- I J Froneman & Salomie Rheeder
- Institute for Tropical and Subtropical Crops, Private Bag X11208, Nelspruit 1200
- 2000
Despite a history of more than a century in South Africa, the choice of commercial cultivars available to the Litchi Industry was until recently limited to only two cultivars, namely HLH Mauritius and McLean’s Red. A variety of cultivars have been imported over the years, but early observations indicated poor adaptability to South African conditions. Evaluation was, however, only carried out in one location at the ITSC in Nelspruit. A cultivar evaluation project was therefore initiated in 1992 to evaluate existing and newly imported cultivars under a range of environments.
A breeding programme, supplementary to the cultivar evaluation project, was initiated soon afterwards in 1993 to breed new, adapted cultivars for South African conditions. The breeding programme is based on seedlings resulting from cross-, open and self pollinated flowers of different cultivars and selections. The seedlings are established in evaluation blocks where they are screened for a variety of production characteristics.
The first bearing seedlings demonstrated that considerable genetic diversity could be achieved through sexual reproduction. Several promising selections have been identified for further horticultural evaluation. To speed up the evaluation process, limited quantities of the best selections available will be released to growers for semi-commercial evaluation. This paper deals with the performance of the first bearing seedlings and a discussion of the most promising selections.
Summary:
- Historically, South African commercial litchi cultivation was limited to mainly two cultivars, HLH Mauritius and McLeans Red, with other imported cultivars poorly adapted to local conditions.
- A cultivar evaluation project began in 1992 to assess existing and newly introduced cultivars across different South African climates, followed by a breeding program started in 1993 to develop new, adapted cultivars.
- The breeding program uses seedlings from self-, open-, and cross-pollinated flowers of different cultivars, with seedlings evaluated for production traits in field trials.
- Significant genetic diversity was observed among the first bearing seedlings, almost exclusively progeny of open-pollinated HLH Mauritius, showing varied tree and fruit characteristics.
- Promising seedling selections were identified based on early to late ripening, high yield, fruit size and quality, skin color, seed size, flavor, and other horticultural traits.
- Methods like controlled hybridization and marker techniques are used to accelerate breeding and identify parentage, aiming to overcome the typically long juvenile phase of litchis (5-10 years).
- Techniques such as cincturing were tested to induce earlier flowering with limited success.
- The breeding program aims to release promising selections for semi-commercial evaluation via grafting and propagation to speed up their adoption by growers.
- Over 7,000 seedlings have been established in various trial orchards across South Africa, with ongoing evaluation to select superior cultivars for future commercial use.
- The program continues to expand, planting approximately 1,000 new seedlings annually, and focuses on managing genetic diversity, field space, and irrigation resources effectively.