Sweet Sorghum Lines Research Articles

Production of Sweet and High Biomass Sorghum Lines with Optimized Cell Wall Components for Increased Biofuel Bioconversion Yield

The current research focuses on the estimation of fibre content in sweet and high biomass sorghum lines for Production of sweet and high biomass sorghum lines with optimized cell wall components for increased biofuel bioconversion yield, through partially replicated experimental design for F3 populations based on BLUPs values; this study was carried out for four seasons (from postrainy 2020 to rainy 2022) to develop F3 populations of sweet and high-biomass bmr sorghum lines. The proximate fibre component analysis was done in the matured F3 populations by drying the plant samples and grinding them into a fine powder. Fibre quality components such as cellulose, hemicellulose, acid detergent fibre (ADF), acid detergent lignin (ADL), neutral detergent fibre (NDF), metabolizable energy (ME), nitrogen, in vitro organic matter digestibility (IVOMD), and ash, were assessed using Near-Infrared Reflectance Spectroscopy (NIRS). ICSV18003 had the lowest acid detergent fibre (ADF) percentage at 37.04%, while it also had the highest acid detergent lignin (ADL) percentage at 3.84%. The ash percentage was 3.73% in SSV84 × N609. Moreover, the bmr transferred lines of the F3 population exhibited higher levels of cellulose and hemicellulose, while lignin and ash content were decreased. This indicates that the bmr6 and bmr12 alleles can be confidently utilized in sorghum breeding for bioenergy production, as they meet the requirements for bioethanol production.

Sweet Sorghum for Biofuel Production in Sub-Tropical India

Sweet sorghum (Sorghum bicolor L. Moench), a sugar crop with wider adaptation and high potential for bioenergy and ethanol production is expected to meet food, feed, fodder, fuel and fibre demands. It produces high biomass (50-80 t/ha) and alcohol (1500-2800 l/ha) and multiple income opportunities exist with this crop. Some sweet sorghum lines attain juice yields of about 78% of total plant biomass, containing from 15 to 23% soluble fermentable sugars which are composed mainly of sucrose (70–80%), fructose and glucose. Due to its short growing period (3-4 months), it could be cultivated and supplied during the lean period of sugarcane crushing thus extending the crushing period before and after sugarcane crushing and stretch the sugar mill operation. The major advantage with this crop is that no CAPEX is required when used in a sugar mill system as same machinery can be used for crushing and fermentation. It will help farmers to fetch additional income and provide an opportunity for better utilization of industrial facilities during sugarcane off-season. Promising sweet sorghum genotypes developed by ICAR-IIMR, Hyderabad are being tested for their suitability to sub-tropical conditions in February and June-July plantings at the NSI, Kanpur to establish a sustainable cropping system. Five sweet sorghum genotypes were tested during kharif 2021 for sweet sorghum productivity traits. The fresh stalk yield ranged from 45-60 t/ha and based on TRS, maximum alcohol percentage in wash was observed in three varieties, i.e., Phule Vasundhara, CSH 22SS and SSV 74 which was 8.4%, 8.38% and 7.8% respectively. Maximum ethanol yield of 53.05 L/T was recorded in CSH 22 SS followed by SSV 74 (50.93 L/T). Phule Vasundhara, with a highest stalk yield of 60 t/ha recorded highest ethanol content of 2837 L/ha followed by CSH 22SS (2780 L/ha) and SSV 74 (2411 L/ha).

Heterozigosidade, adaptabilidade e estabilidade fenotípica de genótipos de sorgo sacarino

ABSTRACT Sweet sorghum (Sorghum bicolor L.) is a promising energy crop for bioethanol production. This study aimed to investigate the influence of genetic structure on the adaptability and phenotypic stability of sweet sorghum lines and hybrids regarding the main agro-industrial traits, as well as selecting hybrids that associate high ethanol yield and yield stability in different growing environments. A total of 45 genotypes were evaluated in experiments conducted in a 5×9 triple alpha lattice design in three locations in the state of Minas Gerais, Brazil. The following traits were measured: fresh matter production, juice extraction percentage, total soluble solids content, tons of Brix per hectare, and ethanol production. Adaptability and phenotypic stability were assessed by the Wricke and Annicchiarico methods. Sweet sorghum adaptability and phenotypic stability depend on genotype genetic structure, with hybrids being more stable than parental lines. Additionally, H2x9 and H3x8 were the most promising hybrids.

