Effect of parental genotypes on haploid embryo and plantlet formation in wheat x maize crosses

Genotypic influence of both male and female parents on haploid production through interspecific crosses was studied using eight wheat and four maize genotypes. The average numbers of embryos and green haploid plantlets obtained per pollinated floret were 17.6% and 10.1%, respectively. Clear genotypic influence of the wheat genotype was detected, but heterozygosity of the wheat did not affect haploid production. Analogous response to anther culture and interspecific crossing was observed, still a wheat variety which did not respond to anther culture, produced 1.1 plantlets per pollinated spike upon maize pollination. This appears to be a major advantage of interspecific crossing compared to anther culture technique in wheat. Circumstantial evidence is presented for specific wheat x maize interaction on haploid plantlet formation. Rye chromatin enhanced haploid production but only in a complete 1B/1R substitution line. Ovaries with an embryo were found to be dispersed evenly all over the wheat spike, suggesting that within certain limits the developmental stage of ovaries and thus time of pollination within a spike are not as important as it was previously assumed.