ISHS Acta Horticulturae 301: IV International Symposium on Processing Tomatoes
GENETICAL, PHYSIOLOGICAL AND BIOCHEMICAL ASPECTS OF A MONOSTEM TOMATO PHENOTYPE SUITABLE FOR MECHANIZATION AND PROCESSING |
| Authors: | G.P. Soressi, S. Mapelli |
| Keywords: | Lycopersicon esculentum, torosa-2 mutant, breeding, phytohormone, growth parameters. |
| Abstract:
The monostem tomato phenotype characterized by absence of side-shoots, determinated growth with 1–2 trusses and severe reduction in flower number (2–3 per truss) is essentially due to the torosa-2 (to-2) mutant. This mutant has constituted the basis for designing a monostem tomato plant model usefull for breeding monostem lines suitable for processing. During subsequent cycles of crossing and selection, involving processing cultivars and monostem lines, have been evidenced genetic background and environment effects on the expression of the monostem trait. Measurements of harvest index, net assimilation rate, specific leaf dry weight and other growth parameters were carried out to characterize the monostem phenotype versus the normal one from crop physiological point of view. Biochemical and physiological investigations on the possible control mechanism of the side-shoot development were carried out. The alterations in the level and metabolism of phytohormones (gibberellins, cytokinins, abscisic acid) appear clearly in relation with the to-2 gene expression leading to a lacking of lateral shoot bud differentiation. | |
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