GENETIC VARIABILITY, HERITABILITY AND
CORRELATION IN WATERMELON
Abd Rabou, A.M. and E.M. El-Sayd
Veg. Res. Depts., Horticulture Res. Inst., Agric. Res. Center, Giza, Egypt.
Email- aymanabtrabou40@gmail.com
Key words: Genetic Variability, Heritability, Correlation, Watermelon.
ABSTRACT
This study was conducted at Kaha Vegetable Research Farm
(K.V.R.F), Qalubia governorate, Egypt and private farm in Wady El-
Nitroun during the period from 2015 to 2017 to determine the variability,
heritability and correlation among some watermelon inbred lines. The
treatments consist of forty two watermelon inbred lines, laid out in
randomized complete block design (RCBD) and replicated three times.
Inbred lines were evaluated for ten characters to determine variability,
estimate heritability and correlation. Analysis of variance revealed highly
significant (P<0.05) for all characters. The results indicated the presence of
substantial variability among the genotypes. Genotypic coefficient of
variation (GCV), phenotypic coefficient of variation (PCV) and broad Sense
heritability (h2) estimates ranges from 14.05-72.98, 14.86-73.84 and 89.36-
99.94% respectively. The high estimates of GCV and PCV in this study
indicated the existence of variability and selection can be done. Whereas
high estimate of h2 for the tested traits indicated that these characters were
highly heritable and selection can be imposed. Significant phenotypic
correlation for fruit diameter, fruit length, fruit weight and number of fruits
per plant with total yield per plant revealed that, these characters were
primarily influenced by their direct contribution to higher yield. Four inbred
lines had best marketable yield and fruit quality as red and yellow
watermelon inbred lines. Therefore, it is recommended for an effective
selection of those characters which could be adopted for cultivar
improvement and hybridization program and more research is needed to
validate the findings.
INTRODUCTION
Watermelon (citrullus lanatus thunb.) is one of the most popular and
widely grown cucurbitaceous fruit vegetable crops in tropical and subtropical
countries of the world. It’s global consumption is greater than that of
any other cucurbits (Goreta et al. 2005). In desert areas, the juicy flesh
serves as substitute for drinking water. The flesh which is soft and spongy is
reddish or pink or yellow or yellowish white in color (Anburani et al. 2019)
Success of watermelon production and profits accrued are
determined by the choice of genotype, production method and market
demand. Basic market requirements relate primarily to fruit characteristics
such as fruit size, rind thickness, taste, meat color, fruit shape and color
Egypt. J. of Appl. Sci., 36 (3) 2021 43-58
(Jelica et al. 2011). Current demands of both consumers and producers are
an important item in watermelon breeding programs, especially for fruit
traits. These requirements are: fruit size of 4-6 kg, good taste (8-10% TSS),
rind thickness up to 1.5 cm, round to oval-shaped fruit, small seeds, and very
high meat ratio. Watermelon breeding includes the development of breeding
lines, cultivars and hybrids using different crossing methods. To increase the
efficiency of breeding, it is necessary to know the genetic basis of the traits
that are being improved in the available material selection.
Anburani et al (2019) studied the genetic variability and heritability
in thirty watermelon genotypes and the results showed significant
differences among all studied characters.
Genetic variation among traits is important for a crop improvement
programme and in breeding or selecting desirable types. Information of
variability patterns allows breeders to comprehend the evolutionary associations
among genotypes in a better way, to collect genotypes in a more organized
manner, and to make plan to incorporate valuable material in their germplasm
(Bretting and Widrlechner,1995). Anburani et al. (2019) reported that
characters, viz., fruits diameter, , number of fruits per plant and yield per plant,
recorded high estimate of PCV and moderate estimation of GCV. Meanwhile,
the characters, viz., number of seeds per fruits, and fruit diameter recorded
moderate estimate of PCV and GCV. Also, high heritability (broad sense) was
observed for 100 seed weight, number of seeds per fruit, fruit diameter, fruit
length, yield per plant, and number of fruits per plant.
Hence, the present investigation was attempted to find out the extent
of genotypic variability and heritability for yield and yield components with
a view to identify the best red and yellow watermelon inbred lines.
MATERIALS AND METHODS
This study was conducted during the three successive summer seasons
from 2015 to 2017.Forty two watermelon inbred lines (Table 1) collected from
diverse sources (40 from Netherland Gene Bank and 2 from Philippine Agr.