Phenylpropanoids Following Wounding and Infection of Sweet Sorghum Lines Differing in Responses to Stalk Pathogens.

Sweet sorghum (Sorghum bicolor) lines M81-E and Colman were previously shown to differ in responses to Fusarium thapsinum and Macrophomina phaseolina, stalk rot pathogens that can reduce the yields and quality of biomass and extracted sugars. Inoculated tissues were compared for transcriptomic, phenolic metabolite, and enzymatic activity during disease development 3 and 13 days after inoculation (DAI). At 13 DAI, M81-E had shorter mean lesion lengths than Colman when inoculated with either pathogen. Transcripts encoding monolignol biosynthetic and modification enzymes were associated with transcriptional wound (control) responses of both lines at 3 DAI. Monolignol biosynthetic genes were differentially coexpressed with transcriptional activator SbMyb76 in all Colman inoculations, but only following M. phaseolina inoculation in M81-E, suggesting that SbMyb76 is associated with lignin biosynthesis during pathogen responses. In control inoculations, defense-related genes were expressed at higher levels in M81-E than Colman. Line, treatment, and timepoint differences observed in phenolic metabolite and enzyme activities did not account for observed differences in lesions. However, generalized additive models were able to relate metabolites, but not enzyme activities, to lesion length for quantitatively modeling disease progression: in M81-E, but not Colman, sinapic acid levels positively predicted lesion length at 3 DAI when cell wall-bound syringic acid was low, soluble caffeic acid was high, and lactic acid was high, suggesting that sinapic acid may contribute to responses at 3 DAI. These results provide potential gene targets for development of sweet sorghum varieties with increased stalk rot resistance to ensure biomass and sugar quality.

Morphological characterization of sweet sorghum lines which has the potential as a raw material for bioethanol

Sweet sorghum is a potential plant as a raw material for bioethanol. This plant has the potential to be developed in tropical, semi-tropical and arid climates. To obtain information on elite lines as raw material for ethanol, it is necessary to characterize qualitative and quantitative traits. This study aims to obtain information about the quantitative and qualitative characters of several sweet sorghum lines that have the potential as raw materials for bioethanol. The research was carried out from August to December 2019 on the Experimental Farm of Indonesian Cereals Research Institute (ICERI), at Maros, South Sulawesi, Indonesia. The genetic materials used in this study were ten sweet sorghum lines, namely 15020B, 1115-C, 4-183ABEOTO, AB-6-1-1, EA-13-1-1, KL2, 10 (1-1), 23 (1-1), Buleleng Abang and WR2 and two varieties as check, namely Super-1 and Super-2, using a randomized block design in which genotype was the treatment factor. Qualitative data is explained by a descriptive method which refers to UPOV. Analysis of variance indicated significant differences in the quantitative and qualitative characters. Significantly different characters quantitatively were plant height, leaf length, leaf width, day to flowering, panicle length, and weight of 1000 grains. While the significant qualitative data are green leaf intensity, leaf bone color, pistil color, pistil length, dry stamen color, panicle shape, panicle density after pollination, self-pollination, husk color, husk length, grain color, seed shape, and endosperm texture. Based on morphological data, the promising elite lines as raw material for bioethanol were EA-13-1-1, KL2, WR2, Buleleng Abang, 61 (1-1) and 15020B. However, other scientific supporting data are needed to recommend superior sweet sorghum lines as raw material for bioethanol.

MicroRNAs balance growth and salt stress responses in sweet sorghum.

Salt stress is one of the major causes of reduced crop production, limiting agricultural development globally. Plants have evolved with complex systems to maintain the balance between growth and stress responses, where signaling pathways such as hormone signaling play key roles. Recent studies revealed that hormones are modulated by microRNAs (miRNAs). Previously, two sweet sorghum (Sorghum bicolor) inbred lines with different salt tolerance were identified: the salt-tolerant M-81E and the salt-sensitive Roma. The levels of endogenous hormones in M-81E and Roma varied differently under salt stress, showing a different balance between growth and stress responses. miRNA and degradome sequencing showed that the expression of many upstream transcription factors regulating signal transduction and hormone-responsive genes was directly induced by differentially expressed miRNAs, whose levels were very different between the two sweet sorghum lines. Furthermore, the effects of representative miRNAs on salt tolerance in sorghum were verified through a transformation system mediated by Agrobacterium rhizogenes. Also, miR-6225-5p reduced the level of Ca2+ in the miR-6225-5p-overexpressing line by inhibiting the expression of the Ca2+ uptake gene SbGLR3.1 in the root epidermis and affected salt tolerance in sorghum. This study provides evidence for miRNA-mediated growth and stress responses in sweet sorghum.

