Sweet Stalks Research Articles

Sorghum biomass yield and allocation as affected by the combination of photoperiod sensitivity, sweet-stalk and brown midrib traits

Context or problemTraits like photoperiod sensitivity, sweet-stalk and brown midrib (bmr) have been introgressed to increase the biomass yield and quality of sorghum (Sorghum bicolor (L.) Moench) towards bioenergy yield improvement. The effects of combined traits on sorghum performance are far from clear. ObjectivesThe objectives were to investigate the effects of different combinations of photoperiod sensitivity, sweet-stalk and bmr traits on sorghum biomass yield and allocation, and to discuss the implications of such effects on bioenergy production. MethodsData from our own as well as publicly available field trials were analyzed. A corpus of 51 hybrids grown in 49 environments were classified based on photoperiod sensitivity trait (PS or PI for photoperiod sensitive or insensitive), sweet-stalk trait (sweet- and sweet+), and bmr trait (bmr- and bmr+), and differences in the yields of shoot biomass and biomass fractions were determined. Biomass allocation was further evaluated in terms of allometric analysis. ResultsSignificant triple interaction of the effects of the traits on shoot biomass and plant fractions yields were found. In PS-sorghum, bmr decreased shoot biomass only in sweet- genotypes. In PI-sorghum, sweet-stalk trait increased shoot biomass only in bmr- genotypes. In both PS and PI-sorghum, sweet–stalk and bmr traits drove changes in plants’ stem to leaves biomass ratio. In PI-sorghum they also promoted an increase of stem biomass at the expense of panicle biomass. Allometric analysis allowed us to capture different effects of traits on biomass allocation when the yield of biomass shoot changed. ConclusionsInteraction among the effect of traits on shoot biomass yield help to explain discrepancies of biomass yield responses to traits found in the literature. Sweet-stalk and bmr traits produced changes in biomass distribution that depended on plant size, and that ultimately would impact on bioenergy production. Implications or significanceUnraveling the mechanisms underlying biomass and quality changes in response to increasing biomass yield is essential to simultaneously improve bioconversion efficiency and biomass yield. This work provides a starting point for studying the mechanisms behind the effects of combined traits of agronomic interest on biomass yield and allocation of sorghum as an energy crop.

Evaluation of genetic variability for major agro-morphological and stalk sugar traits in African sorghum genotypes

The study aimed to assess one hundred and twelve (112) accessions of sorghum sourced from Nigeria and other four African countries for their genetic variability, heritability (broad sense) and genetic advance components to identify promising accessions with high grain yield and sweet stalk which can serve as future parents for breeding dual-purpose lines. The accessions were evaluated at Ilora, Oyo State, Nigeria in a randomized complete block design (RCBD) layout with three replicates in two planting seasons (2020 and 2021). The results showed that the phenotypic coefficient of variation (PCV) was higher than the genotypic coefficient of variation (GCV). The highest PCV and GCV were grain yield (51.89%) and inflorescence length (42.26%), respectively, while a hundred seed grain weight had the lowest PCV (17.83%) and GCV (21.55%). The range of genetic advance over mean (GAM) was 28.33% for leaf width and 81.62% for inflorescence length. Inflorescence length had the highest values of heritability and GAM (0.88, 81.62%), while a low value was obtained for grain yield (0.27, 29.32%). Twenty-two accessions had higher grain yields than the yields of check varieties. The high-yielding accessions, SG57, SG31, SG06, and SG12 had grain yields of 3.07 t/ha, 2.89 t/ha, 2.76 t/ha and 2.73 t/ha, respectively. Fourteen accessions had wet stalks, of which 12 of the accessions had soluble stalk sugar (Brix) above 12%, which is comparable to the amount found in sweet sorghum. Three accessions with Brix above 12% (SG16, SG31, SG32) and high grain yields (2.32 t/ha, 2.89 t/ha and 2.02 t/ha) were identified as promising accessions. There is considerable genetic diversity among African sorghum accessions in Nigeria's southwest agroecosystem, which should improve food security and breeding potential.

