Morphological characterization of Tomato (Solanum lycopersicum)

Tomato (Solanum esculentum L.) is the second most consumed vegetable of the world after potato and is used in various ways like for fresh market, processing, and also forms an integral part of protected cultivation as the crop is self-pollinated and have indeterminate forms. The variability present in the population is crucial for utilizing them in the breeding programs. The genetic variability and diversity among the plants can be assessed using morphological, biochemical and molecular markers, the former being the most cost effective and easily accessible. The present investigation was undertaken with the aim of morphological characterizing of tomato genotypes collected from diverse breeding environments. The study was in the department of Vegetable Science, College of Agriculture, Thrissur. The experimental material (18 accessions) comprised of exotic lines, varieties and improved lines, laid out in RBD with two replications. Characterization based on 18 qualitative characters by IPGRI, revealed significant variation among the genotypes. Determinate growth habit was noted in 18 genotypes while, 7 were semi determinate. Potato leaves and standard leaves were observed in seven accessions each while peruvianum types found in 4 accessions. Dense foliage was observed 5 accessions, sparse foliage in 2 and intermediate foliage in 1 accession. All the accessions produced perfect flowers with yellow coloured corolla and an open corolla blossom type. Oblate or flattened fruit shape were seen in two accessions, whereas, slightly flattened fruits were observed in 7 accessions.  Three had round shaped fruits while, high round fruit were seen in six accessions. Nine genotypes produced greenish-white fruits at immature stage, while seven produced light green and one produced green. Fifteen accessions produced red coloured fruits on maturity while three gave orange coloured fruits. Two accessions produced fruits with prominent green shoulders. Fruit shoulder shape varied from flat, slightly depressed and moderately depressed. Four accessions showed flat shoulder, whereas, five had moderately depressed and nine showed slightly depressed fruit shoulder. Fruit cross-sectional shape was categorized into rounded and irregular shape in the study. All accessions produced fruits with round cross section whereas, angular shape was the unique character of LE19. Four different shaped pistil scars namely dot, stellate, linear and irregular were observed. Flat blossom end was observed in all the eighteen genotypes.  Fruit cracking was observed in two accessions namely LE 32 and LE 22.  Concentric and radial cracking were seen in the fruits of LE 32 and LE 22 respectively.