Identification of novel brown midrib genes in maize by tests of allelism

Abstract

<p><em>Brown midrib</em> (<em>bm</em>) mutations are known to affect cell-wall digestibility by altering the quantity and composition of lignins in cell walls, resulting in higher ethanol yield and increased cell-wall digestibility. So far, four <em>bm</em> genes (<em>bm</em>1<em>, bm</em>2<em>, bm</em>3 and <em>bm</em>4) were identified and mapped in maize, the last one (<em>bm</em>4) in 1947. In this study, 13 spontaneous mutations (<em>bm</em>*A–M) resulting in the appearance of brown midribs were crossed with <em>bm</em>1–4 for tests of allelism. From these tests, we report two new <em>bm</em> mutants <em>bm</em>5 (<em>bm</em>*F) and <em>bm</em>6 (<em>bm</em>*J) while other <em>bm</em>* lines were either found allelic to <em>bm</em>1–4 or to one of the <em>bm</em>* lines.</p>