Testa (seed coat) retention by aubergine (Solanum melongena L.) seedlings during emergence in sand, peat and perlite

When seeds of aubergine (Solanum melongena L.) var. Emi and Long Negro were covered with perlite after sowing, a large percentage of the seedlings wer e unable to shed the testa during emergence. Under conditions of high atmos pheric humidity the cotyledons would be expected to subsequently free thems elves of the testa, but in the warm, dry climate of the Mediterranean regio n (especially between June and September) this process is more difficult, a nd when the tips of both cotyledons were trapped within the testa, early pl ant growth was significantly inhibited. Testa retention was reduced when se eds were covered with pear, a mixture of peat and perlite, or with 1 cm san d, but when the sowing depth in sand was increased to 3 cm emergence was re duced, Osmoconditioning or the soaking of seeds in cold water (15-18 degree s C for 24 h) or warm water (45 degrees C for 20 or 45 min) also reduced te sta retention, but deep (3 cm) sowing of seeds that had been treated for 45 min at 45 degrees C reduced emergence.