Variations in the resistance to Heterodera rostochiensis of potatoes derived from Solarium tuberosum ssp. andigena and S. multidissectum

The proportion of larvae from ten populations of Heterodera rostochiensis Woll. that became female was determined on five potato clones containing genes for resistance derived from S. tuberosum ssp. andigena., on three with genes from S. multidissectum and on four with genes for resistance from both sources. Variations in the resistance of the clones bred from andigena, especially to two of the populations, suggest the presence of more than one gene for resistance.     

Regeneration of neural crest derivatives in the <Emphasis Type="Italic">Xenopus</Emphasis>tadpole tail

Background  

After amputation of the Xenopus tadpole tail, a functionally competent new tail is regenerated. It contains spinal cord, notochord and muscle, each of which has previously been shown to derive from the corresponding tissue in the stump. The regeneration of the neural crest derivatives has not previously been examined and is described in this paper.