Adaptation test and selection of numbu mutant sweet sorghum lines for character improvement of numbu variety

Sweet sorghum is a potential crop of agro-industry for food, feed and bioenergy. The availability of sweet sorghum varieties in Indonesia is still limited. One of the varieties that have a great demand is Numbu. Numbu has a large seed size, attractive color and contains juice in the stem, however it is still has weaken on small stems and low and unstable brix juice content. The efforts to assemble new superior varieties can be achieved through mutation breeding activities. Mutant lines produced from irradiation of Numbu varieties are expected to experience better character improvements than Numbu varieties. This study aims to find out the character improvements that occur in Numbu mutant lines which are tested in several different locations and to select potential Numbu mutant lines to be released as new superior sweet sorghum varieties. The research was conducted in five environments using 10 Numbu mutant lines and arranged into randomize block design with 3 replications. The results showed that the environment, genetic and interaction of genetic x environment had a significant effect for all observed, while the interaction of genetic x environments value for all observed characters have high variation depend on environment and environement gave the biggest contribution to variation, however generally mutant lines were have a better characters than Numbu variety There is no important characters has stability performance in various environment, but they have a good performance on specific environment. Four mutant lines those have the potential to be released as new superior varieties were MNB3, MNB5, MNB8 and MNB10.

Grain sink removal increases stalk juice yield, sugar accumulation, and biomass in sweet sorghum [Sorghum bicolor (L.) Moench

Sweet sorghum is cultivated primarily for its sugar-rich stalks. The extent to which stalk sugar accumulation occurs is determined by several factors including the grain sink. A Genetic system exists whereby the grain sink can be eliminated to maximize sugar accumulation in the stalks. Before engaging in the development of such system, establishing the extent to which stalk sugar can be improved by removing the grain sink becomes necessary. The aim of this study was to determine the effect of eliminating the grain sink on biomass and sugar accumulation. The experiment consisted of two factors, genotype and sink load. The genotype factor consisted of 22 sweet sorghum lines of variable sugar content, and the sink factor consisted of no-grain and full-grain set. Treatments were arranged in split plot in a randomized complete block design with genotypes assigned to the main plot and the sink effect to the subplot. The study was conducted in four replications in three environments. The no-grain sink treatment was applied by manually removing the panicles prior to anthesis. Analysis of the data collected from one-meter sections of each plot at physiological maturity showed that the genotype effect was significant (P ≤ 0.01) for all traits. Elimination of the grain sink prior to anthesis significantly increased °Brix, wet and dry biomass, and total sugar by 18, 28, and 43%, respectively. These results justify further development of sorghum varieties without a grain sink to maximize sugar yield for biofuel production.

QTL mapping for bioenergy traits in sweet sorghum recombinant inbred lines.

During the past decade, sweet sorghum (Sorghum bicolor Moench L.) has shown great potential for bioenergy production, especially biofuels. In this study, 223 recombinant inbred lines (RILs) derived from a cross between two sweet sorghum lines (Brandes × Wray) were evaluated in three trials. Single-nucleotide polymorphisms (SNPs) derived from genotyping by sequencing of 272 RILs were used to build a high-density genetic map comprising 3,767 SNPs spanning 1,368.83 cM. Multitrait multiple interval mapping (MT-MIM) was carried out to map quantitative trait loci (QTL) for eight bioenergy traits. A total of 33 QTLs were identified for flowering time, plant height, total soluble solids and sucrose (five QTLs each), fibers (four QTLs), and fresh biomass yield, juice extraction yield, and reducing sugars (three QTLs each). QTL hotspots were found on chromosomes 1, 3, 6, 9, and 10, in addition to other QTLs detected on chromosomes 4 and 8. We observed that 14 out of the 33 mapped QTLs were found in all three trials. Upon further development and validation in other crosses, the results provided by the present study have a great potential to be used in marker-assisted selection in sorghum breeding programs for biofuel production.

