Germination, vigour and field emergence of sweet corn seeds infected by Fusarium moniliforme.
Maize seed lots produced commercially in 1975, 1976 and 1977 were assayed for infection by Gibberella fujikuroi in an agar health test, and for germination and vigour in the standard towel, modified towel, accelerated ageing, sand bench and cold tests. Seeds were also planted in the field at Beltsville in 1976, 1977 and 1978 both before and at the recommended date. Additional plantings were made at the recommended date, or soon after, at 4 other locations in 1977 and 1978. The 1975 seed lots were not infected by G. fujikuroi but were heavily surface-contaminated by the fungus, this having no apparent effect on germination, vigour or field emergence. The seed lots from 1976 and 1977 contained substantial amounts of internal G. fujikuroi. Infection of the former may have had a marked effect on germination, vigour and emergence but this was not appreciable in the 1977 lots. Environmental factors which led to substantial seed infection in 1976 may also have affected seed vigour. The correlation of the normal seedlings count in the standard towel test, the strong normal count or the av. root length in the modified towel test, with field emergence, was significant or highly so at 12 out of 14 test sites (86%). That of the normal seedlings count or total seedlings count in the accelerated ageing test with field emergence was similarly significant at 11 of the sites (79%). Emergence in the sand bench correlated well with field emergence at 13 sites (93%) and the figure for the cold test (not run in 1976) was 58% (7 of 12 sites). Seed-borne G. fujikuroi was correlated with field emergence at 7 of 14 sites (50%).