Co.). Selfed pollinated at Kaha Vegetable Research Farm (K.V.R.F), Qalubia
governorate, Egypt were done for 7 generations to have pure inbred lines. These
inbred lines cultivated at K.V.R.F in 2015 to ensure their purity. Forty two
watermelon inbred lines cultivated at private farm at Wady El- Nitroun in
summer seasons of 2016 and 2017 to estimate phenotypic coefficient of
variation (PVC), genotypic coefficient of variation (GCV) and heritability for
yield, yield components and fruit quality. Seedlings were transplanted on March
1st, 2016and March 2nd 2017in the open field. The experiment was set up in a
randomized complete block design with three replications. The experiment unit
area was 20 m2. Twelve watermelon plants were planted in each unit: three
rows 2 m apart, and plants spacing in row, 1m. Land preparation, fertilizer
application and other field practices were conducted according to
recommendations of the Egyptian Ministry of Agriculture.
44 Egypt. J. of Appl. Sci., 36 (3) 2021
Table 1. performance of studied watermelon genotypes.
1
2
3
Genotypes 2-2-1-2 2-3-3-8
2-3-1-
1(11)
Flesh color Rose Rose Dark red
Rind color
Dark
Green
Green
with dark
Green
lines
Dark
Green
Seed color Brown Black Black
Seed size Large Large Medium
4
5
6
Genotypes
2-3-1-
1(12)
2-3-1-2 2-3-1-3
Flesh color Rose Red White
Rind color
Dark
Green
Green
Dark
Green
Seed color Brown Brown Brown
Seed size Medium Large Large
7
8
9
Genotypes 2-3-1-7 2-3-2-1 2-3-3-11
Flesh color Orange Rose White
Rind color Green
Green
with dark
Green
lines
Dark
Green
Seed color Brown Black Black
Seed size Large Large Small
Egypt. J. of Appl. Sci., 36 (3) 2021 45
Table 1. Count
10
11
12
Genotypes 2-4-4-8 2-3-4-11 2-3-4-8
Flesh color Rose Orange Red
Rind color
Dark
Green
Green
Dark
Green
Seed color Black Black Black
Seed size Medium Large Small
13
14
15
Genotypes 2-4-1-1 3-1-1-6 3-4-2-2
Flesh color Orange Yellow
light
Yellow
Rind color
Dark
Green
Green
Dark
Green
Seed color Brown Brown Black
Seed size Medium Medium Large
16
17
18
Genotypes 3-4-2-5 6-1-4-9 6-2-1-11
Flesh color Red Canary Canary
Rind color
Dark
Green
Dark
Green
Green
Seed color Brown Brown Black
Seed size Medium Medium Small
46 Egypt. J. of Appl. Sci., 36 (3) 2021
Table 1. Count
19
20
21
Genotypes 6-2-2-12 6-2-2-16 6-2-3-1
Flesh color Canary Canary Red
Rind color Green Green Green
Seed color Black Black Black
Seed size Small Medium Large
22
23
24
Genotypes 6-2-3-10 6-2-3-11 6-2-3-15
Flesh color Canary yellow
Light
yellow
Rind color
Dark
Green
Green
Dark
Green
Seed color Brown Black Black
Seed size Medium Large Medium
25
26
27
Genotypes 6-2-3-16 6-2-3-2 6-2-3-3
Flesh color Yellow
Light
yellow
Dark red
Rind color
Dark
Green
Dark
Green
Dark
Green
Seed color Black Black Black
Seed size Small Large Medium
Egypt. J. of Appl. Sci., 36 (3) 2021 47
Table 1. Count
28
29
30
Genotypes 6-2-3-3-18 6-2-3-8 6-2-3-9
Flesh color Dark red Canary Yellow
Rind color Green
Dark
Green
Green
Seed color Black Black Black
Seed size Medium Medium Small
31
32
33
Genotypes 8-1-1-18 8-1-1-20 8-1-1-21
Flesh color Yellow Orange Orange
Rind color
Dark
Green
Green
with dark
Green
lines
Green
with dark
Green
lines
Seed color Brown Brown Black
Seed size Large Large Medium
34
35
36
Genotypes 8-2-1-1 8-2-1-10 8-2-1-12
Flesh color Dark red Dark red Dark red
Rind color
Dark
Green
Green
Dark
Green
Seed color Brown Black Black
Seed size Medium Large Small
48 Egypt. J. of Appl. Sci., 36 (3) 2021
Table 1. Count
37
38
39
Genotypes 8-2-1-3 8-2-1-6 8-2-1-9
Flesh color Light rose Red Orange
Rind color
Dark
Green
Dark
Green
Green
with dark
Green
lines
Seed color Black Black Black
Seed size Large Large Small
40
41
42
Genotypes 7-5-3-5
Philippine
28-2
Philippine
25-3
Flesh color yellow White Rose
Rind color
Dark
Green
Light
Green
Light
Green
with dark
Green
lines
Seed color Black Black Black
Seed size Large Large Medium
Egypt. J. of Appl. Sci., 36 (3) 2021 49
Studied watermelon genotypes were recorded for 10 quantities
traits, viz., number of fruits per plant (NF), average fruit weight (kg)
(FW), total yield per plant (kg) (TY), rind thickness (cm) (RT), total
soluble solids (%) (TSS), fruit length (cm) (FL), fruit diameter (cm)
(FD), number of seeds per fruit (NS), 100 seeds weight (g) (SW),and
fruit shape index (SHI)).
