Maturity index as related to growing season and supply chain management of musa (aa group) 'kluai khai' in Thailand

Maturity index is one of the important factors in the supply chain management of export bananas. This paper consists of two components; 1) analysis of the supply chain management of 'Kluai Khai' in Chanthaburi and Sukhothai provinces during October 2009-May 2010 by structured interview of farmers, collectors, and exporters; and 2) analysis of 'Kluai Khai' for export from October 2010-August 2011 in three growing seasons at Sukhothai (winter season) and Chanthaburi provinces (summer and rainy seasons) using maturity index .The objectives of these studies were to describe the supply chain management practices for 'Kluai Khai' produced in two planting areas to determine the optimum time for bunch harvest and the relationship between growing seasons, bagging bunches and bunch harvest. 'Kluai Khai' cultivar was grown in fruit orchards in Chanthaburi through intercropping, with an average yield of 6.25 t/ha. Bunches were harvested at 3/4 full and sold to the collectors who took charge of postharvest handling procedures. Approximately, 60-70% of the total production met the standard grade, the remainder was off-grade due to insect and/or disease and/or under-sized fruit, hence, priced 8-10 times lower than the standard grade. In Sukhothai, bananas were grown as the main crop at a density of 2,500 plants/ha. Postharvest handling operations were conducted at the orchard by the exporters. Fruit hands that met the standard criterion (60-70%) were graded into three sizes (AAA, AA and A). Average yield was 14.2 t/ha and the production cost was around 79,662 Baht/ha (US2,600/ha). For maturity index, the banana was harvested at different physiological ages; 30, 33, 35, 37, 40, 45 and 50 days after debudding. Most fruit quality parameters at different physiological ages were not vary significantly, but optimum time for bunch harvest (70-80% maturity) in winter, summer and rainy seasons was 45-50, 37-40 and 33-37 days, respectively, after debudding. Similarly, the growing degree days from flower bloom to harvested in winter, summer and rainy seasons was 918-1008, 676-731 and 613-690 degree days, respectively. The greater physiological ages produced greater starch 12.11-17.69%. Bunches bagged with paper coated, polyethylene reduced skin defects.