Parthenocarpic tomato can be cultivated in glasshouses with the advantage that fruit set is not dependent upon weather conditions. The greenhouses most commonly use in Meditteranean area are simple, unheated, plastic-covered structures and the daily fluctuations in temperature and humidity are therefore high.
The aim of the work was to determine the potential the expression of the parthenocarpic pat-2 gene in relation to changes of weather temperature. The comparison of F1 hybrids Monalbo x Porphyre with of without the pat-2 genes (generous gift from Dr. J. Philouze, INRA, Montfavet, France) show the influence of the minimum night temperature on the parthenocarpy expression at flower anthesis (Fig. 1). Surprisely more significant on pat-2 gene expression is the minimum temperature during flower development. In Fig. 2 the correlation between fruit set and temperature at the 11th day before anthesis is reported. We have evidence to conclude that pat-2 gene exerts its action, already, during flower ontogenesis with probably interactions between the different flower organs. In this light, the possibility that more than a single recessive gene (Vardy et al, 1987) is necessary to parthenocarpy expression, in tomato genotypes containing the pat-2 gene, can have further consistence.
Vardy, E., D. Lapushner, A. Genizzi, J. Hewitt 1989. Euphytica 41: 9-15.
Figure 1. Fruit set regression lines for maxima (A), mimima (B) and mdia (C) day tempoeratures measured at anthesis for pat-2 (solid lines) and normal (dotted lines) tomato genotypes.
Figure 2. Fruit set regression lines for maxima (A), mimima (B) and mdia (C) day tempoeratures measured eleven days before anthesis for pat-2 (solid lines) and normal (dotted lines) tomato genotypes.