Mujaju (2009) reported that the pulp of watermelon varies from
yellow or green (wild forms) to dark red (cultivars).Soluble solids were
measured in degrees brix using a refractometer that was dipped three
times into the flesh in the center of the fruit (Gusmini and Wehner,
2005).
Observations were recorded on various characters and subjected
to statistical analysis. Collected data were subjected to analysis of
variance (ANOVA) using Statistix 8software version 8.0 (2003) and
correlation was also determined. Genotypic coefficient of variation
(GCV), phenotypic coefficient of variation (PCV), and environmental
coefficient of variation (ECV) were calculated according to
Sivasubramanian and Menan(1973) and heritability (h2) was calculated
according to Johnson et al(1955).
RESULTS AND DISCUSSION
The general analysis of variance showed significant differences
among the 42 genotypes of watermelon for all ten studied characters in
2016 and 2017 (Table 2).
1- Number of fruits per plant:
Data showed that only line 6-2-3-16 and 6-2-3-15 had the highest
values of number of fruits per plant in both two seasons (7.0, 6.6, 6.7 and
6.2, respectively), with significant differences with the other inbred lines
in 2016 and 2017. The lowest number of fruits per plant was ranged
from 2.8 to 3.2 and obtained at 5 inbred lines in first season and 4 inbred
lines in second season with significant differences with the other inbred
lines.
2-Fruit weight:
Data obtained on fruit weight are illustrated in Table (2).It is clear
that the genotype6-2-2-16 gave the heaviest fruit weight in both two
seasons (8.2 and 8.1 kg, respectively). The lightest fruit weight was
obtained in genotype 2-4-1-1 (1.9 and 2.0 kg) in both seasons
respectively. it could be concluded that genotype 6-2-2-16had the highest
value of fruit length, diameter and weight. (Gusmini and Wehner 2005)
studied 80 cultivars and found the range of mean value revealed
sufficient variation for average watermelon fruit weight between 1.59 to
9.58.
50 Egypt. J. of Appl. Sci., 36 (3) 2021
3- Total yield/plant:
Data obtained on the total yield per plant are illustrated in Table
(2). The results indicated that evaluation of genotypes based on higher
yield per plant ranged from (7.6 to 40.5 kg) and (8 to 42.5Kg) in both
seasons respectively, genotype8-2-1-12 (40.50 and 42.5Kg) as the top
ranking genotype with significant differences with other inbred lines.
Philippine 28-2 had the lowest values of total yield per plant in two
season without significant differences with 4 inbred lines in 2016 and 7
inbred lines in 2017.
4- Rind thickness:
Rind thickness in the studied 42 watermelon inbred lines studied
ranged from 0.34 to 2.0 cm (Table 2) in the two summer seasons of 2016
and 2017. Rind thickness was significantly greatest in the genotype6-2-3-
8 in both seasons of study (2.00 and 1.98 cm, respectively). Slim rind
were obtained with Philippine 28-2 in both seasons (0.4 and 0.34 cm)
respectively. Gusmini et al. (2004) divided watermelons into three
groups based on the rind thickness. The first group were genotypes with
the rind thickness >1.9 cm, the second from 1.0 to 1.9 cm and the third
<1,0 cm.
5- Total soluble solids (%):
Total soluble solids in the studied 42 watermelon inbred lines in
both seasons had wide ranged from 3.0 % to 12.4 (Table 2). In both
seasons, total soluble solids was significantly greatest in 6-2-3-16 in both
seasons of study (12.3 and 12.4 %) respectively. LowestTSS was
obtained with Philippine 28-2 in both seasons (3 and 3 %, respectively).
Jelicaet al. (2011) studied six parents and their 30 hybrids for sugar
content which ranged from 8.8 to 10.8%.
6-Fruit length
Data obtained on the trait fruit length are illustrated in table (2).
The results obtained that the 4 inbred lines (2-3-1-1-11, 2-3-3-11, 6-2-2-
16 and 8-2-1-12) gave fruit length above 40 cm in both two seasons. On
the contrary, 2-4-1-1gave the shortest fruit length on both season (18.8
and 17.7cm, respectively). These results agreement with Gusmini and
Wehner(2005) who studied 80watermelon cultivars and found that fruit
length ranged from20.17 to 52.00 cm.
