Tray seedling density and transplanting date impacted onion yield and bulb size
An onion field experiment was conducted to evaluate the effects of tray seedling density (one or three seeds per cavity and planting date (November 14, 2016; December 8, 2016; and January 9, 2017) on three cultivars ('Caramelo', 'Don Victor' and 'Lambada'). At transplant maturity seedlings were transplanted in Uvalde, TX during fall 2016 and winter 2017. November plantings required more days to reach maturity than December and January plantings. Both November and December planted-transplants resulted in higher yields compared to January transplants, even though the initial transplant fresh weight was greater in the latter. Transplants grown from one seed per cavity produced a higher number of more valuable jumbo and colossal bulb sizes compared to those from three seeds per cavity. However, no significant differences in total marketable yield were observed across the plant density treatments. Onion quality was mainly affected by cultivar, with 'Lambada' expressing the highest levels of pyruvic acid and anthocyanin. Establishing onions from transplants grown from one or multiple (two or more) seeds per cavity provides an economical alternative to produce earlier crops, reducing the time of exposure to biotic and abiotic stresses during stand establishment.
Macías-León, M.A. and Leskovar, D.I. (2020). Tray seedling density and transplanting date impacted onion yield and bulb size. Acta Hortic. 1273, 377-386
Allium cepa L. maturity, bulb size distribution, pyruvic acid, anthocyanin