No abstract

Field studies were conducted at the USDA-ARS Sugarcane Research Laboratory in southeast Louisiana to evaluate the ethanol yield potential of five sweet sorghums (Dale, M81-E, Rio, Theis, and Topper) and two nonflowering sorghum × sudangrass forage hybrids (MMR 333/27 and MMR 333/47). The sorghums were planted in the spring and harvested at 85, 101, 119, and 138 days after planting (DAP). Theoretical sugar-based ethanol yield increased for the sweet sorghums (except Rio) from 85 through 119 days, but did not significantly increase further at 138 days. The forage sorghums did not show a similar increase, though the theoretical sugar-based ethanol yield of MMR 333/47 at 138 DAP was greater than at 85 DAP. Conversely, theoretical fiber-based ethanol yields increased two-fold in the two forage sorghums from 85 to 138 DAP; a significant increase in fiber-based ethanol yield was not observed in any of the sweet sorghums over the same period. At 138 DAP, sugar-based ethanol yield of Theis (6,060 L ha −1 ), was greater than that of Rio or either of the two forage hybrids. Fiber-based ethanol yield of MMR 333/ 47 (8,860 L ha −1 ) was greater than that of any other variety in the test. Theoretical ethanol yield from hexose sugar and fiber components averaged across varieties was 6,500, 7,720, 9,100, and 10,810 L ha −1 at 85, 101, 119 and 138 DAP, respectively. As a complementary crop for Louisiana's sugarcane growers, sorghum would need to be harvested not later than 120 DAP so as to not interfere with the planting of sugarcane in these fields. Both Theis and MMR 333/47 produced greater than 11,000 L ha −1 combined theoretical ethanol at 119 DAP, Theis, equally from sugar and fiber, MMR 333/47 about two-thirds from fiber. Choice of sorghum type would depend on the conversion process(s) being used at the biorefinery.

PI 665695) sugarcane (a complex hybrid of S. officinarum L., S. spontaneum L., S. barberi Jeswiet, and S. sinese Roxb. Amend. Jeswiet) was released by the USDA-ARS Sugarcane Research Unit working cooperatively with the Louisiana State University Agricultural Center and the American Sugarcane League of the USA. This high-fiber sugarcane cultivar was released for use as a biofuel feedstock to fill the rising industry demand. Ho 02-113 is a progeny of the cross SES 234 × 'LCP 85-384' made in Houma, LA in 2001. The cultivar was selected at the USDA-ARS research farm in Schriever, LA, evaluated in multiple locations, and harvested from six southern Louisiana locations in six plant-cane, two first-ratoon, two second-ratoon, and two third-ratoon replicated tests. Ho 02-113 averaged 125.3 Mg ha −1 total cane (TC) on a wet-weight basis, 12.8 Mg ha −1 total soluble solids (TSS), 32.8 Mg ha −1 total fiber (TF), and 45.3 Mg ha −1 total fiber and soluble solids (TFSS). These values were significantly higher than those for the leading high-fiber sugarcane cultivar L 79-1002, which averaged 102.7 Mg ha −1 TC, 9.6 Mg ha −1 TSS, 27.8 Mg ha −1 TF, and 37.4 Mg ha −1 TFSS. The cultivar is resistant to leaf scald [caused by Xanthomonas albilinenas (Ashby) Dawson] and smut (caused by Ustilago scitaminea H. and P. Sydow) in inoculated tests and showed no symptoms either of brown rust (caused by Puccinia melanocephala H. and P. Sydow) or mosaic (caused by either Sugarcane mosaic virus or Sorghum mosaic virus) when exposed to high levels of natural inoculums.

‘Ho 00‐961’ (Reg. No. CV‐146, PI 659769) sugarcane (a complex hybrid of Saccharum officinarum L., S. spontaneum L., S. barberi Jeswiet, and S. sinense Roxb. amend. Jeswiet) was selected by the USDA‐ARS Sugarcane Research Unit and evaluated cooperatively with the Louisiana State University Agricultural Center and the American Sugar Cane League, Inc. Ho 00‐961 is a progeny of the cross US 94‐1 × ‘HoCP 91‐552’ made in 1995 and selected in the first‐ratoon seedling crop in 1997. Ho 00‐961 is being released as a cultivar with moderately high fiber content, moderately high sugar content, and high total cane yield—important traits for sugarcane to be grown as a biofuel feedstock. In 12 harvested evaluations, Ho 00‐961 had an overall mean Brix value of 141 g kg−1 versus 146 g kg−1 for the cultivar standard ‘LCP 85‐384’. The mean fiber content (stalks processed with tops and leaves) for Ho 00‐961 was 186 g kg−1, compared with a fiber content of 164 g kg−1 for the cultivar LCP 85‐384. Finally, Ho 00‐961 had a total cane yield 14% greater than that of LCP 85‐834. Ho 00‐961 appears resistant to mosaic (caused by Sugarcane mosaic virus and Sorghum mosaic virus), brown rust (caused by Puccinia melanocephala H. and P. Sydow), and leaf scald [caused by Xanthomonas albilineans (Ashby) Dowson]. Although natural infection of smut (caused by Ustilago scitaminea H. and P. Sydow) was not observed in yield evaluations, Ho 00‐961 was susceptible under artificial inoculation. Ho 00‐961 is also resistant to the sugarcane borer (Diatraea saccharalis F.).

H oCP PI 659990) sugarcane is a complex hybrid whose genomic makeup consists largely of genes contributed by S. offi cinarum L. and S. spontaneum L. with minor input from S. barberi Jeswiet and S. sinense Roxb. amend. Jeswiet. Modern sugarcane cultivars such as HoCP 91-552 are allopolyploid (and often aneuploid) hybrid derivatives of a few progeny populations developed by crossing S. offi cinarum by S. spontaneum and