7-Fruit diameter
Data obtained on the trait fruit diameter of 42 watermelon inbred
lines are presented in table (2). Data showed that only line 6-2-2-16gave
the highest values of fruit diameter in both seasons (39.5 and 38.2 cm,
respectively), with significant differences with the other inbred lines in
2016 and 2017. The lowest fruit diameter was obtained on2-4-1-1 (12.6
and 13.0 cm) in both seasons, respectively.
Egypt. J. of Appl. Sci., 36 (3) 2021 51
Table 2. Means performance of studied watermelon genotypes.
NF FW TY RT TSS FL FD NS SW SHI
Genotypes 2016 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 2017
1 2-2-1-2 4.5 4.1 3.3 3.2 13.5 13.1 0.64 0.69 10.0 10.0 28.1 30.5 20.2 21.7 291.1 294.6 14.6 15.2 1.40 1.41
2 2-3-3-8 3.2 3.0 4.9 4.8 15.1 14.4 1.30 1.32 8.1 8.1 32.9 36.7 32.2 31.0 314.1 309.7 7.4 8.0 1.10 1.18
3 2-3-1-1(11) 4.4 4.8 6.4 6.2 30.3 29.8 1.19 1.11 11.0 10.7 43.7 41.3 34.8 33.5 156.0 150.0 7.7 8.3 1.23 1.23
4 2-3-1-1(12) 4.8 4.3 4.6 4.8 21.9 20.5 1.00 0.97 9.0 9.0 32.9 35.6 29.7 29.2 351.0 354.5 7.3 7.9 1.17 1.22
5 2-3-1-2 4.5 4.1 4.0 4.1 18.0 16.7 1.57 1.52 5.5 5.5 32.1 34.5 22.0 23.9 435.5 429.5 10.8 10.3 1.47 1.44
6 2-3-1-3 4.9 5.3 3.0 2.8 14.4 14.7 1.00 0.97 8.6 8.7 29.6 28.2 20.9 20.2 265.5 269.0 5.6 5.1 1.40 1.40
7 2-3-1-7 4.5 4.1 4.9 4.8 22.3 19.6 1.00 0.98 8.1 8.1 33.2 35.6 29.9 28.6 168.1 163.7 5.9 6.4 1.17 1.24
8 2-3-2-1 4.2 3.7 5.1 5.3 21.4 19.2 1.60 1.58 9.8 9.8 37.1 39.5 33.7 32.4 298.9 292.9 4.9 4.4 1.17 1.22
9 2-3-3-11 3.9 4.3 6.9 7.0 26.6 29.8 1.70 1.67 8.7 8.8 42.4 41.3 35.9 34.6 211.4 214.9 6.1 6.7 1.20 1.19
10 2-4-4-8 4.2 3.8 4.0 3.8 16.7 14.4 1.60 1.62 7.2 7.3 31.5 33.9 24.5 23.2 131.8 127.3 4.9 4.4 1.40 1.46
11 2-3-4-11 4.5 4.0 5.8 6.0 26.5 23.9 1.20 1.18 6.9 6.9 38.7 41.1 34.6 33.3 36.4 37.8 6.9 7.4 1.17 1.23
12 2-3-4-8 5.5 5.9 3.3 3.5 18.3 20.6 1.50 1.47 8.9 8.9 36.0 31.9 24.2 22.9 268.8 264.3 6.0 6.5 1.43 1.39
13 2-4-1-1 4.5 3.8 1.9 2.0 8.1 7.6 1.40 1.38 6.3 6.4 18.8 17.7 12.6 13.0 327.8 321.8 3.0 3.1 1.43 1.36
