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Sex type identification of papaya seedling by molecular markers

Sex type identification of papaya seedling by molecular markers


Papaya is one of important tropical fruit trees and can be grown year-round in Taiwan. Papaya fruit is popular by the local consumers and with export potential because it contains vitamin A, vitamin C, carotenes and rich in other nutritional value. The cultivation of seedlings gender is an important characteristic in fruit production. How do we ensure the fruit quality by identifying the sex type of papaya seedling? Papaya plants are divided into three sex types: male, female and hermaphrodite (both sex type). Hermaphrodite papaya plants have more commercial value than female papaya plants due to their fruit production advantage. Hermaphrodite type which is oblong shaped contain smaller fruit lumen and thicker flesh and less cost for packing and shipping, is the most important fruit sex type.

Hermaphrodite papaya plants are preferred to female papaya plants on the market. However, sex determination in papaya is delay until flowing stage which takes six to eight months from seeds planting without early morphological characteristics. Hence, as sex determination of papaya plants at the seedling stage is difficult. Generally, farmers plant three seeds in one pit, growing for 6-8 months until the sex type are identified, then remove the undesired plants to develop the field with only hermaphrodite plants, which entailed space and labor cost. Thus the development of rapid and reliable technique for papaya sex type identification is necessary to reduce production costs.

Taiwan Seed Improvement and Propagation Station (TSIPS) said, the application of molecular markers in papaya sex type identification, is available at the seedling stage and from single seed. This method can truly specific identify hermaphroditic papaya plants without the time-waste sex type observation testing and eliminating the uprooting costs and make production more efficient.
In addition to develop a papaya sex type identification technique, TSIPS have a unique variety "TSS No.7", which can produce 100% hermaphroditic seedlings, would be benefit to papaya industrial production.