Cucurbit Genetics Cooperative Report 8:50-54 (Article 19) 1985
Genetic Linkages in Muskmelon
Pitrat, M.
Institut National de la Recherche Agronomique, 84140 Montfavet, France
We have continued the work presented in the 1984 CGC report (5) on the research of genetic linkages in muskmelon.
1. Necrotic spot virus resistance (nsv)
This gene was already found independent from genes belonging to linkage groups 2 to 6 (5). Its linkage with bush (b) (group 1) was investigated. In a F2 progeny between VA 435 (nsv b+) and Topmark bush (nsv+ b) we have observed: 226 virus susceptible and long internode plants, 81 susceptible and bush, 59 resistant and long internode and 32 resistant and bush. With a chi- square value equal to 5.877 (Prob. = 12%) we conclude to the independence between nsv
and b.
The gene for nsv being independent from the 6 linkage
groups already described is alone in linkage "group" 7.
2. Localization of Pale mutant (Pa)
Pale
(Pa) is a semi dominant marker (3). Homozygous Pa/Pa
(white pheno-type) ia lethal. Only Pa/Pa+
(yellow phenotype) and Pa+/Pa+
(normal green) have been observed for linkage with other characters.
The following genes have been used:
a. Pale
(Pa) is 30567 (supplied by J. D. McCreight)
b. bush
(b) in Topmark bush (F. W. Zink)
c. glabrous
(gl) in Arizona glA (R. E. Foster)
d. Zucchini yellow mosaic
resistance (Zym) in PI 414723 (G. W. Bohn)
e. Flaccida necrosis
(Fn) and Fusarium oxysporum f. melonis
resistance
(Fom-1) in Doublon.
Pa
was found linked with gl
(linkage group 3) and independent from b
(group 1), Fn
(group 2), Zym
(group 4), and Fom-1
(group 5) (Table 1).
Four genes belong to linkage group 3: red stem
(r), male sterile-1
(ms-1), gl, and Pa. Pa
and r
have been found independent (2). Distance between r
and ms-1
was
estimated to 25.6 ± 0.8 (2) and between r
and gl
to
30.9 ± 3.6 (5). Distance between Pa
and gl
was estimated on the test cross F1 (Pa/Pa+ gl/gl+) x (Pa+/Pa+ gl/gl). We have observed 167 [Pa gl+], 174 [Pa+ gl], 22 [Pa gl], and 19 [Pa+ gl+].
The distance can be estimated to 10.7 ± 1.6.
In linkage group 3 gl
is very probably between r
and Pa. The position of ms-1 is under study.
3. Localization of halo marker (h)
Halo
cotyledons (h) gene has been still found independent from glabrous
(gl) and yellow green
(yg) (4).
We found halo
independent from b
(linkage group 1), Fn
(group 2), r
(group 3), and nsv
(group 7) but linked with Zym
(group 4) (Table 2).
The distance may be estimated using the maximum likelihood
method to 15.0 ± 7.5. Zym
was already found linked with andromonoecious
(a) and one gene for powdery mildew resistance (Pm-x). The order between Zym, a, h, and Pm-x
in group 4 is unknown.
4. Localization of male sterile-2 (ms-2)
Male aterile-2
(ms-2) has been described as independent from male sterile-1 (ms-l) (1). Male sterile-2
(ms-2) was found independent from b
(group 1), gl (group 3), h
(group 4), and nsv
(group 7) but linked with yg
(group 6) (Table 3). The linkage between ms-2
and yg
is
very loose as the distance may be estimated to 37.1 ± 5.4. The
order in linkage group 6 (Fom-2
- yg
- ms-2) is unknown.
5. Research for other linkages
Linkages between virescent
(v) (supplied by P. E. Nugent) and other genes were investigated. Virescent plants (v/v) may sometimes die before turning green. So there may be a deviation from the 3:1 expected ratio from normal: virescent in F2 progenies. We only present in Table 4 the segregation for the second character among the normal green plants.
The results indicate the v
segregates independently from Virus aphid transmission
resistance (Vat) (group 2), r
(group 3), ms-2
(group 6), and nectarless
(n).
We also found no linkage between nectarless
(n) (in 40099 supplied by J. D. McCreight) and Vat
(group 2), a
(group 4), yg
(group 6), and nsv
(group 7) (Table 5).
6. Conclusion
The linkages described in muskmelon may be summarized as follows:
group 1 : b
- yv
2 : Vat
- Fn
3 : r
- g1
- Pa
- ms-1
(place of ms-1
unknown)
4 : Zym
- a
- h
- Pm-x
(order unknown)
5 : Wmv
- Fom-1
6 : yg
- Fom-2
- ms-2
(order unknown)
7 : nsv
v
is independent from group 2, 3, 6, and n
n
is independent from group 2, 4, 6, 7, and v
Literature Cited
- Bohn, G. W. and J. A. Principe. 1964. A second male sterility gene in the
muskmelon. J. Heredity
55:211-215.