The A3 cytoplasm mediated male sterility increased biomass, soluble solids, and total sugar in sweet sorghum hybrids

Sweet sorghum [Sorghum bicolor (L.) Moench] is listed as one of the viable high energy crops for use as feedstock in biofuel production and table sugar industry. Research has shown that eliminating the grain sink can remarkably increase stalk sugar buildup through reducing competition for assimilate. The objective of this study was to explore the opportunity for deploying the A3 cytoplasmic male sterility (CMS) system to achieve hybrid sterility and thereby increase sugar yield. Four seed parents in the A1 and A3 CMS systems were intercrossed with 10 diverse sweet sorghum lines to create 80 hybrids, 40 each in A1 (fertile) and A3 (sterile) backgrounds. All of the hybrids and their parents were evaluated in single row plot in three replicates across three environments using a randomized complete block design. Heads from all A3 hybrid rows were covered before anthesis to avoid seed set from random pollen. Data were collected on days to flowering and lodging on plot basis. At maturity, the entire above ground part in a one-meter section of each plot were harvested for measuring °Brix value, juice, biomass, and sugar yields. Significant differences were obtained among the hybrid entries, and between the A1 and A3 CMS systems for all biofuel traits. The A3 hybrids had 27, 29, 25 and 57 % higher °Brix value, biomass, juice yield and total sugar, respectively, than their corresponding A1 hybrids. They were also more resistant to stalk lodging. In conclusion, sterile sweet sorghum hybrids can be deployed using the A3 CMS system to allow accumulation of more biomass and sugar in the stalk.

Insight into genetic potential of male sterile sweet sorghum A-lines for agroindustrial traits using tester R-lines

There is a growing demand for the development of alternative fuels from renewable sources, thus sweet sorghum an autogamous species has potential for bioethanol production. Traditionally recommended cultivars were varieties, however, with the development of cytoplasmic male sterile sweet sorghum lines, sweet sorghum hybrids have become economically viable. The sweet sorghum breeding program of the Brazilian Agricultural Research Corporation (Embrapa Milho e Sorgo) has been developing sweet sorghum hybrids for bioethanol production according to the scheme of A, B and R-lines are used, where A-lines are used as females in the production of hybrid seeds. A and B-lines are isogenic, which differ only its cytoplasm source, sterile and normal, respectively, and fertility restorers R-lines. Thus the objective of this work was to evaluate the genetic potential of new male-sterile sweet sorghum A-lines using testcross hybrids developed with two sweet sorghum R-line as testers for agroindustry characteristics for bioethanol production. Forty testcross hybrids were developed using 20 experimental A-lines and two testers sweet sorghum R-lines. Experiments were conducted at experimental stations in Sete Lagoas-MG and Nova Porteirinha-MG, to evaluate 20 A-lines, two 2 R-lines, the resulting 40 testcross hybrids, and two controls. The 64 treatments were evaluated for days to flowering, fresh biomass yield and total soluble solids (Brix). The data obtained were analyzed using the ASReml package, for the estimation of variance components and the prediction of genetic and non-genetic values via REML/BLUP. Two models were adopted, called Multi-Tester and Single-Tester. The genotypic values of the A-lines when crossed with tester T2, were positive for nine A-lines (12, 17, 6, 20, 18, 16, 19, 11 and 3) with emphasis on A-lines 12, 17 and 6, which were the highest values, respectively, the same tester for the trait FLOW, ten A-lines were positive values (3, 16, 17, 4, 12, 15, 5, 6, 8, 20) with emphasis on 3, 16 and 17. The genotypic values for TSS (Brix) trait of the A-lines when crossed with tester T1 were positive for A-lines (19, 18, 20, 16, 1, 5, and 6) with emphasis on lines 19, 18, 20, and 16, with the highest values, respectively. Only two A-lines showed positive genotypic values for three traits, A-line 16 and 20. These results indicate the need for continuing simultaneous improvement of A-lines for FLOW, FBY, and TSS. A-lines from the sorghum breeding program of Embrapa Milho e Sorgo have the potential for use as parents in the development of superior sweet sorghum hybrids for bioethanol production. The A-lines 6 and 20 have positive genotypic values for three traits, this A-lines has a potential for producing hybrids dedicated to bioethanol production. The T1-L tester was more efficient in discriminating the genetic values between the A lines for TSS, while the T2-L tester for FBY and FLOW. The development of a tester with genotype "drydry" and "Ma1Ma1" is important in order to develop superior hybrids to produce bioethanol involving the A, B and R scheme.

