bk-5 (214S2L) , an allelic variant of bk-5, as high-quality silage maize genetic resource.

INTRODUCTION: Stem brittleness significantly affects both yield and quality of maize. METHODS: Using phenotypic identification and sequence analysis, we identified a new brittle stalk maize mutant. Furthermore, we assessed its feeding value by content determination of cellulose, hemicellulose, lignin crude fiber, starch, and protein contents. RESULTS: Here, we identified a brittle stalk maize mutant, bk-5 (214S2L) , an allelic variant of bk-5. The stem brittleness of bk-5 (214S2L) was similar to that of bk-5, but not identical. Unlike bk-5, bk-5 (214S2L) leaves did not fall off completely and its stems did not break in windy conditions. We identified a missense mutation (C>T) in the fifth exon of the candidate gene Zm00001d043477, resulting in an amino acid change from serine to leucine at position 214. A significant reduction in cell wall thickness in the leaf veins and stems of bk-5 (214S2L) compared with the inbred line RP125. Among the major cell wall components in stems and leaves, total cellulose, hemicellulose, and lignin were lower in bk-5 (214S2L) than in RP125. We also evaluated the application value of bk-5 (214S2L) silage and found that the detergent fiber contents of bk-5 (214S2L) stems were significantly reduced compared with RP125, while the crude fiber, starch, and protein contents remained unchanged. The reduced tannin content improved the palatability of the silage for livestock. CONCLUSION: Overall, bk-5 (214S2L) , an allelic variant of bk-5, is a high-quality genetic resource for breeding forage and grain-feed maize.