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United States Department of Agriculture

Agricultural Research Service

Research Project: SUSTAINING RURAL ECONOMIES THROUGH NEW WATER MANAGEMENT TECHNOLOGIES Title: Comparison of sorghum classes for forage and grain yield, forage nutritive value, agronomic characteristics, nutrient composition, and fiber digestibility

Authors
item Bean, Brent -
item Mccollum, F. -
item Baumhardt, Roland
item Mccuistion, Kim -

Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 20, 2012
Publication Date: N/A

Interpretive Summary: Sorghum is a broad category of plants grown for forage (FS) or grain and includes sorghum sudan crosses (SS). These can be subdivided into brown midrib (BMR), nonBMR, photoperiod sensitive (PS), and nonPS groups. In our study, multiple cultivars of these sorghum classes were compared based on forage and grain yield, nutrient composition, fiber digestibility, and plant traits like height, lodging, and moisture at harvest. Although some overlap between cultivars of different sorghum classes was detected, clear yield and forage quality tendencies were observed between sorghum classes. The SS-PS class had the highest forage yield of all classes, and the nonBMR classes consistently yielded more than those with the BMR trait. Grain yield varied greatly among the FS and FS-BMR cultivars, with some FS cultivars yielding as much as those in the grain class. Sorghum classes with the BMR trait consistently had the lowest acid detergent fiber (ADF), neutral detergent fiber (NDF), and were lower in lignin content. The BMR trait increased digestibility of the NDF fraction (NDFD). In-vitro-true-digestibility (IVTD) was highest with FS-BMR and grain sorghum classes followed by the FS, FS-PS-BMR, and SS classes. The SS-PS consistently had the lowest IVTD. Very little correlation occurred between grain yield and IVTD. Lodging was not increased in BMR cultivars compared to the nonBMR cultivars when harvested at the soft-dough stage. There was little correlation between lodging and lignin content, grain yield, or plant height.

Technical Abstract: Sorghum represents a broad category of plants that includes those grown primarily for forage (FS) or grain. Sorghum sudan crosses (SS) are also considered sorghum. Each of these groups can be further classified as brown midrib (BMR), nonBMR, photoperiod sensitive (PS), and nonPS. In our study, sorghum classes representing multiple cultivars were compared for forage and grain yield, agronomic characteristics (i.e. height, lodging, moisture at harvest), nutrient composition, and fiber digestibility. Although some overlap between cultivars of different sorghum classes was detected, clear tendencies in yield and forage quality characteristics between sorghum classes were observed. The SS-PS class had the highest forage yield of all classes, and the nonBMR classes consistently yielded more than those with the BMR trait. Grain yield varied greatly among the FS and FS-BMR cultivars, with some FS cultivars yielding as much as those in the grain class. Those sorghum classes with the BMR trait consistently had the lowest acid detergent fiber (ADF) and neutral detergent fiber (NDF), and as expected were lower in lignin content. The BMR trait also increased digestibility of the NDF fraction (NDFD). In-vitro-true-digestibility (IVTD) was highest with FS-BMR and grain sorghum (Grain) classes followed by the FS, FS-PS-BMR, and SS classes. The SS-PS consistently had the lowest IVTD. Very little correlation was present between grain yield and IVTD. Lodging was not increased in BMR cultivars compared to the nonBMR cultivars when harvested at the soft-dough stage. There was little correlation between lodging and lignin content, grain yield, or plant height.

Last Modified: 11/27/2014
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