Cucurbit Genetics Cooperative Report 13:34-35 (Article 13) 1990

A Fifth Gene for Male Sterility in Cucumis melo

M. Lecouviour

Clause Semences Professionnelles, Mas St Pierre, F-13210 St Rémy, France

M. Pitrat and G. Risser

INRA, Station d'Amélioration des Plantes, BP 94, F-84143 Montfavet Cedex, France

Four genes of male sterility have been described in muskmelon (1,2,3,4). A fifth gene has been observed and used for a long time for F1 hybrid seeds production by Clause Seed Company but its description and inheritance have never been published.

This mutation was first observed in 1966 in a breeding program for introducing the powdery mildew resistance of PMR 45 in the Charentais muskmelon type.

On male-sterile plants the number of male flowers blooming is fewer than in male-fertile plants because of abortion at the bud stage. On the male or hermaphroditic flowers, the anthers are of reduced size and empty. The pollen begins to degenerate at the meiotic stage.

Inheritance of male sterility. F1 hybrids between male-sterile and male-fertile plants belonging to different types (Charentais, American Cantaloupes, Indian lines as MR-1...) are fertile and in F2 progenies we have always observed about 25% of male sterile plants (1784 male-fertile vs 560 male-sterile, x² = 1.5381, Prob = 21%). These results support the hypothesis of a recessive monogenic control of the male sterility.

Allelism tests. Allelism tests have been made with the four genes of male-sterility which have been described (Table 1). As all the observed plants are fertile,it appears that the allele under study is not allelic of the already known genes. We propose to name it male sterile-5 (symbol ms-5). This gene has been used for commercial F1 hybrid production for instance '68-02' and 'Jivaro' in the Charentais type or 'Fox' in the netted type.

Table 1. Allelism tests between the new male-sterile mutant (ms-5) and the four male sterile mutants already described.
Genotype female parent	Genotype male parent	Number of sterile plants	Number of fertile plants
ms-1 ms-1	ms-5 ms-5+	0	49
ms-5 ms-5	ms-1 ms-1+	0	30
ms-2 ms-2	ms-5 ms-5+	0	44
ms-5 ms-5	ms-2 ms-2+	0	25
ms-5 ms-5	ms-3 ms-3+	0	92
ms-5 ms-5	ms-4 ms-4+	0	90

Literature Cited

1. Bohn, G. W. and J. A. Principe. 1964. A second male-sterility gene in the muskmelon. J. Hered. 55:211-215.
2. Bohn, G. W. and T. W. Whitaker. 1949. A gene for male sterility in the muskmelon (Cucumis melo L.). Proc. Amer. Soc. Hort. Sci. 53:309-314.
3. Lozanov, P. 1983. Selekcija na mazkosterilni roditelski komponenti za ulesnjavana na proizvodstvoto na hibridni semena ot papesi. Dokl. na parva naucna konferencija po genetika i selekapa, Razgrad.
4. McCreight, J. D. and G. W. Elmstrom. 1984. A third male sterile gene in muskmelon. HortScience 19:268-270