ISHS Acta Horticulturae 724: IX International Symposium on the Processing Tomato
PRACTICAL USE OF QTLS ASSOCIATED WITH YIELD AND FRUIT QUALITY IN TOMATO |
| Authors: | S. Inai, E. Ichihashi, H. Sayama, E. Ishimura |
| Keywords: | quantitative trait loci, marker assisted selection, plant breeding |
| Abstract:
Tomato varieties can principally affect product quality. Therefore, in tomato breeding programs, improving fruit quality attributes such as flavor, fruit color and nutritional values has been emphasized along with many traits of economic importance such as yield and earliness. However, such traits have been difficult to improve since they are governed by quantitative trait loci (QTL). We have introgressed into NDM breeding lines two DNA segments from two tomato wild species, Lycopersicon pennelii and L. chmielewskii. One QTL (dw1) derived from L. pennelii was closely associated with a phenotype of increasing yield and earliness but decreasing fruit firmness, while the other QTL (hs1a) derived from L. chmielewskii associated with increasing soluble solids of fruits but reducing yield and internal fruit color. To improve those undesirable characteristics closely linked with dw1 and hs1a, we have sequentially backcrossed dw1 and hs1a lines to several breeding lines with different genetic backgrounds. In one of our commercial varieties, DR447, dw1 dramatically increased earliness. The ratio of the first two harvests to the total yield was 20% more in dw1/+ lines than in +/+ ones. The total yield was slightly increased in dw1/+ lines compared to +/+ lines. In hs1a lines undesirable characteristics such as inferior fruit color were also improved only in a particular genetic background. This implies that putative QTL that improved fruit colour mainly in columella tissue may exist in the genetic background. | |
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