Seeds of S. ochranthum LA 2682 and S. juglandifolium LA 2788 received from the University of California, Davis, were sown in April 1987 in glasshouse in Avignon (Lat. 44 deg. N., Long. 5 deg. E). Three plants of each species were grown in pots.
S. ochranthum blossomed in November, giving bunches of about fifteen flowers each. After vibration of the inflorescence, a large number of fruits developed and reached maturity (soft fruits with dry peduncles) in August 1988, that is, nine months after blossoming. The fruits from this species are round, 3 to 4 cm in diameter, whitish-green when ripe, with a pericarp 6 to 7 mm thick and greenish-brown juice. The seeds measure 5 to 6 mm; they are wide, flat and rough.
After natural attacking in the glasshouse, S. ochranthum was severely infested with Trialeurodes vaporariorum and Aphis gossypii, but was not attacked by Liriomyza trifolii. This resistance to L. trifolii was checked under controlled attack conditions by placing 5 one-month- old plants in the presence of caged L. trifolii, in conditions already described elsewhere (Laterrot et al. Tomato Genetics Cooperative Report N deg. 37, 47-49, 1987). No mine was found on this species whereas 47 mines on average were found to be susceptible to Meloidogyne incognita under controlled attack conditions.
S. juglandifolium placed under the same conditions as above, gave a rough attempt at flowering on a single plant in November 1987. Two cuttings of this plant flowered abundantly, but in November 1988. After vibration of the inflorescence, a large number of fruits were formed and reached maturity in March 1989, that is, about 5 months after flowering. The fruits of this species are round, 3 cm in diameter, greenish when ripe, with a 3 mm thick pericarp and brownish juice. The seeds measure 3 mm; they are flat and rough. Under natural attack conditions, S. juglandifolium was found to be infested with Trialeurodes vaporariorum, Aphis gossypii and Liriomyza trifolii.
Seeds extracted from S. ochranthum with the aid of a pectolytic enzyme solution containing 0.6% of acetic acid germinate rapidly whereas those extracted using pectolytic enzymes and 2% of hydrochloric acid do not germinate. It might be added that S. juglandifolium seeds germinate rapidly whichever the two above-mentioned methods used for extraction.