Sex-specific karyotyping of Garcinia indica (Thouars) Choisy for differentiation of male and female trees at an early juvenile stage.

The study provides karyomorphological details of male and female plants of Garcinia indica, a polygamodioecious tree endemic to western Ghats of India. Whereas, the female plants are valued in commercial cultivations, but there are no distinct morphological or vegetative traits that could differentiate such plants at an early juvenile stage among a mix of male, female and bisexual trees. Karyotype preparation was done from leaf tip by Giemsa staining. In female tree we found to have two karyotypes (karyotype I and karyotype II). A comparative study showed that the number of chromosomes in the male and female trees were the same (2n = 54), but that there were substantial differences in the shape of satellites, number of satellite chromosome pair and presence of one asymmetric chromosome pair in female's ideogram. In male the satellites were mushroom-shaped, while in female the satellites were knob-shaped. Male and female karyotype I ideograms showed four pairs of satellite chromosomes, whereas female karyotype II ideogram showed five satellite chromosome pairs. Female of karyotype II differed drastically when compared with karyotypes of male and female of karyotype I. Male (41.06 m) and Female karyotype I (41.95 m) values for genome total length were found to be reasonably similar, however Female karyotype II had a greater value for total genome length (51.20 m). This chromosomal size difference between female of karyotype II and male might be responsible for failure of sexual reproduction in Garcinia indica species. [ABSTRACT FROM AUTHOR]