Karyotypic analysis of parents and F1 hybrids of intra-specific crosses in Momordica charantia L.

Abstract

A detailed karyotypic study of the most commonly cultivated and the medicinally important species Momordica charantia var. charantia along with its wild variety M. charantia var. muricata (two accessions) and their F1 hybrids were analysed to find out the interrelationships of the taxa. It has been observed that the somatic chromosome number of the parents and hybrids was 2n=22, and they can be differentiated by their karyotype formula and quantitative parameters. The parents involved in the cross combinations belonged to the karyotpic category 4A whereas the F1 hybrids were grouped under the karyotype 3A. The TF% and intra chromosomal asymmetry indices along with the asymmetrical karyotype pointed out the advanced nature of the cultivated variety. Chromosome polymorphism was observed both at the intra- specific and intravarietal level. The Principal Component Analysis suggested that the TF%, total chromosome length and short arm length were the karyotypic features that distin- guished the parents and the hybrids. Unweighed Pair Group Method with Arithmetic Mean (UPGMA) dendrogram differ- entiated the wild accessions at the intra varietal level. Close relationship of the F1 hybrids with the wild accession W2 was also evident. UPGMA clustering indicates that the wild acces- sion W1 may be the immediate ancestor of the cultivated variety. The karyotypic data can be utilized to differentiate the wild and the two cultivated varieties of Momordica charantia and to clarify their intra specific relationships. The findings may provide useful information on the systematics of Momordica charantia.