Effect of Treatments of Colchicine, Diethyl Sulphate and Triethylamine in Tomato (Lycopersicon esculentum Mill.)

The present investigation was undertaken in one variety of Tomato, Best of All, to compare the cytogenetic effects of treatments of seeds of tomato with colchicine, diethyl sulphate and triethylamine and also to compare the morphological and physiological effects of these chemicals.

Lowest number of seeds germinated from diethyl sulphate treatment. Plants originating from colchicine, diethyl sulphate and triethylamine treatments showed many variant types. Interesting among these were those showing spotting on leaves originating from diethyl sulphate treatment, dwarf ones originating from colchicine and diethyl sulphate treatments and those with abnormal leaves originating from treatment with all the three chemicals.

Mitotic irregularities included clumped chromosomes and fragments at metaphase and bridges and fragments at anaphase while in meiosis clumped chromosomes, univalents, trivalents and quadrivalents were noted at metaphase I. Anaphase I irregularities included cells with fragments, bridges with or without fragments, lagging chromosomes and unequal separation of chromosomes. In metaphase II cells with aneuploid chromosome numbers and those with fragments were noticed while in anaphase II cells were found with fragments and unequal separation of chromosomes.

The importance of detecting interesting mutants in the M_a generation and the importance of finding translocations and inversions have been pointed out.