Luffa Research Report
Growth Regulator Effects on Sex Expression of Luffa
Sponge Gourd
Todd C. Wehner, and Tammy L. Ellington
Department of Horticultural Science, North Carolina
State University, Raleigh, NC 27695-7609
Cucurbit Genetics Cooperative Report 18: 68
Luffa sponge gourd (Luffa aegyptiaca Mill)
is increasingly popular in North Carolina for use in cosmetics
and cleaning products. We are interested in developing luffa cultivars
suited to industry in the southeast U.S. However, most of the
cultivars and breeding lines we are working with are monoecious.
In order to make hybrid production easier, we would like to make
the plants gynoecious. Sex expression of another cucurbit, the
cucumber (Cucumis sativus L.) can be altered using growth
regulators to increase the percentage of pistillate flowers (1)
or the percentage of staminate flowers (2). Our objective was
to study the effects of the growth regulator, ethephon, on sex
expression in luffa sponge gourd.
Seeds of 'Fletcher' luffa were planted on raised,
shaped beds in the field on 20 May 1993. Plants were supported
by a trellis 1.8 m high. The experiment was a randomized complete
block design with 12 replications of 5 plants per plot. Ethephon
was sprayed onto seedlings when they reached the first true leaf
stage at a rate of 100 mg/L (+4 drops Tween-20) until runoff.
Ethephon was applied 1 time (1st true leaf stage) or 2 times (1st
and 3rd true leaves), 0 times for the control.
Traits measured were percentage of seeds that emerged
as seedlings (counted at the 1st true leaf stage), percentage
of the total flowers that were pistillate in the first 20 nodes,
total number of fruits per plot at harvest (5 October), and percentage
of fruits that were marketable (total - cull - immature) or early
(total - immature). Data were analyzed using the general linear
models procedure of SAS.
Seedlings treated with ethephon had no change in sex
expression (Table 1). If anything, there was a slight (but non-significant)
trend for a smaller percentage of pistillate flowers as the number
of ethephon applications was increased. In cucumber, ethephon
applications used in this experiment would result in plants that
had more than 90% pistillate flowers.
The only significant effect observed in this experiment
was for a lower percentage of early fruits in the treatment receiving
1 application of ethephon. We were unable to explain that effect,
but ethephon may cause some plant injury after application. In
conclusion none of the ethephon treatments affected the percentage
of pistillate flowers in 'Fletcher' luffa. Perhaps sex expression
can be modified with different concentrations or numbers of applications
of ethephon, or with other growth regulators.
Literature Cited
1. McMurray, A.L. and C.H. Miller. 1968. Cucumber
sex expression modified by 2-Chloroethanephoasphonic acid. Science
162:1396-1397.
2. Pike, L.M. and C.E. Peterson. 1969. Gibberellin
A4/A7 for induction of staminate flowers on the gynoecious cucumber.
Euphytica 18:106-109.
Table 1. Ethephon treatment of luffa sponge gourd
for attempted alteration of sex expression.z
|
No. ethephon
|
%
|
% pistillate
|
Total
|
%
|
%
|
|
applications
|
emergence
|
nodes
|
fruits/plot
|
marketable
|
early
|
|
0
|
63
|
21
|
10
|
70
|
60
|
|
1
|
65
|
20
|
10
|
60
|
42
|
|
2
|
59
|
18
|
11
|
66
|
51
|
|
Mean
|
63
|
20
|
11
|
66
|
51
|
|
LSD (5%)
|
12
|
7
|
3
|
16
|
14
|
|
CV (%)
|
22
|
39
|
29
|
29
|
33
|
z Data are means of 12 replications of 5 plants per plot. |
