Maize-Tripsacum-Teosinte allopolyploid (MTP), a novel dwarf mutant inducer tool in maize

Area of Science:

• Plant genetics and breeding
• Crop science
• Agricultural biotechnology

Background:

• Dwarf plant architecture in maize allows for dense planting, potentially increasing crop yields.
• Current breeding applications of maize dwarfing materials are limited, hindering the use of valuable dwarf resources.

Purpose of the Study:

• To develop novel maize dwarf germplasm through distant hybridization.
• To identify and characterize dwarf genes and their regulatory mechanisms in maize.

Main Methods:

• Distant hybridization of Maize-Tripsacum-Teosinte allopolyploid (MTP) with maize.
• Fine mapping of dwarf gene d024, identifying linkage to indel-4 in ZmCYP90D1.
• Analysis of ZmCYP90D1 regulation by ZmBES1/BZR1-5 and interaction with ZmFDXs and ZmNAD(P)H.

Main Results:

• Ten independent dwarf maize families were identified, with five germplasms controlled by unique dwarf genes (none by Br2).
• The d024 dwarf phenotype is linked to indel-4 in ZmCYP90D1, originating from Tripsacum, and affects brassinosteroid (BR) synthesis.
• Introgressing the Tripsacum allele (indel-4) into modern hybrids improved yield potential and harvest index under high-density planting.

Conclusions:

• A novel method for creating engineered dwarf maize using MTP was established.
• The identified dwarf allele (indel-4 in ZmCYP90D1) offers a promising strategy for enhancing maize yield and harvest index in high-density cultivation.
• This research addresses challenges in applying dwarf resources for improved maize production.