Segregation distortion and linkage of mango isozyme loci

The inheritance of five polymorphic enzyme systems, aconitase (ACO), isocitrate dehydrogenase (IDH), phosphoglucose isomerase (PGI), phosphoglucomutase (PGM), and triosephosphate isomerase (TPI), was studied in selfed progenies of four mango (Mangifera indica L.) cultivars and selections. Only in 'Haden' did the allozymes of all of the studied loci segregate in the expected Mendelian ratios. Distorted segregations were present in the other cultivars at some loci; three of the five analyzed in 'Edward' showed distorted segregations, as did two of three loci in '13/1', and both loci in '21/6'. The distorted ratios in 'Edward', a descendant of 'Haden', did not appear to b e associated with gametic selection because pollen viability in both of these cultivars was high. The five enzymic loci were not linked to one another in 'Edward', '13/1', or '21/6'. In 'Haden', however, Pgi-2 and Aco were linked, with a distance of about 19.4 map units.