Badajoz, Spain (SP), Stockton, California (CAH); Woodland, California (CAP); and Numata, Japan (JP). There
were 3 reps of Pto-R/R and Pto-R/S and 9 reps of E6203 at each site. The only exception was JP where there
were 2 reps of the Pto-NILs and 6 reps of E6203. Details of field condition and cultural practices can be found in
Tanksley et al. (1997). All plots were harvested at the end of the season and evaluated for plant growth/cover,
maturity, stem scar size , fruit color (internal and external), fruit shape, fruit firmness, pericarp thickness, venation
of the fruit, puffiness, stem core depth, pH, soluble solid, yield (total, red and green), brix*yield, fruit weight and
viscosity as described in Tanksley et al. (1997a). The only exception was for yield which was not measured at
CAH. Table 1 summarizes ANOVA's comparing the performance of the NILs and E6203 for each trait for which a
significant difference (P<0.1) was observed.
For most traits no difference could be detected between the NILs or between the NILs and the E6203
control. The exceptions were puffiness, venation, pH and total yield. The Pto-R/S NIL produced fruit which were
significantly more puffy (more intralocular air) than the E6203: control. The heterozygous NIL (Pto-R/S) also had
more veins in the fruit wall (as determined by visual inspection) than either E6203 or Pto-R/R. Both the puffiness
and venation observed in the heterozygous NIL are undesirable from a horticultural perspective. All NIL
comparisons revealed significant differences in fruit pH (Table 1, fig 1). These results suggest that Pto has a
largely dominant effect on suppressing pH. The greatest suppression was seen in the Pto-R/S heterozygotes.
Total fruit yield (green + red fruit) was also great for the Pto-R/S NIL compared to E6203 or Pto-R/R. However,
there was no significant difference in the yield of red fruit or brix*yield among comparisons of the NILs and E6203.
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