Characterization of starch structures isolated from the grains of waxy, sweet, and hybrid sorghum (Sorghum bicolor L. Moench)

In this study, starches were isolated from inbred (sweet and waxy) and hybrid (sweet and waxy) sorghum grains. Structural and property differences between (inbred and hybrid) sweet and waxy sorghum starches were evaluated and discussed. The intermediate fraction and amylose content present in hybrid sweet starch were lower than those in inbred sweet starch, while the opposite trend occurred with waxy starch. Furthermore, there was a higher A chain (30.93–35.73% waxy, 13.73–31.81% sweet) and lower B2 + B3 chain (18.04–16.56% waxy, 24.07–17.43% sweet) of amylopectin in hybrid sorghum starch. X-ray diffraction (XRD) and Fourier transform infrared reflection measurements affirm the relative crystalline and ordered structures of both varieties as follows: inbred waxy > hybrid waxy > hybrid sweet > inbred sweet. Small angle X-ray scattering and 13C CP/MAS nuclear magnetic resonance proved that the amylopectin content of waxy starch was positively correlated with lamellar ordering. In contrast, an opposite trend was observed in sweet sorghum starch due to its long B2 + B3 chain content. Furthermore, the relationship between starch granule structure and function was also concluded. These findings could provide a basic theory for the accurate application of existing sorghum varieties precisely

Does 'Forage-Livestock Balance' policy impact ecological efficiency of grasslands in China?

Grassland has critically important ecological efficiency as well as economic values. While overgrazing and climate change have been reported to lead to the deterioration of grassland ecosystem functions and ecological efficiency, the implementation of a rational policy may mitigate such effects. The 'Forage-Livestock Balance' policy refers to balancing the relationship between forage productivity and grazing capacity of grasslands, and has been implemented in northern grassland areas in China since the year of 2000. In this study, we firstly examined spatio-temporal changes in the ecological efficiency of grass based livestock husbandry in Hulunbuir, Inner Mongolia, China, using the Super-efficiency Data Envelopment Analysis method, and then analyzed the effects of the 'Forage-Livestock Balance' policy on the ecological efficiency. The Difference-in-Difference (DiD) approach was applied to investigate the differences of ecological efficiency in county-level outcomes between prior to and after the implementation of policy. The results showed that the county-level ecological efficiency in Hulunbuir was low in the year of 2000, thereafter it displayed an increasing trend from year of 2000-2015, though no significant differences were occurred in each of counties of Hulunbuir. Among the counties, Yakeshi county and Zha-lantun county had the highest ecological efficiency, and Chen County had the lowest. The DiD analysis suggested that the 'Forage-Livestock Balance' policy had a remarkable effect on the ecological efficiency of grass-based livestock husbandry. Compared to traditional pasture management, the policy has greatly improved the ecological efficiency of grasslands. Our research results provide a useful reference for the sustainable development of grassland livestock management, which is an important countermeasure to improve the efficiency of grassland livestock husbandry, alleviate the pressure on grassland ecosystems, and ensure the living standards of residents in the context of climate change and the risk of recurring disasters. (C) 2018 Elsevier Ltd. All rights reserved

Assessment of the sustainability of different cropping systems under three irrigation strategies in the North China Plain under climate change

The annual double-cropping system of winter wheat and summer maize requires a large amount of irrigation which has led to the rapid depletion of groundwater resources in the North China Plain (NCP). Alternate cropping systems and limited irrigation strategies should be developed for the purposes of maintaining sustainable groundwater use now and in the future. In this study, the water use and crop production of seven cropping systems under three irrigation strategies were assessed using the Agricultural Production Systems SIMulator (APSIM) during 1987-2017 as a baseline and in 2040, 2060, and 2080 under climate change conditions at a typical site in the NCP. The APSIM was calibrated and validated using field experimental data collected during 2007-2016. The seven cropping systems included the current double annual cropping system (2C/1Y) and six other reduced cropping-intensity systems with either three crops every two years (3C/2Y) or one crop per year (1C/1Y). The three irrigation strategies were full irrigation (FI), minimum irrigation (MI, only one irrigation at sowing for seedling establishment) and critical stage irrigation (CI, adding one more irrigation at the critical stage based on MI). The results showed that under current growing conditions, sustainable groundwater use could be achieved with 2C/1Y under MI, 3C/2Y and 1C/1Y under FI. However, the annual yield production was reduced by 9-22% under 3C/2Y and 54-79% under 1C/1Y compared with that under 2C/1Y. The results indicated that 2C/1Y was a better choice for crop production under similar water use. The simulated yield for future scenarios was lower than that during the baseline period; and the reduction rate varied from 2 to 11% under FI; 6-9% under CI; and 10-21% under MI, suggesting that crop production would be more negatively affected under water-limited conditions than that under full water supply condition. The annual water use of the reduced cropping systems was projected to increase because of relative high soil evaporation during the fallow period (Ef). Water use efficiency (WUE) was reduced partly due to the increased Ef. The traditional 2C/1Y under MI had the potential to sustain the groundwater balance in the region and concurrently resulted in higher grain production and WUE than that of the systems with reduced cropping intensity, both now and under climate change, and therefore, this system should be prioritized in this region