14 3-1-1-6 4.2 4.0 5.2 5.0 23.4 20.1 1.90 1.87 11.6 11.2 34.6 37.0 32.6 31.3 376.1 370.2 8.6 9.2 1.13 1.18
15 3-4-2-2 3.9 4.3 4.4 4.5 17.0 19.4 1.20 1.22 11.2 11.0 32.6 35.2 28.9 27.6 303.9 298.0 10.6 11.0 1.20 1.28
16 3-4-2-5 4.2 3.8 2.2 2.3 9.2 8.5 1.10 1.07 8.8 8.5 29.0 25.3 19.6 18.3 388.9 392.4 4.3 3.9 1.43 1.38
17 6-1-4-9 5.4 4.8 2.7 2.5 14.5 12.4 1.40 1.42 11.0 10.8 23.7 26.1 20.4 19.1 198.6 192.6 11.1 11.6 1.30 1.37
18 6-2-1-11 5.4 4.9 3.3 3.4 17.7 16.7 0.60 0.58 9.5 9.6 28.9 31.3 24.1 22.8 267.7 263.2 8.3 8.9 1.30 1.37
19 6-2-2-12 6.0 6.4 4.3 4.5 26.2 28.9 0.50 0.48 6.9 7.0 32.4 34.8 28.6 27.3 152.8 148.3 5.9 6.5 1.20 1.27
20 6-2-2-16 6.4 3.3 8.2 8.1 31.8 26.9 1.00 0.98 11.8 11.8 40.3 42.1 39.5 38.2 363.2 358.7 7.7 7.2 1.07 1.10
21 6-2-3-1 3.9 5.8 2.6 2.7 16.7 15.9 1.60 1.57 8.0 8.9 24.1 26.5 20.9 19.6 399.6 393.6 6.5 7.0 1.30 1.35
22 6-2-3-10 4.5 4.1 3.2 3.3 14.5 13.6 1.40 1.38 9.4 9.4 28.4 30.8 24.7 22.0 393.3 396.8 10.5 10.0 1.27 1.40
23 6-2-3-11 4.5 4.9 4.4 4.5 19.7 22.2 1.30 1.27 5.8 5.8 32.3 35.1 28.6 27.3 308.3 303.8 8.9 9.4 1.20 1.29
24 6-2-3-15 6.7 6.2 3.8 4.0 25.5 24.3 1.20 1.22 11.9 11.8 31.8 34.2 25.0 23.7 152.0 155.5 11.1 11.6 1.37 1.44
25 6-2-3-16 7.0 6.6 4.5 4.6 31.6 30.3 0.70 0.67 12.3 12.4 34.7 35.5 29.4 28.1 35.8 39.3 5.9 6.5 1.23 1.26
26 6-2-3-2 4.2 4.6 4.1 4.2 17.3 19.4 1.30 1.32 8.9 8.9 37.7 34.6 27.1 25.8 251.3 254.8 3.4 3.2 1.37 1.34
27 6-2-3-3 3.2 2.8 2.9 2.7 9.3 7.6 1.10 1.07 3.9 3.9 24.2 26.6 21.3 19.9 200.8 196.3 9.4 10.0 1.20 1.34
28 6-2-3-3-18 5.1 4.6 5.9 6.0 29.9 27.2 1.20 1.18 10.5 10.3 36.9 39.8 34.1 32.8 193.5 190.7 9.1 8.6 1.13 1.21
29 6-2-3-8 3.9 4.3 5.1 5.2 19.6 22.3 2.00 1.98 6.8 6.9 36.9 39.3 33.6 32.3 231.4 224.9 4.6 5.1 1.17 1.22
30 6-2-3-9 2.9 3.3 4.3 4.4 12.4 14.5 1.30 1.27 7.9 7.9 32.2 34.6 27.9 26.6 280.5 284.0 8.9 9.4 1.23 1.30
31 8-1-1-18 3.0 2.8 3.3 3.2 10.7 8.8 1.50 1.48 5.8 5.8 33.4 30.1 22.6 21.5 165.6 161.1 8.9 9.5 1.43 1.40
52 Egypt. J. of Appl. Sci., 36 (3) 2021
Table 2. Cont.
