Effects of Planting Density and Row Spacing on Grass Yield of Forage Sweet Sorghum(Sorghum bicolor [L.]Moench)

[Objective] The aim was to explore high-yielding cultivation techniques for forage sweet sorghum. [Method[ The effects of planting density and row spacing on plant productivity and grass yield of forage sweet sorghum （Sorghum bicolor （L.） Moench） were compared using split-plot design and LSD method of IBMSPSSStatis- ticsv22. [Result]The planting density and row spacing had important influence on the plant productivity and yield of forage sweet sorghum. The optimum planting density- row spacing combination for plant productivity of forage sweet sorghum was A1B,, i. e., planting density of 75 000 plants/hm2 and row spacing of 40 cm, and the opti- mum combination for yield of forage sweet sorghum was A2B,, i.e., planting density of 225 000 plants/hm2 and row spacing of 40 cm. [Conclusion] This study will pro- vide theoretical basis and technical support for the production practice of forage sweet sorghum.

Effect of Planting Date on Yield and Yield Components of Grain Sorghum Hybrids

In Kansas, productivity of grain sorghum [Sorghum bicolor (L.) Moench] is affected by weather conditions at planting and during pollination. Planting date management and selection of hybrid maturity group can help to avoid severe environmental stresses during these sensitive stages. The hypothesis of the study was that late May planting improves grain sorghum yield and yield components compared with late June planting. The objectives of this research were to investigate the influence of planting dates yield and yield components of different grain sorghum hybrids, and to determine the optimal planting date and hybrid combination for maximum biomass and grains production. Three sorghum hybrids (early, medium, and late maturing) were planted in late May and late June without irrigation in Kansas at Manhattan/Ashland Bottom Research Station, and Hutchinson in 2010;and at Manhattan/North Farm and Hutchinson in 2011. Data on dry matter production, yield and yield components were collected. Grain yield and yield components were influenced by planting date depending on environmental conditions. At Manhattan (2010), greater grain yield, number of heads per plant, were obtained with late-June planting compared with late May planting, while at Hutchinson (2010) greater yield was obtained with late May planting for all hybrids. The yield component most affected at Hutchinson was the number of kernels∙panicle−1 and plant density. Late-May planting was favorable for late maturing hybrid (P84G62) in all locations. However, the yield of early maturing hybrid (DKS 28-05) and medium maturing hybrid (DKS 37-07) was less affected by delayed planting. The effects of planting dates on yield and yield components of grain sorghum hybrids were found to be variable among hybrid maturity groups and locations.

Characterization of subunits encoded by Sn RK1 and dissection of combinations among these subunits in sorghum(Sorghum bicolor L.)

Sucrose nonfermenting-related protein kinase 1(SnRK1)is one of the critical serine/threonine protein kinases.It commonly mediates plant growth and development,cross-talks with metabolism processes and physiological responses to biotic or abiotic stresses.It plays a key role in distributing carbohydrates and sugar signal transporting.In the present study,eight SnRK1 coding genes were identified in sorghum(Sorghum bicolor L.)via sequences alignment,with three forαsubunits(SnRK1α1 to SnRK1α3),three forβ(SnRK1β1 to SnRK1β3),and one for bothγ(SnRK1γ)andβγ(SnRK1βγ).These eight corresponding genes located on five chromosomes(Chr)of Chr1–3,Chr7,and Chr9 and presented collinearities to SnRK1s from maize and rice,exhibiting highly conserved domains within the same subunits from the three kinds of cereals.Expression results via qRT-PCR showed that different coding genes of SnRK1s in sorghum possessed similar expression patterns except for SnRK1α3 with a low expression level in grains and SnRK1β2 with a relatively high expression level in inflorescences.Results of subcellular localization in sorghum leaf protoplast showed that SnRK1α1/α2/α3/γmainly located on organelles,while the rest four of SnRK1β1/β2/β3/βγlocated on both membranes and some organelles.Besides,three combinations were discovered among eight SnRK1 subunits in sorghum through yeast two hybrid,includingα1-β2-βγ,α2-β3-γ,andα3-β3-γ.These results provide informative references for the following functional dissection of SnRK1 subunits in sorghum.

