Somaclonals from F3 of the hybrid L. peruvianum and L. esculentum (IVT 741505) were produced from leaf explants on modified Murashige and Skog (MS) medium (Mahir et al., 1989). From 12 transplanted somaclonal plants (R0F3), only two plants (R0F3-1 and R0F3-2) survived normally and produced fruits.
Percentages of pollen fertility (IKI fertility test) and fruit setting (no. of fruits/no. of flowers for a cluster) were measured on plant populations of R0F3-1, R0F3-2, non-fruit bearing and fruit bearing F3 plants with Intan (a local L. esculentum) as a control. For both parameters, R0F3-1 was significantly higher than that of original F3's but lower than Intan (Table 1). Both R0F3's plants had roughly a higher ratio of 1:3 (Fertility %:Fruit setting %) as compared to fruit-bearing F3 (1:2) and Intan (1:1).
These results suggest that propagation of this hybrid could be done successfully through in vitro culture and the barrier of self-incompatibility, maybe utilized for hybridization, could be broken as seen in the ratio increase of pollen fertility and fruit setting.
Hybridization between these R0F3's plants and Intan as a female parent was attempted. From 20 crossings, only two small normal fruits were produced. One of these fruits had two seeds which germinated normally. Initial observation showed that both these seedlings had branches as compared to non-branching Intan. Further observation of these plants is currently carried out.
Table 1. Percentages of pollen fertility and fruit setting of interspecific somaclonals, original F3 and Intan.
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% Pollen % Fruit
Lines Fertility Setting Ratio
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R0F3-1 22.11b 62.22a 1:3
R0F3-2 10.11c 26.67b 1:3
F3(unbearing-fruit) 10.11c 0.00c ---
F3 (bearing-fruit) 13.58c 26.67b 1:2
Intan 83.37a 73.33a 1:1
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Values in a column followed by a different letter are significantly differentLiterature cited:
Mahir, A.M., H. Noridah and A. Ismail 1989 Tomato Genetics Cooperative report 39: 25.