Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]
Volume 54: 3925 - 3934. Published June 30, 2012.
Emergence and early growth of Gongronema latifolia in relation to sowing depth and date
Agbo C.U.
Department of Crop Science, University of Nigeria, Nsukka 410001, Nigeria,
Correspondence email: c_agbogenetics@yahoo.com ; christian.agbo@unn.edu.ng
RESUME
Objective: This research was designed to determine the optimum sowing depth for G. latifolia at two planting seasons in 2007.
Methodology and results: Treatments comprised of 9 sowing depths including 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 cm. The experiment was arranged in a completely randomized design with 10 replications under 65 % shading. The first and second sowing dates were on 5 May and 5 September 2009, respectively. The results showed that sowing depths of 0-1.5 cm gave significantly (p<0.05) higher level of emergence, ranging from 93 to 83 % respectively, than in deeper sowing, for the first planting period. In the same way, the coefficient of velocity of emergence (CVE %) for 0 and 0.5 cm sowing depth were the same and significantly (p=0.05) higher than the CVE of seedlings emerging from depths beyond 1.5 cm during the former sowing period. The second sowing period led to a low emergence rate of 53 % to 5 % at the sowing depths of 0 to 2.0 cm, respectively. Seeds sown at 2.0 cm depth gave significantly (p=0.05) higher hypocotyl lengths in both sowing dates. The hypocotyl diameter was increasing with increasing depth up to 1.5 cm and it decreased thereafter.
Conclusion and application of finding: The findings revealed that G. latifolia must be sowed at a depth of 0 to 1.5 cm beyond this depth, emerging rate and CVE will be poorer. The significant influence of sowing date and depth gives room for choice of a better option. In this vein, sowing at the first date and at shallower depths of 0-1.5 cm will be preferred as it led, in addition to the highest emergence rate, to faster growing seedlings with longer internodes reaching transplantable height and size earlier than those sown deeper and latter. This leads to rapid and adequate field establishment
Keywords: Sowing depth; G. latifolia; hypocotyls growth; seedling vigor; time of sowing
