars [110]. Panicum virgatum shows low [66].…”

Changes in the sugar content of sweet sorghum stems under natural conditions during winter in saline soil of the Yellow River Delta

“…Among annual herbaceous crops, sweet sorghum is regarded as one of the leading bioenergy crops because it contains large amounts of soluble sugar in its stalks along with other substances that can be used for alcoholic fermentation (Zegadalizarazu et al, 2012). As energy issues become increasingly prominent, efforts to produce clean, renewable biomass energy have significantly increased over the last decade (Iniyan and Sumathy, 2003).…”