Routinely used in maize breeding programs of some multinational, large seed companies, doubled haploids (DH) dramatically speed development of genetically uniform inbred lines—key to generating hybrids and making selection decisions using DNA markers.
However, lack of tropicalized haploid inducer lines as well as technical know-how have held back the use of DH technologies by small and medium sized seed companies and public breeding programs in developing countries.
Now those programs and companies can join the revolution: after five years of collaborative research with the Institute of Plant Breeding, Seed Science and Population Genetics of the University of Hohenheim, Germany, the CIMMYT global maize program publicly unveiled the tropical haploid inducers on 15 August 2012, and is making them available to interested breeders. With technical support from University of Hohenheim, CIMMYT has also established a DH production pipeline at the Agua Fría station in Mexico.
As part of efforts to foster widespread use of DH technology in developing countries, CIMMYT recently organised a training course pn the subject, that offered theoretical and practical knowledge to 16 participants from 10 countries (China, Ethiopia, Iran, Kenya, Mozambique, Pakistan, Tanzania, Turkey, Uganda, Zimbabwe), including visits to facilities at the El Batán and Agua Fría experiment stations in Mexico. Topics included haploid induction, chromosomal doubling technology, rapid-cycle breeding with DH lines and genomic selection, and use of DH lines in genetic studies. Participants gained hands-on experience in identifying haploid kernels, the chromosomal doubling treatment, and assessing haploid induction rate. Field visits demonstrated the advantages of tropical over temperate inducers, induction nursery designs, agronomic management of the induction and haploid nurseries, and development of new haploid inducers.
Lectures were delivered by BM Prasanna, Vijay Chaikam (course organizer), George Mahuku, and Xuecai Zhang of CIMMYT; by Wolfgang Schipprack, University of Hohenheim; and Brian Dilkes, Purdue University. CIMMYT maize technicians Leocadio Martínez and Luis Antonio López contributed significantly to the practical demonstrations. Special thanks to CIMMYT training logistics staff, especially Laura Ruíz and Eleuterio Dorantes, for their excellent support. This YouTube video Doubled Haploids: A simple method to improve efficiency of maize breeding provides further useful information and guidance.