Heritability, genetic advance, and correlation studies of morpho-agronomic traits and brix in Burkina Faso sweet stalk sorghum genotypes

Heritability, genetic advance, and correlation studies of morpho-agronomic traits and brix in Burkina Faso sweet stalk sorghum genotypes

Genetic Relationship between Sweet Grain Sorghum and the Other Sorghum Types Cultivated in Burkina Faso Assessed with Nuclear Microsatellite Markers SSRs

In Burkina Faso, sweet grain sorghum [Sorghum bicolor (L.) Moench] is generally cultivated in association with several other types of sorghum. However, the lack of information on the genetic relationship between this sorghum and grain sorghum as well as sweet stalk sorghum hinders the efficient management of its genetic resources. Thus, 34 sorghum accessions consisting of 14-grain sorghum, 10-sweet stalk sorghum, and 10 sweet grain sorghum were evaluated using 15 nuclear microsatellites markers (SSRs) to determine their genetic relationship. Results revealed significant genetic diversity within each sorghum type and a significant index of genetic differentiation per pair of sorghum types (0.017) between sweet grain sorghum and sweet stalk sorghum. The minimum Nei distance was also high (0.12) between these two sorghum types. Sweet grain sorghum indeed showed the lowest values of theoretical heterozygosity (0.35), of observed heterozygosity (0.13). Structuring of the accessions of the three types of sorghum cultivated in two distinct groups, one of grain sorghum and sweet stalk sorghum and another consisting of accessions of grain sorghum and sweet grain sorghum was also obtained. The low differentiation observed would suggest greater genetic proximity between the three types of sorghum. The differences observed would be more of a physiological and biochemical nature. These results could contribute to better management of the genetic resources of sweet grain sorghum.

Phenotypic variability and correlation estimates for traits of Burkina Faso’ sweet grain sorghum genotypes

Sweet grain sorghum [Sorghum bicolor (L.) Moench] is a neglected crop mainly grown for its sweet grains in the pasty form. Although its taste is the main character of interest, knowledge of protein related content of the grain, especially when linked to its value for infant porridge appears equally important. The objective of this study was to evaluate the status of crude protein content of pasty grains and to determine genetic correlations between morphological and biochemical traits among sweet grain of sorghum genotypes in Burkina Faso. Eight sweet grain sorghum cultivars (BTO2, BZI1, KBZ4, PBO5, PGO3, SBR7, SPI2, STO4) were evaluated through 13 morphological and two biochemical variables. Crude protein content of these genotypes was also compared with the composition of two controls of sweet stalk sorghum (ETS) and ordinary grain sorghum or common sorghum (EBS). The analysis of variance revealed variability within sweet grain sorghum accessions, mainly on the biochemical traits (crude protein and water content) and two morphological traits (peduncle and panicle lengths), which discriminated significantly in the thresholds of 1 and 5%, respectively. In addition, sweet grain sorghum had low crude protein content compared to other types of sorghum, except, two genotypes of sweet grain sorghum (BZI1 and STO4) which recorded higher protein content compared to the common sorghum. An important and negative correlation was noted between sowing-flowering cycle and protein content.

Varieties of sweet sorghum Super-1 and Super-2 and its equipment for bioethanol in Indonesia

The demands for alternative sources of energy are currently growing because people now are more aware of the many negative impacts fossil fuel gives to the environment. Plant based renewable energy provides potential sources of energy with advantages of cleaner fuel effect and capability of integration with food crop production. Sorghum have been considered to be a highly potential source of food, feed and fuel, especially sweet stalk sorghum that posses both functions as source of food from its grain and fuel made from its stalk juice. Sorghum varieties are well known to have excellent adaptability in marginal areas, especially drought prone areas where other food crops are unable to thrive. The current paper aimed to share ongoing research on many functional uses of sweet stalk sorghum varieties released at Indonesian Cereals Research Institute (ICERI). Among many varieties that had been released were two sweet stalk sorghum varieties SUPER-1 and SUPER-2 released in 2013 that stands out in biomass yield and bioethanol production. Based on various researches conducted at different location and planting season, yield potential of biomass ranged at 30 - 40 t/ha with higher yield occurred during dry season. Stalk juice sugar content in brix were found to be higher in dry season ranged at 13.6 % to 18.4 %, and the amount of juice stalk was obtained at about 30–50 % from total biomass yield. Furthermore, bioethanol production from stalk juice after fermentation was at the range of 8 to 10 % from total stalk juice volume. Modification of processing equipment of bioethanol have also been carried out and was able to increased the concentration of ethanol being distilled from 85% -92% to 90% -95%. Another result obtained was able to decreased fermentation time from 14–21 days to 6–10 days. Furthermore, the yield of ethanol from juice was also from an average of 4.95% to 6.75%.