Juice, Ethanol, and Grain Yield Potential of Five Sweet Sorghum (<i>Sorghum bicolor</i>[L.] Moench) Cultivars

Sweet sorghum (Sorghum bicolor [L.] Moench) accumulates fermentable sugars in the stem and is increasingly being studied as a potential source of feedstock for bioethanol production. The objective of this study was to evaluate biomass and grain yield in five sweet sorghum cultivars (Dale, M81E, Sugar Drip, Della and Keller) and to determine quality of extractable juice and grain. Randomized complete block experiments were performed in the summer of 2009, 2010, and 2011. Leaf dry weight varied with year and cultivar and averaged 6177 kg·ha-1. Fresh stem weight ranged from 21 to 54 Mg·ha-1 with a mean across years and cultivars of 32.9 Mg·ha-1. Variations in stem weight were correlated with extractable juice volumes that ranged from 10 to 24 m3·ha-1. Juice Brix values fell within a narrow range (14% - 19%) across years and cultivars with an average of 15.6%. In all production years, theoretical sugar and ethanol yield were always numerically higher for Keller and M81E. Grain yield was lowest in Keller (90 kg·ha-1), but ranged from 400 to 1300 kg·ha-1 in other cultivars with a mean of 584 kg·ha-1 across years. However, Keller had the highest starch content with a lower proportion of resistant starch in the grain. Except for Keller, the cultivars tested are potential sources of both fermentable sugars and grain.

Effect of ^(12)C^(6+) Ions Beam Irradiation on Seed Germination and Enzymes Activity in Seedlings of Sweet Sorghum

[ Objective] The aim was to study the effect of 12C6 ＋ ions beam irradiation to two varieties of sweet sorghum on seed germination and some enzymes activity in seedlings with different doses, and provided a theoretical foundation for sweet sorghum breeding. [ Method] After germination, the germination potential, germination fraction and enzyme activity were detected, respectively. [ Result] The results showed that with the dose increased, the germination potential of sweet sorghum increased first and then decreased, while their germination fraction presented ＂shoulder like shape＂ ; the activity of LDH, SOD, CAT and GSH-Px increased first and then decreased with doses, they presented slight differences among different enzymes. [ Conclusion] Low dose radiation could accelerate germination of sweet sorghum seeds and enzyme activity could remain at a relatively high level. Enzyme activity decreased with high doses and the growth of sweet sorghum was inhibited.

建立甜高粱(Sorghum bicolor)高频、高效再生体系的研究

【目的】建立能源植物甜高粱(Sorghum bicolor L.Moench)的高频、高效离体培养再生体系,为遗传转化奠定基础。【方法】以甜高粱品种凯勒的芽顶端分生组织为外植体,探讨在甜高粱直接诱导丛生芽的培养过程中,无菌实生苗的适合苗龄,适宜的激素组合与比例;并将获得的最佳培养方法应用于其它两个甜高粱品种:M-81E和意达利,以研究此途径的基因型依赖性。【结果】利用3d苗龄的芽顶端分生组织作为外植体容易获得较高的分生组织膨大率。甜高粱丛生芽诱导的适宜激素组合为4.0mg·L-16-苄基腺嘌呤+0.5mg·L-12,4-二氯苯氧乙酸+0.5mg·L-1噻重氮苯基脲,可获得91%的丛生芽诱导频率。适合甜高粱快速生根的激素配方为0.5mg·L-1萘乙酸。通过芽顶端分生组织直接诱导丛生芽途径,每个外植体可诱导出上百个芽,最终产生30—40株再生苗。M-81E和意达利具有与凯勒相似的丛生芽诱导频率及效率。【结论】本研究成功地建立了甜高粱的高频、高效离体培养再生体系,且具有外植体来源不受限制,基因型依赖性弱,遗传稳定性好的优点。

