Relationships between seed oil percentage and kernel oil percentage (w/w) as affected by plant density and solar radiation intercepted during grain filling in sunflower

NOLASCO, S.M.; DOSIO, G.A.A.; RICCOBENE, I.C.; SANTALLA, E.M.; AGUIRREZÁBAL, L.A.N.

Toulouse, Francia

Conferencia; 15è Conférence Internationale Tournesol; 2000

International Sunflower Association

The oil percentage of sunflower whole seeds is a main component of its industrial quality.  Its variations can originate changes in the kernel oil percentage or in the kernel proportion in the whole seed. Seed oil percentage has been increased by genetic improvement mainly by changes in kernel percentage. On the other hand, oil percentage could be highly modified by environmental factors and plant growth conditions. It has been less investigated which components of seed oil percentage account for its changes in these cases. This knowledge could be important for industry. This work showed that  changes in oil percentage of the whole seed originated by effects of variations in plant density and solar radiation intercepted by plant during seed filling are linked to changes in the oil percentage of kernel or in the proportion of kernel. Three hybrids with different oil potential content (Dekalb G-100, Aromo and Contiflor 3) were grown in field conditions at four plant densities (12000, 19000, 32000 and 55000 plants/ha). The solar radiation intercepted by a plant of Dekalb G-100 was modified by thinning or shading the crops. Modifications in plant density and intercepted solar radiation varied the seed oil percentage. In all cases, these changes were not related to the percentage of kernel in the whole seed. Otherwise, the kernel oil percentage and seed oil content were positively related. It is concluded that  variation in seed oil percentage in sunflower seeds by effects of plant density and solar radiation intercepted are largely originated in changes of the kernel oil content.