7 RESEARCH NOTES TGC REPORT No . 31, 1981 repulsion gave 36% crossovers . The imb - irr distance was 20 units in one test in repulsion and averaged 20 units in three tests in coupling . The irr - y distance was 36 units for one repulsion and 23 units for five coupling tests . This suggests that the order is y - irr - imb . This was confirmed by two F 2 populations having the three genes in coupling (Table 2) . From our work the order and location of the genes is   Kerr,E . A . Linkage studies of green ripe Green ripe arose as a chimeral fruit and never ripe . (Kerr, TGC 8:22) . This would suggest that the mutant was dominant but in greenhouse trials the green color of the heterozygous fruits disappeared . Accordingly the gene was considered to be recessive and was designated gr . However, tests on the inheritance of this gene were inconclusive . Never ripe (Rick, TGC 6:22 - 23) also appeared as a chimeral fruit and appeared superficially to be a complete dominant . It was designated Nr . It has been assigned to chromosome 9 (Kerr, TGC 19:12) . Under field conditions, I have not been able to distinguish these genes reliably . Both have delayed production of red color, the heterozygous fruits are intermediate in color and can be identified under most conditions . I have found both easier to score as dominant genes and have used the symbol Gr for green ripe in my tests . In 1980, an F 2 was produced between homozygous Nr and homozygous Gr . Of the 110 plants that produced ripe fruit, 10 were normal red, only 3 were scored as heterozygous mutant and 97 were either Nr or Gr . This population was segregating for some genes with low viability and 33 plants died before maturity . Consequently, no conclusions on possible linkage could be drawn . However, these genes are definitely not alleles . It is proposed that the symbol for green ripe be changed from gr to Gr .