Pg. 51 Gene Source Potential for Breeding of New Litchi Cultivars

The South African litchi industry has relied on only two cultivars, namely HLH Mauritius and McLean’s Red, for commercial production since the establishment of the industry approximately 100 years ago. Various other cultivars have been imported, but due to the limited environmental adaptation of litchis, early observations have shown poor suitability to South African climatic conditions, with subsequent low yields. None of these cultivars was therefore released to the industry.

Summary:

• The South African litchi industry has relied mainly on two cultivars, HLH Mauritius and McLean’s Red, for commercial production over approximately 100 years.
• Various other cultivars have been imported, but many showed poor adaptation to South African climatic conditions leading to low yields, and none were commercially released.
• The Institute for Tropical and Subtropical Crops (ITSC) holds a collection of 20 litchi cultivars and nine vegetative selections, which although not all outstanding, possess favorable characteristics useful for breeding.
• The breeding program focuses on evaluation of seedling trees from open pollination and controlled hybridization to combine favorable traits into adapted cultivars.
• Evaluations conducted in 1994/95 and 1995/96 assessed fruit yield, interior and exterior characteristics, morphological traits, and fruit quality for these cultivars and selections.
• Favorable traits identified include early and late maturing cultivars, good fruit color, small seed size, good yield, and high eating quality.
• The gene source has an abundance of late-maturing cultivars, some ripening two weeks later than McLean’s Red, and a need for more early maturing cultivars was noted.
• Cultivar Brewster was highlighted for its bright red fruit color, while Salathiel was notable for producing many shriveled seeds (small seed size).
• Selection 2 and Late Large Red showed good crop yields over multiple seasons, with Wai Chee and Kwai May Pink identified as promising from new imports.
• Suitable breeding parents are readily available for improving fruit size, with Late Large Red, Fay Zee Siu, Brewster, and Kwai May Pink being top performers.
• Eating quality is generally high across the gene pool.
• Considerable genetic variation exists among the cultivars and selections, though none currently surpass HLH Mauritius in yield per tree.
• Many selections with outstanding individual traits will be used in the breeding program to develop improved new cultivars.