NF FW TY RT TSS FL FD NS SW SHI
Genotypes 2016 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 2017
32 8-1-1-20 3.5 3.1 5.1 5.2 18.2 16.2 1.40 1.38 10.5 10.3 36.4 38.8 33.2 31.9 386.8 382.3 8.0 8.5 1.17 1.22
33 8-1-1-21 3.5 3.9 2.2 2.3 7.6 8.9 1.20 1.22 11.8 11.6 22.9 25.3 19.3 18.0 376.0 370.0 13.9 13.4 1.30 1.41
34 8-2-1-1 3.9 3.3 2.8 2.7 10.9 9.0 1.30 1.32 9.0 9.1 23.9 26.3 20.6 19.3 380.5 384.0 8.0 8.6 1.30 1.36
35 8-2-1-10 4.5 4.1 3.8 4.0 17.4 16.3 1.50 1.52 6.4 6.4 32.1 34.5 24.2 23.7 295.5 291.0 9.4 9.9 1.40 1.46
36 8-2-1-12 5.4 5.8 7.5 7.3 40.5 42.5 0.90 0.88 11.7 11.5 40.0 41.5 32.3 35.6 188.0 184.0 5.3 4.8 1.20 1.17
37 8-2-1-3 3.1 3.0 4.9 5.1 17.4 15.1 1.20 1.17 5.8 5.8 35.0 37.4 32.7 31.4 238.5 232.5 5.6 5.1 1.13 1.19
38 8-2-1-6 4.9 4.3 3.1 3.1 16.2 13.8 1.70 1.68 9.1 9.1 24.9 29.8 18.2 21.0 430.5 434.0 11.4 11.9 1.40 1.42
39 8-2-1-9 5.9 5.4 2.7 2.9 16.0 15.5 0.90 0.87 10.7 10.5 26.0 28.4 21.7 20.4 337.8 331.8 8.6 9.2 1.30 1.39
40 7-5-3-5 4.2 3.7 2.8 2.9 11.6 10.4 0.80 0.82 9.6 9.6 26.9 29.3 20.5 20.8 339.5 330.0 6.2 6.6 1.37 1.41
41
Philippine
28-2
3.8 3.2 2.1 2.3 8.0 7.3 0.40 0.34 3.0 3.0 23.4 22.8 18.5 17.2 119.0 114.5 14.9 15.2 1.30 1.33
42 Philippine
25-3
3.8 3.3 3.8 3.6 14.1 12.0 1.60 1.57 5.0 5.0 28.7 32.7 25.9 23.1 288.0 282.0 8.3 7.8 1.27 1.42
Mean 4.5 4.3 4.1 4.2 18.5 17.9 1.24 1.22 8.6 8.6 31.7 33.2 26.5 25.6 269.0 266.4 8.0 8.2 1.27 1.32
Range
2.9 to
7
2.8 to
6.6
1.9 to
8.2
2 to
8.1
8.1 to
40.5
7.3 to
42.5
0.4 to 2
0.34 to
1.98
3 to
12.3
3 to
12.4
18.8 to
43.7
17.7 to
42.1
12.6 to
39.5
13 to
38.2
35.8 to
435.5
37.8 to
434
3 to
14.9
3.1 to
15.2
1.07 to
1.47
1.1 to
1.44
LSD 4.5 4.3 4.1 4.2 18.5 17.9 1.24 1.22 8.6 8.6 31.7 33.2 26.5 25.6 269.0 266.4 8.0 8.2 1.27 1.32
NF=Number of fruits per plant, FW= fruit weight (kg), TY=Total yield per plant (kg), RT=Rind thickness(cm), TSS= Total soluble solids (%), FL=Fruit length (cm), FD=Fruit
diameter (cm), SHI = shape index, NS= Number of seeds per fruit and SW =100 seed weight (g)
Egypt. J. of Appl. Sci., 36 (3) 2021 53
8- Number of seeds per fruit
Number of seeds per fruit of the studied inbred lines had wide rang
from 35.8 to 435.5 seeds (Table 2) in both seasons. The genotypes 2-3-4-11 and
6-2-3-16 had the lowest number of seeds per fruit with significant differences
with the other inbred lines in 2016 and 2017. on the other hand, 2-3-1-2 and 8-
2-1-6 had the highest number of seeds per fruit with significant differences with
the other inbred lines in 2016 and 2017. Anburani et al (2019) studied thirty
watermelon genotypes and found that number of seeds per fruit ranged from
115.00 to 422.67 seeds. Messiaen (1994) reported that watermelon seeds are
relatively large, with 7–20 seeds/g, varying in color i.e., white, green, yellow,
grey, tan, brown, red, black as well as mixed colours. Seeds continue to mature
as the fruit ripens and the rind lightens in color.
9- 100 seeds weight (g):
100 seeds weight of the studied inbred lines had wide rang from 3 to
15.2 g (Table 2) in both seasons. The inbred lines 2-4-1-1and 6-2-3-2 had the
lightest 100 seed weight with significant differences with the other inbred lines
in 2016 and 2017. on the other hand, 2-2-1-2 and Philippine 28-2 had the
heaviest 100 seeds weight with significant differences with the other inbred
lines in 2016 and 2017. Anburani et al (2019) studied thirty watermelon
genotypes and found that 100 seed weight ranged between 4.25 and 12.63g.
10-Fruit shape index
Data obtained on fruit shape index trait are presented in table (2).The
results showed that the values of fruit shape index ranged from 1.07 to 1.43 in
the both seasons, these values referred that the shape of all inbred lines were
round and cylindrical, this scale of fruit shape index of melon fruits by Rashidi
and Seyfi (2007). These shapes are excellent for market. Gusmini and
Wehner (2005) studied the length/diameter ratio (L/D) in watermelon and
found that fruit shape index ranged between 1.1 and 2.3.
