Cucurbit Genetics Cooperative Report 12:24-25 (article 11) 1989
Katarzyne Niemirowicz-Szczytt and Robert Dumas de Vaulx
Department of Genetics and Horticulture Plant Breeding, University of Agriculture, ul. Nowoursynowska 166, 02-766, Warszawa, Poland (1st. author); INRA, Station d’Amelioration des Plantes Maraicheres, 84140 Montfavet-Avignon, France (2nd author)
Pollination of muskmelon (Cucumis melo L.) with irradiated pollen resulted in the production of haploid embryos which developed into haploid plants in vitro (2). The same method was used to induce haploid cucumber embryos (3). In the latter case pollination with irradiated pollen (400 to 600 Grays, 60 Co) followed by ovule culture gave 0.3 percent viable plants. These plants were haploid (x=7) when first meristems were evaluated and exhibited mixoploid chromosome numbers (with some 3x and 4x cells) later. No details of varieties, media or plant numbers were published. The objective of this study was to determine whether a haploid cucumber F1 cultivar (2n=2x=14) could be obtained using this method.
Methods. Pistillate flowers of the cultivar Polan F1 were pollinated with pollen which had been subjected to one of two levels of irradiation (900 or 300 Grays, 60 Co.). All flowers pollinated with normal pollen produced fruits with on average 400 seeds each. After irradiation of pollen, fewer fruits developed with 250 seeds per fruit. All control seeds contained normal embryos, while only 13 embryos were produced after irradiation of pollen with 300 Grays (Table 1). Eighteen to 20 days after pollination, these embryos (heart to cotyledonary stage) were excised from seeds and cultured on E20 medium (2). Embryos were smaller than those of the control, with abnormalities on cotyledons (with respect to size, position and color) and in proper embryo development.
From these 13 embryos, 8 plants were obtained. These plants were transplanted onto a P medium (1) which promoted further development. The chromosome number of four of these plants was estimated in root and stem meristems using the Feulgen method. After four weeks in culture these four plants were micropropagated and their chromosome number was estimated a second time (Table 2).
Results. It was found that, after micropropagation of plant n°3 and plant n°4, a number of cells in new root meristems had undergone spontaneous chromosome doubling. The four remaining plants exhibited tetrological changes and were difficult to micropropagate.
Table 1. Number of fruits and embryos obtained after pollination of ‘Polan’ F1 with irradiated pollen.
Grays |
Pollinated flowers |
Number of fruits |
Embryos |
| 900 | 10 | 5 | 0 |
| 300 | 10 | 6 | 13 |
| Control | 5 | 5 | All seeds with embryos |
Table 2. Number of chromosomes before and after micropropagation in mitotic division and numbers of plants in clones.
Plant number |
Chromosome number |
Number of plants in clones |
|
Before prop. |
After prop. |
||
| 1 | 7 | 7 | 13 |
| 2 | 7 | 7 | 11 |
| 3 | 7 | 7 and 14 | 7 |
| 4 | 7 and 8 | 7 and 14 | 11 |
Fig. 1 Chromosomes in root meristem of haploid n=x=7 cucumber plant.
Literature Cited
- Masson J., M. Lecerf, P. Rouselle, P. Perennec and G. Pelletier. 1987. Plant regeneration from protoplast of diploid potato derived from crosses of Solanum tuberosum with wild Solanum species. Plant Sci. 53:167-176.
- Sauton A. and R. Dumas de Vaulx. 1987. Obtention de plantes haploides chez le melon Cucumis melo L. par gynogenese induite par du pollen irradie. Agronomie 7, 2:141-148.
- Truong-Andre, I. 1988. In vitro haploid plants derived from pollinisation by irradiated pollen on cucumber. Proc. Eucarpia Meeting on Cucurbitaceae 88:143-144.