Germplasm Resources of Citrullus lanatus in the Genebank of the Polytechnic University of Valencia

Cucurbit Genetics Cooperative Report 18:52-54 (article 25) 1995

Fernandez de Cordova, P., M.J. Diez, A. Iglesias and F. Nuez
Departmento de Biotechnologia, Universidad Politecnica de Valencia, 46022, Valencia, Spain

The Genebank of the Polytechnic University of Valencia holds 5436 accessions of vegetable species. Of these, 2221 of them belong to the Cucurbitaceae, 201 of which are watermelon (Citrullus lanatus (Thunb.) Matson and Nakai). Approximately one third of the accessions have already been characterized, with the others in the process of characterization.

Most of the watermelon accessions were collected in Spain. Some of them come from Latin-America, the Mediterranean basin and a few from other countries (1, 3, 4). An important number of accessions were collected in the states of Cataluna (27% of accessions), Valencia (18%), Canarias (16%) and Andalucia (14%) (Fig. 1). Andalucia and Valencia are the two principal watermelon producers in Spain. In these areas, and in Cataluna, the majority of the crop is irrigated. Extremadura and Castilla-La Mancha occupy third and fourth places, respectively, in relation to yield. Nevertheless, this is a secondary crop in these areas and is grown as a dry land crop.

The following are the characteristics recorded in field trials:

• Fruit characteristics: shape, skin color, spots on the skin, blossom scar, weight, longitudinal and transverse sections, skin width, flesh color,.color of the cortical zonal and 0 Brix.
• Vegetative characteristics: leaf length and width, number of leaf lobes, shape of the first lobe (double or single), width of the lobes.
• Other agricultural characteristics: fruit set, set homogeneity, number of fruits per plant, agricultural interest.

Accessions regenerated and characterized have been classified into groups, depending on fruit weight, shape, skin color, flesh color and seed coat color (2, 5). Table 1 shows the accessions grouped by fruit size, and their place of origin.

Table 1. Characteristics of Citrullus lanatus accessions grouped by fruit size.

Shape	Skin color	Fruit surface	Flesh color	Seed coat color	Accessonsz
Small-fruited accessions (<4 kg)
globular	light green	netted, lighter	white	black	CA-CI-4
			pink	tan	V-CI-17
				black	CA-CI-2, CA-CI-7, V-CI-3, V-CI-14, V-CI-30-A-CI-3
	dark green	smooth	pink	tan	MU-CI-3
			red	black	AN-CI-10, AN-CI-13
		netted, darker	pink	tan	MU-CI-2, AN-CI-1, AN-CI-15, CL-CI-11, V-CL-33
oval	light green	netted, darker	white	tan	AN-CI-26-(1)
				black	AN-CI-26-(2)
			pink	black	V-CI-31, CM-CI-6, CM-CI-11-(1)
	dark green	smooth	pink	tan	E-CI-4, A-CI-4
Medium-fruited accessions (4-6 kg)
globular	light green	smooth	red	tan	AN-CI-7
		netted, darker	white	tan	CM-CI-I
				black	V-CI-32
			yellow	black	AN-CI-14
			pink	black	AN-CI-16, AN-CI-2, V-CI-21, CM-CI-7-(1)
			red	black	AN-CI-25, V-CI-16-(1), V-CI-16-(2)
	dark green	smooth	pink	tan	V-CI-18, CM-CI-2, AN-CI-14
				black	A-CI-6
			red	white	C-CI-I
			red	tan	CA-CI-8-, CM-CI-11-(2)
			red	black	C-CI-3
		netted, lighter	red	tan	CM-CI-7-(2)
		netted, darker	red	black	AN-CI-6-V-CI-16-(2)
elliptical	light green	netted, darker	pink	tan	11620
Large-fruited accessions (608 kg)
globular	light green	smooth	red	black	11621, 10357
		netted, darker	red	black	CA-CI-17
elliptical	light green	smooth	pink	tan	CA-CI-5
Very-large-fruited acessions (8012 kg)
globular	dark green	smooth	pink	black	CA-CI-1
elliptical	light green	smooth	pink	black	10198
		netted, lighter	pink	tan	10278
			red	black	V-CI-15, 9599

^zIn the accessions collected in Spain, the first letters of the code indicate the place of origin: Aragon (A), Andalucia (AN), Cataluna (C), Castilla-La Mancha (CM), Castilla-Leon (CL), Extremadura (E), Murcia (MU), and Valencia (V). An exclusively numeric code has been given to accessions coming from other countries.

Figure 1. Areas collected.

Acknowledgements: Expeditions for material collecting for the Polytechnic University of Valencia Genebank have been subsidized by IBPGR and INIA.

Literature Cited

1. Iglesias, A., M.J. Diez and F. Nuez. 1994. Recursos Genetiocos de Cucurbitaceas en el Banco de Germoplasma de la U.P.V. Actas de Horticultura 12:85-89.
2. International Organization for Standardization, Fruits and Vegetables. 1989 Morfological and structural terminology, Part 2. International-Standard: 1965-2; 1989, 31 pp.
3. Nuez, F., M.J. Diez, G. Palomares, C. Ferrando, J. Cuartero and J. Costa. 1987. germplasm resources of Citrullus lanatus (Thunb.) Matson and Nakai from Spain. Cucurbit Genet. Coop. Rept. 10:64-65.
4. Nuez, F., P. Fernandez de Cordova and M.J. Diez. 1992. Collecting vegetable germplasm in the Canary Islands. FAO/IBPGR. Plant Genetic Resources Newsletter 90:34-35.
5. Trisonthi, C. 1992. Description and identification key for some edible tropical fruit. Fruits 47:425-449.