Production of Wheat Doubled Haploids Through Intergeneric Hybridization with Maize

Abstract

The intergeneric hybridization of wheat (Triticum aestivum L.) with maize (Zea mays L.) enables the production of doubled haploids (DHs) of wheat from all wheat hybrids with high efficiencies. Wheat and maize donor plants are raised in environmentally controlled greenhouses until crossing. Before anthesis, wheat spikes are emasculated and then pollinated with maize. Auxin is applied to each individual wheat floret 1day after pollination. About 2weeks after crossing, in vitro embryo culture is performed, enabling the regeneration of haploid wheat plantlets after maize chromosome elimination. Haploid plantlets are transferred to the greenhouse and after recovery, their genome is doubled with colchicine. Haploid plantlets can be sampled for DNA extractions and molecular analyses to aid the rapid discard of undesirable plantlets. Doubled haploid plants are raised in a greenhouse until maturity. Seeds of each fertile DH are harvested and often sown the same year. Several cycles of multiplication and evaluation in replicated plot trials and different geographical locations are then done to select the best candidate(s) for varietal registration.