Ethylene Production by Germinating Seeds of Different Sexual Genotypes of Muskmelon (Cucumis melo L.)

admin

Cucurbit Genetics Cooperative Report 12:51-52 (article 22) 1989

L. Alvarez
Universidad de Horticultura, Servicio de Investigacion Agraria, Apartado 727, 50080 Zaragosa

The use of gynoecious genotypes has been proposed as a method for muskmelon hybrid seed production. The identification of gynoecious plants is necessary for the introduction of this character into agronomically interesting lines; in order to save time and space this identification should be done as early as possible.

It is known that cucumbers and muskmelon gynoecious lines produce more ethylene than monoecious genotypes (1, 3). Ethylene production from cotyledonary disks of cucumber changes with different sexual expressions (5). Germinating seeds of gynoecious cucumbers produce more ethylene than monoecious, andromonoecious or hermaphroditic lines (4). In this study, we tried to assess whether it was possible to identify different muskmelon sexual genotypes by measuring the ethylene produced by germinating seeds.

The plant material used in these experiments were made up of the following cultivars or lines: ‘Piel de Sapo’ and ‘Invernizo’, both andromonoecious local cultivars, line 8502, a monoecious local line, and the gynoecious line WI 998.

Ten seeds of each of the above muskmelon lines or cultivars were placed on moistened filter paper and introduced into 12.5 ml glass flasks sealed with a rubber serum cap and maintained at 30±0.5°C. Five replications were performed on each line or cultivar and the number of germinated seeds were counted 3 days later. One ml of the internal gas was taken from each flask with a chromatographic syringe and the ethylene contents of that gas determined by gas chromatography.

During the germination, seeds of the gynoecious ‘WI 998’ produced more ethylene than the other sexual genotypes, among which no significant differences were found (Table 1).

Table 1. Mean ethylene production (nl) by germinated seeds of four sexual muskmelon genotypes.

Genotype

Total C2H4 production (nl)

C2H4 production/germinated seed
Piel de Sapo 1.2 0.14 az
Invernizo 0.8 0.10 a
8502 0.9 0.11 a
WI998 1.9 0.21 b

z Means followed by different letters are significantly different (Newman-Keuls’ test, p≤0.05).

Thus, it seems possible to identify the gynoecious line WI 998 by measuring the ethylene produced by germinating seeds. This agrees with Rudich et al. (4), who found that germinating seeds of gynoecious monoecious and hermaphroditic plants. It will be necessary in the future to assess whether this higher ethylene production in germinating seeds of WI 998 will be kept when the gynoecious trait is introduced into other genetic backgrounds.

Literature Cited

  1. Byers, R.E., L.R. Baker, H.M.Sell, R.C. Herner and D.R. Dilley. 1972. Ethylene: a natural regulator of sex expression in Cucumis melo L. Proc. Nat. Acad. Sci. USA 69:717-720.
  2. Peterson, C.E., K.W. Owens and P.R. Rowe. 1983. Wisconsin 998 muskmelon germplasm. HortScience 18:116.
  3. Rudich, J., A.H. Halevy and N. Kedar. 1972. Ethylene evolution from cucumber plants as related to sex expression. Plant Physiol. 49:998-999.
  4. Rudich, J., L.R. Baker and H.M. Sell. 1978. Ethylene evolution during germination of different sex phenotypes of cucumber. Sci. Hortic. 9:7-14.
  5. Takahashi, H. and H. Suge. 1972. Sex expression and ethylene production in cucumber plants as affected by 1-aminocyclopropant-1-carboxylic acid. J. Jap. Soc. Hort. Sci. 51:51-55.