Folia Horticulturae

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Effect of etephon (CEPA) on the growth dynamics of seed stalk of onion (Allium cepa L.)

Roman Hołubowicz*, Tomasz W. Bralewski*, Mariola Kaczmarek**, Zhao Yinbo***

***Seed Science and Technology Department
***August Cieszkowski Poznań Agricultural University
***Baranowo, 62-081 PrzeĽmierowo, Poland
***graduate student
***present address: Grębów, 63-708 Rozdrażew, Poland
***graduate student
***present address: Technical Information and Documentation Centre
***Chinese Academy of Agricultural Sciences
***Beijing, 30 Baishi Qiao Rd., P.R. China
***e-mail: seed@owl.au.poznan.pl

In the years 1997-1999 experiments were carried out on the effect of etephon (CEPA) spraying on the growth dynamics of seed stalks of 5 cultivars of onion (Allium cepa L.). These were: ‘Kristine’, ‘Fiesta’, ‘Efekt’, ‘Kutnowska’, and ‘Wolska’. Spraying was carried out with 2% Flordimex T when the seed stalks were 20-25 cm high. The changes in growth during the first 3 days after spraying were measured every 2 hours, then - every day for the following 3 weeks, and finally, for the next 14 days, once a week. The spraying with etephon (CEPA) reduced the seed stalk height from 43.3 to 49.5%. The unsprayed seed stalks showed two types of day rhythm of growth. The intensity of the first type increased from 10 a.m. to 10 p.m., whereas that of the second had a longer increase, i.e. from 2 a.m. to 10 p.m. The growth intensity decrease for the period 10 p.m. to 2 a.m. was smaller for the first type than for the latter. The observed growth dynamics was very similar for both unsprayed and sprayed stalks, although varying more for the sprayed plants. The onion seed stalk growth dynamics was of cultivar character and depended on weather conditions. The whole seed stalks growth had 3 stages: 2 static and 1 dynamic. The duration of these stages was also of cultivar character. The mean day temperature was a crucial factor with regard to the effectiveness of CEPA.

Hołubowicz R., Bralewski T.W., Kaczmarek M., Yinbo Z., 2002. Effect of etephon (CEPA) on the growth dynamics of seed stalk of onion (Allium cepa L.). Folia Horticulturae 14/1: 21-29.