Pg. 72-73 Litchi cultivar evaluation

A short harvesting period is one of the main constraints of the South African litchi industry. Litchi cultivation in South Africa dates back to 1876 when the first litchi tree was imported from the island of Mauritius. However, plants were noticed during 1875 in the Durban Botanical gardens – thus there is evidence that litchi came into the country earlier. For more than a century only two cultivars have dominated plantings, with ‘Mauritius’ consisting of 75% of the litchi industry and ‘McLean’s Red’ 25% of the industry (Oosthuizen, 1993). Progress in litchi cultivar expansion and development has mostly been slow for a large part of this period. A demand arose in the early 1990s for high quality early and late cultivars in the wake of increasing competition from other Southern Hemisphere producing countries, also producing the midseason ‘Mauritius’ cultivar. To address this situation, a project was initiated in 1992 where available cultivars, mainly limited to research orchards, were evaluated in a co-ordinated manner. In 1993, a breeding project was initiated to purposefully combine favourable traits of promising cultivars through hybridisation (Froneman et al., 2014). 

Litchis have a large genetic variation, which is a benefit for any breeding programme. It is therefore important to breed the crop for improved fruit and tree characteristics. The objective is to breed for large fruit with small seed, good taste and long shelf life and heavy yields. Furthermore, the shortcoming in terms of the relatively short harvesting period also needs to be addressed (Froneman et al., 2014).

Summary:

• The South African litchi industry has traditionally been dominated by two cultivars: Mauritius (75%) and McLeans Red (25%), with limited cultivar expansion until the early 1990s.
• Increasing competition and a short harvesting period spurred a project initiated in 1992 to evaluate and breed new litchi cultivars with improved traits like early or late harvesting, fruit quality, small seed size, taste, shelf life, and yield.
• Breeding strategies evolved from open pollination to controlled hand pollination and targeted hybridization using specific male and female parents to combine favorable characteristics, with over 7,000 seedlings currently under evaluation.
• Promising new cultivars including Early Delight (R1G22) have been released, with ongoing trials and multiplications of over 20 selections for commercial testing across different climatic regions in South Africa.
• The program also expanded the gene pool by importing cultivars from Australia and Israel to combine superior traits and improve future breeding outcomes for the South African market.