Cucurbit Genetics Cooperative Report 21:62-62 (article 22) 1998
Humberto Rios Labrada, Yunaima Perera Ibarra y Antonio Fernandez Almirall
Instituto Nacional de Ciencias Agricolas (INCA). GP no1 San Jose de las Lajas, La Habana, Cuba cp 32700
Introduction. The “informal seed sector” describes the ability of farmers – rather than breeders – to maintain, develop, enhance, enrich and utilize pumpkin diversity. This sector has played an important role in seed management under low income conditions in developing countries (1,2). It would be of interest to identify some of the factors influencing the maintenance of pumpkin yields on low income farms using this model, particularly since seed farmers’ production is undergoing an economic crisis in Cuba.
Materials and methods. The Marucha and Fifi lines, selected from Cuban landraces, were sown according to two seed management systems. The Formal Model, frequently used by seed companies in Cuban describes when seed of a variety is increased for several cycles in isolation (i.e., without any other pumpkin genotypes within 1000 m). In this experimental case, Marucha and Fifi lines were sown separately, avoiding any mix with extraneous pollen, for two cycles (winter and summer). The Informal Model, a common approach among farmers, describes when farmers grow pumpkins from other farms alongside their own pumpkins and save the seeds, In this experiment, Marucha and Fifi lines were grown among eight pumpkin landraces selected from those previously evaluated, and seeds were saved.
The seeds of Marucha and Fifi obtained by simulating the two models were compared by a random block design under San Jose de las Lajas low input growing conditions during the summer and winter.
Results. The isolation approach used by formal sector resulted in decreased yields for both Marucha and Fifi, with yield depressions ranging from 25 and 58% (Table 1). The higher depression of yields observed during the winter planting may have been due to increased water stress.
These results assume that inbreeding, and hence increased homozygosity, is occurring during seed multiplication in the Formal Model. On the contrary, in the Informal Model seeds from different sources are introduced by the farmers, and interpollination of Marucha and Fifi with these sources may have increased heterygosity, resulting in increased pumpkin yields under low input conditions.
Table 1. Yield depression and yield of two lines multiplied under summer and winter time.
Sowing period |
Yield (t.ha-1) |
|
Marucha |
Fifi |
|
Summer |
||
| Formal Model | 5.17 | 3.06 |
| Informal Model | 7.95 | 4.14 |
| Yield depression z | 35% | 26% |
Winter |
||
| Formal Model | 3.20 | 1.10 |
| Informal Model | 5.93 | 2.63 |
| Yield depression z | 46% | 58% |
As Cuba’s economic crisis continues, it is becoming essential that breeders involve the informal seed sector in pumpkin breeding. Also, breeders need to rethink the potential roles of farmers and breeders in breeding process.
Literature Cited
- Almekinders, C, J.M., N.P. Louwaars and G.H. de Bruijn. 1994. Local seed systems and their importance for an improved seed supply in developing countries. Euphytica 78:207-216.
- de Boef, W.S., T. Berg and B. Haverkot. 1995. Farmers crops and landraces: farmers roles in the development and conservation of crop diversity. Internal discussion paper, CPRO-DLO Centre for Genetic Resources. Wageningen.