MSc

The present study, entitled “Identification of superior tomato (Solanum
lycopersicum L.) hybrids with high yield under water stress” was conducted in the
Department of Genetics and Plant Breeding, College of Agriculture, Vellayani
during 2021–2023 with the objective of screening of tomato (Solanum lycopersicum
L.) hybrids for high yield under water stress condition.
The materials for research were chosen from a previous project in the
Department of Genetics and Plant Breeding. The experimental material included ten
F1 hybrids, viz., Vellayani Vijay x Palakkad local, PKM-1 x Kuttichal local, PKM-1 x
Palakkad local, PKM-1 x Kottayam local, Akshaya x Kuttichal local, Akshaya x
Palakkad local, Akshaya x Kottayam local, Arka Meghali x Kuttichal local, Arka
Meghali x Palakkad local and Arka Meghali x Kottayam local. These hybrids were
evaluated in both field and pots to identify the F1 hybrid combination with superior
performance for yield under water stress condition.
The field experiment was laid out in a randomized block design (RBD) with
ten treatments and three replications, and the pot experiment was conducted in a
completely randomized design (CRD) with ten treatments and three replications.
Water stress was imposed by restricting irrigation once in three days from the
flowering stage onwards in both field and pot experiments. The analysis of variance
was carried out for the characters under study, viz., plant height (cm), number of
primary branches per plant, number of days to 50% flowering, number of flower
cluster per plant, number of fruits per cluster, number of fruits per plant, fruit weight
(g), yield per plant (g), relative water content, membrane stability index, total soluble
solids (0Brix) and total acidity in both field and pot experiments. A significant
difference was noticed for all the characters of F1 hybrids in both field and pot
experiments.
The mean performance of the F1 hybrids for the characters under study was
recorded. The highest yield per plant was shown by Akshaya x Palakkad local, which
also showed the maximum value for other characters like flower cluster per plant,
fruits per cluster and fruits per plant in both field and pot experiments under water
stress condition. The F1 hybrid Arka Meghali x Kottayam local showed the minimum
value for most of the characters in both field and pot experiments under water stress
condition, hence it is noted as drought susceptible.
Qualitative analysis was carried out for F1 hybrids. The Maximum total
soluble solids was observed for PKM-1 x Palakkad local, and the maximum total
acidity was shown by Arka Meghali x Kottayam local in the field under water stress
condition. In the pot experiment, the maximum total soluble solids was recorded by
Akshaya x Palakkad local, and the highest total acidity was recorded by PKM-1 x
Kottayam local.
Analysis of physiological traits showed that the F1 hybrid, Akshaya x Palakkad
local recorded the highest relative water content and membrane stability index in both
field and pot experiments under water stress condition, indicating that this F1 hybrid
is tolerant to electrolyte loss under water stress condition.
Genetic parameters were also estimated for all the characters under study. The
highest PCV and GCV were shown by yield per plant, primary branches per plant,
total acidity, and flower cluster per plant in the field experiment. The characters fruits
per cluster and total acidity showed the maximum PCV and GCV in the pot
experiment. Under both field and pot conditions, high heritability with high genetic
advance was observed for yield per plant, flower cluster per plant, fruits per plant,
fruits per cluster and fruit weight.
Correlation and path analysis were also performed for the selected traits. All
characters showed a significant positive correlation with yield per plant, except days
to 50% flowering and membrane stability index, which showed a negative association
with the yield per plant in the field experiment. In pot studies, all characters showed a
positive association with yield per plant except membrane stability index, which
showed a negative association with the yield per plant. The characters plant height,
flower cluster per plant and fruits per plant showed a significant positive direct effects
on yield per plant in both field and pot experiments.
The present study revealed that the F1 hybrid Akshaya x Palakkad local showed
superior performance for most of the characters in both field and pot experiments
under water stress condition. Hence, this F1 hybrid is considered as water stress
tolerant and can be utilized in further crop improvement programs.