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Sorghum X almum Parodi

Hybrid between Sorghum halepense x S. bicolor
Poaceae
Five-year sorghum, Almum, Sorghum, Columbus grass

Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.

  1. Uses
  2. Folk Medicine
  3. Chemistry
  4. Toxicity
  5. Description
  6. Germplasm
  7. Distribution
  8. Ecology
  9. Cultivation
  10. Harvesting
  11. Yields and Economics
  12. Energy
  13. Biotic Factors
  14. References

Uses

Cultivated for its high yields of palatable herbage for silage, hay, and grazing. Better adapted to rotational grazing as it ts sensitive to trampling. In Argentina, where it was first developed, it is used almost exclusively for grazing. Good silage can be ensiled from material at least 9–11 weeks old and not moistened by rain. Very palatable and nutritive when young, less so when mature. HCN content about equal to that of johnsongrass, which it resembles but is coarser and taller growing with large stems and leaves. Clark concluded the species had some technological potential for pulping in the US, the fibers running 0.8–1.8 mm long, 8–16 microns wide, the lumen ca 6 microns wide, the cell wall 3–4 microns thick. Russians report a new food dye from sorghum, 1 kg yielding 17–40 g flavonoid dye (cyanidin, quercitrin, pelargonidin) (Olifson et al, 1978). The dye was suggested useful in the food industry for confectioner's cream products, caramels, and fruit starch jellies.

Folk Medicine

Columbus grass probably shares folk medicinal attributes of sorghum, reported to be antiabortive, demulcent, diuretic, emollient, and used as a folk remedy for abortion, epilepsy, flux, and stomachache (Duke and Wain, 1981).

Chemistry

DM content varied from 16% at 4 weeks old to 23.9% at 8 weeks. The CP content varied from 7.8–11.3%, CF from 29.4–36.6%, ash 7.3–9.7%, EE 2.6–3.8, NFE 45.2–48.2% in Thai material 4–8 weeks old (Gohl, 1981). Grown near Brisbane, Australia, 4 week old material, yielding 2,680 kg DM, contained on a dry weight basis, 3.3% N and 7.3% ethanol extractable sugar, grading down at 9 weeks with yields of 13 MT to 1.6% N and 5.0% ethanol extractable sugar (Catchpoole, 1972). Clark (1965), evaluating the species as a fiber source, notes that there is a crude cellulose content of 38–55%, a-cellulose of 22–36%.

Toxicity

There is possibility of cyanide poisoning if grazed too young. Deficiencies of P in the soil may amplify HCN production in young herbage (Bogdan, 1977), as might excessive N-fertilization. The food dye (containing cyanidin, quercitrin, and pelargonidin, fed to experimental animals for 6 months, produced no morphological changes in liver, kidney, thyroid, and pancreatic glands, and did not affect hepatic glycogen levels (Olifson et al, 1978).

Description

Tall, robust perennial tetraploid, spreading by short stout rhizomes; culms normally about 2 m tall, sometimes up to 4.5 m tall; leaves resembling those of johnsongrass but wider, waxy, 30–100 cm long, 5–4 cm broad; heads longer, lax, more spreading with more branches at whorl than in johnsongrass; the panicle 3–10 cm wide; articulation of pedicelled spikelet breaking off at maturity with the uppermost portion of the pedicel; seed slightly larger than in johnsongrass, brown, ovate, 3.3–4 mm long, 2–2.3 mm broad (115,000–170,000 kg).

Germplasm

Reported from the South American Center of Diversity, Columbus grass, or cvs thereof, is reported to tolerate drought, high pH, laterite, poor soil, salt, virus, and weeds. Though slightly drought- and salt-resistant, it is susceptible to frost, and not resistant to grazing. Established plants do not tolerate waterlogging for long or flooding. Columbus grass is predominantly cross Pollinated with a certain degree of variability. It hybridizes easily with Johnsongrass as well as diploid fodder and grain sorghums and with Sudan grass, also a diploid, but such crosses occur naturally much less frequently. Progenies of these crosses can be either tetraploids or triploids. The former can contain male-sterile plants and be of value for breeding of S. almum and other types of sorghum. The triploids are sterile and may have longer, stronger rhizomes, more difficult to eradicate. Triploid seeds present an undesirable admixture to S. almum seed. Sorghum almum has been used in breeding grain and fodder sorghums for developing tetraploid forms or for creating perennial types in annual fodder sorghums. When breeding for the improvement of S. almum, apart from common general objectives, high yields, high herbage quality, drought resistance, etc., a special objective can be the uniformity of seed color distinctive from that of S. halepense seed. Obtaining low-HCN cultivars is another important, feasible objective (Bogdan, 1977). Parodi recognized var. almum with spikelets 5.5–7 mm long and awn to 1 cm long and var. parvispiculum Parodi with spikelets 4.5–6 mm long, and with no or short awn, and smaller plants in general (Bogdan, 1977). (2n = 40; 8x.40.)