高粱(Sorghum bicolor)分子图谱的构建及寄生草(Striga asiatica)萌发诱导物基因的定位

高粱是世界上第五大主要粮食作物，也是非洲国家的主要粮食来源之一，Ｓｔｒｉｇａ ａｓｉａｔｉｃａ是一种寄生于高粱等主要农作物的野生草之一。选用两个对寄生草抗性表现差异的 高粱品系“山桂红”和“ＳＲＮ３９”作亲本，构建了一个重组近交系群体（Ｒｅｃｏｍｂｉｎａｎｔ ｉｎｂｒｅｄ， ＲＩ），并随机筛选出９４个系用于构建分子连锁图谱和基因定位。在应用的２８６个多态性标记 中，有２５１个标记分别标定在１０条不同的连锁群上，标记间的平均图距为７．１ｃｍ，总图谱覆盖 了高粱基因组的１７７９ｃｍ，是目前国际上几个比较完整的高粱分子连锁图谱之一。群体的共 分离分析表明，与寄生草抗性有关的萌发诱导物基因（Ｇｅｒｍｉｎｉｎａｔｉｏｎ ｓｔｉｍｕｌａｎｔ ｇｅｎｅ－ＧｅｒｍＳｔｉｍ） 位于高粱的遗传连锁群Ｊ上，相距较近的分子标记为１３ｃｍ。进一步的精细定位分析，发现有 两个分子标记分别位于基因的两侧，距离为１．６和２．１个ｃｍ。

Effects of Heavy-ion Beams Irradiation on Survival Rate and Antioxidant Enzymes of Sweet Sorghum Seedlings

[Objective] This study aimed to investigate the effects of heavy-ion beams irradiation on the seed germination potential, survival rate, antioxidant enzyme activi- ties and lipid peroxidation of sweet sorghum. [Method] The dry seeds were irradiated by ＇2（36. heavy ion beams with absorbed doses： 0, 40, 80, 120, 160 and 200 Gy, respectively. Then, the seed germination potential, survival rate, antioxidant enzyme activities and lipid peroxidation of sweet sorghum were measured. [Result] Heavy-ion beams irradiation exhibited different influence on germination potential and survival rates. Germination rate showed a downward trend, but the corresponding survival curve of seedlings was saddle-shaped. The activities of SOD, POD, CAT and ASA- POD changed in different trends as well. The MDA content rose toward increasing irradiation dose, suggesting that high dose of heavy-ion beams irradiation enhanced the damage to membrane of sweet sorghum seedlings. [Conclusion] After being irra- diated, germination potential and survival rates of sweet sorghum were decreased, and antioxidant enzymes activity changed greatly. This study laid the basis for fur- ther work on breeding and improvement of sweet sorghum irradiated by ,^（12）C^（6＋） heavy ion beams.

高粱(Sorghumbicolor(L.)Moench)未成熟胚乳培养的研究

高粱未成熟胚乳在含有 BA或 2 .4-D与 KT组合的培养基上诱导启动 .诱导形成愈伤组织的适宜激素是 :2 .4-D4mg/L,BA1m g/L,NAA0 .2 mg/L 的组合或 2 .4-D2 mg/L,KT1m g/L 的组合 .适宜的分化激素组合是 (1)2 .4-D0 .5 mg/L,NAA0 .2 mg/L,BA0 .7mg/L,KT4mg/L;(2 ) NAA0 .5 mg/L,ZT1mg/L;(3 ) 2 .4-D0 .5 m g/L,KT1m g/L.脱分化后的胚乳细胞 ,部分细胞进入分裂期形成愈伤组织 ,胚乳愈伤组织有较强的分化能力 .植株形成方式为器官发生 .

Sweet sorghum and Miscanthus：Two potential dedicated bioenergy crops in China

Among the potential non-food energy crops,the sugar-rich C4 grass sweet sorghum and the biomass-rich Miscanthus are increasingly considered as two leading candidates.Here,we outline the biological traits of these energy crops for largescale production in China.We also review recent progress on understanding of plant cell wall composition and wall polymer features of both plant species from large populations that affect both biomass enzymatic digestibility and ethanol conversion rates under various pretreatment conditions.We finally propose genetic approaches to enhance biomass production,enzymatic digestibility and sugar-ethanol conversion efficiency of the energy crops.