Common metabolic networks contribute to carbon sink strength of sorghum internodes: implications for bioenergy improvement

BackgroundSorghum bicolor (L.) is an important bioenergy source. The stems of sweet sorghum function as carbon sinks and accumulate large amounts of sugars and lignocellulosic biomass and considerable amounts of starch, therefore providing a model of carbon allocation and accumulation for other bioenergy crops. While omics data sets for sugar accumulation have been reported in different genotypes, the common features of primary metabolism in sweet genotypes remain unclear. To obtain a cohesive and comparative picture of carbohydrate metabolism between sorghum genotypes, we compared the phenotypes and transcriptome dynamics of sugar-accumulating internodes among three different sweet genotypes (Della, Rio, and SIL-05) and two non-sweet genotypes (BTx406 and R9188).ResultsField experiments showed that Della and Rio had similar dynamics and internode patterns of sugar concentration, albeit distinct other phenotypes. Interestingly, cellulose synthases for primary cell wall and key genes in starch synthesis and degradation were coordinately upregulated in sweet genotypes. Sweet sorghums maintained active monolignol biosynthesis compared to the non-sweet genotypes. Comparative RNA-seq results support the role of candidate Tonoplast Sugar Transporter gene (TST), but not the Sugars Will Eventually be Exported Transporter genes (SWEETs) in the different sugar accumulations between sweet and non-sweet genotypes.ConclusionsComparisons of the expression dynamics of carbon metabolic genes across the RNA-seq data sets identify several candidate genes with contrasting expression patterns between sweet and non-sweet sorghum lines, including genes required for cellulose and monolignol synthesis (CesA, PTAL, and CCR), starch metabolism (AGPase, SS, SBE, and G6P-translocator SbGPT2), and sucrose metabolism and transport (TPP and TST2). The common transcriptome features of primary metabolism identified here suggest the metabolic networks contributing to carbon sink strength in sorghum internodes, prioritize the candidate genes for manipulating carbon allocation with bioenergy purposes, and provide a comparative and cohesive picture of the complexity of carbon sink strength in sorghum stem.

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 °C and 65 °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.

DEVELOPMENT AND ECONOMIC-BIOLOGICAL CHARACTERISTICS SORGHUM-SUDAN HYBRIDS

Due to a high stooling coefficient and good growing after cutting, sorghum can be used in the green conveyor in the summer between the cutting of annual and perennial grasses, in the fall when the growth of perennial grasses stops. Hybridization of Sudan grass with CMS-lines of various sorghum types (grain and sweet), produces highly heterotic sorghum-Sudan hybrids which exceed the parental forms in green mass productivity by 1.5 times or more. The identification of new sorghum-Sudan hybrids with high heterotic effects on productivity of green mass and dry matter with their future introduction into production is an important direction of sorghum breeding. The purpose of this work is to identify the main stages of the development of sorghum-Sudanese hybrids and to estimate indicators of their productivity and quality. The CMS lines of grain and sweet sorghum, highly productive varieties of Sudanese grass and new sorghum-Sudan hybrids are the objects of the study. The initial stage is the selection of parental forms. Highly productive and permanent varieties are of great necessity as pollinators. In our studies, these are the varieties “Svetloplenchataya 1”, “Chernoplenchataya 11” and “Chernoplenchataya 10” with 33–42 t/ha of green mass for 2 cuttings. Due to the more powerful plant development the new sorghum-Sudanese hybrids produce 52–77 t/ha of green mass for 2 cuttings. Genuine heterosis is 22.6–102.6%. During the study there have been identified the hybrids “APV-1115 x Svetloplenchataya 1” and “Zersta 38 x Chernoplenchataya 11”, that combine the maximum values of the productivity of green mass and dry matter.

Heterosis in sweet sorghum

Abstract: The objective of this work was to evaluate the potential per se of male-sterile and fertility-restorer lines of sweet sorghum (Sorghum bicolor), as well as to detail the heterosis manifested for some traits directly or indirectly related to ethanol production, accumulation rate, and predictability. Evaluations were performed for 20 genotypes, of which 4 are fertility-restorer lines (R), 3 are male-sterile lines (A), and 12 are experimental hybrids (H) resulting from the partial diallel cross between lines A and R, besides a commercial hybrid CV198 used as a check, in four harvest seasons. The experiments were carried out in the municipalities of Lavras and Sete Lagoas, in the state of Minas Gerais, Brazil. The measured traits were plant height, green mass production, juice extraction, total soluble solids content, and megagrams of Brix per hectare. The male-sterile A1 and the fertility-restorer R1 and R3 lines show the best potential per se, considering all traits and their accumulation rate and predictability over harvest times. Heterosis is significant for all traits. The H11, H13, H14, H21, H22, and H33 hybrids are promising because of their better performance per se and higher heterosis.

