Cucurbit Genetics Cooperative Report 3:45-46 (article 26) 1980

Synonymy of Cucurbita martinezii and C. okeechobeensis

R. W. Robinson and J. T. Puchalski

New York State Agricultural Experiment Station, Geneva, NY 14456 (first author); Botanical Garden of the Polish Academy of Science, Warsaw, Poland (second author)

The okeechobee gourd was first given the name Pepo okeechobeensis by Small in 1930 (7). Bailey (2) retained the species name for this denizen of the Lake Okeechobee area in Florida but correctly revised its genus designation to Cucurbita.

Cucurbita martinezii was named by Bailey in 1943 (1). He distinguished C. martinezii from C. okeechobeensis primarily on the basic of pubescence and exocarp characteristics. Although he reported that the petiole and lower leaf surface of C. okeechobeensis is pubescent and that of C. martinezii is nonpubescent, we found no significant difference in pubescence of different accessions of the two putative species. Also, pubescence is evident on the lower as well as the upper leaf surfaces and the petioles of herbarium specimens of C. martinezii in the Bailey Hortorium, Cornell University, that were collected by M. Martinez in Aloyac, Mexico in 1941 and sent to Bailey. Accessions of okeechobeensis from Florida as well as those of martinezii from Mexico had similar light and dark green longitudinal striping on the fruit, although Bailey reported okeechobeensis to have striped and martinezii nonstriped fruit. He described the fruit rind of martinezii as being thick, very hard, and difficult to the knife whereas that of okeechobeensis was thin and not usually resisting. However, we found the exocarp of each accession of okeechobeensis to be equally thick and hard as those of martinezii. The morphological similarity of C. martinezii and C. okeechobeensis is supported by the numerical taxonomy study of Bemis et al. (3).

Cucurbita martinezii and C. okeechobeensis are also alike in disease resistance. Munger (4) reported that C. martinezii is resistant to cucumber mosaic virus, and he confirmed T. W. Whitaker's finding that it is resistant to powdery mildew. Cucurbita okeechobeensis has an equally high level of resistance to cucumber mosaic virus (5), and it is also resistant to powdery mildew. Both are also alike in being resistant to the severe strain of bean yellow mosaic virus, tobacco ringspot virus, and tomato ringspot virus. Both C. martinezii and C. okeechobeensis recovered from squash mosaic virus inoculation, unlike most of the other species tested, and both were susceptible to watermelon mosaic virus-1 and watermelon mosaic virus-2. They did not differ in reaction to any disease.

There is no sterility barrier isolating C. martinezii from C. okeechobeensis. Reciprocal crosses were easily made and the F₁ hybrids were fully fertile.

Cucurbita martinezii differs from all but one of the know species of Cucurbita by having a cream colored corolla. The only other species to have cream instead of yellow petals in C. okeechobeensis. A single recessive gene and a modifier governs this flower fruit in C. martinezii (6). Our results indicate that C. okeechobeensis also has single recessive basic gene for cream corolla color, and it is allelic to the gene of C. martinezii.

Convincing evidence for synonymy of C. martinezii and C. okeechobeensis was obtained by starch gel electrophoresis of isozymes. Four accessions of C. okeechobeensis were compared to six accessions of C. martinezii and also with 17 different species of Cucurbita. Each accession of okeechobeensis and martinezii was identical in esterase, peroxidase, and leucine amino peptidase isozymes and all were distinct in isozymes from each of the other Cucurbita species.

The only apparent difference between the two entities is their origin, C. martinezii being from Mexico and C. okeechobeensis from Florida. In the absence of any other significant difference, it is concluded they are the same species, which was introduced to Florida from Mexico in prehistoric times. An unsolved question is how this species traveled such a great distance. One possible explanation is that it was acquired by an Indian tribe in Florida by trade with Indians from the west. The extremely bitter flesh of this species precludes it from being used for food, but the seeds are edible and nutritious and the fruit could also have been used for its detergent quality. The hard rind and good keeping ability would make it possible for the fruit to be transported from Mexico to Florida, even with the very long time such a trip must have taken. Another possible explanation for the migration of the species from Mexico to Florida is by oceanic drift in the Gulf Stream of fruit containing viable seed.

The species name okeechobeensis has priority, hence, is preferred to its synonym, martinezii.

Literature Cited

1. Bailey, L. H. 1943. Species of Cucurbita. Gentes Herbarum 6:266-322.
2. Bailey, L. H. 1930. Three discussions in Cucurbitaceae. Gentes Herbarum 2: 175-186.
3. Bemis, W. P., A. M. Rhodes, T. W. Whitaker, and S. G. Carmer. 1970. Numerical taxonomy applied to Cucurbita relationships. Amer. J. Bot. 57: 404-412.
4. Munger, H. M. 1976. Cucurbita martinezii as source of disease resistance. Veg. Imp. Newsletter 18:4.
5. Provvidenti, R., R. W. Robinson, and H. M. Munger. 1978. Resistance in feral species to six viruses infecting Cucurbita. Plant Dis. Rpt. 62:326-329.
6. Roe, N. E. and W. P. Bemis. 1977. Corolla color in Cucurbita. J. Hered. 68: 193-194.
7. Small, J. K. 1930. The okeechobee gourd. J. New York Bot. Gard. 31: 10-14.