MSc

The present study entitled “Evaluation of tomato (Solanum lycopersicum L.) genotypes
for yield under water stress conditions” was carried out in the Department of Plant Breeding and
Genetics, College of Agriculture, Vellayani during 2015-2017, with an objective to identify high
yielding genotypes of tomato under water stress conditions.
Twenty genotypes including 12 accessions from the previous project in the Department
viz., Nellanadu local, Kuttichal local I, Venpalavattam local, Palakkad local, Vellayani local I,
Kottayam local , Kuttichal local II, Kaithamukku local, Pettah local, Vellayani local II, Haripad
local and Thrissur local along with 8 released varieties Arka Alok, Arka Vikas, Arka Saurabh,
Arka Meghali, Vellayani Vijay, Anagha, Akshay and Manulekshmi were evaluated in a
Randomized Block Design (RBD) with three replications during October 2016- February 2017.
Water stress was imposed from flowering onwards by restricting the irrigation to once in three
days at 10mm depth. The analysis of variance was calculated for the characters under study viz.,
plant height (cm), number of primary branches plant-1, number of leaves plant-1 , days to 50 %
flowering, number of fruits cluster-,1, number of fruits plant-1, fruit length (cm) , fruit girth (cm),
fruit volume (cm3), fruit weight (g), yield plant-1(g), stomatal frequency, relative water content
(%), canopy temperature (0C) and proline content of leaves (μmol g-1) and was found to be
significant for all the genotypes evaluated.
The mean performances of the genotypes for the characters under study were evaluated.
The maximum yield was recorded for the accession A6 (Kottayam local) and the minimum yield
was observed for accession A1 (Nellanadu local). The accession A6 (Kottayam local) showed
the highest mean values for stomatal frequency, relative water content and proline content.
The proline content of leaves exhibited the highest GCV (66.02 %) and PCV (68.00 %).
High heritability coupled with high genetic advance was observed for stomatal frequency, yield
plant-1, proline content, number of fruits plant-1, fruit volume (cm3), number of leaves plant-1 and
number of primary branches plant-1. The yield plant-1 was found to be significantly and
positively correlated with plant height (cm), number of primary branches plant-1, number of
fruits cluster-1, number of fruits plant-1, fruit length (cm), fruit girth (cm), fruit volume (cm3),
fruit weight (g), stomatal frequency (number cm-2), relative water content (%), canopy
temperature (0C) and proline content of leaves (μmol g-1) both at genotypic and phenotypic
levels. Days to 50% flowering was found to be negatively correlated with yield plant-1. The path
analysis revealed that number of fruits cluster-1 and fruit weight had the maximum positive direct
effect on yield plant-1.
The study revealed that accession A6 (Kottayam local) was superior in yield performance
under water stress condition followed by the accession A4 (Palakkad local), accession A2
(Kuttichal local I) and accession A7 (Kuttichal local II). The accession A6 (Kottayam local) also
recorded the highest relative water content, stomatal frequency and proline content.
Accumulation of proline in leaves was found to be an important water stress tolerance
mechanism.