Germination and Expression of α-Amylase of KF0680-1 and KF0680-2(Cultivars of Sweet Sorghum) under Salt Stress

[Objective] The aim was to study on germination and expression of α-amy- lase of KF0680-1 and KF0680-2 （cultivars of sweet sorghum） under salt stress. [Method] In the research, KF0680-1 and KF0680-2, cultivars of sweet sorghum, were used to measure related indices of germination and expression of co-amylase to discuss effect of salt stress on two cultivars. [Result] Germination of sweet sorghum would be promoted if treated with salt in low concentration and inhibited if treated in high concentration. In the latter condition, roots and seedlings were smaller than that of control group in length, but expression of s-amylase in the two cultivars was pro- moted under proper salt stress. [Conclusion] The research indicates that KF0680-1 and KF0680-2 are inhibited in growth by salt stress and the latter is stronger in salt resis- tance than the former under low salt concentration. In addition, expression of α-amy- lase could be promoted by salt in proper volume. The results provide references for selection of sweet sorghum which could be planted in northwestern areas.

Synergistic responses of NHX, AKT1, and SOS1 in the control of Na^+ homeostasis in sweet sorghum mutants induced by ^(12)C^(6+)-ion irradiation

Sweet sorghum mutants induced by^(12)C(6+)-ion irradiation were planted under different soil salinity conditions to investigate the mechanisms maintaining the transport and spatial distribution of Na^+. The functions of the synergistic responses of NHX, AKT1, and SOS1 related to Na^+ accumulation were investigated in control(KFJT-CK) sorghum and KF1210-3 and KF1210-4 mutants. The results indicated that the NHX, AKT1, and SOS1 proteins in sweet sorghum are mainly involved in the transport, exclusion, and spatial distribution of Na^+,respectively. In addition to physiological parameters, we also measured the expression levels of NHX, AKT1, and SOS1 genes. The experimental results indicated that 150 m M Na Cl induced marked increases in the transcripts of NHX and SOS1 after 8 and 12 h in the KF1210-3,KF1210-4, and KFJT-CK cultivars. In contrast, however, a decrease in AKT1 was observed. On the basis of our results, we propose a model in which cooperation amongNHX, AKT1, and SOS1 facilitates Na^+ homeostasis in sweet sorghum in response to an increase in salt concentration. Accordingly, study of the regulatory mechanisms in sweet sorghum generated by carbon ion irradiation is essential for the selection of salt-tolerant cultivars.

A novel aeration strategy in repeated-batch fermentation for efficient ethanol production from sweet sorghum juice

To improve the efficiency of ethanol production in a batch fermentation from sweet sorghum juice under a very high gravity(VHG)condition(~290 g/L of total sugar)by Saccharomyces cerevisiae NP01,repeatedbatch fermentation under an aerated condition(2.5 vvm for the first 4 h during every cycle)was done in a5-L fermenter.The average ethanol concentration(P),productivity(Qp)and yield(Yp/s)for five successive cycles were 112.31 g/L,1.55 g/L·h^-1 and 0.44,respectively with 80.97%sugar consumption.To complete sugar consumption,the total sugar of the juice was reduced to a high gravity(HG)level(~240 g/L).The results showed that yeast extract was not necessary for ethanol production,and aeration during every other cycle i.e.,alternating cycles,was sufficient to promote both yeast growth and ethanol production.The average P,Qpand Yp/svalues for eight successive cycles with aeration during alternating cycles were97.58 g/L,1.98 g/Láh and 0.41,respectively with 91.21%sugar consumption.The total fatty acids in the yeast cells under the aerated condition were^50%higher than without aeration,irrespective the initial sugar concentration,whereas the ergosterol contents under aeration condition were^29%to 49%higher than those without aeration.

