ARS | Publication request: GENETIC ANALYSES OF SEED YIELD IN ONION

Submitted to: International Symposium on the Edible Alliaceae
Publication Type: Abstract Only
Publication Acceptance Date: January 30, 2001
Publication Date: N/A

Technical Abstract: Cytoplasmic male sterility is used extensively to produce hybrid-onion (Allium cepa L.) seed. Most onion cultivars in the USA are three-way hybrids, produced using an F1 male-sterile female. Two-way hybrids are desirable because of greater uniformity, as well as less time and fewer resources required for production. However, the development of two-way hybrids in onion is difficult due to poor seed yields on the inbred female parents. We used a standard diallel to determine combining ability for seed yield among seven inbred lines and parent-offspring regressions to estimate heritabilities for seed yield in three open-pollinated populations. Across three environments, seed yields showed significant (p less than 0.05) mean differences among inbreds per seed and general combining abilities (GCA). SCA was significant in two of the environments. Correlations between mean seed yield per bulb and scape height were significant. Inbred lines with short scapes tended to yield less seed; those with taller scapes tended to produce more seed. Parent-offspring (PO) regressions revealed no significant relationship between the seed yield of parental plants and their S1 progenies, suggesting that there is little to no additive genetic variance for seed yield in these populations. These results indicate that the relative seed yield of individual bulbs after self pollination cannot be used to predict the seed yield of progeny families. However, the seed yield of inbred lines of onion may reflect the potential seed yield of hybrid male-sterile lines.