A SIMPLIFIED AND EFFECTIVE PROTOCOL FOR PRODUCTION OF BREAD WHEAT HAPLOIDS (n = 3x = 21, ABD) WITH SOME APPLICATION AREAS IN WHEAT IMPROVEMENT

Somaclonal variation, aneuploidy, and genotypic specificity are major limitations of anther culture and bread wheat x Hordeum bulbosum crosses for producing haploids (n=3x=21, ABD). Sexual combinations of wheat x Zea mays have since emerged as an alternate and significant procedure as wheat genotypic specificity does not exist. This procedure has been refined and simplified over the last decade. It is in extensive use in wheat breeding, cytogenetics, genetics, wide crosses, genetic transformation and molecular mapping. Described here is this simplified wheat x maize haploid production protocol that is 100% effective across all bread wheat cultivars, generating data means of 25% for embryo excision, 90 to 95% for plantlet regeneration and between 95 to 100% for doubled haploid (2n=6x=42, AABBDD) outputs. Simplification steps that enhance efficiency involve hot water emasculation on detached tillers, bud-pollination, elimination of the use of several exogenous chemicals between post-pollination and embryo rescue with no cold shock given to the plated embryos; thus making the product costs significantly competitive and economical.