Overview – The Cucurbita Species

Cucurbit Genetics Cooperative Report 6:77-78 (article 39) 1983

Miguel Holle
CIAT, Cali, Columbia

The genus Cucurbita is spread through America. Several species (C. moschata, C. maxima, C. pepo, C. mixta, C. ficifolia) are cultivated in Latin America. Cultivation is mostly in a few plants usually within a field of corn with or without other plants. The fruits are harvested mostly mature as needed or wanted in the household; at the end of the season fully matured fruits are picked and stored in the house or on the roof. Depending on temperatures, fruits keep from 2 to 6 months. Relatively little gets to the market although in the market days in any town one will find 5–10 fruits handled by the sales women. There are several collections available (see IBPGR publication on Cucurbit Genetic Resources to be published in 1983), but agriculturists in Latin America who handle genetic material of Cucurbita spp. are few. To our knowledge only Mexico (INIA), Colombia (ICA-Palmira), Brasil (Piracicaba), Peru (UNA-La Molina) and Costa Rica (CATIE-Turrialba), have looked at partial variability. No systematic efforts, to collect cultivated land races or home selections has been made. T. W. Whitaker and others have made expeditions to collect in several areas. T. W. Whitaker probably has seen more Cucurbita variability than any other scientist and published extensively on those observations. Still, with regards to accessions of cultivated material of Latin America, the number of collections and their evaluation has been a very haphazard process; Cucurbita pepo is probably better known than the other cultivated species.

Cucurbita spp. are losing ground to other crops due to changes in land use pattern and technological emphasis in monoculture. It is very probable: that the variability available is now in more remote and traditional agricultural areas.

A concentrated effort is needed by several scientists taking responsibility for certain countries or regions in Latin America in collaboration with local Latin American horticulturists to do a systematic collection and evaluation of genetic material based on an analysis of what is available in each country or region. A preliminary list of people and areas in Latin America is shown (Table 1).

Table 1. Preliminary list of Latin American horticulturists working with Cucurbita spp. germplasm.

 

Area or Country	Institution(s)/Person	Species Emphasized
Mexico	INIA (CIAB) – J. Labor de	C. pepo. C. moschata, C. mixta, C. ficifolia
Guatemala	ICTA – O. Morocco?	“
Other Central America	CATIE – H. Heinz?	“
Venezuela	U.S. – C. Liars	C. moschata, C. maxima
Colombia	ICA (Palm ira) – J. Armadillo	Low altitude types (C. moschata)
	ICA (Tidbit) – F. Digital	High altitude types (C. maxima)
Ecuador	INIAP
Peru	UNA-La Molina – F. Degrade	C maxima, C. moschata, C. ficifolia
Brasil	ESALQ-Piracicaba – Rochelle?	C. moschata, C. maxima

? = Scientists have not been specifically consulted at this time.

In evaluation, a descriptor list is proposed in the IBPGR publication, but the main practical problem is to find the field size needed to evaluate an appropriate number of plants per accession and a good number of accessions (in cases of polymorphic populations, using 6 m² per plant, one hectare would be needed to plant 30 to 50 accessions and 30 to 50 plants per accession) under appropriate isolation. I have used rows of close planted corn between accessions to reduce cross pollination.

Some collection activities could be financed with IBPGR collaboration since Cucurbita spp. have a high priority within the vegetables.

Funding or support for increment and preliminary characterization can also be partially available from IBPGR.

Any ideas or suggestions from colleagues would be most welcome. It is especially important if anyone is interested in collaboration with a specific colleague, from the accompanying list. Please send them to: Miguel Holle, IBPGR Regional Offices of Latin America, cv/o CIAT, Apart ado 6713, Cali, Colombia.