High frequency of parthenogenesis in a cross of tetraploid X diploid --Ting, YC, Tran, L In order to produce a triploid perennial maize, several crosses between a tetraploid(Clg clg clg clg) and a diploid (clg clg) were attempted. In one of the crosses, the F0 progeny kernels were of predominantly defective endosperm, which was unexpected. According to previous observations, pentaploid maize endosperms had normal growth and were like the triploid type. However, in this particular cross, 99 percent of the progeny kernels were defective. It appears that the ovules were not fertilized or fertilizations had occurred without union of the parental gametes. In consequence, the progeny kernels were not fully developed. With the objective of testing this explanation, 10 defective kernels, together with the same number of their normal sibs, were grown in the greenhouse. It was interesting to note that the viability of these two types was surprisingly high, approximately 99 percent. As soon as their root-tips, as well as their male inflorescences, become available for cytological investigations, their chromosome constitutions will be examined.
 
 
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