الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
Three experiments were conducted in the ”Agricultural
Experimental STation” and the ”Preservation and utilization or Primitive
Gennplasm Laboratory”; Department of Horticulture; Faculty of
Agriculture at Moshtohor, zagazig University; Benha Branch, during the
period 1993 to 1996 to study the inheritance of cold tolerance of tomato
at three different phases i.e. germination, seedling, and adult plant stages.
Experiment I : Inheritance of genninability under low temperature:
Seeds of the parental genotypes Super Marmand and Castle Rock,
and F2 population of the cross Super Marmand x Castle Rock were used
in this experiment which was conducted according to the randomized
complete block design with two replicates. Each replicate contained one
group of seeds from each of the parental genotypes and 58 groups of seeds
from F2 population, whereas each group contained SO seeds were
incubated at 8 + l°C inside an incubator. The results of this experiment
can be summarized as follows:
1. Genetic differences between the parental cultivars Super Marmand
and Castle Rock were detected concerning germinability under low
temperature, where the c.v. Super Marmande was superior in this
respect.
::f. Low temperature germinability, wheather measured as germination
percentage or germination rate, was found to be inherited
quantitatively.
3. Partial dominance for low germination percentage and low
germination rate under low temperature conditions was observed.
4. The broad sense heritability estimates for low temperature
germination ranged from low to above intermediate indicating the
involvement of environmental effects on the inheritance of this
character.
Experiment 2: Inheritance 01seedllng • cold tolerance:
Seedlings of the parental cultivars Super Marmande and Castle
Rock, and seedlings of the FI and F2 populations of the cross Super
Marmande x Castle Rock were exposed to a temperature of 8° + 2°e and
a photoperiod of 14 hours for 12 days to study the inheritance of seedlingcold
tolerance. Seedlings which survived the low temperature conditions
during this period were considered tolerant while those showed leaf bums
and/or died were considered suscepetabile. The results of this experiment
can be summerized as follows:
1. Seedlings of the parental genotype Super Marmande survived the
low temperature which exposed to. However, seedlings of the
parental genotype Castle Rock did not survive this temperature and
began to bum and/or wilt.
2. Tolerance of seedlings to low temperature conditions showed
qualitative inheritance pattern.
3. Tolerance of seedlings to low temperature was found to be
controlled by one recessive gene pair (r r).
Experiment ill. Inheritance of adult plant tolerance to low
temperature
Plants of the different populations (Pb P2, Fb F2’ Be1and BC2) of
the crosses Super Mannande XCastle Rock, DC 97-3 X Super
Marmande, Line # 3 X Super Mannande, and Super Mannande X
Floradade were evaluated in the field for cold tolerance under an average
temperature of 20.9°C day and 9.1°C night during November 1994 ,
December 1994 , and January 1995. The results of this experiment can
be summerized as follows:
1. Genetic differences were detected among the different parental
genotype concerning cold tolerance of adult plants evaluated by
different measurements where the c.v, Super Mannande was the
superior to other parental cultivars/line in this respect.
2. High level of foliage cold tolerance was partially dominant over
the low level.
3. Absence of dominance for earliness of flowering under low
temperature conditions was revealed.
4. The high percentage of fruit set under low temperature showed
partial dominance over the low percentage of fruit set.
5. Partial dominance for low yield/plant under cold conditions was
observed over high yield/plant under such conditions.
6. Foliage cold tolerance, fruit set, total yield/plant under low
temperature in the field showed quantitative inheritance pattern.
7. Earliness of flowering under low temperature conditions showed
qualitative inheritance pattern.
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8. Non of the Fi hybrids showed better parent heterosis concerning
foliage cold tolerance, low temperature fruit set, and total
yield/plant under low temperature conditions. However, mid-parent
heterosis was observed for foliage cold resistance in the crosses.
Super Marmande X Castle Rock (39.44%) and UC 97-3 X Super
Marmande (17.41%), for low-temperature fruit set in the crosses
Super Marmande X Castle Rock (30.10%), UC 97·3 X Super
Marmande (62.72%), and Super Marmande X Floradade (4.83%),
and for total yield/plant in the cross UC-97 -3 X Super Marmande
(19.46%).
9. Transgressive segregatiocs for foliage cold tolerance were observed
in the F:zpopulations of the crosses Super Marmande X Castle Rock
and Line # 3 X Super Marmande and in the BCl population of the
cross Line # 3 X Super Marmande indicating that the involved
parental genotypes possess different genes controlling foliage cold
tolerance.
10. Relatively, high frequency of transgressive regregation for high
percentage of fruit set under low temperture conditions were
observed in the F:zpoulations of all crosses.
11. The broad sense heritability estimates for foliage cold tolerance
were 91.23%, 82.45, 74.69%, and 75.93% while the estimates of
the narrow sense heritability were 45.19%, 77.60, 24.18%, and 5.07
for the crosses Super Marmande X Castle Rock, UC 97-3 X Super
Marmande, Line # 3 X Super Marmande, and Super Marmande X
Floradade, respectively.
12. The broad sense heritability estimates for the ability of tomato
plants to set fruits under low temperture conditions were 96.21 %,
95.28%, 93.72%, and 96.4% for the crosses Super Mannande X
Castle Rock, DC 97·3 X Super Marmande, Line # 3 X Super
Mannande, and Super Marmande X Floradade, respectively.
13. The broad sense heritability estimates for total yield per plant were
52.63%, 52.34%, 68.74%, and 25.95% for the crosses Super
Mannande X Castle Rock, DC 97-3 X Super Marmande, Line # 3
X Super Mannande, and Super Mannande x Floradade,
respectively.
14. Number of major effective genes controlling foliage cold tolerance,
percentage of fruit set under low temperature conditions, and total
yield/plant under low temperature were 1-2, 1, 3-39 gene pairs,
respectively.
15. Earliness of flowering under low temperature condition was
controlled by one gene pair. The genotype of the late flowering
plant will be LL while that of the early flowering will be 11.Due to
the absence of dominance and possible additive effect, the
genotype L1 will give an intermediate flowering phenotype.
16. Significant positive correlation was detected between foliage cold
tolerance and each of number of branches per plant, percentage of
fruit set under low temperature conditions, number of fruits per
plant, and fruit weight.
17. Significant positive correlation was observed between percentage
of fruit set under low temperature and number of fruits per plant.
18. Significant positive correlation between total Yield/plant under low
temperature conditions and foliage cold tolerance.
19. Significant positive correlations between cold tolerance of adult
plant foliage and the studied chemical characteristics of fruits i.e.
vitamin C content, juice acidity, and total sugars content.
20. The combined effect of plant yield, percentage of fruit set under low
temperaure, fruit number/plant and fruit length was found to have
significant linear relationship with plant foliage tolerance to low
temperature.
21. The combined effect of number of fruits per plant and fruit weight
was found to have a significant linear relationship with the
percentage of fruit set under low temperature conditions.
22. High number and weight of fruits per plant in addition to low fruit
diameter were found to have a significant combined effect on total
yield per/plant. Furthermore, the combined effect of number of
fruits/plant, fruit weight, and fruit flesh thickness was highly
correlated with the amount of total yield/plant.
23. No association was observed between number of locules per fruit
and degree of foliage cold tolerance.
24. Significant association was observed in one of the crosses (line # 3
X Super Marmande) between lobulated fruits and high degree of
foliage cold tolerance.