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

Gang Li ^1* Jiyuan Du ² Xiaohu Li ^2* Shilin Zhuge ^2* Shuolin Ren ^2* Min Wu ^2* Haoran Ma ^2* Xinrui Guo ¹ Ziqiang Chen ^1* Haiping Ding ^2*

• ¹ Biotechnology Institute, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian, China
• ² Shandong Agricultural University, Taian, China

Stem brittleness significantly affects both yield and quality of maize. Here, we identified a brittle stalk maize mutant, bk-5 214S2L , an allelic variant of bk-5.Phenotypic characterization revealed that 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. Using sequence analysis, 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. Paraffin sections and scanning electron microscopy results showed 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. Overall, bk-5 214S2L is a high-quality genetic resource for breeding forage and grain-feed maize.