AIMS Agriculture and Food (Apr 2017)
Fall nitrogen enhances spring nitrogen enhanced flowering in the long day strawberry cultivar ‘Elan’
Abstract
Architectural analysis describes the position and fate (vegetative or floral) of plant meristems to account for differences in their sensitivity to stimuli depending on developmental stage and position on the plant. To provide further insight into the flowering responses of long day strawberries to nitrogen, ‘Elan’ seedlings were fertilized in mid-October, overwintered in a greenhouse, then dissected the following March and their floral architecture evaluated. Additional plants from fall N treatments were placed under ND and fertilized weekly for four weeks with 100, 400, 800 or 1200 ppm N during greenhouse-forcing under ND and growth monitored until June. Plants were dissected after forcing and their floral architecture evaluated. Fall fertilized plants were significantly more floral than non-fertilized controls before forcing. Some axillary buds of fertilized plants formed floral branch crowns but there were no floral branch crowns on non-fertilized plants. Precocity was not affected by fall N and 400, 800 or 1200 ppm spring N were equally effective in accelerating flowering (+1 week) compared to 100 ppm spring N. Fall N enhanced the number of inflorescences and flowers produced by the primary crown. Spring N enhanced flowering of branch crowns and the total numbers of inflorescences and flowers per plant. Inflorescence production was a qualitative response to N while flower production was quantitative. Architectural models of post-forcing dissected plants provided additional insight. All 100 ppm spring N terminal meristems were floral while 400 and 800 ppm spring N meristems were less floral. All terminal meristems of plants receiving 100 ppm fall N before 1200 ppm spring N were floral but meristems from plants that did not receive fall N before 1200 ppm spring N were much less floral. Branch crown formation was enhanced with elevated (400, 800 or 1200 ppm) spring N and prior fall N enhanced their floral nature.
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