ARS | Publication request: 'US Early Pride', a very low-seeded, early-maturing mandarin hybrid

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 21, 2011
Publication Date: N/A

Interpretive Summary: It is widely accepted that the presence of seeds in citrus fruit for the fresh market is undesirable to consumers and there is currently a belief that to be successful in the commercial mandarin (tangerine) market, fruit need to be seedless. Various approaches for developing seedless citrus fruit have been utilized; however, using irradiation to induce seedless mutants is the most rapid approach and can result in mutants that produce fruit essentially identical to the parental type with the exception of being seedless. 'Fallglo' is an important early season mandarin hybrid that is valued for its attractive, flavorful fruit; however, the fruit typically contain in excess of twenty seeds. In an effort to produce a seedless version of the 'Fallglo' hybrid, budwood was irradiated and used to produce trees that were evaluated for the production of seedless or very low-seeded mutants. A seedless mutant was identified and trees were propagated from it for further evaluation. The seedless 'Fallglo' mutant appears to be essentially identical to the 'Fallglo' hybrid with the exception of being essentially seedless, although occasionally as many as five seeds may be present. The seedless 'Fallglo' mutant has been released as 'US Early Pride'. Evaluation of ‘US Early Pride’ began on the original tree in Lake Co., Florida in 1995. Tree size, growth and fruit production, along with fruit quality characteristics of ‘US Early Pride’ have been compared with ‘Fallglo’ grown in the same proximity. ‘US Early Pride’ trees have also been evaluated for four years at the USDA farm in St. Lucie Co., Florida. Tree size and habit of ‘US Early Pride’ have been consistent with ‘Fallglo’ throughout the evaluation. ‘US Early Pride’ combines early season maturity, moderately sized fruit, pebbled rind texture with a deep orange color, and a rich sweet flavor similar to ‘Fallglo’; however, ‘US Early Pride’ distinguishes itself by being very low seeded (average <1 seed /fruit) and relatively easy to peel. ‘US Early Pride’ fruit consistently contain <5 and frequently 0 seeds in mixed plantings with a wide variety of other citrus cultivars, including mandarins, pummelos (C. maxima, (Burn.)Merrill), and oranges. Because 'Fallglo' is an important commercial cultivar with market identity, the seedless version, 'US Early Pride' should be an attactive alternative to 'Fallglo' for growers, marketers, and consumers.

Technical Abstract: ‘US Early Pride’ is an irradiation-induced, very low-seeded mutant of the ‘Fallglo’ mandarin hybrid [‘Bower’ (Citrus reticulata Blanco x (C. paradisi Macf. X C. reticulata) x Temple’]. Mature ‘Fallglo’ budwood was irradiated in 1991 using 3 kRAD units of gamma irradiation from a Cobalt-60 source in an effort to generate seedless mutants. In 1995, two trees from irradiated budwood produced seedless fruit. One of the trees (evaluated as 1-62-122) performed better than the other and was selected for further evaluation. Following evaluation of 1-62-122 trees in the field and fruit quality characteristics, 1-62-122 was released as 'US Early Pride' in 2009. ‘US Early Pride’ combines early season maturity, moderately sized fruit, pebbled rind texture with a deep orange color, and a rich sweet flavor similar to ‘Fallglo’; however, ‘US Early Pride’ distinguishes itself by being very low seeded (average <1 seed /fruit) and relatively easy to peel. ‘US Early Pride’ fruit consistently contain <5 and frequently 0 seeds in mixed plantings with a wide variety of other citrus cultivars, including mandarins, pummelos (C. maxima, (Burn.) Merrill), and oranges. Evaluation of ‘US Early Pride’ began on the original tree at the A.H. Whitmore farm, Lake Co., Florida in 1995. Tree size, growth and fruit production, along with fruit quality characteristics of ‘US Early Pride’ have been compared with Fallglo’ grown in the same proximity. ‘US Early Pride’ trees have also been evaluated for four years at the USDA farm in St. Lucie Co., Florida. Tree size and habit of ‘US Early Pride’ have been consistent with ‘Fallglo’ throughout the evaluation. The seedless character of ‘US Early Pride’, coupled with its similarity to ‘Fallglo’ in terms of maturity, fruit quality and postharvest behavior, suggest it will be an attractive alternative to ‘Fallglo’ for an early season mandarin.