- McCreight, J. D. 1983. Linkage of red stem
and male sterile-1
in
muskmelon. Cucurbit Gen. Coop. Report
6:48.
- NcCreight, J. D. and G. W. Bohn. 1979. Descriptions, genetics and
independent assortment of red stem
and pale
in muskmelon (Cucumis melo
L.). J. Amer. Soc. Hort. Sci. 104:721-723.
- Nugent, P. E. 1978. Independence of halo, glabrous
and yellow green
mutants in muskmelon. HortScience
13:287-288.
- Pitrat, M. 1984. Linkage studies in muskmelon. Cucurbit Genet. Coop.
Report
7:51-63.
Table 1. Segragation data for Pale
(Pa) marker and b, Fn, g1, Zym, and Fom-1
in F2 progenies.
Genotypes |
[yellow] |
[normal green] |
chi square (6:3:2:1)
|
|
Pa/Pa+ |
Pa+/Pa+ |
Value |
Probability |
|
b+/- |
143 |
65 |
|
|
b/b |
35 |
26 |
3.342 |
34 % |
|
|
|
|
|
Fn/- |
94 |
41 |
|
|
Fn+/Fn+ |
33 |
21 |
2.651 |
45 % |
|
|
|
|
|
gl+/- |
104 |
10 |
|
|
gl/gl |
13 |
53 |
135.300 |
<.01 % |
|
|
|
|
|
Zym/- |
113 |
43 |
|
|
Zym+/Zym+ |
40 |
27 |
6.964 |
7 % |
|
|
|
|
|
Fom-1/- |
83 |
24 |
|
|
Fom-1+/Fom-1+ |
29 |
16 |
7.211 |
7 % |
|
Table 2. Segregation data for halo
(h) marker and b, Fn, r, Zym, or nsv
in F2
progenies.
Genotypes |
[normal green] |
[halo cotyledons] |
chi square (9:3:3:1)
|
|
h+/- |
h/h |
Value |
Probability |
|
b+/- |
160 |
54 |
0.446 |
93 % |
b/b |
54 |
15 |
|
|
|
|
|
|
|
Fn/- |
168 |
65 |
2.177 |
54 % |
Fn+/Fn+ |
54 |
15 |
|
|
|
|
|
|
|
r+/- |
148 |
53 |
1.505 |
68 % |
r/r |
48 |
12 |
|
|
|
|
|
|
|
Zym/- |
106 |
14 |
91.344 |
<.01 % |
Zym+/Zym+ |
11 |
37 |
|
|
|
|
|
|
|
nsv+/- |
185 |
47 |
2.860 |
41 % |
nsv/nsv |
56 |
19 |
|
|
|
Table 3. Segregation data for male sterile-2
(ms-2) and b, g1, h, yg, and nsv
in F2 progenies.
Genotypes |
[male fertile] |
[male sterile] |
chi square (9:3:3:1)
|
|
ms-2+/- |
ms-2/ms-2 |
Value |
Probability |
|
b+/- |
118 |
41 |
3.568 |
31 % |
b/b |
33 |
7 |
|
|
|
|
|
|
|
gl+/- |
141 |
53 |
4.306 |
23 % |
gl/gl |
34 |
16 |
|
|
|
|
|
|
|
h+/- |
108 |
34 |
1.279 |
73 % |
h/h |
32 |
15 |
|
|
|
|
|
|
|
yg+/- |
117 |
58 |
10.732 |
1 % |
yg/yg |
58 |
11 |
|
|
|
|
|
|
|
nsv+/- |
104 |
39 |
1.742 |
63 % |
nsv/nsv |
42 |
15 |
|
|
|
Table 4. Segregation data observed among the normal green plants in F2
progenies segregating for virescent
(v) and Vat, r, ms-2, or n.
Genotypes |
Segregation among the
normal green plants
|
chi square (3:1)
Value Probability
|
|
Vat/- : Vat+/Vat+ |
141 : 46 |
0.016 |
90 % |
r+/- : r/r |
167 : 52 |
0.184 |
67 % |
ms-2+/- : ms-2:ms-2 |
134 : 44 |
0.007 |
93 % |
n+/- : n/n |
175 : 49 |
1.167 |
28 % |
|
Table 5. Segregation data observed in F2 progenies between nectarless
(n) and
Vat, a, yg, or nsv.
Genotypes |
[with nectar]
n+/-
|
[without nectar]
n/n
|
chi square (9:3:3:1)
Value Probability
|
|
Vat/- |
53 |
20 |
4.444 |
22 % |
Vat+/Vat+ |
9 |
6 |
|
|
|
|
|
|
|
a+/- |
50 |
18 |
3.420 |
49 % |
a/a |
9 |
5 |
|
|
|
|
|
|
|
yg+/- |
94 |
39 |
|
|
yg/yg |
33 |
13 |
1.628 |
65 % |
|
|
|
|
|
nsv+/- |
94 |
34 |
|
|
nsv/nsv |
31 |
10 |
0.226 |
97 % |
|