ИЗУЧЕНИЕ СЕЛЕКЦИОННЫХ ЛИНИЙ САХАРНОГО СОРГО ПО КОМПЛЕКСУ ПРИЗНАКОВ В УСЛОВИЯХ НИЖНЕГО ПОВОЛЖЬЯ

Расширение площадей под посев сахарного сорго в Нижнем Поволжье сдерживается отсутствием сортов и гибридов, хорошо адаптированных к условиям региона. С целью изучения исходного материала для создания высокопродуктивных конкурентоспособных сортов в течение трёх лет проводили комплексную оценку 85 селекционных линий сахарного сорго. В качестве стандарта использовали районированный сорт Волжское 51.В результате проведенных исследований установили, что селекционные линии сахарного сорго Л-16, Л-25 и Л-42 можно выделить как скороспелые. Линии Л-84 и Л-115 имели высоту растения в среднем на 12,5% выше, чем сорт Волжское 51. По содержанию жира в зеленой массе селекционные линии достоверно не отличались от сорта-стандарта, за исключением линии Л-8 и Л-115, которые уступили сорту Волжское 51. Линии Л-3, Л-5, Л-8, Л-84 достоверно превысили сорт-стандарт Волжское 51 по процентному содержанию сахара в соке в фазу выметывания.По урожайности зеленой массы линии сахарного сорго Л-3, Л-13, Л-26, Л-60, Л-84, Л-109, Л-115, Л-1106 превысили сорт-стандарт на 16,5-36,4%. По урожайности сухого вещества только линии Л-23 и Л-109 значимо превысили сорт Волжское 51 в среднем на 26,6%. Селекционная линия Л-1898/2 имела значение признака «масса 1000 зерен» на 13,4% выше, чем сорт-стандарт. Все изучаемые линии по урожайности зерна превысили сорт-стандарт в среднем на 50,7%, за исключением линии Л-25, которая не отличалась от стандарта.Таким образом, по результатам научных исследований выявили перспективные линии, которые существенно превысили сорт-стандарт Волжское 51 по комплексу хозяйственно-ценных признаков и свойств. Селекционные линии сахарного сорго: Л-109, Л-1106, Л-1327, Л-1898/2 и Л-84 рекомендованы для дальнейшего испытания. Лучшие селекционные линии целесообразно включить в скрещивания для получения гибридов зернового и кормового сорго.

The Environment Strongly Affects Estimates of Heterosis in Hybrid Sweet Sorghum

Sweet sorghum [Sorghum bicolor (L.) Moench] has potential as a biofuel feedstock, but hybrid cultivars are needed to support an industry based on this crop. The purpose of this study was to compare five inbred sweet sorghum lines and 15 hybrids derived from them and to determine the extent of environmental effects on estimates of hybrid vigor (heterosis) and heritability for various agronomic traits. The test was repeated across 2 years (2013 and 2015) and three planting dates each year (April, May, and June) at Tifton, GA, USA. Environmental conditions were highly variable, and thus, estimates of heterosis for various traits, as well as correlations between hybrids and midparents (average of the inbred parents), were also variable. In the 2015 season, a new insect pest, sugarcane aphid (Melanaphis sacchari Zehntner), appeared to cause reduced juice Brix in the April planting. Hybrids generally flowered earlier than their inbred male-parent lines, and flowering time was highly correlated between midparents and hybrids. Hybrids frequently had greater lodging percentage than inbreds, but lodging was also correlated between midparents and hybrids in four environments. Heterosis for juice Brix and sugar yield was uncommon, while heterosis for panicle (grain) yield was frequently observed. Based on this study, it will be difficult to predict hybrid performance for juice Brix, sugar yield, and panicle yield based on inbred performance. Testing in multiple environments will be essential for the development of sweet sorghum hybrids, and there is a critical need for sweet sorghum cultivars with resistance to sugarcane aphids.

