During an assessment of tomato lines exhibiting various necrosis phenotypes, we noticed a distinct similarity between the necrosis-2 and neglecta phenotypes. On the classical map (Mutschler et al. 1987), neg is located at position 40 on chromosome 11 and ne-2 is assigned to chromosome 11 but not localised. The possibility of allelism was tested by crossing LA2454 ne-2 / ne-2 as the pollen parent to the chromosome 11 tester LA881 a - hl - neg / a - hl - neg and examining the phenotype of the F1. All of the progeny from replicate crosses were purple stemmed (a+) and hairy (hl+) confirming their F1 status, but showed necrosis, revealing that ne-2 was allelic to neg. The neg gene was first described by Stubbe in 1957 and ne-2 by Yu and Yeager in 1960. The designation neg therefore has precedence over ne-2, which should now be designated a reoccurrence of neg . Renaming ne-2 also removes the inconsistency of the suggested mimicry with ne (necrosis), since from our observations ne-2 little resembles ne in either the timing or nature of necrosis, effect on plant growth or the interaction of ne with the CF2 gene for resistance to Cladosporium fulvum.
Literature cited:
Mutschler, M.A., Tanksley, S.D. and Rick, C.M. (1987) 1987 Linkage maps of the tomato (Lycopersicon esculentum). TGC Report 37:5-34.
Stubbe, H. (1957) Mutanten der kulturtomate Lycopersicon esculentum Miller I. Die Kulturpflanze 5:190-220.
Yu, S. and Yeager, A.F. (1960) Ten heritable mutations found in the tomato following irradiation with X-rays and thermal neutrons. Proc. Amer. Soc. Hort. Sci. 76:538-542.