Curbit Genetics Cooperative Report 16:42-43 (article 15) 1993
Harry S. Paris, Ron Cohen, Yael Danin-Poleg, and Shoshanna Schreiber
Department of Vegetable Crops, Agricultural Research Organization, Newe Ya’ar Experiment Station, P.O. Haifa, ISRAEL
Several races of Fusarium oxysporum f. melonis afflict melons. The dominant genes Fom-1, carried by ‘Doublon’, and Fom-3, carried by ‘Perlita’, confer resistance to races 0 and 2, whereas the dominant gene Fom-2, carried by ‘CM 17187’, confers resistance to races 0 and 1. ‘Charentais T’ is susceptible to races 0, 1, and 2 (2, 3).
Resistance to Fusarium wilt races 0 and 1 was found in a number of Oriental pickling melon (Cucumis melo L. var. conomon Makino) accessions and breeding lines, including ‘Freeman’s Cucumber’ (R. Cohen and H. Herson, unpublished observations). The objective of this investigation was to determine the mode of inheritanceof resistance and identify the gene(s) responsible. for thispurpose, ‘Freeman’s Cucumber’ (seed sample kindly provided by H. M. Munger, Cornell Univ., U.S.A.) was crossed with ‘Charentais T.’ and ‘CM 17187’ (seed samples kindly provided by G. Risser, Station d’Amelioration des Plantes Maraicheres, France) to obtain filial, backcross, and testcross generations. The plants used for crossing had resulted from one or two generations of self-pollination of the original samples. Inoculation of melon seedlings with Fusarium wilt race 1 was described previously (1); identification of the pathogen as race 1 was confirmed by ising ‘Hemed’ (seed sample obtained from Hazera’ Co., Israel), which is resistant to races 0 and 2, as a control. The results presentedin Table 1 are based on inoculations made in May 1991 and in November of the following year.
All plants of ‘Charentais T’ and ‘Hemed’ were, as expected, susceptible to Fusarium wilt race 1 (Table 1). All plants of ‘CM 17187’ and ‘Freeman’s Cucumber’ were resistant. All plants of all possible F1s between ‘Charentais T’, ‘CM 17187’, and ‘Freeman’s Cucumber’ were also resistant. Therefore, the resistance to race 1 in ‘Freeman’s Cucumber’ is dominant.
The F2 of ‘Charentais T’ and ‘Freeman’s Cucumber’, with the former the female parent, fit the expected 3:1 ratio of a single dominant gene conferring reistance. Although the reciprocal cross did not fit this ratio, having an excess of susceptible individuals, the overall F2 population of this cross had a reasonable fit. Inaddition, the backcross to the susceptible ‘Charentais T’ fit reasonably well the expected 1:1 ratio for a single dominant gene conferring resistance. Therefore, it would appear that ‘Freeman’s Cucumber’, like ‘CM 17187’, carries a single gene for resistance to Fusarium wilt race 1. All plants of the bckcross to ‘Freeman’s Cucumber’ were, as expected, resistant.
No susceptible individuals out of 176 were found in the F2 of the cross of the two resistant accessions. Likewise, no susceptible individuals were found in the testcross for allelism: ‘Charentais T’ crossed with the F1 of the two resistant accessions. As stated above, ‘Freeman’s Cucumber’ was found to be resistantto race 0. These results and observations suggest that ‘Freeman’s Cucumber’ carries the same gene for resistance as ‘CM 17187’, Fom-2.
Number of plants Expected |
|||||||
Generation |
Description |
Total |
R |
S |
ratio |
X² |
P |
| P1 | Charentais T | 48 | 0 | 48 | |||
| P2 | CM 17187 | 17 | 17 | 0 | |||
| P3 | Freeman’s Cucumber | 52 | 52 | 0 | |||
| P4 | Hemed | 81 | 0 | 81 | |||
| F1 | P1 x P2 | 32 | 32 | 0 | |||
| F1 | P2 x P1 | 40 | 40 | 0 | |||
| F1 | P1 x P3 | 56 | 56 | 0 | |||
| F1 | P3 x P1 | 49 | 49 | 0 | |||
| F2 | (P1 x P3)(X) | 127 | 96 | 31 | 3:1 | 0.024 | 0.87 |
| F2 | (P3 x P1)(X) | 87 | 53 | 34 | 3:1 | 9.199 | <0.01 |
| F2 | Total | 214 | 149 | 65 | 3:1 | 2.472 | 0.12 |
| BC1 | P1 x (P1 x P3) | 220 | 100 | 120 | 1:1 | 1.818 | 0.18 |
| BC1 | P3 x (P3 x P1) | 104 | 104 | 0 | |||
| F1 | P2 x P3 | 16 | 16 | 0 | |||
| F1 | P3 x P2 | 13 | 13 | 0 | |||
| F2 | (P2 x P3)(X) | 40 | 40 | 0 | |||
| F2 | (P3 x P2)(X) | 136 | 136 | 0 | |||
| Test | P1 x (P3 x P2) | 224 | 224 | 0 | |||
Literature Cited
- Cohen, R. T. Katan, J. Katan,. and R. Cohn. 1989. Occurrence of Fusarium oxysporum F. sp. melonis race 1, 2 on muskmelon in Israel. Phytoparasitica 17:319-322
- Risser, G., Z. Banihashemi, and D.W. Davis. 1976. A proposed nomenclature of Fusarium oxysporum f. sp. melonis. Phytopathology 66:1105-1106.
- Zink, F.W. and Gubler. 1985. Inheritance of resistance in muskmelon to Fusarium wilt. J. Amer. Soc. Hort. Sci. 110:600-604.
Contribution No. 3701-E from the Agricultural Research Organization, Bet Dagan, Israel.