State of the art

Papaya, conclusions of the 2nd. Int. Symposium

The Second International Symposium on Papaya was held at Madurai, India from 9 to 12 December 2008 under the aegis of the International Society for Horticultural Science

(ISHS) and Tamil Nadu Agricultural University (TNAU), Coimbatore, India. Professor Dr. N. Kumar organized it and is the author of the article published by Chronica Horticulturae Vol.49/Nr.1 which represents a view of the state of the art in papaya. The present text includes the most relevants parts of Dr. Kumar text.

The theme of the symposium “Papayas for Nutritional Security” addressed the need for cultivating papaya from traditional small holdings to commercial orchards to alleviate the problem of malnutrition, especially Vitamin A deficiency, in many developing countries. 

Dr. K.L. Chadha, in his inaugural address gave an overview of the papaya industry at a global level and highlighted the need to establish a global gene bank for papaya in line with other tropical fruit crops like banana. Dr. C. Ramasamy underlined the importance of maintaining the genetic purity of the released cultivars of papaya because of its high cross pollinating nature. 

The session “International Trade, Marketing and Papaya Industry” came out with the recommendation to explore the possibility of increasing the export potential of papaya in many countries.

The recommendations from the session, on “Genetic Resources and Crop Improvement” are that there should be a free flow of germplasm with strict quarantine between the countries and more studies on inheritance of quantitative characters and mutation breeding to create more variability should be carried.

During the session on “Biotechnology” it was discussed the reasons for non-adoption of transgenic Papaya Ringspot Virus (PRSV) resistance technology in countries other than Hawaii: due to variation in the strains, anti-GM attitude, regulatory and quarantine barriers.  PRSV shows genetic diversity within isolates originating from different locations.

Regarding “Nursery Practices, Planting and Cropping Systems in Papaya”, recommendations are following:

1. A comprehensive trial including seedlings, cuttings and grafts should be conducted to study the growth, productivity and quality in papaya.

2. Studies on the influence of rootstock on scion has to be investigated in detail.

3. Systematic studies on suitable cropping systems including high density planting are to be taken up.

The session, “Growth Regulators, Nutrient and Water Management in Papaya” came out with the following recommendations:

1. Isolation and characterization of native microbial organisms to identify efficient

strains of bio fertilizers for papaya.

2. Monitoring soil health to recommend integrated nutrient management (INM) practices for sustainable papaya production.

3. Foliar nutrition studies to enhance nutrient use efficiency and faster nutrient disorder corrections.

The session on “Pest and Disease Management” emphasized the following:

1. A need to prevent the spread of papaya mealy bug using local quarantine. Efforts must be made to locate suitable natural enemies for its management.

2. Monitoring the incidence and extent of aphid vectors at a national level would be of immense value in initiating PRSV management strategies.

3. More studies on basic and strategic research for the management of papaya leafcurl virus.

4. Biotechnological approaches on PRSV management should be in the lines of work in Taiwan through gene silencing based on gene sequence of PRSV-p and PRSV-W.

5. A global network on PRSV is required to tackle this disease consisting of virologists, biotechnologists and entomologists.

The Working Group on Papaya of the ISHS developed a series of recommendations around three pertinent issues:

1. There is an urgent need to establish a Global Field Gene Bank for papaya. It was decided that India will explore the possibility to establish this global gene bank for which ICAR and Bioversity International global fiat may be requested.

2. Papaya researchers attending the symposium wanted an “Electronic News Letter” through which the researchers could interact and focused on the research activities going on in different countries.

3. The researchers also felt that there is an immediate need to compile all the research information in the form of a book (may be published in an international publication) so that the researchers could have all the information on papaya production, post harvest, value addition, breeding, and biotechnology.  

Recommendations concerning “Post Harvest Handling and Storage” are:

1. All the papaya growing countries need to have their priority shifting towards post production research and to this effect the research infrastructure and networking are to be strengthened.

2. The expertise on post harvest handling, packing, transport in Brazil is an excellent base and a role model for other countries. Effective exchange programmes need to be worked out on both technologies and machineries/infrastructure.

3. There is an urgent need to encourage scientists working on post harvest technologies so as to develop sufficient human resources in this relatively neglected field.  

Concerning “Product Development and Processing” the recommendation is to develop a number of products from papaya and also the possibility of blending it with other cheaper fruits in view of the escalating price of papaya fruits.

Contact

Dr. N. Kumar, Professor (Hort), Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu-641003, India, email: kumarhort@yahoo.com

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