Studies on aneuploids of Petunia : Part 1: Cytomorphological Identification of primary trisomics

The seven possible primary trisomics of Petunia (2 n= 14) located in the progenies of triploid, hypertriploid and hypotriploid plants were distinguished from one another and from diploid on the basis of cytological and morphological criteria. They were provisionally named as "Oval", "Semi", "Slender", "Pseudonormal", "Arrow", "Narrow" and "Giant". In three of the trisomics, the extra chromosome was identified for the first time at pachytene stage. Postpachytene studies revealed no precise relationship between the length of extra chromosome and the frequency of multiple association.