Ten Holstein cows in midlactation were used in a 5 x 5 replicated Latin square design with 21-d periods to determine the effects of feeding ground or steam-flaked broom sorghum (Sorghum bicolor) and ground barley (Hordeum vulgare L.) on lactation performance and nutrient digestibility. Diets were fed as total mixed ration and consisted of 46% forage and 54% concentrate (DM basis). Treatment diets included ground barley, ground barley plus ground broom sorghum, ground broom sorghum, ground barley plus steam-flaked broom sorghum, and steam-flaked broom sorghum. Yield of fat-corrected milk was 2.3 kg greater for cows fed diets containing steam-flaked broom sorghum than for cows fed its ground form (24.4 vs 22.1 kg) and was 2.8 kg greater for cows fed diets containing a blend of steam-flaked broom sorghum plus ground barley than for cows fed ground sorghum (24.9 vs 22.1 kg). Yields and percentages of milk fat, protein, SNF, total solids, and apparent digestibility of crude protein were greater for cows fed steam-flaked broom sorghum and ground barley vs. ground broom sorghum. Including steam-flaked rather than ground broom sorghum in diets significantly increased fecal pH (7.10 vs 6.87) and improved efficiency of feed conversion (1.26 vs 1.15). Feeding steam-flaked broom sorghum alone or with ground barley compared with ground sorghum or the blend of ground barley and ground broom sorghum decreased plasma urea nitrogen increased glucose in plasma. Results of this study showed that feeding steam-flaked broom sorghum compared with ground broom sorghum could supply a more efficient source of energy for lactating cows.

Sorghum Improvement Conference of North America, Lubbock, USA, International Sorghum and Millets Newsletter 45:5-12. This paper covers goals, strategies and methods for sorghum breeding and improvement. Some improved sorghum cultivars and elite hybrid parents with resistance to Striga sp., grain mould, shoot fly (Atherigona soccata), stem borer (Chilo partellus) and midge (Stenodiplosis sorghicola), and soil mineral toxicity are described. Improved sweet-stalked and forage sorghum are also described. The adoption and impact of improved sorghum cultivars along with the natural resources management technologies, as well as the cost:benefit ratio of improved sorghum cultivar production are discussed. Innovations in science, technology sharing, publications and capacity building that would improve the efficiency of sorghum improvement programmes are presented.

As part of a comparative mapping study between sugarcane and sorghum, a sugarcane cDNA clone with homology to the maize Rp1-D rust resistance gene was mapped in sorghum. The cDNA probe hybridised to multiple loci, including one on sorghum linkage group (LG) E in a region where a major rust resistance QTL had been previously mapped. Partial sorghum Rp1-D homologues were isolated from genomic DNA of rust-resistant and -susceptible progeny selected from a sorghum mapping population. Sequencing of the Rp1-D homologues revealed five discrete sequence classes: three from resistant progeny and two from susceptible progeny. PCR primers specific to each sequence class were used to amplify products from the progeny and confirmed that the five sequence classes mapped to the same locus on LG E. Cluster analysis of these sorghum sequences and available sugarcane, maize and sorghum Rp1-D homologue sequences showed that the maize Rp1-D sequence and the partial sugarcane Rp1-D homologue were clustered with one of the sorghum resistant progeny sequence classes, while previously published sorghum Rp1-D homologue sequences clustered with the susceptible progeny sequence classes. Full-length sequence information was obtained for one member of a resistant progeny sequence class ( Rp1-SO) and compared with the maize Rp1-D sequence and a previously identified sorghum Rp1 homologue ( Rph1-2). There was considerable similarity between the two sorghum sequences and less similarity between the sorghum and maize sequences. These results suggest a conservation of function and gene sequence homology at the Rp1 loci of maize and sorghum and provide a basis for convenient PCR-based screening tools for putative rust resistance alleles in sorghum.

As part of a comparative mapping study between sugarcane and sorghum, a sugarcane cDNA clone with homology to the maize Rp1-D rust resistance gene was mapped in sorghum. The cDNA probe hybridised to multiple loci, including one on sorghum linkage group (LG) E in a region where a major rust resistance QTL had been previously mapped. Partial sorghum Rp1-D homologues were isolated from genomic DNA of rust-resistant and -susceptible progeny selected from a sorghum mapping population. Sequencing of the Rp1-D homologues revealed five discrete sequence classes: three from resistant progeny and two from susceptible progeny. PCR primers specific to each sequence class were used to amplify products from the progeny and confirmed that the five sequence classes mapped to the same locus on LG E. Cluster analysis of these sorghum sequences and available sugarcane, maize and sorghum Rp1-D homologue sequences showed that the maize Rp1-D sequence and the partial sugarcane Rp1-D homologue were clustered with one of the sorghum resistant progeny sequence classes, while previously published sorghum Rp1-D homologue sequences clustered with the susceptible progeny sequence classes. Full-length sequence information was obtained for one member of a resistant progeny sequence class (Rp1-SO) and compared with the maize Rp1-D sequence and a previously identified sorghum Rp1 homologue (Rph1-2). There was considerable similarity between the two sorghum sequences and less similarity between the sorghum and maize sequences. These results suggest a conservation of function and gene sequence homology at the Rp1 loci of maize and sorghum and provide a basis for convenient PCR-based screening tools for putative rust resistance alleles in sorghum.

