In tomato the acid phosphatase-1 isozyme (Apase-1) is inherited as a single locus linked to the nematode resistance gene (Mi)

SUMMARYA growth analysis of plants raised under controlled environment conditions was used to examine the response to temperature of five contrasting tomato cultivars bred for outdoor production. Curves were fitted to the data of dry weight and leaf area and, to compensate for ontogenetic drift, instantaneous values of growth analysis parameters were calculated from these curves at a specific growth stage. Differences in relative growth rate which could be exploited in a breeding programme were not detected, though there were large differences in the components of relative growth rate. These were, however, compensatory within a cultivar. It was concluded that in order to select a genotype with improved growth rate it would be necessary to disrupt the compensation mechanism between the components of relative growth rate.

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An investigation was carried out into the genotypic variation in the response to temperature of leaf area in tomatoes . Differences between genotypes in the response of the area of a leaf to contrasting temperature regimes were found, and this was due to variation in the number of epidermal cells . The epidermal cell size showed little response to temperature . The results are discussed in relation to the potential for selection for improved leaf area and the development of a rapid screening test for cold tolerance .

Genotypic variation in the response to temperature of the rate of leaf production is reported . Leaf production was measured as the rate of successive leaves passing a specific length and by dissecting plants to obtain the rate of leaf initiation . These results together with the results of leaf size from the previous paper, are compared to the effect of temperature on the total leaf area . The use of information from these experiments in selecting for increased leaf area at low temperature is discussed .