Vacuolar invertase genes SbVIN1 and SbVIN2 are differently associated with stem and grain traits in sorghum (Sorghum bicolor)

In higher plants, vacuolar invertases play essential roles in sugar metabolism, organ development, and sink strength. In sorghum (Sorghum bicolor), two vacuolar invertase genes, SbVIN1 (Sobic. 004G004800) and SbVIN2 (Sobic. 006G160700) have been reported, but their enzymatic properties and functional differences are largely unknown. We combined molecular, biochemical and genomic approaches to investigate their roles in sorghum stem and grain traits. SbVIN1 and SbVIN2 showed different expression levels in internodes, leaves, and panicles, indicating that their importance in each organ was different. In an in vitro sucrose hydrolysis assay, proteins of both genes heterologously expressed in Pichia pastoris displayed similar enzyme properties including the same optimum reaction pH (5) and similar Km for sucroe (49 mmol L-1 and 45 mmol L-1 for SbVIN1 and SbVIN2, respectively). The optimum reaction temperatures of SbVIN1 and SbVIN2 were 45 degrees C and 65 degrees C, respectively. SbVIN2 showed higher tolerance to high temperature than SbVIN1. We characterized the sequence variation of these two vacuolar invertase genes in a panel of 216 diverse inbred lines of sweet and grain sorghum and performed gene-based association analysis. SbVIN1 showed significant associations with stem traits including stem length, stem diameter, internode number, stem fresh weight, and Brix, as well as grain traits including hundred-grain weight and grain width. Significantly associated variation sites were mainly in 5' upstream and intron regions. SbVIN2 only associated with grain width and stem water-soluble carbohydrates (WSCs) content. We conclude that the vacuolar invertase genes SbVIN1 and SbVIN2 are differently associated with stem and grain traits in sorghum. (c) 2019 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Cropping system yield gaps can be narrowed with more optimal rotations in dryland subtropical Australia

Closing the gap between yields currently achieved on farms and those that can potentially be achieved with best practice and current technology (the yield gap) is a key strategy to intensify grain production without expanding cropland. Much research has been done to quantify the yield gap of wheat, maize and rice globally and of wheat, barley, canola, sorghum and pulse crops in Australia. However, crops are grown in rotations (recurring crop sequences) that vary in their cropping intensities and in the diversity of their species. Little is known about yield gaps at the cropping system level, especially in regions where there are many possible combinations of crop types and fallow periods. This prompted us to investigate crop rotations in Australia's subtropical grains region where current crop rotations include winter and summer cropping with cereal, pulse and oilseed crops interspersed with fallow periods ranging from nil to 18 months duration. To determine the system level yield gaps, we simulated the water-limited yield potential of 26 locally practiced crop rotations for over 800 weather stations by up to 3 soil types per station. We captured the impact of climate variability with 30-35 years by 2-7 fields per rotation for each site. We expressed the results in terms of energy, protein and revenue per hectare per year and mapped the results of the optimal rotations over the cropping zone. Surprisingly, a single rotation (sorghum/ fallow/mungbean/wheat/fallow/chickpea rotation; with 4 crops in 3 years, balanced between summer and winter crops and between cereal and pulse crops) was optimal for revenue over almost the whole subtropical grain zone. Using revenue as the metric for yield gaps at statistical local area scale we found, over the whole subtropical zone, a mean revenue gap of 970 $/ha/yr. This represents a relative revenue (Revenue% = 100 x (actual revenue/water-limited revenue)) of 34% which is much lower than expected from the 40-60% relative yields achieved by individual crops. We investigated whether growers may select rotations that have lower revenue than the optimal rotation in response to economic factors such as profit and risk. We found that for much of the area the same rotation that optimised revenue also optimised profit. However, for some of the cropping zone, particularly in the south western portion, a different, less intensive and more winter dominant, rotation was most profitable. Similarly, risk averse farmers may choose less productive and profitable rotations with less risk

