Cucurbit Genetics Cooperative
Other Crop Genetics Cooperatives
Home About Membership Reports Gene Lists Conferences Links Search NCSU
Cucurbit Genetics Cooperative Report 12:59-63 (article 26) 1989

Inheritance of Orange Flesh Color in Watermelon

Warren R. Henderson

Department of Horticultural Science, North Carolina State University, Raleigh, NC 27695-7609

A variety of flesh colors are present in watermelon: red, orange, yellow, and white. Porter (3) reported yellow flesh from 'Golden Honey' was recessive, y to red flesh, Y . Poole (2) showed that yellow flesh, which he termed golden yellow, was also from 'Golden Honey' as well as from 'Yellow Flesh Ice Cream', was controlled by a single recessive gene, y. Poole demonstrated that Canary yellow from 'Honey Cream' was controlled by a single dominant gene, C, to pink flesh, c from 'Dove'. Shimotsuma (5) found that two pairs of genes with epistasis controlled white, yellow and red flesh color derived from 1) a cultivated form of Citrullus lanatus; 2) a bitter, wild type of C. lanatus; and 3) a non-bitter wild C. lanatus. White flesh was controlled by a single dominant gene, Wf, to yellow and red flesh; thus Wf = B and Wf = bb both gave white flesh; yellow flesh was dominant to red flesh and was expressed only when wfwf was present, thus yellow = wfwf B_, and red flesh was the double homozygous recessive,wfwf bb. An F2 phenotype segregation ratio would thus be 12 white: 3 yellow: 1 red.

In the present investigation the inheritance of orange flesh derived form 'Tendersweet Orange Flesh' ('Tendersweet OF') was studied in crosses with red flesh from 'Dixielee' and 'Sweet Princess', and yellow flesh from 'Golden Honey'. Following the flesh color symbols referred to earlier and those given by Robinson et. al. (4) and by Henderson et. al. (1) y will be used in this study to designate yellow flesh from 'Golden Honey' and Y red flesh color.

The F1 of 'Dixielee' x 'Tendersweet OF' was red, indicating dominance of red flesh to orange flesh. The F2 and BC1 data support a single gene hypothesis whereby orange flesh was recessive to red flesh (Table 1). Chi-square values are all non-significant indicating a good fit to the single recessive gene hypothesis for orange flesh to red flesh. Also an orange fleshed F2 selection segregated 3:1 for red to orange flesh as would be expected in 2/3 of the red selections.

A test for heterogeneity for Chi-square goodness of fit (Table 2) showed that each family segregated in a similar direction and was similar to the pooled value in both the F2 and backcross generations. Thus, reliability can be placed in the pooled data e.g. a deficiency in a character of one family was not cancelled by a surplus in another family.

In the test for allelism (Table 3) orange flesh was dominant to yellow flesh in the cross 'Tendersweet OF' x 'Golden Honey'. Further, red flesh was dominant to yellow flesh in the cross 'Golden Midget' (red flesh) x 'Golden Honey' (yellow flesh). It is tempting to hypothesize a multiple allelic system as is shown in Table 1 and 2 whereby yy = yellow flesh, yoyo or yoy = orange flesh and Y_ = red flesh. However, a dihybrid system with epistasis has not been ruled out and awaits the F2 and backcross data. Tentatively the symbol yo is given to orange flesh which is recessive to red flesh (Y) but dominant to yellow flesh (y).

Table 1. Segregation and Chi-square goodness of fit test for watermelon flesh color in the cross 'Tendersweet Orange Flesh' (orange) x 'Dixielee' (red).

