Submitted to: Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 2/19/2005
Publication Date: 7/5/2005
Citation: Hooks, T., Pedersen, J.F., Marx, D.B. 2005. Variation in the u.s. photoperiod-insensitive sorghum collection for chemical and nutritional traits. Meeting Proceedings of 24th Biennial Grain Sorghum Research and Utilization Conference, Feb. 19-22, 2005; Reno, NV. Interpretive Summary:
Technical Abstract: Screening germplasm for chemical and nutritional content can be expensive and time consuming. Near Infrared Spectroscopy (NIRS) and application of geostatistical models can make screening more efficient. The objectives of this study were to utilize these two technologies to: 1) generate chemical and nutritional values for the U.S. photoperiod insensitive sorghum [Sorghum bicolor (L.) Moench] collection, 2) describe variability for those traits, 3) select accessions in the highest 1% and lowest 1% for each trait, and 4) describe relationships among the accessions. Accessions from the U.S. photoperiod insensitive sorghum collection were grown and seed produced at Ithaca, NE, during 2001 and 2002 in non-replicated single-row plots. Samples were scanned on a NIRS spectrometer and equations developed for starch, fat, crude protein, acid detergent fiber, phosphorous, total digestible nutrients, metabolizable energy, net energy gain, net energy maintenance, and net energy lactation. The NIRS generated values for each accession can be accessed in GRIN at http://www.ars-grin.gov/cgi-bin/npgs/html/desclist.pl?69. The highest and lowest 1% of accessions were identified for each trait using best linear unbiased predictors (BLUPs). Means and standard deviations for observed values and variances due to accessions were calculated. Rank correlations of selections based on BLUPs and observed values ranged from r=0.77 to r=0.98. Principal component analysis showed that much of the total variation among the accessions is attributable to a contrast of starch with a weighted average of fat, crude protein, acid detergent fiber, and phosphorus. Cluster analyses showed clear separation of clusters based on canonical values, but no geographical or sociological interpretation of the clusters was apparent.