Evaluation of a possible use of brachytic 2 mutation in corn breeding

摘要

In maize Brachytic 2 (Br2) gene encodes for an auxin polar transporter similar to adenosine triphos-phate (ATP)-binding cassette transporter of the multi-drug resistant (MDR) class of P-glycopoteins (PGPs) protein family. Mutations in Br2 gene cause a reduc-tion in plant stature (about 50%) due to shortening of the internodes length without a corresponding re-duction in the number of internodes or in the size of other organs. Furthermore br2 mutation confers several positive agronomic traits such as stay green, resistance to lodging and in general a modified plant architecture mimicking modern hybrids. The aim of this work is to evaluate a possible application of br2 mutation as heterozygous (Br2/br2) in maize genetic improvement (in fact br2 mutation exhibits a phenom-enon of incomplete dominance). Methods. With this purpose we constituted several hybrids differing only for br2 constitution (Br2/Br2 vs Br2/br2) and we compared some agronomic traits, such as plant height and ear height. We supported the breeding activity using a Sequence-Specific Amplifica-tion Polymorphism (S-SAP) molecular marker to con-firm the presence of br2-23 mutation in the genetic material constituted.