Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: February 1, 2008
Publication Date: June 2, 2008
Citation: Russo, V.M. 2008. Plant response of onion cultivars developed from greenhouse-grown transplants to plant density and fertilizer rate [abstract]. HortScience. 43(3):616. Technical Abstract: Onions (Allium cepa L.) can be established from seed or transplants. The latter planting material can be dormant or actively growing when transplanted to the field. Onion transplants can be produced in a greenhouse, but there are gaps in the knowledge of the cultural requirements for these plants after transplanting. Greenhouse grown transplants of 'Candy,' intermediate-day plant, and 'Texas Grano 1015 Y,' short-day plant, were established at densities of 41,000, 82,000 or 124,000 plants.ha**-1 and 100 (recommended) and 400 kg.ha**-1 of nitrogen in mid-March of 2006 and 2007. Nitrogen fertilizer rate did not affect yield; yield increased as density increased, and yield of 'Texas Grano 1015 Y' was higher in 2006 than in 2007. 'Candy' had a higher number of large size bulbs and 'Texas Grano 1015 Y' more small bulbs. Bulb nutrient content was affected only by year with nitrate-N, K, Na and SO4 were higher in 2006 and nitrite-N, Ca, Mg, and PO4 were higher in 2007. Precipitation levels in the two years were different with 2007 being the wetter. This may have contributed to the responses to year and it appears that 'Candy' was better able to respond in a more uniform manner to the changed environmental conditions. For plants developed from greenhouse grown transplants the recommended rate of fertilizer and the highest plant density are beneficial to improved marketable yield.