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ARS Home » Plains Area » Lincoln, Nebraska » Wheat, Sorghum and Forage Research » Research » Publications at this Location » Publication #306414
Title: Yield and forage value of a dual-purpose bmr-12 sorghum hybrid

Author
item Yerka, Melinda
item WATSON, ANDREA - University Of Nebraska
item ERICKSON, GALEN - University Of Nebraska
item Pedersen, Jeffrey
item Mitchell, Robert - Rob

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2014
Publication Date: 3/20/2015
Publication URL: https://dl.sciencesocieties.org/publications/cs/pdfs/55/2/681?search-result=1
Citation: Yerka, M.K., Watson, A., Erickson, G., Pedersen, J.F., Mitchell, R. 2015. Yield and forage value of a dual-purpose bmr-12 sorghum hybrid. Crop Science. 55:681-687. DOI: 10.2135/cropsci2014.06.0437.

Interpretive Summary: Grain sorghum is an important crop for rainfed production systems with 2.7 million ha grown in the USA in 2013. The brown-midrib (bmr) trait, conditioned by a chemical-induced mutation, results in low stover lignin and high fiber digestibility without reducing grain yield in some sorghum lines. However, the effect of the bmr trait on beef cattle performance when grazing crop residue is unknown. Our objectives were to validate previous small-plot results reporting no yield drag in a bmr version of the A Wheatland × R Tx430 sorghum hybrid, relative to a wild-type control, in a field-scale experiment; to determine if bmr stover enhances beef production in a grazing experiment. Four replicated paddocks were planted in 2006 and 2008 near Mead, Nebraska. Crossbred yearling steers grazed paddocks following grain harvest for 72 d in 2006 and 61 d in 2008. Steer average daily gain (kg hd-1 d-1) and body weight (kg ha-1) were determined. Bmr grain yield was 6% less than the control, but the stover was more digestible. The increased steer body weight from grazing bmr stover resulted in an estimated increase in net return of $131 ha-1. Results suggest that the A Wheatland × R Tx430 bmr hybrid is an effective dual-purpose sorghum crop for both grain and beef production.

Technical Abstract: Grain sorghum [Sorghum bicolor (L.) Moench] is an important crop for rainfed production systems with 2.7 million ha grown in the USA in 2013. The brown-midrib (bmr) mutations, especially bmr-12, have resulted in low stover lignin and high fiber digestibility without reducing grain yield in some sorghum lines. However, the effect of the bmr trait on beef cattle (Bos taurus) performance when grazing crop residue is unknown. Our objectives were to validate previous small-plot results reporting no grain yield difference between isogenic bmr-12 (BMR) and wild-type control (CON) A Wheatland × R Tx430 sorghum hybrids in a field-scale experiment, and to determine if BMR stover enhances beef production in a grazing experiment. Four replicated paddocks (2.3 ha) were planted in 2006 and 2008 near Mead, Nebraska. Crossbred yearling steers (239 ± 17 kg hd-1) grazed (2.6 animal units ha-1) paddocks following grain harvest for 72 d in 2006 and 61 d in 2008. Forage was sampled 4, 30, and 60 d after grazing began. BMR grain yield was 6% less (P = 0.01) than CON with no difference in stover NDF content, but BMR stover had higher in vitro NDF digestibility (IVNDFD) (7%; P < 0.001), steer average daily gain (ADG 0.17 kg hd-1 d-1; P = 0.001), and body weight (BW) gain (110 kg ha-1; P = 0.002), resulting in an estimated increase in net return of $131 ha-1 due to BMR. Results suggest that the A Wheatland × R Tx430 bmr-12 hybrid is an effective dual-purpose sorghum crop for both grain and beef production.