Factors affecting germination and growth of sugarcane transplants.
Loading...
Date
1998
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Transplants are produced and sold in South Africa for the planting of seedcane supply plots
(nurseries), commercial fields, and for gap filling. The most important factor constraining the use
of transplants is the low germination of single-budded setts (SBS) planted in polystyrene trays.
The main aims of this project were to develop practical methods for optimising germination and
to control pathogens without adversely affecting germination.
Seedcane quality, cane age, storage and treatments using heat, chemicals and fungicides affected
germination and growth. Germination of SBS from old seedcane was significantly higher when
taken from the top than from the middle and bottom of the stalk. Storage of seedcane for three
and eight days after harvest adversely affected germination and growth. Topping of stalks three
days before harvest increased germination potential, but results were variable, depending on cane
age, cane quality and further treatments. Treatment of SBS at both 50°C for 120 minutes and
52°C for 30 minutes controlled Clavibacter xyli subsp. xyli (C. x. xyli) (the causal organism of
ratoon stunting disease) more effectively than treatment of whole setts. After treatment of SBS
at 52°C for 30 minutes, germination was greater than that after treatment at 50°C for 120 minutes,
and C. x. xyli was eliminated from stalks of six out of seven varieties. Treatment of SBS at 52°C
for 10 minutes significantly improved both germination and plant growth. Treatment of SBS for
10 minutes after addition of ethephon to the hot water significantly increased germination
compared with the untreated control, but not compared with treatment with hot water alone. After
treatment of SBS with fungicides, germination was highest after treatment with Eria® (Novartis),
a chemical with two active ingredients, namely carbendazim and difenoconazole. Compared with
no treatment and the short hot water treatment, treatment with Eria® in hot water (52°C)
significantly improved germination and plant growth in both unsterilised and sterilised medium.
Treatment of SBS and drenching of trays with a solution of propamocarb-HCl and benomyl had
no effect on germination or growth, indicating the limited role of systemic infections and soilborne
pathogens in germination failure. However, germination and growth were significantly increased
when the same SBS were also treated with Eria®, suggesting that germination was predominantly
increased by the plant growth regulator activities of its active ingredients. When used separately,
both difenoconazole and carbendazim significantly increased germination, and difenoconazole
significantly increased plant growth. The conclusion drawn from these results is that germination
failure of SBS in trays is mainly due to the inappropriate hormonal balance for germination within
.the SBS, rather than systemic infections or infection by soilborne pathogens. Therefore,
germination and growth can be optimised by using mature, good quality seedcane, and by
treatment of SBS with chemicals that adjust the hormonal balance in the bud region to one
appropriate for germination.
Description
Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1998.
Keywords
Sugarcane--Cuttings., Sugarcane--Propagation., Sugarcane--Growth., Germination., Plant regulators., Theses--Plant pathology.