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Cucurbit Genetics Cooperative Report 13:55-57 (article 22) 1990

Relationship Between the B Genes of Two Cucurbita Species, IV.

Oved Shifriss

21 Walter Avenue, Highland Park, NJ 08904

Raymond B. Volin and Tom V. Williams

Northrup King Co., 10290 Greenway Rd., Naples, FL 33962

This report provides data on the inheritance of precocious depletion of chlorophyll in C. moschata based on the cross NJ-B x IL-B (see Table 1 in the preceding report). The data were obtained in Naples, Florida, during the past three growing seasons. The spring and fall data of 1989 are presented in Tables 1 and 2 respectively. The combined data for the three seasons, including fall of 1988, are presented in Table 3.

The focus in classification is on the effects of two "precocious" genes on ovaries and stems. The genetic basis for the myriad effects of these genes on leaves, in response to environmental variations, requires a separate analysis.

With the exception of one baffling case (F2 from clone NOMP, Table 1; see also Table 3, test #5), the data agree with the hypothesis that the two "precocious" genes are non-linked (see Table 2 as well as Table 3, tests #4 and 6).

In addition to the total of 306 F2 plants in Table 2, there were 12 F2 individuals of doubtful phenotypes. These were listed in our notebook as unclassified. Of the 12, one plant, 807-34, was tentatively described as having green stems and bicolor fruits. The bicolor fruits were of the type we usually associate with plants heterozygous for the "precocious" gene of C. maxima. Nevertheless, there was a lingering doubt about the genetic basis for the bicolor fruits.

Breeding tests of plant 807-34 (or tests of other similar plants) should reveal its genotype. Any one of the following three answers is conceivable. (a) Plant 807-34 was heterogygous for the "precocious" gene of C. pepo. (b) It was a cross-over product involving the "precosious" gene of C. maxima. (c) It was heterozygous for the "precocious" gene of C. maxima, but carried elements that selectively switch one of the dual effects of this gene from dominant to recessive expression. At present we incline to believe that the third answer (c) is the correct one.

Table 1. Inheritance of chlorophyll depletion in C. moschata. Field data, spring 1989, Naples, Florida.

 

Phenotypic Classes

 

X2

 

 

PDC-O or GOTy

PDC-O

GO

 

F2

 

 

PDC-S

GS

GS

 

12:3:1

 

 

PDC-P or GB

GP

GP

 

Testcross

 

Breeding Materialsz

PDC-B or GB

GB

GB

Total

2:1:1

P

P1, NJ-B

0

5

0

5

-

-

P2, IL-B

5

0

0

5

-

-

F1, P1 x P2

20

0

0

20

-

-

F2

 

 

 

 

 

 

from clone MP

167

37

15

219

0.5738

0.70-0.80

from clone NOMP

124

47

4

175

10.9353

0.001-0.01

Testcross

 

 

 

 

 

 

F1 x Black Line

74

27

49

150

6.4800

0.02-0.05

F1 x 'Butterbush'

54

26

30

110

0.3273

0.80-0.90

zThe description of the breeding materials is given in Table 1 of the preceding report.
yThe key to phenotypic symbols is given in the text of the preceding report.

Table 2. Inheritance of precocious depletion of chlorophyll in C. moschata. Field data, fall 1989. Naples, Florida.

 

Phenotypic Classes

 

X2

 

 

PDC-O or GOTy

PDC-O

GO

 

F2

 

 

PDC-S

GS

GS

 

12:3:1

 

 

PDC-P or GP

GP

GP

 

Testcross

 

Breeding materialsz

PDC-B or GB

GB

GB

Total

2:1:1

P

P1, NJ-B

0

5

0

5

-

-

P2, IL-B

5

0

0

5

-

-

F1, P1xP2

10

0

0

10

-

-

F2

 

 

 

 

 

 

(a) from F1 plant 153-2

88

18

9

115

1.0812

0.50-0.70

(b) from F1 plant 153-8

75

15

8

98

1.2245

0.50-0.70

(c) from F1 plant 154-1

65

19

9

93

2.2115

0.30-0.50

F2 pooled

228

52

26

306

3.0729

0.20-0.30

 

 

 

Heterogeneity

1.44

0.80-0.90

Testcrosses

 

 

 

 

 

 

(a) 153-2x Black Line

24

9

15

48

1.5000

0.30-0.50

(b) 153-8x Black Line

31

9

9

49

3.4489

0.10-0.20

(c) 154-1x Black Line

27

14

9

50

1.3200

0.50-0.70

Testcrosses pooled

82

32

33

147

1.9796

0.30-0.50

 

 

 

Heterogeneity

4.29

0.30-0.50

zThe description of the breeding materials is given in Table 1 of the preceding report.
yThe key to phenotypic symbols is given in the text of the preceding report.

Table 3. Inheritance of precocious chlorophyll depletion in C. moschata. Summary of field data from fall 1988 to fall 1989, Naples, Florida.

 

 

Phenotypic Classes

 

 

 

PDC-O or GOTy

PDC-O

GO

 

 

 

PDC-S

GS

GS

 

 

Breeding materialsz

PDC-P or GP

GP

GP

 

Test

Generations & growing seasons

PDC-B or GB

GB

GB

Total

1.

P1, NJ-B: Fall '88, Spring '89, Fall '89

0

22

0

22

2.

P2, IL-B: Fall '88, Spring '89, Fall '89

22

0

0

22

3.

F1, P1xP2: Fall '88, Spring '89, Fall '89

48

0

0

48

4.

F2:

 

 

 

 

 

(a) from clone MP, Fall '88

162

34

18

214

 

(b) from clone MP, Spring '89

167

37

15

219

 

(c) from new F1 plants, Fall '89

228

52

26

306

 

F2 of test 4 pooled

557

123

59

739

 

 

X2

df

P

 

Deviation (12:3:1)

5.32

2

0.05-0.10

 

Heterogeneity

1.00

4

0.90-0.95

5.

F2 :

 

 

 

 

 

(a) from clone NOMP, Fall '88

96

25

1

122

 

(b) from clone NOMP, Spring '89

124

47

4

175

 

F2 of test 5 pooled

220

72

5

297

 

 

X2

df

P

 

Deviation (12:3:1)

14.72

2

<0.001

 

Heterogeneity

2.39

2

0.30-0.50

6.

Testcrosses:

 

 

 

 

 

(a) F1 x Black Line, Spring '89

74

27

49

150

 

(b) F1 x 'Butterbush', Spring '89

54

26

30

110

 

(c) F1 x Black Line, Fall '89

82

32

33

147

 

Testcrosses pooled

210

85

112

407

 

 

X2

df

P

 

Deviation (2:1:1)

4.00

2

0.10-0.20

 

Heterogeneity

4.79

4

0.30-0.50

7.

BC1, F1 x P1:

 

 

 

 

 

(a) Clone MP x NJ-B, Fall '88

47

43

0

90

 

(b) Clone NOMP x NJ-B, Fall '88

50

52

0

102

 

BC1 of test 7 pooled

97

95

0

192

zThe description of the breeding materials is given in Table 1 of the preceding report. The F1 seed was produced in small samples in New Brunswick, NJ, between 1983 and 1985. Most of the F2 seed (test 4, a and b; test 5, a and b) and all the BC1 seed (test 7) was also prodiced in New Brunswick, NJ. Other F2 seed (test 4, c) and all testcross seed (test 6) was produced in Naples Florida.
yThe key to phenotypic symbols is given in the text of the preceding report.
xThe data for fall 1988 were taken from Table 1 in reference 2. The data for spring and fall 1989 are in Tables 1 and 2 of the present report.
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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