The physiological consequences of polyploidy - II. The effect of polyploidy on variability in the tomato
1. Experiments described in a previous paper, comparing diploid and tetraploid tomatoes with regard to size and growth, are analysed from the point of view of variability.
2. New data on fruit weight in diploid and tetraploid tomatoes are given.
3. Tetraploids are found to be consistently less variable than diploids. When the weight of whole plants is considered, it is shown that this reduction of relative variability lies entirely in theWo term of Blackman’s growth equationWt =Woert. In fruits, the reduction of variability is between fruits on the same plant, and not between different plants.
4. It is considered that this diminished variability cannot be accounted for by a direct genetic effect involving segregation, as had been suggested by other workers.
5. An alternative hypothesis is proposed. It is assumed that doubling the number of genes results in an increased probability of the action of quantitative factors. This is reflected in the greater physiological stability of early meristems.
6. The fact that tetraploidy results in diminished fruit size is confirmed.
Volume 100, 2021
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