The South African mango breeding programme: gaining momentum towards the release of promising new cultivars

It is common knowledge, and extensively documented that classical breeding of mango cultivars is a time-consuming exercise, taking many years for a new cultivar to be released to the Industry. The Agricultural Research Council - Tropical and Subtropical Crops' (ARC-TSC) mango breeding program started 28 years ago, in 1990. From inception, only 5 cultivars were registered and released to the Industry. This situation is now starting to change mainly due to the more scientific approach of using seed from polycross nurseries as a source of natural crosses (open pollination), establishing these as Phase I seedlings. A high percentage of promising selections are derived from these orchards. This can be attributed to the concentration of superior genotypes in the polycross nursery. In addition, relocation of the mango breeding program by means of topworking onto existing trees, had the unexpected advantage of shortening the juvenile stage, as well as increasing the uniformity of the seedling plant material. During 2013 and 2014, 831 Phase I selections, 120 Phase I extension selections and 16 Phase II selections, using 5,600 grafts, were topworked at the new site. The first evaluations at the new site were carried out during the 2015/2016 season, when 168 trees were evaluated. From 35 selections that will advance, 7 selections of exceptional quality will bypass Phase I extension, and will proceed directly to Phase II. During the 2016/2017 season, 462 trees were evaluated, of which a further 37 promising selections were identified. Eighteen of these selections were deemed good enough to enter Phase II directly. Working with only 831 Phase I seedlings, and being able to identify 90 selections with potential, shows the momentum gained during the last few years of the program.