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

## TL;DR

A new brittle stalk maize variant, bk-5 214S2L, is identified as a high-quality resource for forage and feed maize breeding due to its improved stem properties and palatability.

## Contribution

Discovery of bk-5 214S2L, an allelic variant of bk-5, with unique stem brittleness and reduced cell wall components for improved silage quality.

## Key findings

- bk-5 214S2L has a missense mutation in Zm00001d043477 gene causing serine to leucine amino acid change at position 214.
- Stem and leaf cell wall thickness and cellulose, hemicellulose, lignin contents are significantly reduced in bk-5 214S2L compared to RP125.
- bk-5 214S2L silage has reduced detergent fiber and tannin content, improving palatability without affecting crude fiber, starch, or protein.

## Abstract

Stem brittleness significantly affects both yield and quality of maize.

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.

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.

Overall, bk-5

214S2L
, an allelic variant of bk-5, is a high-quality genetic resource for breeding forage and grain-feed maize.