International Journal of Horticulture 2015, Vol.5, No.17, 1
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per plant, three hybrids recorded positive higher
parents heterotic values, with Currant x GoldenRoma
recording the highest heterotic value, followed by
Cherry x Romavf and Currant x UC28B. For number
of leaves per plant at 60 DAT. Two hybrids recorded
positive heterotic values, the highest positive higher
parents heterotic value for these character was
exhibited by Cherry x RioGrandei. Three hybrids
recorded positive higher parents heterotic values for
number of fruits per plant. Among these Cherry x
RioGrandei showed the highest heterotic value,
followed by Cherry x GoldenRoma. Three hybrids
showed positive higher parents heterotic values for
number of flower clusters, Cherry x GoldenRoma had
the highest heterotic values. All the hybrids recorded
negative heterotic value for percentage damaged fruits.
The highest was shown by Cherry x UC28B, closely
followed by Currant x UC28B while the lowest was
recorded by Cherry x RioGrandei. Four hybrids
expressed negative higher parent heterotics values for
number of days to final harvest. Among these, Currant
x UC28B and Cherry x Romavf had higher negative
heterotics values for these characters.
Highly significant difference observed in the
mean squares for location among the genotypes for
percentage damaged fruits is an indication that
performance of the entries differ in difference
locations in terms of temperature stress. Highly
significant difference observed in the mean squares
for parents and for crosses for all character except
weight of fruit per plant indicates the existence of
genetic variability between the parents and their
respective crosses implying that the materials could be
used for varietal improvement or could respond to
selection pressure. This is in accordance with Falconer
(1981) that the amount of improvement that is
obtained by selection among a number of cross is
dependent on the level of genetic variance between the
crosses and the intensity of selection applied. Highly
significant mean squares for location and entries
interaction noticed on most characters further,
suggested that difference genotypes used in this study,
behaved differently in the respective locations with
respect to agronomic characters such as plant height at
60 days after transplanting, number of flower cluster
percentage damaged fruits and number of days to final
harvest. Highly significant differences observed in all
characters except trichome count for location x
crosses and parents x crosses interaction had a lso
suggested that the genotypes used in this study
performed differently in different locations. This
is similar to the report of Hannan and Kulkami (1998)
on tomato. They found significant di fference in
genotypes by environmental interaction for number of
fruits damaged by heat. They stated that genotypes
and environmental effect is important for heat
tolerance in tomato. This finding suggested that more
than one test environment might be needed to obtain
reliable information on the characters among the
parents and crosses. This is also similar to the report
of Kenga et al. (2004). Significant differences
observed in the general combining ability (GCA)
variances in all the agronomic characters under study
except trichome count indicates the importance of
additive gene actions in governing characters in
tomato. This is in accordance with the report of Ghosh
and Syamal (1993). The significant different observed
in the specific combining ability in most characters
under study except trichome count and number of
days to final harvest indicate the important of
non-additive gene action in controlling this characters
in tomato. Less than unity GCA:SCA observed with
respect to number of fruits per plant and trichome
count suggest the preponderance of non-additive
component of variances in the control of these
characters, this also conformed to the findings of Rao
(1978) in number of fruits per plant. Greater than
unity ratio observed in most characters indicate
additive gene actions while unity ratio observed in
characters such as number of leaves at 60 days after
transplanting and number of flower cluster indicates
these characters are controlled by both gene actions.
The study reveals that cherry, currant, UC28 and
Romavf has been identified as the best general
combiners for all agronomic characters under study.
The positive general combining ability shown by these
genotypes for all characters under study except for
percentage damaged fruits where negative is
preferable, indicated that these genotypes are good
testers and lines that had shown superiority of their
hybrids where they are both used as parents or one of
the parent. The negative general combining ability
(GCA) shown by these genotypes in case of
percentage damaged fruits is an indication of tolerance
to heat damage. The parent with good general
combining ability (GCA) also exhibited good perse