These results agreement with Jelica et al (2011) which reported that the
current demands of both consumers and producers are an important item in
watermelon breeding programs, especially for fruit traits and said these
requirements are: fruit size of 4-6 kg, good taste (8-10% SS), rind thickness up
to 1.5 cm, round to oval-shaped fruit, small seeds and very high meat ratio.
Genetic studies
Selection is the fundamental process in the development of superior
varieties and it depends on the variability available in the crop. Genetic
variability is the basic need for a plant breeder to initiate any breeding
programme. A wide range was observed for the major yield contributing
characters and wide variances were observed for these traits.
- PCV and GCV
Greater variability ensures better changes of producing new desirable
forms. Phenotypic coefficient of variation (PCV) and genotypic coefficient of
variation (GCV) were computed for ten studied characters on 42 genotypes of
54 Egypt. J. of Appl. Sci., 36 (3) 2021
watermelon (Table 3). The PCV for different characters ranged from 14.86%
(fruit shape index) to 73.84% (total yield per plant). The GCV ranged from
14.05% (fruit shape index) to 72.98% (total yield per plant). High amount of
fixable variation in watermelon characters has been reported by Lalta et al.
(1998). In the present study, high estimates of both GCV and PCV were
registered for the studied traits, viz., FW (60.21 and 60.31% respectively), NS
(66.04 and 66.06% respectively), SW (61.84 and 62.12% respectively) and TY
(72.98 and 73.84% respectively) which suggest greater phenotypic and
genotypic variability among the accession and responsiveness of the attributes
for making further improvement by selection.
Moderate estimates of GCV and PCV were registered for the traits FD
(40.13and 40.13% respectively), TSS (46.43 and 46.45% respectively), NF
(39.18 and 40.31% respectively) and RT (51.27and 51.32% respectively).
Low estimates of GCV and PCV were registered for the traits viz., FL
(29.14and 29.79% respectively) and SHI (14.05and 14.86% respectively),
which indicated that these traits were less affected by environment. (Indiresh
1982) reported similar results in bitter gourd. This suggests that these characters
may be less influenced by environment which is agreement with the findings of
Tomer et al. (2008) in muskmelon.
Table 3. Estimation of PCV, GCV, heritability and genetic advance
as per cent of mean for various characters in watermelon.
No. Characters VE VG VP GCV PCV h2
1 FD 0.99 105.35 106.34 40.13 40.31 99.07
2 FL 4.23 93.46 97.69 29.14 29.79 95.67
3 FW 0.02 6.27 6.28 60.21 60.31 99.69
4 NF 0.16 2.80 2.97 39.18 40.31 94.45
5 NS 17.30 30956.40 30973.70 66.04 66.06 99.94
6 SW 0.23 25.49 25.72 61.84 62.12 99.11
7 TSS 0.02 16.30 16.31 46.43 46.45 99.90
8 TY 4.05 169.97 174.02 72.98 73.84 97.67
9 RT 0.00 0.39 0.39 51.27 51.32 99.82
10 SHI 0.004 0.032 0.04 14.05 14.86 89.36
NF=Number of fruits per plant, FW= fruit weight (kg), TY=Total yield per plant (kg), RT=Rind
thickness TSS= Total soluble solids (%), FL=Fruit length (cm), FD=Fruit diameter (cm), SHI =
shape indexNS= Number of seeds per fruit and SW =100 seed weight (g)
- Heritability
In the present study, almost all the characters exhibited high heritability
value which ranged from 89.36 to 99.94 per cent. The characters included 100
seed weight, number of seed per fruit, single fruit weight, fruit diameter, fruit
length, flesh thickness, and yield per plant. High heritability values obtained for
all traits in the present study suggest that these traits may generally be governed
by additive gene action and hence the phenotype would provide a fairly reliable
measure of the genotype which provides scope for selection based on the
phenotypic performance.
In general, we can notice that the differences between phenotypic
and genotypic variance for all studied traits were low. In other words, the
Egypt. J. of Appl. Sci., 36 (3) 2021 55
large portion of phenotypic variance (σ2
p) was due to the genetic variance
(σ2
g). Consequently, estimated broad-sense heritability showed high
values for these traits, indicating that the observed significant phenotypic
differences among the studied inbred lines are of genetic nature and there
are small environmental effects on the phenotypic variation. Therefore,
these characters can be improved through selection based on phenotypic
observations in early segregating generations in watermelon germplasm.
- Correlation
Simple correlation coefficient among 42 watermelon inbred lines
is presented in (Table 4). The result indicated highly significant positive
correlation for FD with FL (0.66), FW(0.23) and TY (0.44). Whereas
negative correlation was recorded with SHI(-0.26). Significant and
highly positive correlation for FL with FW (0.33) and TY (0.50)
respectively were also observed. Whereas negative correlation was
recorded with SHI (-0.12). Significant and highly positive correlation for
FW with RT (0.15) and TY (0.82) respectively were also observed.