Non-dormant Axillary Bud 1 regulates axillary bud outgrowth in sorghum

Tillering contributes to grain yield and plant architecture and therefore is an agronomically important trait in sorghum (Sorghum bicolor). Here, we identified and functionally characterized a mutant of the Nondormant Axillary Bud 1 (NAB1) gene from an ethyl methanesulfonate-mutagenized sorghum population. The nabi mutants have increased tillering and reduced plant height. Map-based cloning revealed that NAB1 encodes a carotenoid-cleavage dioxygenase 7 (CCD7) orthologous to rice (Oryza sativa) HIGH-TILLERING DWARF1/DWARF17 and Arabidopsis thaliana MORE AXILLARY BRANCHING 3. NAB1 is primarily expressed in axillary nodes and tiller bases and NAB1 localizes to chloroplasts. The nab1 mutation causes outgrowth of basal axillary buds; removing these non-dormant basal axillary buds restored the wild-type phenotype. The tillering of nab1 plants was completely suppressed by exogenous application of the synthetic strigolactone analog GR24. Moreover, the nab1 plants had no detectable strigolactones and displayed stronger polar auxin transport than wild-type plants. Finally, RNA-seq showed that the expression of genes involved in multiple processes, including auxin-related genes, was significantly altered in nab1. These results suggest that NAB1 functions in strigolactone biosynthesis and the regulation of shoot branching via an interaction with auxin transport

Crop 3D-a LiDAR based platform for 3D high-throughput crop phenotyping

With the growing population and the reducing arable land, breeding has been considered as an effective way to solve the food crisis. As an important part in breeding, high-throughput phenotyping can accelerate the breeding process effectively. Light detection and ranging (LiDAR) is an active remote sensing technology that is capable of acquiring three-dimensional (3D) data accurately, and has a great potential in crop phenotyping. Given that crop phenotyping based on LiDAR technology is not common in China, we developed a high-throughput crop phenotyping platform, named Crop 3D, which integrated LiDAR sensor, high-resolution camera, thermal camera and hyperspectral imager. Compared with traditional crop phenotyping techniques, Crop 3D can acquire multi-source phenotypic data in the whole crop growing period and extract plant height, plant width, leaf length, leaf width, leaf area, leaf inclination angle and other parameters for plant biology and genomics analysis. In this paper, we described the designs, functions and testing results of the Crop 3D platform, and briefly discussed the potential applications and future development of the platform in phenotyping. We concluded that platforms integrating LiDAR and traditional remote sensing techniques might be the future trend of crop high-throughput phenotyping

A near infrared spectroscopic assay for stalk soluble sugars, bagasse enzymatic saccharification and wall polymers in sweet sorghum

In this study, 123 sweet sorghum (Sorghum bicolor L.) accessions and 50 mutants were examined with diverse stalk soluble sugars, bagasse enzymatic saccharification and wall polymers, indicating the potential near infrared spectroscopy (NIRS) assay for those three important parameters. Using the calibration and validation sets and modified squares method, nine calibration optimal equations were generated with high determination coefficient on the calibration (R-2) (0.81-0.99), cross-validation (R(2)cv) (0.77-0.98), and the ratio performance deviation (RPD) (2.07-7.45), which were at first time applied by single spectra for simultaneous assay of stalk soluble sugars, bagasse hydrolyzed sugars, and three major wall polymers in bioenergy sweet sorghum. (C) 2014 Elsevier Ltd. All rights reserved

A near infrared spectroscopic assay for stalk soluble sugars, bagasse enzymatic saccharification and wall polymers in sweet sorghum

In this study, 123 sweet sorghum (Sorghum bicolor L.) accessions and 50 mutants were examined with diverse stalk soluble sugars, bagasse enzymatic saccharification and wall polymers, indicating the potential near infrared spectroscopy (NIRS) assay for those three important parameters. Using the calibration and validation sets and modified squares method, nine calibration optimal equations were generated with high determination coefficient on the calibration (R-2) (0.81-0.99), cross-validation (R(2)cv) (0.77-0.98), and the ratio performance deviation (RPD) (2.07-7.45), which were at first time applied by single spectra for simultaneous assay of stalk soluble sugars, bagasse hydrolyzed sugars, and three major wall polymers in bioenergy sweet sorghum. (C) 2014 Elsevier Ltd. All rights reserved