Temperature growth models of guava (Psidium guajava L.)

P.A. Chen, M.Y. Huang, S.Y. Lin, S.F. Roan, I.Z. Chen
Guava (Psidium guajava L.) can start a new growth cycle after branch pruning all year round in Taiwan. Guava production seasons could be regulated by pruning. However, the period of growth cycle is affected by the pruning season. We studied establishing temperature models for good prediction of growth cycle and harvest time in guava production. A commercial guava cultivar 'Diwang Ba' was pruned every two months from February to December in 2008 in Kaohsiung, Taiwan. The phenology of guava including flushing, anthesis, fruit setting, and fruit harvesting were observed every week after pruning. Three thermal requirement models of (A) anthesis (from pruning to 50% branch anthesis); (B) fruit growth (from 50% branch anthesis to 25% fruit harvest); (C) full growth period (from pruning to 25% fruit harvest) were estimated. The models were established by 'coefficient of variation in accumulated thermal unit method' and 'regression method'. The average days of each period were 70.83 (coefficient of variation: 28.06%), 113.50 (22.54%), and 184.33 (10.85%), respectively. The base temperatures of three models were 8.48, 9.11 and 4.33°C, respectively. The thermal requirements degree-hour of three models were 25754.39 (9.59%), 40273.18 (6.08%), and 85704.53 (4.31%). Our results indicated that the three thermal requirement models could estimate the separated growth periods well, and the accuracy of our models was much better than what was predicted by growth days.
Chen, P.A., Huang, M.Y., Lin, S.Y., Roan, S.F. and Chen, I.Z. 2017. Temperature growth models of guava (Psidium guajava L.). Acta Hort. (ISHS) 1166:157-160
pruning, phenological stage, cropping cycle

Acta Horticulturae