THE UCD PROCESSING TOMATO BREEDING PROGRAM

The overall objective of the U.C.D. processing tomato breeding program is to provide germplasm to meet the needs of the processing tomato industry of California.
This report focuses on studies related to two of the most important objectives: developing horticulturally superior, high yielding lines resistant to root rot caused by Phytophthora parasitica and combining increased soluble solids with high yield.
Studies on Phytophthora indicate: 1) In most cases seedling resistance is a good predictor of resistance of field-grown plants through all stages of growth, 2) resistance is present both in currently grown cultivars and accessions of L. esculentum var. cerasiforme and 3) there appears to be more than 1 type of resistance occurring in different genotypes.

Studies related to increasing soluble solids content are aimed at characterizing the path of sugar transport in tomato fruits.
Results indicate that sucrose is unloaded from the phloem into the apoplast where it is cleaved by invertase to glucose and fructose.
The three sugars can apparently be transported across the plasma membrane at similar rates.
Nonsaturating kinetics of sugar uptake suggests that transport from the apoplast to the cytoplasm is passive.
Disks removed from the pericarp of fruits of a high solids genotype, LA1563, took up sucrose at a greater rate than disks from 2 lower solids cultivars, UC82 and VF145B-7879.

II International Symposium on Processing Tomatoes, XXII IHC

J.D. Hewitt, N.S. Blaker, S.E. Damon, A.B. Bennett

https://doi.org/10.17660/ActaHortic.1987.200.6