A Cytological and Morphological Analysis of Tomato Species

抄録

1. The cytology and micromorphology of Lycopersicum esculentum, and L. pimpinellifolium and their hybrid were studi, ed. A comparative study was also made of 10 small-fruited cultures from various parts of the world.
2. Chromosome behavior in both species was normal. L. pimpinellifolium had somewhat fewer chiasmata than esculentum.
3. The hybrid was cytologically regular except for certain constant weaknesses of pairing at pachytene and a much reduced chiasma number throughout.
4. In the following micromorphological characters pimpinellifolium was significantly smaller: pollen size, chromosome size and volume, both somatic and meiotic, size of cell and nucleus in root tips, and size of stoma.
5. Flower parts are constantly five in pimpinellifolium. In esculentum they are variable but usually six or seven.
6. Three of the 11 cultures from foreign locations were true L. pimpinellifolium; the rest were small-fruited L. esculentum.
7. Secondary association is considered of no significance in the tomato.
I wish to express my gratitude to Dr. E. W. Lindstrom, head of the Department of Genetics at Iowa State College, for the use of his tomato cultures and for his advise and helpful criticism in the performance of this investigation.