Fruit Development, Harvest Index and Growing Degree Day of ‘Kimju’, ‘Teangmo’ and ‘Nikro’ guavas

Abstract

     Study on fruit growth, fruit quality and growing degree day (GDD) for suitable harvesting period of three guava cultivars: ‘Kimju’, ‘Teangmo’ and ‘Nikro’ grown in Chiang Mai Province. There were two major objectives including: 1) study of fruit growth and development using three replications. For each cultivar, both physical and chemical characteristics were determined for each stage of development. 2) study of suitable period of harvesting by consideration of fruit quality, sensory assessment and GDD. The results showed that pattern of guava fruit growth was double sigmoidal curve separating in to three stages. For first stage (7-42 DAF), width of the fruit gradually increased with time before shifting to second stage (49-84 DAF) which slow rate of fruit growth and finally the third stage (91-118 DAF) after rapidly growth, fruit entered maturity and ripening. For quality of fruit, it was found that when the guava ripened, the rind was light green, edible portion percentage (EP) and total soluble solids content (TSS) increased, while firmness, titratable acid (TA) and vitamin C decreased, the best harvesting period indicated for eating fruit fresh by assessment of physical, chemical and organoleptic qualities, It was found that Kimju cultivar should be harvested at 108-116 DAF with 2,204-2,346 GDD, Teangmo cultivar should be harvested at 104-110 DAF with 2,238-2,351 GDD, while Nikro cultivar should be harvested at 99-101 DAF with 2,142-2,176 GDD.