Nutritional Quality of Mixed Silage of Lablab purpureus and Sweet Sorghum

[ Objective ] The paper was to evaluate the fermentation quality of mixed silage of Lablab purpureus and sweet sorghum, and to find out the appropriate mixing ratio. [ Method] L. purpureus were mixed with sweet sorghum at different proportions, to identify the sensory character and quality of silage. [ Result] The nutrient content of mixed silage of L. purpureus and sweet sorghum at different proportions decreased significantly at 30 - 60 d, while no significant changes were observed after 60 d. Mixed silage of L. purpureu.s and sweet sorghum had the best effort at the proportion of 3：7 ; followed by the proportion of 5： 5. These two proportions significantly improved dry matter （DM） content and effectively alleviated the crude protein （CP） loss of raw materials; significantly improved the contents of crude fiber and crude ash; and significantly reduce ammonia nitrogen/total nitrogen （AT/TN）. [ Conclusion ] From the perspective of silage quality, the appropriate mixing ratio ofL. purpureus and sweet sorghum is 3：7 or 5：5.

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,Sb VIN1(Sobic. 004 G004800) and Sb VIN2(Sobic. 006 G160700) 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. Sb VIN1 and Sb VIN2 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 p H(5)and similar Kmfor sucroe(49 mmol L-1 and 45 mmol L-1 for Sb VIN1 and Sb VIN2,respectively). The optimum reaction temperatures of Sb VIN1 and Sb VIN2 were 45 °C and65 °C, respectively. Sb VIN2 showed higher tolerance to high temperature than Sb VIN1. 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. Sb VIN1 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. Sb VIN2 only associated with grain width and stem water-soluble carbohydrates(WSCs) content. We conclude that the vacuolar invertase genes Sb VIN1 and Sb VIN2 are differently associated with stem and grain traits in sorghum.

Genome-wide identification and characterization of the JAZ gene family and its expression patterns under various abiotic stresses in Sorghum bicolor

The jasmonate ZIM domain(JAZ)protein belongs to the TIFY((TIF[F/Y]XG)domain protein)family,which is composed of several plant-specific proteins that play important roles in plant growth,development,and defense responses.However,the mechanism of the sorghum JAZ family in response to abiotic stress remains unclear.In the present study,a total of 17 JAZ genes were identified in sorghum using a Hidden Markov Model search.In addition,real-time quantification polymerase chain reaction(RT-qPCR)was used to analyze the gene expression patterns under abiotic stress.Based on phylogenetic tree analysis,the sorghum JAZ proteins were mainly divided into nine subfamilies.A promoter analysis revealed that the SbJAZ family contains diverse types of promoter cis-acting elements,indicating that JAZ proteins function in multiple pathways upon stress stimulation in plants.According to RT-qPCR,SbJAZ gene expression is tissuespecific.Additionally,under cold,hot,polyethylene glycol,jasmonic acid,abscisic acid,and gibberellin treatments,the expression patterns of SbJAZ genes were distinctly different,indicating that the expression of SbJAZ genes may be coordinated with different stresses.Furthermore,the overexpression of SbJAZ1 in Escherichia coli was found to promote the growth of recombinant cells under abiotic stresses,such as PEG 6000,NaCl,and 40℃ treatments.Altogether,our findings help us to better understand the potential molecular mechanisms of the SbJAZ family in sorghum in response to abiotic stresses.

Farmers’ Perception of Phenotypic Variation of Different Types of Sorghum Cultivated in Burkina Faso

Sorghum bicolor is a multi-purpose species adapted to many agroecological zones of Burkina Faso. In the local farming system, different types of sorghum are cultivated together. Such farming conditions could increase gene flow between the different types of sorghum and contribute to the evolution of their main morphological characteristics. Understanding the effect of the farming system on the characteristics of different types of sorghum could contribute to building a strategy for the management of its genetic diversity. A survey and accessions collection was carried out in ten villages selected in two agroclimatic zones of Burkina Faso. A total of 133 accessions were collected and thirty local names were recorded. The results revealed a significant variability within sorghum characteristics based on farmers’ descriptions. Four types of sorghum were identified by farmers based on their uses. These are sweet grain sorghum, grain sorghum, sweet sorghum and dyer sorghum. Most of farmers (54.6%) practised intercropping, and 28.86% of them intercropped several types of sorghum in the same or nearby fields. A high coincidence of the flowering period of the types of sorghum was observed by farmers in both agroclimatic zones. The results also showed that most of the farmers (55.7%) noted changes in the morphological characteristics of different types of sorghum. These variations included the reduction in potential yields and changes in grain taste and colour within the same type. Understanding these variations could help conserve and sustain sorghum genetic resources in Burkina Faso.