Recent Advances in Sorghum Genetic Enhancement Research at ICRISAT

Sorghum is one of the most important cereal crops widely grown for food, feed, fodder/forage, and fuel in the semi-arid tropics of Asia, Africa, the Americas and Australia. The global sorghum areas remained static as the increased area in Africa compensated the area loss in Asia. In spite of rapid decline in sorghum area in Asia due to competition from other remunerative crops, sorghum grain production levels have not declined at the same rate owing to adoption of high yielding hybrids. Though impressive gains have been made in improving productivity levels, biotic and abiotic challenges such as shoot fly, stem borer, grain molds, and terminal drought stress continue to haunt the sorghum growers across the world. International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and the respec-tive national programs are working on genetic enhancement of sorghum for high yield; shoot fly, and grain mold resis-tance, and sweet stalk traits. In addition, research focus at ICRISAT also includes adaptation to postrainy season, ter-minal drought tolerance, and increasing micronutrient contents (Fe and Zn) in grain. Genetic and cytoplasmic diversi-fication of hybrid parents and varieties for key traits are critical for sustaining the productivity gains. The grain and stover quality requirements of different market segments needs special attention in sorghum improvement research to enhance its market value. This paper analyses the progress made in sorghum improvement research at ICRISAT in partnership with national programs in recent years and the way forward.

Inheritance of sugar concentration in stalk (brix), sucrose content, stalk and juice yield in sorghum

Sweet sorghum is gaining importance as a raw material for ethanol production. Information on genetics of sugar content in stalk is required to facilitate the breeding of cultivars with high ethanol yield. Generation mean analysis and frequency distribution studies were carried out in crosses 27 B × kellar, and 27 B × BJ 204 for sweet stalk during 2006 and 2007. Kellar (a US sweet sorghum line) and BJ 204 (a Chinese line) are high brix (sweet stalk) lines. The traits studied were: brix, sucrose, stalk, and juice yield and plant height. The mean performance of families showed that the F 1 in crosses for high brix and sucrose percentage were tending towards P 2 (higher sugar percentage parent) implying these traits to be dominant for higher brix and sucrose content. However, the mean values of F 1 for stalk and juice yields and plant height showed over-dominance for the traits. Frequency distribution of F 2 showed that brix and sucrose percentage are polygenic traits, and stalk and juice yields are oligogenic traits. Generation mean analysis showed that both additive and dominant gene actions for traits, sucrose and brix in stalk juice were significant. Since the plant traits important for high stalk sugar percentage show dominance and over-dominance inheritance, hybrid breeding will be useful. Selection for pure lines with high brix is to be practised in later generations.

Evaluation of agronomic and energy traits of Wray sweet sorghum and the N39 × Wray hybrid

Recent emphasis on energy problems has stimulated efforts to identify crops capable of producing high yields of biomass that can be converted into ethanol. The sorghum [ Sorghum bicolor (L.) Moench] crop includes cultivars and hybrids that vary widely in the relative amounts of grain and stalks produced, and also in the sugar content of the stalks. N39 × Wray, a relatively sweet hybrid with good grain potential, and Wray, a cultivar with sweet stalks, were compared for their grain and sugar yields, alcohol production potential, and other related characters. The hybrid produced heavier seeds, more seeds per head, and more heads per ha than the Wray. This resulted in a grain yield of 6630 kg/ha, about 3.4 times that of Wray. Wray produced about 10% more biomass with the stalk sugars accounting for about 80% of the total alcohol potential as compared to 45% for the hybrid. The total alcohol production potential (stalk plus grain) was 1.11 times as great for the hybrid as for Wray.

Sugar distribution in sweet stalk sorghum

Among the seventeen cultures of sweet stalk sorghum screened for their juice and sugar content at two different stages, IS 9889 contained the highest percentage of total sugars. Sugar content was found to increase from the soft dough stage to the dead ripe stage. Analysis of the internodes revealed that the midportions of the stalk contained higher amounts of sugars than the other parts.