Transcription Profiles of Genes Related to Hormonal Regulations Under Salt Stress in Sweet Sorghum

Sweet sorghum is an annual C4 crop that has high salt tolerance. However, the role of hormones in salt tolerance of sweet sorghum remains unelucidated. In the present study, growth parameters, endogenous hormone concentrations, and transcriptomes of leaves and roots of two inbred lines of sweet sorghum (salt-tolerant M-81E and salt-sensitive Roma) were analyzed under 0 or 150 mM NaCl in order to elucidate hormonal regulation for salt tolerance in sweet sorghum. We found that salt stress inhibited the growth of both genotypes. The concentration of abscisic acid (ABA) changed more significantly in M-81E leaves, and concentration of jasmonate (JA) changed more significantly in Roma roots. While, the concentration of indole-3-acetic acid (IAA) increased in both genotypes, particularly in the leaves. We identified 17 and 15 differentially expressed genes in M-81E between control plants and those subjected to salt stress annotated into pathways of hormone biosynthesis and hormone signal transduction, respectively. In Roma, 16 and 34 differentially expressed genes annotated into pathways of hormone biosynthesis and hormone signal transduction were identified, respectively. Hormone biosynthesis, and signal transduction, may play an important role in regulating the growth and development of sweet sorghum under salt stress. In salt-tolerant inbred line M-81E, ABA may play a key role in salt stress response. In salt-sensitive inbred line Roma, JA may act as the key hormone in response to salt stress. These revealed that hormones are involved in the response of sweet sorghum to salt stress. Furthermore, in different inbred lines, different hormones might play significant roles in regulating the growth and development of sweet sorghum through different regulation pathways.

СЕЛЕКЦИЯ ЗЕРНОКОРМОВЫХ КУЛЬТУР В УСЛОВИЯХ ПОВОЛЖЬЯ

With the aim of creating varieties forage-grain directions for a ten years, conducted a comprehensive assessment of 80 lines of grain sorghum, 55 lines of sweet sorghum, 70 lines of Sudan grass and 15 varieties and lines of foxtail millet. The result of testing new lines of grain sorghum on the complex biological and economic-valuable signs of breeding lines L-211, L-226 and L-355, which on average over the five years exceeded the grade standard at the studied signs. These lines will be submitted for State variety testing. By results of studying breeding material of sweet sorghum 4 identified promising lines which significantly standard cultivar Volzhskoe 51 in the complex of signs and properties. Breeding lines of sweet sorghum: L-109, L-1106 L-1327, L-1898/2 and L-84 were recommended for further evaluation in the competitive variety trial . Long-term study of initial material for breeding Sudan grass allowed identifying promising lines of L-67, L-730 and L-14, which for five years had a high breeding performance. Thus, on the basis of years of scientific research created a unique working collection for breeding crops. All prospective line will be used in the final stages of the selection process, and included in the crossing for obtaining hybrids of grain and forage sorghum. According to the results of selection obtained the copyright certificate and the patent for the cultivar Anastasia foxtail millet and copyright certificate for the grade of the grain sorghum Garant. For State trials in 2015, passed a variety of Sudan grass Eugene.

Response of Sweet Sorghum Lines to Stalk Pathogens Fusarium thapsinum and Macrophomina phaseolina

Sweet sorghum (Sorghum bicolor (L.) Moench) has potential for bioenergy. It is adapted to a variety of U.S. locations and the extracted juice can be directly fermented into ethanol. However, little research on fungal stalk rots, diseases that pose serious constraints for yield and quality of juice and biomass, has been reported. A greenhouse bioassay was designed to assess charcoal rot (Macrophomina phaseolina) and Fusarium stalk rot (Fusarium thapsinum) in plants at maturity, the developmental stage at which these diseases are manifested. Multiple plantings of a susceptible grain line, RTx430, were used as a control for variation in flowering times among sweet sorghum lines. Lesion length measurements in inoculated peduncles were used to quantify disease severity. Sweet sorghum lines 'Rio' and 'M81E' exhibited resistance to F. thapsinum and M. phaseolina, respectively; and, in contrast, 'Colman' sorghum exhibited susceptibility to both pathogens. Lesion development over time in Colman was monitored. These results will enhance molecular and biochemical analyses of responses to pathogens, and breeding stalk-rot-resistant sweet sorghum lines.