Water and Radiation Use Efficiencies in Sorghum

Abstract

Increasing water and radiation use efficiencies (WUE and RUE, respectively) are critical to enhance crop production. Exploring genetic variability in WUE and RUE is necessary to improve these traits. The objectives of this research were to evaluate eight sorghum [Sorghum bicolor (L.) Moench] genotypes for biomass production, WUE, and RUE and to test whether the differences in WUE among sorghum genotypes were associated with increased biomass production or decreased water use under field conditions. The WUE was estimated as the slope of the regression of aboveground biomass on cumulative water use for specified sampling intervals. The RUE was estimated as the slope of the regression of aboveground biomass on cumulative intercepted photosynthetically active radiation (IPAR). Sorghum genotypes showed significant differences in biomass production, WUE, and RUE. The WUE varied from 3.39 ± 0.80 to 5.42 ± 0.80 g kg−1 in 2009 and from 4.04 ± 0.58 to 7.63 ± 0.58 g kg−1 in 2010. Similarly, RUE varied from 2.13 ± 0.33 to 3.53 ± 0.31 g MJ−1 IPAR in 2009 and from 2.08 ± 0.35 to 3.83 ± 0.33 g MJ−1 IPAR in 2010. Among the eight sorghum genotypes tested in this study, IS 27111 and IS 27150 had the largest biomass production, WUE, and RUE. The WUE was more strongly correlated to biomass production than to water use. This result implies that it is possible to improve WUE without compromising biomass production. The sorghum genotypes evaluated for biomass production, WUE, and RUE in this study offer useful plant materials for identifying the mechanisms causing differences in these traits.

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

“…WUE, EY, and EWR were higher for both species in 2015, likely due to greater SWtot, GDD, and precipitation in 2015, relative to 2014. Interannual variability in WUE was explained by different biomass accumulation between growing seasons, rather than changes in total ET, which is consistent with findings in the literature (Steduto et al, 1997;Narayanan et al, 2013;Hao et al, 2014;Dietzel et al, 2015). While both species had similar total ET, the pattern of ET accumulation within the season (Fig.…”

“…Other investigations have found that the WUE of irrigated sweet sorghum was greater than other C4 crops at the canopy scale, but similar to other C4 crops at the leaf scale; however, the comparisons were made using previously reported WUE values for C4 crops, rather than measurements provided in a side-by-side field comparison (Steduto et al, 1997). Research has shown that WUE can vary significantly with climate conditions, complicating comparisons made across different years and climates (Narayanan et al 2013;Bernacchi & VanLoocke, 2015).…”

“…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).…”

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“…Conservation farming improved soil moisture, yield and water use efficiency of crops such as Winter wheat, (He et al, 2011;Hou et al, 2012). Narayanan et al (2013) evaluated eight Sorghum genotypes for biomass production, water productivity (WP) and RUE and concluded that WP was more strongly correlated to biomass production than to crop water use and that WP can be improved without compromising biomass production. RUE of grass was found to respond rapidly to soil moisture content and strong dependence of RUE on soil SWS and air temperature has also been reported (Potters et al, 1999;Tserenpure et al, 2012;).…”

“…The fIPAR of the measured data (Fi) was determined by using Eqn. 1: The λ of the crop for each treatment was determined by using Equation 2 with intercept set at zero because PARabove is equal to the PARbelow when LAI = 0 and the slope of each graph was taken as the seasonal λ (Narayanan et al, 2013;Robertson et al, 2001;Farahani, 2009):…”