RESEARCH NOTES Dominance of Lapageria (Lpg) is reversed in crosses with Lycopersicon pennellii. Balint-KurtI, P.J., Jones, D.A. and Jones, J.D.G. The Sainsbury Laboratory at the John Innes Centre Rick (1964) reported Lapageria (Lpg) as an incompletely dominant morphological marker causing, among other things, reduced trichome size and number and reduced viability. Although this is true for crosses involving L. esculentum, we have observed that Lpg is completely recessive when crossed to L. pennellii. A L. esculentum plant heterozygous for Lpg was crossed to L. pennellii. Of the resulting 30 progeny none showed any features associated with the Lpg phenotype. Three of these F1 plants were crossed back to L. esculentum plants wild type at the Lpg locus. The progeny of one cross segregated 8:16 Lpg:wild type (fitting a 1:1 ratio). F2 progenies from these same three F1 plants were also examined. The same plant that gave Lpg progeny when test-crossed, produced 6:83 Lpg:wild type progeny in the F2. The low number of Lpg individuals here is presumably due to segregation distortion in this region previously as observed among F2 progeny from L. esculentum x L. pennellii crosses (Chetelat and de Verna 1991). The other 2 F1 plants gave no Lpg F2 progeny out of a total 51 plants. RFLP analysis of the 24 test cross plants segregating for Lpg showed that Lpg cosegregated with the RFLP marker TG310 located on chromosome 1 (Tanksley at al. 1992). The fact that no plants gave RFLP data inconsistent with their phenotypes and the absence of a modified segregation ratio in the test cross indicates that the locus in L. pennellii responsible for masking the Lpg phenotype in the F1 is at or near the Lpg locus. Thus it seems likely that the L. pennellii gene at the Lpg locus is dominant over the Lpg mutation. It also seems likely that Lpg is a loss of function mutation and that its dominance in L. esculentum may be due to haplo-insufficiency of the wild type allele. Literature cited: Chetelat and de Verna (1991) Expression of unilateral incompatibility in pollen of Lycopersicon pennellii is determined by major loci on chromosomes 1,6 and 10. Theor. Appl. Genet. 82:704-712 Rick C. M. (1964) Inheritance and linkage relations of Lapageria (Lpg) TGC report 14:24-25 Tanksley et al. (1993) High density molecular linkage maps of the tomato and potato genomes. Genetics 132:1141- 1160

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