Green Stripe (gs) - A new characteristic

Larson R. E. and Pollack, B. L.

During the summer of 1948, a local gardener brought samples of an unusual fruit-striping mutation of a single plant occurring in his garden. Seed was saved and plants grown in 1949. All plants bred true for the characteristic. Unforturately the variety from which this mutant was obtained is unknown but it is believed to have been derived from Gulf State market. The type of striping differs from that reported by Young and Macarthur (Texas Ag. Exp. Sta. Bul. 698. 1947) and is thought to be a new characteristic. It appears to be caused by irregular pigmentation of the inner epidemis. The affected layer has a high chlorophyll content as evidenced by the dark green stripes or blotches in the immature fruits of either the UU or uu type. In the maturation process the stripes or blotches maintain theier green color for a longer period of time than on the remainder of the fruit. The pigmentation of the inner epidermis is sufficient to prevent the expression of the flesh color though the skin, although the characteristic does not affect the flesh color per se.

In the mature fruit of the R Y types the stripe appears gold in color. The R y segregates produce a beige colored stripe in contrast to the pink appearance of the remainder of the fruit. The exterior color of the r y fruits is a light translucent yellow in the normal and an opague golden yellow in the presence of the affected layer.

The characteristic appears to be inherited as a monorecessive, as shown in the table, and has been given the gene symbol gs. It is highly probrible the complete recessive promotes a high rate of mutation in the somatic cells of the inner epidermis, whereas the heterozygous or homozygous dominant prevents this expression. On the basis of prelinminary studies, from F2 data, there appears to be no association of gs with the characteristics d, r, c, a, and l.

Segregation in the F2  generation for normal
        and green stripe fruit types
                   Normal       Mutant         P from 
                 _______________________      X^2  for
Population No.    Obs.  Calc.  Obs.  Calc.      3:1
       1          85    89.25   34  29.75   0.50 - 0.20     
       2          91    88.50   27  29.50   0.95 - 0.50
      17         162   172.50   68  57.50   0.20 - 0.10
Total                                       0.50 - O.2O
Deviation        338   350.25  129 116.75   0.20 - 0.10
Heterogeneity                               0.50 - 0.20