Citrus - Conventional Scion and Rootstock Breeding and Evaluation__________________________________________________________________________________________________ The ARC-TSC has been involved in citrus breeding since 1974 and runs South Africa's largest citrus breeding programme. Breeding and evaluation is carried out at the ARC-TSC research farm at Addo in the Eastern Cape and involves conventional scion and rootstock breeding as well as mutation breeding. Some goals of the breeding programme include the production of high quality mandarins and niche market cultivars with improved appearance (rind colour and texture, fruit shape and size), easy peeling, seedless fruit with good flavour that ripen at a time when there is an opening in the market. Evaluation of the products from the breeding programme includes determination of harvest time, internal quality, yield attributes and scion performance on different rootstocks. New varieties are also tested for self-compatibility (to determine seed set without cross pollination), pollen viability (to determine ability to cross pollinate), and ovule fertility (to determine seed set). Biotechnology forms an important part of the citrus breeding programme. For the breeding of new seedless triploid cultivars, in vitro embryo rescue is used and flow cytometry to confirm the ploidy level of crosses. Some of the first cultivars released by the ARC-TSC citrus breeding programme through the industry Citrus Improvement Programme were 'Nelruby', 'Roma', 'Edelgard', 'Robin', 'Pomelit' and 'Nova LS'. More recent releases are Eureka! Seedless LemonTM (the first commercial seedless lemon), 'ARCCIT1614' (B17 or Valley Gold), 'ARCCIT1519' (B24 or African Sunset), 'ARCCIT9' (seedless Nadorcott) and 'Sonet'. Some other promising selections to emanate from the breeding programme are 'SweetHeart' and 'RedHeart' (grapefruit) and 'Ruby Pomelit' (pummelo). Citrus - Mutation Breeding_______________________________________
The goal of this sub-programme is to improve specific traits of citrus cultivars through irradiation. Existing commercial cultivars with some undesirable characteristics can be improved using this breeding method. Some useful improvements include lower seed content, improved internal and external pigmentation, better fruit shape and a shift in ripening time (earlier or later), which would allow these cultivars to be marketed outside of traditional marketing windows and therefore result in potentially higher returns. The ARC-TSC has the largest citrus breeding programme in South Africa and several cultivars have been released from the programme to the industry.
Contact: Johan Husselman at e-mail: infoitsc@arc.agric.za |  'ARCCIT9' Eureka! Seedless LemonTM
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Granadilla (Passion fruit) Improvement
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South Africa has a small but lucrative granadilla industry. Although growers currently rely predominantly on the cultivar 'Ester', several new cultivars are in the pipeline for development. While
Passiflora edulis remains the most important commercial species, other species are also being used in the breeding programme in order to obtain tolerance to diseases, lower temperatures and improved fruit quality. The ARC-TSC has the largest granadilla breeding programme in South Africa and several selections have been identified for cultivar Registration and protection.
Contact: Johan Husselman at e-mail:
infoitsc@arc.agric.za
Guava Improvement______________________________
The ARC-TSC guava breeding programme commenced in 1995 and is currently the largest guava breeding programme in Africa. The main aim is to breed improved varieties not only suitable for the fresh market but also for the processor. The South African guava industry is mainly based on two commercial cultivars, 'Fan Retief' and 'TS-G2', with numerous constraints such as susceptibility to Guava Wilt Disease and nematodes , poor internal fruit colour and high seed content. Due to the guava industry decline during the past 10 years in Mpumalanga and Limpopo as a result of Guava Wilt Disease (Nalanthamala psidii) in these areas, the demand for guava fruit and products has increased substantially. Although guava is one of the minor crops in the fruit industry, it is very rich in antioxidants, vitamin C, potassium and fibre and has therefore been hailed as one of the so-called super fruits due to the numerous health benefits it offers. The main production area for guava production is in the Western Cape. Promising guava selections of the ARC-TSC guava breeding programme were established in the Western Cape and are being evaluated to select new, improved cultivars suitable for that region.
