Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: August 1, 1996
Publication Date: N/A
Technical Abstract: Broccoli (Brassica oleracea L. Italica group) breeders are increasingly using anther culture to produce dihaploid, homozygous lines. During the process of anther culture and subsequent plant regeneration, polyploidization occurs and diploid regenerants can result. However, polyploidization may not occur at all, or it may involve a tripling or quadrupling of the chromosome complement, instead of a doubling. Thus, populations may contain haploids, triploids, or tetraploids, in addition to diploids. In two cycles (1994-95 and 1995-96) of anther culture, regenerants from different broccoli hybrids were evaluated using flow cytometry to distinguish diploids versus haploids, tetraploids or others, and to determine if anther donor genotype has an effect on the frequency of ploidy types. In the first cycle, five hybrids had populations wherein about 3% were haploid, 55% diploid, 37% tetraploid, and 5% other types. 'Marathon' was different; its regenerants were 78% diploid and only 15% tetraploid. In the second cycle, populations were different with a majority of hybrids giving 30-40% diploids and 50-60% tetraploids. Consistent with the previous cycle, 'Marathon' gave significantly more diploids (68%) and fewer tetraploids (25%) than other hybrids. These results indicate that anther donor genotype affects ploidy frequency among regenerants.