Identification of cherry tomato genotypes from f3 segregants of intraspecific cross
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Date
2019
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Department of Plant Breeding and Genetics, College of Agriculture, Vellayani
Abstract
The present study entitled "Identification of cherry tomato genotypes from
F3 segregants of intraspecific cross" was carried out in the Department of Plant
Breeding and Genetics, College of Agricultme, Vellayani during 2018-2019 with
an objective to evaluate F3 segregants of the cross between cultivated tomato variety
Anagha {Solarium lycopersicum L.) and Solarium lycopersicum var. cerasiforme for
morphometric traits and fhiit quality specific to cherry tomato and genotyping the
superior segregants with SSR markers.
The materials chosen for the experiment was obtained from five F2 plants
selected from the cross between Anagha {Solarium lycopersicum L.) and Solarium
lycopersicum L. var. cerasiforme (LA2805) done in a completed Ph.D. project of
the department. A total of 150 F3 segregants from thirty plants from each F2 family
was used for the study.
Observations on nine morphometric traits were recorded in the F3
segregants and based on that twenty superior segregants were selected. These
twenty segregants were subjected to fruit quality analysis and molecular marker
analysis.
Since the F3 segregants were originated from five F2 families the interfamily
and intrafamily variation for each character was assessed.
Among the morphometric traits, plant height did not show much variation
between families and within family. Plant height of selected genotypes showing
determinate to semi-determinate grovrth habit with a maximum of 261 cm and a
minimum of 72 cm indicating selection in these segregants can lead to the
development of a determinate cherry tomato variety. Weight of fruit did not show
much variation between the families but within the family there was much variation,
all the segregants except (P-3-17)-11 had fruit weight higher than LA2805 and (P-
1-21)- 4 is having almost double the fruit weight of LA2805 parent. Number of
finits cluster'^ of all the segregants were less than LA2805. So, more emphasis
should be given on this trait in the selection in further generations.
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Dendrogram based on morphometric and finit quality data revealed that the
selected superior F3 segregants grouped into two major clusters. Anagha formed an
individual cluster and remaining F3 segregĀ£ints along with LA2805 constituting
major cluster indicating all the small fruited cherry tomato genotypes grouped into
one cluster.
Analysis for qualitative traits (Lycopene, vitamin C, pH and TSS) showed
that lycopene showed variation between the families and within the family.
Lycopene content of all the segregants except (P-3-17)- 11 was higher than
LA2805. This is a good indication as higher lycopene content is a valuable character
with respect to quality of cherry tomato. Vitamin C content of two of the segregants
(P-2-11)- 6 and (P-3-17)- 11 were higher than LA2805 parent indicating this
character will have scope for selection in further generations. Intrafamily variation
was seen for all the characters except for pH which showed a constant around 4
with maximum pH recorded in (P-5-27)- 20. TSS (%) of fruits did not show much
variation between the families but within the family there was much variation with
maximum TSS (%) of 6.8 was recorded in (P-3-17)-11.
Molecular marker analysis was done using ten SSR markers reported as
specific to cherry tomato. Out of the twenty segregants, the segregants (P-1-21)- 4
and (P-2-11)- 6 showed the presence of all the SSR markers linked to cherry tomato.
The segregants (P-2-26)- 8, (P-3-17)-11, (P-4-8)- 14 showed eight specific markers
of cherry tomato.
A proximity dissimilarity matrix was constructed between the selected
segregants and the parents based on the recorded morphometric and fruit quality
data. The results of the data revealed that distance from the cherry tomato parent
was less than 9.00 indicating that these selected superior segregants were showing
more to cherry tomato morphometric and fruit quality traits. The segregants (P-2-
26)- 8, (P-3-17)-11 and (P-4-8)-14 which had Euclidean coefficient of dissimilarity
assessed based on morphometric and fruit quality traits 4.22, 4.60 and 6.19
respectively showed eight specific markers linked to cherry tomato. The segregants
(P-1-21)- 4 and (P-2-11)- 6 which showed the presence of all the ten specific markers to cherry tomato had Euclidean coefficient of dissimilarity of 5.54 and 6.53
respectively.
Based on the morphological, biochemical and molecular data five F3
segregants (P-1-21)- 4, (P-2-11)- 6, (P-2-26)- 8, (P-3-17)-11 and (P-4-8)-14 were
selected to carry forward to further generations for getting a cherry tomato variety
with determinate growth habit, higher fruit weight, high number of fruits cluster'^,
high lycopene and vitamin C content.
Description
PG, Master of Science in Agriculture
Keywords
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