Seed Treatment Effects on Emergence 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 20: 63-64
Luffa (or loofah) sponge gourds (Luffa aegyptiaca Mill) are increasing in popularity in North America. However, additional research is needed to solve some of the production problems for luffa, especially in the area of seed germination. There is little published information in luffa on the effects of seed treatment on germination, or of growth regulators on sex expression. However, it would be useful to increase the germination rate of luffa seeds, which is often below 75%. It would also be useful to increase the percentage of pistillate flowers on the luffa plants for easier hybridization. Luffa and cucumbers are members of the Cucurbitaceae family. Cucumbers respond favorably to growth regulators for increasing the percentage of pistillate flowers (1, 2). The objective of this research was to determine the effects of several pre-planting treatments on seed germination and growth regulators on sex expression in luffa sponge gourds.
Six treatments were applied to ‘Fletcher’ luffa seeds prior to planting. A total of 60 seeds were used per treatment combination. The treatments included water, acetone, gibberellic acid-3 (GA3), ethephon, scarification and a control. The control consisted of untreated, dry seeds. In the water treatment, seeds were soaked in distilled, aerated water for 87 hr at 25 C. In the acetone treatment seeds were soaked for 16 hr at 25 C in acetone. In the GA3 treatment, seeds were soaked for 16 hr at 25 C in a solution of 0.1 mM GA3 plus 200 ml acetone. In the ethephon treatment seeds were soaked in 3.5 mM ethephon mixed with 200 ml acetone for 16 hr at 25 C. The scarification treatment involved shaking the seeds for 2 minutes in a 762 mm diameter closed PVC tube lined with sandpaper. After treatment application, the seeds were planted in a peatlite mix in flats in the greenhouse. Emergence data were taken two weeks after seeding.
After seedling emergence data were taken, the seedlings were transplanted into the field. Ethephon was sprayed on seedlings until runoff 0, 1, or 2 times using a rate of 100 mg/L (+4 drops Tween-20). Seedlings received either one treatment of ethephon at the first leaf stage, two treatments of ethephon at the first and third leaf stages, or no treatment (the control). As the plants were maturing, the number of pistillate nodes out of a total of twenty nodes on five plants was recorded. The data collected were analyzed using the GLM procedure of SAS.
There was a significant increase in the percentage emergence when luffa seeds were soaked in water relative to the acetone, ethephon, GA3, and scarification treatments (Table 1). However, the water treatment was not significantly different from the control. Therefore, none of the seed treatments improved the rate of emergence of the luffa seedlings, and all but the water soaking treatment made the percentage emergence worse.
Based on the tests conducted, spraying seedlings of ‘Fletcher’ luffa gourds with ethephon did not increase the percentage of pistillate flowers when the seeds had been treated with acetone, GA3, or scarification. Significant differences were found with the ethephon and water seed treatments when ethephon was applied at the first true leaf stage. The control seed treatment showed a significant increase in percentage pistillate flowers when the seedlings were not sprayed with ethephon (Table 2).
We hoped that luffa would respond to ethephon in the same way that cucumbers do. However, our experiment indicated that ethephon applied at the tested rates had no significant effect on sex expression. Similarly, none of the treatments enhanced seed emergence from the soil. Additional research is needed to identify useful treatments for improvement of seed emergence and pistillate flower production in luffa sponge gourd.
1. McMurray, A.L. and C.H. Miller. 1968. Cucumber sex expression modified by 2-chloroethanephosphonic 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. Effect of seed treatments on seedling emergence in uffa sponge gourd.z
z Data are means of two replications of 60 seeds each.
Table 2. Effect of seed treatments on seedling emergence in uffa sponge gourd.
z Ethephon was applied in one of three treatments: 0=none, 1=once and 2=twice.
y Data are means of two replications of five plants, counting 20 nodes per treatment.