Total mixed rations containing conventional forage sorghum, brown midrib (bmr)-6 forage sorghum, bmr-18 forage sorghum, or corn silage were fed to Holstein dairy cows to determine the effect on lactation, ruminal fermentation, and total tract nutrient digestion. Sixteen multiparous cows (4 ruminally fistulated; 124 d in milk) were assigned to 1 of 4 diets in a replicated Latin square design with 4-wk periods (21-d adaptation and 7 d of collection). Diets consisted of 40% test silage, 10% alfalfa silage, and 50% concentrate mix (dry basis). Acid detergent lignin concentration was reduced by 21 and 13%, respectively, for the bmr-6 and bmr-18 sorghum silages when compared with the conventional sorghum. Dry matter intake was not affected by diet. Production of 4% fat-corrected milk was greatest for cows fed bmr-6 (33.7 kg/d) and corn silage (33.3 kg/d), was least for cows fed the conventional sorghum (29.1 kg/d), and was intermediate for cows fed the bmr-18 sorghum (31.2 kg/d), which did not differ from any other diet. Total tract neutral detergent fiber (NDF) digestibility was greatest for the bmr-6 sorghum (54.4%) and corn silage (54.1%) diets and was lower for the conventional (40.8%) and bmr-18 sorghum (47.9%) diets. In situ extent of NDF digestion was greatest for the bmr-6 sorghum (76.4%) and corn silage (79.0%) diets, least for the conventional sorghum diet (70.4%), and intermediate for the bmr-18 sorghum silage diet (73.1%), which was not different from the other diets. Results of this study indicate that the bmr-6 sorghum hybrid outperformed the conventional sorghum hybrid; the bmr-18 sorghum was intermediate between conventional and bmr-6 in most cases. Additionally, the bmr-6 hybrid resulted in lactational performance equivalent to the corn hybrid used in this study. There are important compositional differences among bmr forage sorghum hybrids that need to be characterized to predict animal response accurately.

A field experiment was conducted during the rainy season of 2000 and 2001 on deep Vertisols of Bhopal, to study the effect of soybean [Glycine max (L.) Merr.] and sorghum [Sorghum bicolor (L.) Moench] intercropping (2:1 row ratio) in comparison to their sole crops at 3 levels of nitrogen (0, 75 and 100 percent recommended dose). Sole sorghum recorded higher seed, straw and soybean-equivalent yield (SEY) compared to either sole soybean or soybean + sorghum intercropping. However at No' soybean + sorghum intercropping resulted in higher SEY and at higher N status (75 or 100 percent), sole sorghum resulted in higher SEY. Nitrogen-uptakeiNas higher in sole soybean, whereas P and K uptake were higher in sole sorghum. Sole sorghum recorded higher nutrientuse efficiency (NUE), whereas sole soybean resulted in iower NUE. However, nutrient harvest index of NPK were higher in sole soybean and lowest in sole sorghum. Increased N levels significantly improved the SEY, nutrient uptake and agronomic and recovery efficiency of NPK. However, physiological efficiency and nutrient harvest index of NPK were not affected due to increased N levels.

The objectives of this study were to determine the genetic diversity of Japanese cultivated sorghum (sorghum lines cultivated in Japan), using the simple sequence repeats (SSR) technology and to determine the diversity of sorghum breeding germplasm accessions and their relationship with Japanese cultivated sorghum. The cluster analysis of SSR data showed that Japanese cultivated sorghum showed a wide genetic background, but the lines from the same breeding station tended to have a close genetic background. Sorghum breeding germplasm accessions that included lines from ICRISAT, U.S.A., Japan, and improved lines (elite inbred lines) showed a narrower genetic background than Japanese cultivated sorghum and were distinctly separated from them. An efficient method of using germplasm as a genetic resource is proposed.

Australian species make up seventeen of the world’s twenty-five recognised species of Sorghum, with the genus separated into five sections: Eu-sorghum, Chaetosorghum, Heterosorghum, Para-sorghum and Stiposorghum. Whereas the genetic relationships within section Eu-sorghum are well known, little is known about the genetic relationships and crossabilities outside the primary genepool. We made a detailed investigation of phylogenetic relationships within Sorghum to identify wild species most closely related to cultivated sorghum (with outgroups Zea mays and Saccharum officinarum). The ribosomal ITS1 gene of ten species and the chloroplast ndhF gene from nineteen species were sequenced. Independent and combined analyses of the ITS1 and ndhF data sets were undertaken. The Eu-sorghum species were resolved into a strongly supported lineage by all three analyses, and included the Australian natives S. laxiflorum and S. macrospermum in the ITS1 and combined analyses. All remaining sorghum species were resolved into a second well-supported lineage in the combined analyses, although some internal relationships within this second lineage remain unresolved. We identified S. laxiflorum and S. macrospermum as the Australian species most closely related to cultivated sorghum. Our data support a reduction in the number of subgeneric sections from five to three: Eu-sorghum (unchanged); a combined Chaetosorghum/Heterosorghum to reflect the very close relationship between these two species; and a combined Para-sorghum/Stiposorghum section, thereby removing the unclear taxonomic and genetic boundaries between these species.

Sorghum (Sorghum bicolor (L.) Moench) and sorghum-sudangrass (S. bicolor x S. sudanense (Piper) Stapf) are often used in crop rotation systems in Florida. Not only do they produce a source of forage or silage for animal feed, but many cultivars are effective in reducing population levels of root-knot nematodes, which are key nematode pests in Florida as well as many other parts of the world. Sorghum-sudangrass (S. bicolor x S. sudanense), also known as sorghum x sudangrass, sudax, or sudex, is a hybrid between sorghum (S. bicolor) and sudangrass (S. sudanense). Specific cultivars of either sorghum, sudangrass, or sudex provide a potential for nematode management, with the hybrid having more advantages over either one of its parents. This document is ENY-716, one of a series of the Department of Entomology and Nematology, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Date first printed: September 2004.  ENY716/IN531: Nematode Management Using Sorghum and Its Relatives (ufl.edu)