 

Flesh color Offspring (no. plants)

Expected ratio

Generation

Parents

Hypothesized parental genotype(s)z

Red

Orange

Red:Orange

Chi-Square

Probability

P1

Dixielee

YY

8

0

1:0

-

-

P2

Tendersweet OFy

yoyo

3

0

1:0

-

-

F1

Dixielee x Tendersweet OF

Yyo

12

0

1:0

-

-

F2

Dixielee x Tendersweet OF F1(self)

Yyo (self)

21

11

3:1

1.50

.50-.75

BC1

F1 x Dixielee

Yyo x YY

46

0

1:0

0

1.00

BC2

F1 x Tendersweet OF

Yyo + yoyo

47

65

1:1

2.89

.05-.10

F3

F2 - red selection (self)

Y_ (self)

11

3

1:0 or 3:1

0.10

.75-.90

F3

F2 - orange selection (self)

yoyo (self)

0

10

0:1

0

1.00

z Tentative flesh color genotypes: Y_=red - dominant to orange and yellow; yoyo or yoy=orange - recessive to red, dominant to yellow; yy=yellow - recessive to both red and orange
y Tendersweet OF='Tendersweet Orange Flesh'

Table 2. Heterogeneity test for Chi-square goodness of fit test for F2 and backcross generations for watermelon flesh color in the cross, 'Dixielee' x 'Tendersweet Orange Flesh'.

Generation

df

Chi-square

Probability

F2

     

Sum of two chi-squares

2

1.66

.25 - .50

Pooled

1

1.50

.10 - .25

Heterogeneity

1

0.16

.50 - .75

Backcross (F1 x Tendersweet OF)

 

 

 

Sum of four chi-squares

4

6.73

.10 - .25

Pooled

1

2.89

.05 - .10

Heterogeneity

3

3.84

.25 - .50

Table 3. Allelism tests for watermelon flesh color.z

 

 

Flesh Color (number of plants)

Cross

Family

Red (Y_)

Orange (yoyo or yoy)

Yellow (yy)

Tendersweet OFy (yoyo) x Golden Honey (yy)

1

0

17

0

 

2

0

4

0

 

Total

0

21

0

Tendersweet OF (yoyo) x Golden Midget (YY)

1

16

0

0

 

2

13

0

0

 

Total

29

0

0

Golden Honey (yy) x Golden Midget (YY)

1

12

0

0

Tendersweet OF (yoyo) x Sweet Princess (YY)

1

19

0

0

Golden Honey (yy) x Sweet Princess (YY)

1

9

0

0

Golden Midget (yy) x Sweet Princess (YY)

1

14

0

0

z Yellow derived from 'Golden Honey', orange from 'Tendersweet Orange Flesh' and red flesh color from 'Golden Midget' and 'Sweet Princess'.
y Tendersweet OF = 'Tendersweet Orange Flesh'

x Tentative gene symbols:

  • Y = red
  • yo = orange (recessive to Y dominant to y)
  • y = yellow (recessive to Y and yo)

Literature Cited

  1. Henderson, W. R., M. Pitrat, R.W. Robinson, T.C. Wehner and T.W. Whitaker. 1987. Gene list for watermelon. Cucurbit Genetics Coop. Rpt. 10:106-110.
  2. Poole, C.F. 1944. Genetics of cultivated cucurbits. J. Heredity 35: 122-128.
  3. Porter, D.R. 1937. Inheritance of certain fruit and seed characters in watermelons. Hilgardia 10:489-568.
  4. Robinson, R.W., H.W. Munger, T.W. Whitaker and G.W. Bohn. 1976. Genes of the cucurbitaceae. HortScience 11:554-568.
  5. Shimotsuma, M. 1963. Cytogenetical studies in the genus Citrullus VI. Inheritance of several characters in watermelon. Jap. J. Breeding 13:2235-240.
Home About Membership Reports Gene Lists Conferences Links Search NCSU
Department of Horticultural Science Box 7609North Carolina State UniversityRaleigh, NC 27695-7609919-515-5363
Page citation: Wehner, T.C., Cucurbit Genetics Cooperative;
Created by T.C. Wehner and T. Ng, 1 June 2005; design by C.T. Glenn;
send questions to T.C. Wehner; last revised on 14 December, 2009