EFFICIENCY OF POLLINATING TREATMENTS ON 2 LINES OF SPRING FABA BEAN (VICIA-FABA L VAR EQUINA STEUDEL), WITH DIFFERENT LEVELS OF SELF-FERTILITY AND USING 3 SPECIES OF BOMBUS LATR (HYMENOPTERA, APIDAE)

The objective was to compare the pollinating efficiency of Bombus lapi darius, B pascuorum and B hortorum with 3 types of treatments (hand tr ipping, self pollination and open pollination). This study was conduct ed under insect-proof cages 3 x 3 x 3 m on 2 faba bean lines, one with high self-fertility (D-27) and the other with low self-fertility (D-2 3). Another objective of the study was to further evaluate if self-fer tility might increase the reliability of yield in faba bean. The cages with bumble bees contained 2 queens each, and the experimental design was a randomized complete block with 3 replications, 6 pollination tr eatments and 2 lines per treatment. Data were recorded on reproductive organs (flowers and pods) by node, on abortion rates, pod setting rat es and seed yield components. Treatments did not affect flower product ion, the self-fertile line D-27 yielding almost-equal-to 50% more flow ers than the line D-23 with low self-fertility. But the abortion rates were significantly higher in the self-fertile line D-27 than in D-23. The self-fertile line was not affected by the various conditions of p ollination. On the contrary, the line with low self-fertility was very susceptible to treatments and to the different species of bumble bees . Under self pollination, the low self-fertile line produced significa ntly less pods than with insects. On the contrary self-fertility enabl ed line D-27 to produce as many seeds under self-pollination as with b umble bees. Despite its higher abortion rate, the self-fertile line D- 27 had a greater productivity than that of D-23 for practically all th e treatments. We concluded that the non self-fertile line has a defini te need of pollinating insects to significantly increase its pod setti ng and seed yield. The fact that the yield from the self-fertile line was completely independent of insect activity indicates that self fert ility was an effective means of making faba bean yield more consistent and reliable, but this mechanism did not increase yield.