Yield and Tree Size of Four Citrus Cultivars on 21 Rootstocks in California

Fruit production and tree size were measured and yield efficiency was computed for 11-year-old trees of ‘Washington’ navel and ‘Olinda Valencia’ oranges [ Citrus sinensis (L.) Osbeck], ‘Minneola’ tangelo ( C. paradisi Macf. × C. reticulata Blanco), and ‘Lisbon’ lemon ( C. limon Burm. f.) on 21 rootstocks in the San Joaquin Valley of California. Performance of most rootstocks was similar over all scions, and several rootstocks produced trees with higher yields than ‘Troyer’ and ‘Carrizo’ citranges [ C. sinensis × Poncirus trifoliata (L.) Raf.], the current standard rootstocks. ‘Yuma Ponderosa’ lemon (× C. limon) had the highest yields, but several trees on this rootstock died or were declining. Trees on ‘C-32’ citrange ( C. sinensis × P. trifoliata ) were largest, and yielded nearly as much as those on ‘Yuma Ponderosa’ lemon. ‘C-35’ citrange ( C. sinensis × P. trifoliata ) produced smaller trees with excellent yield efficiencies, and should be suitable for higher-density plantings with most scions, except perhaps navel orange, because this combination yielded poorly at other locations. ‘Rangpur’ lime ( C. limonia Osbeck) was promising only with lemon scion, and ‘Swingle’ citrumelo ( C. paradisi × P. trifoliata) only with ‘Minneola’.