Pollen Germination in Interspecific Crosses Between Muskmelon and Some Wild Cucumis Species

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Cucurbit Genetics Cooperative Report 2:20-21 (article 12) 1979

R. D. de Vaulx
Station d’Amélioration des Plantes Maraîchères, I.N.R.A., Domaine Saint Maurice, 84140 Montfavet-Avignon (France)

Cross pollinations were made among different lines of muskmelon (monoecious, andromonoecious, diploid, tetraploid) and five wild species of Cucumis: C. metuliferus (from Fassuliotis and Vavilov Institute), C. ficifolius (PI 196844, PI 203915), C. prophetarum (PI 193967), C. myriocarpus (1096), and C. zeyheri (PI 273192). For the description of these species, see Deakin and co-workers (1). Chromosome number of each wild species was counted.

Pollen germination and pollen tube growth were observed by means of the fluorescence technique described by Martin (3).

In the crosses between muskmelon (as female parent) and C. metuliferus or C. prophetarum, the stigmas were wounded prior to pollination to promote the pollen tube growth. The stigma was cut in the middle or was rubbed or scraped with a lanceolate needle.

Strong sterility barriers were generally present in these crosses. Frequently, there was neither pollen germination nor pollen penetration into the stigma. After germination, pollen tube growth stopped at different levels inside the style (Table 1). The most promising results were observed in the cross between diploid muskmelon as female parent, with the stigma rubbed, and C. prophetarum as male. Pollen tubes reached the muskmelon ovules and penetrated into the micropylar canal of some ovules. In this cross, the incongruity barrier seems to be localized in the first layers of cells of the muskmelon stigma. By rubbing off the stigma, the pollen tubes can overcome the barrier and reach the ovules.

The purposes of this cross were not only to introduce some disease resistances of C. prophetarum in the muskmelon but also to develop a bridge between muskmelon and other wild species.

Table 1. The effects of various physical treatments on the germination and growth of pollen in interspecific crosses.

Cross

PG1

PP2

PTQ3

PTH4

PTB5

PRO6

PM7

PE8
I-C. melo as female parent
C. melo x C. metuliferus (2x=24)
MEL(2x) x MET (Fassuliotis) xx xx xx x x E 0
MEL(2x) x MET (Vavilov) xx xx xx x 0
MEL(2x) + rubbed stigma* x MET (Vavilov) xx x x x 0
MEL(4x) x MET (Fassuliotis) xx xx xx 0
MEL(4x) x MET (Vavilov) xx x x 0
C. melo x C. prophetarum (PI 193967) (4x=48)
MEL(2x) x PRO xx xx xx E E 0
MEL(2x) rubbed stigma* x PRO xx xx xx xx x x x x
MEL(2x) cut stigma* x PRO 0
MEL(4x) x PRO x x x 0
MEL(4x) rubbed stigma* x PRO 0-x 0
MEL(4x) cut stigma* x PRO x x x 0
C. melo(2x) x C. ficifolius (PI 203915) (2x=24) xx xx xx x
C. melo(2x) x C. ficifolius (PI 196844) (4x=48) x 0 0
C. melo(2x) x C. Zeyheri (PI 273.192) (2x=24) xx 0
C. melo(2x) x C. myriocarpus (1096) (2x=24) xx xx xx 0
II-C. melo as a male parent
C. metuliferus x C. melo
MET (Fassuliotis) x MEL(2x) xx xx xx xx xx 0
MET (Vavilov) x MEL(2x) xx xx xx xx 0
MET (Fasssuliotis) x MEL(4x) xx xx xx xx x x 0
MET (Vavilov) x MEL(4x) xxx xx xx xx x 0
C. prophetarum x C. melo
PRO x MEL(2x) xx xx xx xx xx xx
PRO x MEL(4x) xxx xxx xx xx xx xx

1Pollen germination
2Pollen tubes penetration into the stigma
3Pollen tubes can reach the first fourth part of the style
4Pollen tubes can reach half part of the style
5Pollen tubes can reach the basal end of the style
6Pollen tubes can reach the ovules
7Pollen tubes into the micropyle
8Pollen tubes reach the embryo sac

0 =none; E =very few; x =a few; xx =numerous; xxx =very numerous
* see text

Literature Cited

  1. Deakin, J. R., G. W. Bohn, T. W. Whitaker. 1971. Interspecific hybridization in Cucumis. Economic Botany 25:2, 195-211.
  2. Fassuliotis, G. 1977. Self fertilization of Cucumis metuliferus Naud. and its cross compatibility with C. melo L. J. Amer. Soc. Hort. Sci. 102:3, 336-339.
  3. Martin, F. W. 1958. Staining and observing pollen tubes in the style by means of fluorescence. Stain Technol. 34:125-128.