EFFECTS OF SOAKING TEMPERATURE, STRATIFICATION, POTASSIUM NITRATE AND GIBBERELLIC ACID ON SEED GERMINATION OF LOQUAT TREES

The present study was carried out to increase loquat seed germination with treatments consisting of two soaking temperatures (24 +/- 2 degrees C and 38 +/- 2 degrees C), chemical agents [control, 0.5% potassium nitrate (KNO3) and 250 mgL(-1) gibberellic acid (GA(3)) each for 20 h], and different moist chilling (MC) periods (1, 2, 3 and 4 weeks under 4-5 degrees C). Compared with 24 +/- 2 degrees C, soaking at 38 +/- 2 degrees C reduced germination %, mean daily germination (MDG), and mean germination time (MGT), plumule and radicle lengths. Germination percentage, days to 50% emergence, fresh weight and lateral root numbers significantly reduced as MC period increased. KNO3 and GA(3) had no significant effect on germination percentage, MDG, MGT and lateral root numbers. KNO3 reduced days to 50% emergence and radicle length, but increased fresh weight compared with control and GA(3). Finally, our results suggest the soaking at 24 +/- 2 degrees C followed by 0.5% KNO3 each for 20 h plus 1 week of MC or soaking at 24 +/- 2 degrees C followed by 250 mgL(-1) GA(3) each for 20 h plus 2 week of MC.