Response of prolonged storage time and growth media on seedling emergence of onion (Allium cepa L.) in South Africa

K.E. Lodama, A.S. Gerrano, S.M. Laurie, S. Mavengahama, P.O. Adebola
Onion is a crop of major economic and culinary importance in various regions of the world. Onion seed is also known as short-living among the common vegetable crops, and seed viability after storage could vary. The aim of this study was to determine seed quality response of four seed batches of one onion line stored in the genebank for varying periods of time, and germinated on three different growth media. The seed batches were stored in the seed genebank at a temperature of 4°C and 10-15% relative humidity. Twenty-five seeds of each of four seed batches (2003, 2005, 2009 and 2011), representing four storage periods (11, 9, 5 and 3 years), were evaluated using three different growth media: viz. compost, Hygromix and cocopeat. Emergence parameters (seedling emergence percentage, mean emergence time, and emergence index) and growth parameters (root number, root length in mm, and shoot length in mm) were determined from the first day of emergence (8 days after planting) up to 21 days. Analysis of variance revealed that there was a significant (p≤0.05) effect of storage period and growth media on seedling emergence. Seedling emergence percentage and emergence index of the four seed batches declined with increased duration of storage in the genebank. The seedling emergence varied (p≤0.05) from 41.8% in seed batch S03-1 (stored 11 years) to 64.4% in S011-1 (stored 3 years). Mean emergence time and seedling growth parameters (with exception of shoot length, which was longer for seed stored three years) were not significantly different among the seed batches. Moreover, 60 and 57% emergence was observed on the coco-peat and Hygromix medium, respectively, as compared to 33% for compost. As mean emergence time was significantly shorter and shoot length of seedlings longer in Hygromix than cocopeat, Hygromix was recommended as the best medium.
Lodama, K.E., Gerrano, A.S., Laurie, S.M., Mavengahama, S. and Adebola, P.O. (2018). Response of prolonged storage time and growth media on seedling emergence of onion (Allium cepa L.) in South Africa. Acta Hortic. 1204, 33-40
DOI: 10.17660/ActaHortic.2018.1204.5
storage period, growth media, emergence, onion seed

Acta Horticulturae