Distribution

Native to Argentina, where first collected in 1936. Introduced and widely cultivated in South Africa, Australia, and New Zealand, from all of which sources, lots have been introduced to the United States. Major sources of seed lots traced to Australia and New Zealand. It has been successful in Canada and Russia.

Ecology

Ranging from Cool Temperate Steppe to Wet through Subtropical Very Dry to Dry Forest Life Zones, Columbus grass is reported to tolerate annual precipitation of 3.1 to 21.4 dm (mean of 13 cases = 10.4), annual temperature of 8.4 to 23.5°C (mean of 13 cases = 19.0), and pH of 5.0 to 8.2 (mean of 12 cases = 6.5). In Georgia it survived winter temperatures down to -15°C. Adapted to subtropical and tropical summer-rainfall climate. Thrives on a wide variety of soil types, grows equally well under a wide variety of ecological conditions, particularly suited to areas of lower rainfall. Extremely drought resistant, and does well in drier areas with as little as 20 cm rainfall annually. Normally grows well in areas with 45–63 cm annual rainfall. Good results obtained in New South Wales in both dryland and irrigated conditions.

Cultivation

Seed production is good, and crop can be established easily and rapidly by broadcasting seed or by sowing seed with grain drill at rate of 12–14 kg/ha, or planted in rows 90–100 cm apart at rate of 5–7 kg/ha (as in South Africa). In Argentina, broadcast seed rates of 25 kg/ha are recommended. It has been successfully direct-seeded into the ashes of burned brigalow in Australia. Grows rapidly under favorable moisture conditions. Roots are fairly easily killed by plowing during dry period; therefore quite suitable for an arable rotation. Fertilizer recommended: 20–30 kg/ha P2O5 and 30–40 kg/ha N. In South Africa this species must be separated by at least 720 m from other sorghums for seed production.

Harvesting

Stands normally persist for 5–6 years. As seed shatter very readily, they are harvested by hand or by combine and threshed by ordinary type drum. For hay and silage, top-growth is cut down before frost; regrowth from rhizomes begins in spring. Plants produce shorter rhizomes that are not as aggressive and extensive as those of johnsongrass. Easily eradicated when necessary by plowing out.

Yields and Economics

Average seed yields are 250–1000 kg/ha, but yields up to 1500 kg/ha are reported (Bogdan, 1977). Forage yields are equal to or slightly greater than those of johnsongrass (Reed, 1976). Widely grown in Argentina for grazing and silage. Although it has been popular in Australia, sale of seed in Queensland is forbidden due to danger of HCN poisoning; in other countries where the grass is cultivated, it appears to be no more likely to cause poisoning than sudangrass or other grain sorghums grown for fodder. Valued for its good seed production, ease of establishment, drought and salt resistance and reasonably high yields (Gohl, 1981).

Energy

According to the phytomass files (Duke, 1981b), annual productivity ranges from 4 to 55 MT/ha, with 4–8 reported in South Africa, 11–14 in Australia, 15 in Canada, 19 in Texas, and 55 in Pakistan. Energy output:input ratios may be fairly similar to those by Bukantis (1980) for Sorghum bicolor, with ratios ranging from ca 1 using draft animals in Nigeria to 1.5:1 for irrigated sorghum in Texas, 3:1 for rainfed sorghum in Texas to 37:1 for manual labor in Sudan. (Does this suggest that manual labor might make sense in energy-poor third world countries?)

Biotic Factors

Qureshi and Hussain (1980) demonstrated that S. almum decreased the growth of associated Pennisetum americanum and Setaria italica. Root and rhizosphere extracts showed phytotoxicity to several species while shoot extracts reduced germination, biomass and survival. The following fungi have been reported on this sorghum: Cerebella andropogonis, Helminthosporium turcicum, Puccinia purpurea, and Ramulispora sorghi. It is also attacked by the bacteria Pseudomonas andropogonis and Xanthomonas holsocala. Nematodes known to attack this sorghum include Meloidogyne incognita acrita and M. javanica.

References

Complete list of references for Duke, Handbook of Energy Crops
Last update Friday, January 9, 1998 by aw