improving germination of guava (psidium guajava) seeds by acid scarification

as seed germination of guava (psidium guajava) is poor and time-consuming, the effects of seed extraction technique and scarification methods on the seed germination and seedling growth of guava cv. allahabad safeda, were investigated. first experiment was conducted on extraction of guava seeds using sulfuric acid (h2so4) : seed ratios including: 1:5, 2:5 and 3:5) or manual extraction (control) methods to investigate the effect of these methods on seed germination. the best extraction method was soaking in h2so4 (h2so4): seed ratio 1:5); these seeds exhibited the highest germination (70%) and root dry weight (340 mg). in second experiment, seed scarification using sulfuric acid (h2so4 ) was compared with scarification using hydrochloric acid (hcl). results showed that seed germination and root growth of seedlings were increased by scarification using hcl for 10 or 15 minutes. it seems that delaying seed germination of guava (psidium guajava) is mainly related to seed coat hardiness and physical dormancy.