University of Hawaii at Manoa
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Seed Stocks

HFS was established in 1977 with support of the Hawaii Crop Improvement Association. Corn became the major crop of Hawaii’s seed industry, which in turn came to dominate Hawaii’s agriculture. Thus corn led the early seed stock collections of HFS. Expansion of HFS resources has focused broadly on vegetable, field, forage, and tree crops of particular importance in Hawaii and the tropics.

Field Corn Synthetics and Composites

  1. Inbred-based Synthetics
    Seven synthetics (HIS1 to HIS7) were bred and released, based on tropically-adapted inbreds of high general resistance to specific diseases [download file].

  2. Composites (O.P. varieties)
    Three broad-based composites (HIC1 to HIC3) include a QPM (opaque-2) composite, one based on 25% Zea diploperennis and one bred as an “Indian corn” from highly adapted tropical germplasm [download file].

Sweet Corn Synthetics and Composites
HFS has been involved in breeding and release of 24 sub-tropical populations (inbred-based synthetics and OP composites) of vegetable corns (sweet, supersweet, waxy). These are based on the sweet corn gene sugary1 (9 varieties) and the supersweet genes brittle1 (9 varieties), and shrunken2 (four), brittle2 (one) and waxy1 (one). Breeding has been focused on tolerance to diseases, insects and stresses unique to the tropics [download file].

Corn Inbreds

  1. Grain and Silage Inbreds
    Forty tropically adapted inbreds (Hi25 to Hi68) of high general combining ability were bred in Hawaii and released. Many were based on superior inbreds from international breeders. All were converted to resistance to Maize Mosaic Virus, and hybrids were widely evaluated in Hawaii. In addition many sub-lines of these inbreds are available at HFS [download file]. Several hundred additional breeding lines exist in CTAHR programs for breeding tolerance to tropical pests, diseases and stresses. Examples include inbreds for grain, silage, bioenergy, popcorn and cytosterility.

  2. Near-Isogenic Genetic Stocks (NILs)
    Tropical flint inbred Hi27 was converted (minimally 6 backcrosses) to ~120 mutant genes [download file], most of them are “classical” (morphological) mutants of maize. The ~150 NILs are also stored with the Maize Genetics Stock Center (U. Illinois). Map locations and description are summarized [download file], and details provided on the origin of the gene or allele and its conversion history, appearance and performance [download file]. Photos of the NILs can be seen in the article, Brewbaker, J. L. 2012. Descriptions of near-isogenic lines of inbred Hi27. Maize Genetics Coop. Newsletter 85:14-50.

  3. Recombinant Inbred Lines (RILs)
    HFS maintains ~1200 recombinant inbred lines (RILs) created from a series of 11 singlecrosses (Moon et al., Maydica 44:301-311, 1999). Parentage was largely tropical x temperate, and parents were chosen to investigate genetic of resistance to diseases and insect pests [download file].

  4. Sweet Corn Inbreds
    HFS has released six tropically-adapted inbreds based on high- sucrose gene brittle-1 (described in Brewbaker, J. L. 2010. Six tropical supersweet inbreds of maize. HortSci 45(9):1388-1391). A large additional collection involves introduced supersweet inbreds and multiple sub-line stocks for disease-tolerant breeding [download file].

Corn Hybrids and Varieties
Hybrids and Varieties bred at UHF are available for performance tests, and often sold to growers by the CTAHR Agricultural Diagnostic and Seed Services Center (ADSC). Among the most valued are those described in brief publications (“flyers”) that are revised periodically. Supersweet single-cross and 3-way hybrids include those in the following [download file]. A selection of experimental and commercial field corn hybrids are also available for evaluation as silage or grain in the tropics [download file].

Accessions of the genus Leucaena
More than 1000 accessions of this American legume tree genus have been collected, grown and characterized. Seeds of the most commercially-important varieties and hybrids are described in our flyer [download file]. The HFS collection includes most of the 22 species and over 70 hybrids created in Hawaii. Several seedless triploid hybrids are available from HFS as clones. Major fodder varieties have been improved by further breeding and released in Queensland, Australia, where leucaena is of major commercial significance as forage.

Accessions of Koa (Acacia koa)
HFS oversaw the collection of ~600 accessions of koa (Acacia koa Gray), Hawaii’s premier forest tree. All that have survived the serious koa wilt (Fusarium oxysporum) are growing at the Hamakua Research Station on the Island of Hawaii. Three improved composites have been bred and released [download file].

Accessions of Assorted Vegetable and Field Crops
Faculty of the former Depts. of Horticulture and Agronomy (now Dept. Tropical Plant and Soil Sciences) have been deeply involved in breeding vegetable, fruit and forage crops, and in the assembly of extensive collections of heirloom varieties. These were reviewed in the publication: Brewbaker, J. L. (ed.) 1982. Crop Improvement in Hawaii: Past, Present and Future. Hawaii Inst. Trop. Agric. Human Res. Misc. Public.180. 35 pp. HFS is currently assembling for long-term preservation locally-bred varieties and lines from these and continuing research [download file].