Published online by Cambridge University Press: 27 March 2009
1. In general the juvenile growth of interspecific Triticum and intergeneric Tritioum-Aegilops amphidiploids, was normal and did not deviate from the parental behaviour. However, in the case of the interspecific hexaploids derived from T. monococcum and T. aegilopoides there was an early check in growth, and all the amphidiploids derived from A. caudata developed more or less severe chlorosis.
2. Most amphidiploids were intermediate between their parents in mature plant characters. However, in the hexaploid Triticum interspecific amphidiploids there was a transgressive increase in plant height, and whilst the derivatives of Triticum x Aegilops crosses fell within the range of their parents, they were closer to one or other parent depending upon the Aegilops species involved.
3. The ear morphology of the Triticum interspecific amphidiploid was generally a composite of that of the parents, the influence of each parent being detectable. In the Triticum-Aegilops amphidiploids, however, ear morphology was so strongly influenced by the Aegilops species, that there was frequently no obvious difference between the ears of amphidiploids with a common Aegilops parent but different wheat parents.
4. The fertility of the amphidiploids was low and there was no significant correlation between the fertility of amphidiploids and parents. There was a significant correlation between both the grain weight, and number of spikelets per ear, in parents and amphidiploids, but whilst the mean grain weight was about that of the parent with the heavier grain, the mean of spikelets per ear was about that of the parent with the fewer spikelets.