Whereas negative correlation was recorded with SHI(-0.31).Significant
and highly positive correlation for NF with TSS (0. 51) and TY (0.67)
respectively were also observed. Whereas negative correlation was
recorded with SHI (-0.09).Significant and highly negative correlation
was recorded for TY with SHI -0.27).
Table 4: Simple correlations coefficient among 42 watermelon inbred
lines.
FD FL FW NF NS RT SW TSS TY
FL 0.66
FW 0.23 0.33
NF 0.45 0.38 0.16
NS -0.32 -0.47 -0.21 -0.22
RT -0.34 -0.22 0.15 -0.27 0.40
SW 0.04 -0.18 -0.49 -0.16 0.05 -0.15
TSS 0.39 0.13 0.22 0.51 0.28 0.02 -0.14
TY 0.44 0.50 0.82 0.67 -0.34 -0.08 -0.44 0.41
SHI -0.26 -0.12 -0.31 -0.09 0.13 0.07 0.15 -0.08 -0.27
NF=Number of fruits per plant, FW= fruit weight (kg), TY=Total yield per plant (kg),
RT=Rind thickness TSS= Total soluble solids (%), FL=Fruit length (cm), FD=Fruit
diameter (cm), SHI = shape indexNS= Number of seeds per fruit and SW =100 seed
weight (g)
CONCLUSION
The results can be concluded that variability studies showed
significant differences among the 42watermelon inbred lines for all the
studied10 characters. 8-2-1-12 had the best marketable yield and fruit
quality on shape (excellent round shape), fruit weight (7.3 and 7.5 kg),
56 Egypt. J. of Appl. Sci., 36 (3) 2021
number of fruits per plant (7.5 and 7.3 cm), total yield per plant (above
40 kg), TSS (11.7 and 11.5%) and the flesh color is dark red, but the
seeds is very big, so, this inbred line is suggested to be introduction in
breeding programme for red F1 hybrids production.6-2-2-16, 6-2-3-15
and 6-2-3-16 are the best marketable yield and fruit quality as yellow
watermelon inbred lines of shape, fruit weight, number of fruits per
plant, total yield per plant, TSS and the flesh color, and they are
suggested to be introduction in breeding programme for yellow F1
hybrids production. Genetic analysis indicated maximum phenotypic and
genotypic coefficient of variation for most characters. High heritability
observed for all characters.
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التباين الو ا رثي ونسبة التوريث والارتباط بين سلالات بطيخ مرباة داخليا
ايمن محمد عبد ربه ، عصام محمد السيد
قسم بحوث تربية الخضر- معيد بحوث البساتين - مرکز البحوث الز ا رعية
أجريت ىذه الد ا رسة خلال الفترة من 5102 إلى 5102 وذلک بيدف تقدير التباين
الو ا رثي والتوريث والارتباط لبعض الصفات الإقتصادية فى البطيخ وىى صفات متوسط طول
الثمرة ، متوسط قطر الثمرة ، شکل الثمرة ، متوسط وزن الثمرة،عدد الثمار عمي النبات ،
المحصول الکمى لمنبات ، السکريات الذائبة الکمية ، سمک القشرة،عدد البذور في الثمرة،وزن
011 بذرة. وقد استخدمت فى الد ا رسة 25 سلالة مرباة تربية داخمية.وقد اظيرت النتائج وجود
تباين واسع واختلافات معنوية عالية لمصفات محل الد ا رسة. وت ا روحت قيم کلا من معامل التباين
14.05 ( عمي -72.98, 14.86- الو ا رثي ومعامل التباين المظيري ما بين ) 73.84
التوالي،وتظير ىذه القيم العالية انو يمکن الاختيار بين السلالات بسيولة. وت ا روحت قيم درجة
89.36 (، القيم العالية لمتوريث عمي - التوريث في المستوي العريض ما بين )% 99.94
المستوي العريض اظير ان الصفات قابمة لمتوريث بدرجة عالية وانو يمکن الاختيار فيما بينيا
بسيولة. واظير الارتباط المظير الکبير ما بين کلا من طول وقطر ووزن الثمرة وعدد الثمار
عمي النبات مع المحصول الکمي لمنبات. ىذه الصفات تسيم بدرجة کبيرة في الحصول عمي
انتاجية عالية. و تم اختيار 2 سلالات متفوقة في صفاتيا المحصولية والثمرية لاستکمال برنامج
التربية لانتاج ىجن قابمة لمتسويق.
58 Egypt. J. of Appl. Sci., 36 (3) 2021
