Compendium of Research Projects Completed
Between January 1996 and June 1997

Project Summaries: Cashews

A concerted R&D program in recent years has aimed to provide the platform for future development of a viable cashew industry. It is likely that Australia now has the most diverse and comprehensive genetic collection of cashew material in the world.

Furthermore, breeding efforts and production research arguably puts Australia at the forefront in terms of establishing an internationally competitive industry based on the marketing of high quality fresh nuts and a range of value-added, processed products.

Research Highlights for 1996-97 · While further research and analysis of data is still required to confirm heritability, the best hybrid clones yield up to 14 kg of nut per tree at year four, which is consistent with required yields of 30 kg from the mature tree.

EVALUATION OF CASHEW HYBRIDS

Objectives

· To complete planting and maintain the cashew hybrids (produced during 1988-92) at three test sites (Wildman River Cashew Plantation NT; Melville Forest Products, Melville Island; Cashews Australia, Qld).
· To assess growth habit, yield and nut characteristics of individual trees to identify hybrids with high yield potential.
· To initiate replicated trials with hybrids that produce high individual tree yields and medium-large nut and kernel weight during the early stages of assessment.

Background

There is a large and expanding market for increased cashew production worldwide. Australia currently imports about $A26 m worth of nuts annually. Opportunities for establishing large cashew plantations exist in the tropical areas of north Australia provided such plantings can achieve yields of more than 4 t/ha compared with the current world average production of 0.5-1.0 t/ha nut-in-shell.

Initial plantings in the Northern Territory and Queensland consisted of imported genetic material which produced only moderate yields in Australian conditions. To develop high yielding cultivars suited to local conditions, a hybridisation program involving some of the best imported and local selections was carried out during 1988-92.

Collaborators in this program included RIRDC, CSIRO Horticulture, DPI&F NT, QDPI and several private companies. These hybrids were planted during 1989-93 at three test sites owned by the collaborating private companies (Wildman River Cashew Plantation Pty Ltd, NT; Melville Forest Products Pty Ltd, Melville Island; and Cashews Australia Pty Ltd, Dimbulah Qld).

Research

During this project period the planting of hybrids was completed and initial evaluations, which commenced during the previous phase of the program (RIRDC CSH-36A), were continued and expanded. Information on growth habit, yield and nut characteristics (nut weight, kernel weight and kernel recovery) of individual trees that flowered and fruited well was collected from the hybrids produced during 1988-91 and planted during 1989-92 at the Wildman River Cashew Plantation NT and Cashews Australia Qld. A replicated trial with ten high-yielding 1988-produced hybrids was commenced at Wildman River Cashew Plantation in 1994/5. These selections were multiplied for additional replicated trials at Cashews Australia Qld and Coastal Plantation, La Belle Downs Station NT during the next phase of the project.

Outcomes

Evaluation of individual trees from the 1989-91 plantings (1988-90 hybrids) during 1992-5, resulted in the identification of a total of 49 high-yielding hybrids at the Wildman River Cashew Plantation and Cashews Australia.

Implications

Based on such encouraging results during the early stages of assessment there are good prospects of identifying many more high yielding hybrids during the next 3-5 years of evaluation. Replicated trials with such high yielding selections are planned during the next phase of the program to confirm their ability to achieve high yields in commercial plantings.

RIRDC Project No: CSH-43A

RESEARCHER: Dr Elias Chacko ORGANISATION: CSIRO Division of Horticulture PMB 44 WINNELLIE NT 0821
PHONE: 08 8944 8484 FAX: 08 8947 0052

Last updated: 22 October1997
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