Feed-quality variation in the barley core collection of the USDA National Small Grains Collection

Feed is an important end use of barley (Hordeum vulgare L.). Recent researc h has identified high starch content, low acid-detergent fiber (ADF), low r uminal dry-matter digestibility (DMD), and large particle size after dry ro lling as desirable barley feed-quality characteristics for beef cattle. Kno wledge about the variation available may help barley breeders develop strat egies for feed-quality improvement. Our objective was to estimate the varia tion in feed-quality characteristics in barley around the world. The spring barley core subcollection from the USDA-ARS National Small Grains Collecti on was planted in 1995. Ruminal DMD of 1480 accessions was evaluated. Seven ty-three accessions, selected on variation in DMD, were planted in two fiel d replications in 1996 and 1997. These 73 accessions were evaluated for sta rch, DMD, ADF, and particle size after dry rolling. The range in DMD was 82 to 621 g kg(-1), with a mean of 398 g kg(1) (SD = 75 g kg(-1)). The ranges for other traits of the 73 selected accessions were 387 to 593 g kg(-1) (s tarch); 15 to 96 g kg(-1) (ADF); 187 to 510 g kg(-1) (DMD); and 1118 to 157 2 mum (particle size). Six-row types had greater ADF and particle size (P < 0.001), lower starch, and DMD (P < 0.001), compared with 2-row types. Star ch was higher (P < 0.01), and ADF and DMD were lower (P < 0.01), for hulles s than for hulled accessions. Substantial variation in the spring barley co re collection for feed quality-related characters could be exploited to dev elop barley cultivars for feed quality.