Litchi Breeding and Evaluation
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 In 1992, the Agricultural Research Council initiated a litchi cultivar breeding and evaluation project. The main focus of this programme was to develop new cultivars adapted to South African conditions. Apart from improved yield, one of the main aims was to provide the industry with early and late season cultivars to extend the short marketing period. South Africa has relied on only two commercial cultivars namely 'Mauritius' and McLean's Red', which dominate commercial litchi production. For the most part, litchi breeding at the ARC-TSC is largely reliant on hand-pollination using selected parents with desirable traits. To ensure success, it is critical that viable pollen be used for crosses.
 Evaluation of the developed hybrids consists of infield determinations (yield, flowering and harvest time) and laboratory quality checks (mass, size, taste, peelability and sweetness) which are important factors describing cultivar performance. Since 2014, the programme has managed to expand the germplasm collection through new imports from Australia and Israel. These new cultivars are in the process of being evaluated both on the ARC premises and at collaborating producers for their commercial potential. Since 2012, two new cultivars were also registered with Plant Breeders' Rights, namely 'R1G22' (Early Delight) and 'TS-LIT-049'. The 'R1G22' cultivar was selected for its' earliness as it matures on average three weeks before 'Mauritius' in the eastern parts of the Mpumalanga province. The 'TS-LIT-049' was selected for improved size compared with the standard 'Mauritius', achieving on average 35-37 mm in diameter. Efforts to evaluate the performance of promising selections from the breeding programme continue and selections with favourable characteristics will be registered.
Contact Andani Mmboyi at e-mail: infoitsc@arc.agric.za.
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Macadamia Cultivar Evaluation
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The worldwide macadamia industry is relatively new and relies on cultivars either selected from the wild (in Australia) or which are, at best, only 2 – 3 generations removed from the wild types. As such, no single currently grown cultivar combines multiples of the most desirable characteristics of macadamia – high yield and kernel recovery, thin husk, good kernel appearance and size, concentrated abscission period of mature nuts, etc. Furthermore, many of the traits desirable in other horticultural crops are entirely absent in commercial macadamia cultivars, including pest and disease resistance, dwarfing, regular bearing, etc. In the absence of a South African macadamia breeding programme, the ARC-TSC is currently co-operating with the South African macadamia industry to evaluate new imported cultivars to assess whether these cultivars provide an advantage for the South African industry. Furthermore, the ARC-TSC maintains a germplasm collection of 126 cultivars and selections with the aim of conserving material should the mandate for a local macadamia breeding programme materialise. At the same time, avenues for non-conventional cultivar development are being explored in the form of ploidy doubling in macadamia. This research has yielded a chimeric cultivar which is being evaluated for potential horticultural benefits.
Contact Mark Penter at Email: infoitsc@arc.agric.za.
Mango Breeding and Evaluation
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The South African mango industry relies mainly on five commercial cultivars, namely 'Tommy Atkins', 'Keitt', 'Kent', 'Sensation' and 'Heidi'. These cultivars are not ideally suited for South African growing conditions and have serious shortcomings, e.g. susceptibility to bacterial blackspot in 'Kent' and 'Keitt' , physiological problems in 'Tommy Atkins' and 'Sensation' and poor bearing of 'Heidi' . Therefore, the mango industry is in urgent need of new mango cultivars adapted to local conditions and with improved fruit characteristics. With this in mind, a comprehensive breeding programme was started by the ARC – TSC in 1990. Promising selections from this programme were established in four different mango production areas namely Hoedspruit, Tzaneen, Malalane and Clanwilliam and are annually evaluated to identify the best selection/s for a specific area. Plant Breeder's Rights applications were filed for three selections. There are currently 98 promising mango selections under evaluation and 626 new seedlings were planted for future evaluation. The ARC-TSC competes with other organisations within South Africa regarding the placing of new mango cultivars on the market and ensures growth and competitiveness in the industry. The ARC-TSC has the largest breeding project in SA.
Contact: Salomie Willemse at Email: infoitsc@arc.agric.za. 
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