SHARMA, RASHMI1 and RAKESH, C VERMA2.* 1Department of Botany, Center of Excellence in Environmental Biology, Vikram University, Ujjain, India. Present address, Department of Physiology, Tulane University Health Sciences Center, New Orleans, LA, 70112 USA; 2Department of Botany, Center of Excellence in Environmental Biology, Vikram University, Ujjain, India. - Assessment of extent of naturally occuring genetic diversity and cytogenetic studies in Phlox drummondii.
The genus Phlox is the second largest of the family
Polemoniaceae. Phlox drummondii and other species are
extensively grown for ornamental purposes in gardens. They are
universally cherished by horticulturists because of their foliage and
beautiful flowers. Therefore, new varieties are needed to compete in
floriculture industries. Methods like induced polyploidy, mutation,
hybridization and selection of better genotypes were used in present
study for genetic improvements. For genetic variablity systematic
selection of different types of flower shapes, color and sizes from
the natural population was individually collected over the period of
three years(alomst 500 plants/year of diploids and colchitetraploids).
The pattern of flowers indicated that it does not follow the parental
type in most of the lines, with rare appearance of star type and the
entire type and vice- versa. About 50% of progeny did not resemble the
parent type, and had intersting new patterns(colors, shape and sizes).
The variant seeds were then individually, collected and were
successfully maintained in subsequent generations. The variations led
to improved floral characteristics and new varieties of Phlox
with different patterns and germ plasma collection of more than 100
types with systematic single plant selection. In some induced
colchitetraploid plants white patches on maroon or red flowers could
also be due to transposons, however it need further confirmation. In
conclusion, the probable origin of variations in the natural
population could be either due to cross-pollination by insects leading
to hybridity of induced mutants and/or by recombination and/or by
segregation. This study evolved new exciting varieties of Phlox
drummondii of floricultural and industrial importance.
Key words: Genetic diversity, Phlox drummondii, Phlox, radiation