Udari Rathnathunga

Title : The dependency of latex production on sex expression of Carica Papaya L

Abstract:

Papaya (Carica papaya L.) produces fruits throughout the year which are highly beneficial during pharmaceutical production for their nutraceutical and antimicrobial properties. It is a gynodioecious plant that has three sex forms: female, male, and hermaphrodite. Papain is one of the main products derived from the dried latex of immature fruits used in meat tenderization, cosmetic production, and related drug productions. The study's objectives were to evaluate the performance of female and hermaphrodite plants of papaya Red lady variety during 3 months of planting and 6 months of planting for latex production and to establish a relationship between the growth of papaya plants and latex production. The experiment was conducted at the Faculty of Technology, University of Ruhuna, Karagoda-Uyangoda, Kamburupitiya (6.0635° N, 80.5420° E; 14 m a.s.l.) of IL1A agroecological region. The experiment design was Randomized Complete Block Design (RCBD) of 10 replicates in two varieties with 1.8 m X 1.8 m spacing. The morphological characteristics of the H and the F plants of the papaya Red lady were observed for the plant height (PH), stem diameter (SD), leaf number (LN), leaf length (LL), chlorophyll content (SR), flower number (FN), fruit number (FR) and the total individual latex production per plant (LP) were measured at 3^rd and 6^th month of growing. Fully matured papaya fruits of individual plants were selected for tapping during morning hours between 6.00 – 7.00 am. Longitudinal incisions of about 02 mm from four side of each papaya fruit were directed from the stalk end to the tip and collected the latex in suitable containers. The latex yields were significantly higher in female trees during both growing periods which is contradicted to previous literature and the highest yields were observed during 3^rd month of growing. FR for female plants were also higher in female trees hence the highest FN was observed during 6^th month of growing.  However, with contrast to the latex yields, higher SR, SD, LN and FN were observed for the hermaphrodite plants for both months of growing. According to the correlations observed for the latex production with the other morphological factors; significantly negative correlations were observed with the PH for both female and hermaphrodite plants of both 3^rd and 6^th months of growing while significantly positive correlation was observed for the FR for hermaphrodite plants of both 3^rd and 6^th months of growing and female plants of 6^th month of growing; FR was significantly negatively correlated for female plants of 3^rd month of growing; FL was significantly negatively correlated for the hermaphrodite plants of both 3^rd and 6^th months of growing; LN and SP was negatively correlated for hermaphrodite plants of 3^rd month of growing and female plants of 6^th months of growing. The study summarises the considerable association of morphological factors, sex expression and the development stages with the latex production of papaya fruit.

What will audience learn from your presentation?

• The audience will understand the importance of sex expression of tropical papaya and their relationship with morphological characters.
• It will be utilized in their research work for predicting phenological sub-periods, staggering production, genetic breeding programming, harvest season planning, and climatic zoning
• The research is a practical solution to identify the latex production during different growth stages of plants for the studies on nutraceutical and antimicrobial properties of papaya.

Biography:

Dr. Udari Rathnathunga studied Agriculture at the Faculty of Agriculture, University of Ruhuna, Sri Lanka, specializing in Agricultural Biology. She received her PhD degree in 2016 at the same institution for Plant Genetics and Breeding. After two years of experience as the Senior Lecturer Department of Biosystems Technology, Faculty of Technology, University of Ruhuna, Sri Lanka she later joined the position as a Senior Lecturer at the Department of Urban Bioresources, Faculty of Urban and Aquatic Bioresources, University of Sri Jayewardenepura, Sri Lanka. She published more than 40 publications including 06 research articles in SCI journals.