Doubled haploids of wheat from wheat x maize crosses:genotypic influence, fertility and inheritance of the 1BL-1RS chromosome.

The wheat x maize cross as a technique for haploid induction in wheat was evaluated in a replicated block design comprising 18 wheat F1 hybrids and five Zea mays L. parents. Haploid plants were regenerated at an average of 9.1 (4.4-14.7) plants per 100 florets processed. Genotypic differences for haploid production efficiency were recorded for both wheat and Zea mays L. Interaction between parents was significant for number of plants/100 florets. All 610 of the 1,703 regenerated plantlets that were analyzed by flow cytometry were haploid. At maturity, 70% (60-81 %) of the colchicinetreated haploid plants were fertile, but the frequency of fertile and sterile plants was not consistent over the wheat hybrids from which they were derived. Flow cytometry performed using the first tiller which arose following colchicine treatment enabled prediction of fertility. The 1BL-1RS chromosome was found at the expected ratios in the F2 and in the haploid progenies produced through the wheat x maize cross but deviated from the 1∶1 ratio in the haploid progenies produced by anther culture.