Cytogenetic studies on the F1 hybrid Solanum indicum x S. torvum.

The F1 hybrid Solanum indicum x S. torvum could be maintained only under special conditions. Meiosis was highly irregular: about 45% of chromosomes remained as univalents and wherever pairing was observed, it appeared to be loose. A maximum number of three higher chromosome associations other than bivalents, including 'Y' and 'spoon' type associations, indicate extensive chromosome repatterning. Occasional occurrence of twelve bivalents per PMC suggests that, notwithstanding the extreme divergence, the species have retained sufficient ancestral chromosome homoeologies. Chromosome distribution at anaphase-I was highly irregular and precocious division of chromosomes was observed frequently. This hybrid was 100% sterile and the dropping off of immature flower buds was observed.