Differences in Nuclear DNA Between Male-Sterile and Male-Fertile Lines of Sorghum bicolor

Cytoplasmic male sterility(cms)is determined by nuclear-cytoplasmic interactions. Up to now, most studies are focused on the comparison of cytoplasmic DNAs of male-sterile lines and male-fertile lines, and analysis of nuclear DNA has not been documented yet. In order to find out the possible difference in nuclear genome of male-sterile line A1 Tx623 and corresponding male-fertile line Tx623 of sorghum, random amplified polymorphic DNA(RAPD)approach was used to analyze their cytoplasmic and nuclear genomes. Total DNAs of them were amplified at first to screen primers, which were able to generate reproducible bands specific to male-sterile line or male-fertile line. Then the selected primers were used to amplify their mitochon-drial DNA(mtDNA)and chloroplast DNA(cpDNA). The origins of all the polymorphic fragments were analyzed. After ruling out those amplified from cytoplasmic DNA, seventeen polymorphic fragments were determined to be amplified from nuclear DNA. These fragments originated from nuclear DNA indicate that differences in sequence exist between the nuclear DNA of male-sterile line and male-fertile line of sorghum, which do not agree with the traditional standpoint that they have identical nucleus.

Effects of Replacing Maize Silage with Silage Sweet Sorghum on Milk Production and Blood Biochemical Indexes of Dairy Cows

In order to study the effects of replacing different proportions of silage maize with silage sweet sorghum treated by different fermentation methods on the production performance and blood biochemical indexes of dairy cows,25 Chinese Holstein lactating cows were randomly divided into 5 groups,5 in each group.The control check (CK) was fed the basal diet;for the experimental group 1 and the experimental group 2,50% of the silage maize in the basal diet was replaced with the additive silage sweet sorghum and the conventional silage sweet sorghum,respectively;and as to the experimental group 3 and the experimental group 4,all the silage maize in the basal diet was replaced with additive silage sweet sorghum and conventional silage sweet sorghum,respectively.The preliminary trial period was 7 d,and the trial period was 35 d.The results showed that the experimental group 1 and the experimental group 3 had the dry matter intake significantly higher than that of the experimental group 2,the experimental group 4 and the CK ( P <0.05).The daily milk yields of the experimental group 1 and the experimental group 2 were significantly lower than that of the CK ( P <0.05),and the experimental group 3 and the experimental group 4 were significantly lower than the experimental group 1 and the experimental group 2 ( P <0.05).The milk protein percentage of the experimental group 2 was extremely significantly higher than that of the experimental group 4 ( P <0.01).The experimental group 1,the experimental group 2 and the experimental group 3 showed the blood glucose levels extremely significantly higher than that in the CK ( P <0.01).The blood urea nitrogen contents in the experimental group 2 and the experimental group 4 were significantly higher than those in the experimental group 1 and the CK ( P <0.01).There were no significant differences in other blood biochemical indexes between various groups ( P >0.05).It is feasible to use silage sweet sorghum to feed dairy cows,but the proportion should not be too large,and attention should be paid to the energy and nitrogen balance of the diet.

Effects of Sowing Time on the Growth, Development and Productivity of Sweet Sorghum

The experiments were conducted to determine suitable sowing time in order to achieve high plant biomass and sugar content of sweet sorghum for bioethanol manufacture. The results showed that germination rate reached > 80% in all trial times (p > 0.05). The growth and development speed of sweet sorghum reduced when seeds were sowed in August and was significantly different from other sowing times (p < 0.05). Sowing from March to June obtained the highest plant height during all growth and development stages. Lodging and diseases observed in all periods of sowing, and planting began in July and August had lower percentage. In contrast, the productivity of fresh weight (1310.4 g/whole plant), sugar content (14.9% Brix), biomass yield (122.4 tons/ha) and theoretical converted ethanol yield (5 tons/ha) were the highest when sweet sorghum planted from March to June. It was observed that sowing sweet sorghum in four periods of month from March to June had the desirable biomass for bioethanol production.