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Genetic Studies for Yield and Yield
Attributing Traits in Tomato (Solanum
lycopersicum L.)
Asima Amin
Dr. Kouser Parveen Wani
Ph.D
2012
Solanum lycopersicum L., combining ability,
gca, sca, components of variance, heterosis
ABSTRACT
The present investigation entitled “Genetic Studies for Yield and Yield attributing traits
in Tomato (Solanum lycopersicum L.)” was carried out to generate information on genetic
variability, combining ability (general and specific), nature and magnitude of gene effects and
nature and magnitude of heterosis. The experimental materials consisted of ten diverse lines of
Tomato (Solanum lycopersicum L.) viz. Arka Vikas, KS-227, VLT-32, DARL-63, DVRT-I,
Local, Marglobe, Shalimar-II, Roma and Shalimar-I. The parents were crossed in diallel fashion
to generate forty five crosses. The crosses and parents were evaluated as per Method II and
Model I of Griffing (1956 a, b) in randomized complete block design during Kharif, 2011 at
three different locations viz., Vegetable Experimental Farm of Division of Vegetable Science,
SKUAST (K), Shalimar (E1); Krishi Vigyan Kendra, Malangpora (E2) and Regional Research
Station, SKUAST (K), Wadura (E3). The observations were recorded on days to first fruit set,
days to first picking, plant height (cm), number of primary branches per plant, fruit size (cm 2),
flesh thickness (mm), number of fruits per plant, average fruit weight (g), fruit yield per plant
(kg), number of locules, TSS (°Brix), Vitamin C (mg/100g), Lycopene (mg/100g), Acidity (%),
Dry matter content in fruits (%) and Specific gravity. The data were analysed as per standard
statistical procedures. Analysis of variance revealed significant differences among the parents
and crosses indicating that the materials selected for present investigation were diverse. Analysis
of variance for combining ability revealed that variance due to gca and sca was significant for all
the traits suggesting the importance of both types of variances in the inheritance of traits. GCA
and SCA also interacted significantly with the environments. The estimates of dominance
variance were higher in magnitude than corresponding estimates of additive variance indicating
the preponderance of non-additive gene action. None of the parents exhibited desirable gca
effects for all the traits simultaneously. However, overall ranking of genotypes revealed that the
parents Arka Vikas, KS-227, Roma, DVRT-I and DARL-63 exhibited significant desirable gca
effects for most of the traits. None of the crosses exhibited significant desirable sca effects for all
the traits simultaneously. However, the crosses Arka Vikas x Marglobe, Local x Shalimar-II and
Arka Vikas x DVRT-I were found to be desirable for most of the traits. These cross
combinations also exhibited moderate to high values for TSS, Vitamin C, Lycopene and Acidity
depicting the superior quality of these crosses. The component analysis revealed the
preponderance of non-additive gene effects in the inheritance of traits. Net dominance effect was
significant and positive for most of the traits indicating positive direction of dominance. Positive
and significant ‘F’ values for number of primary branches/plant, flesh thickness, number of fruits
per plant, average fruit weight and fruit yield/plant indicated positive direction of dominance.
Average degree of dominance was more than unity in all the traits indicating over-dominance.
Non-significant values of t2 and deviation of regression coefficient from unity depicted the
absence of epistasis for all the traits in all the environments and pooled analysis. Higher
magnitude of heterosis in plant height, number of primary branches per plant, fruit size, number
of fruits per plant and average fruit weight suggested the possibility of yield enhancement
through exploitation of heterosis.