Study the effect of salicylic acid, harvest method and pollinator (Bee) on seed yield of evening primrose (Oenothera biennis L.)

Backgrounds and in agriculture yield is the most important factor. Plants with indeterminate growth habit are problematic for on time harvesting and causes yield loss. Honey bee helps pollination of self and cross pollinator plants. On the other hand under stressed situation plant eager to complete sexual cycle of its life, so using stress inducing compounds to reduce vegetative growth of indeterminate plants might be beneficial.
Present research conducted in as spieled factorial design based on completely randomized block. Treatments of experiment included pollinator (cage with honeybee, cage without pollinator (isolated) and free pollinators, salicylic acid (0 and 200 ppm), pre-harvest treatments (flame, without flame). In this study parameters such as plant height, number of flowers and capsule, capsule length, weight of seed contained capsule, number of seeds, TSW and seed yield investigated.
Based on obtained results, honey bee significantly affected capsule length, weight of 1000 seeds (TSW), and weight of seed contained capsules, seed yield of plant, number of seeds in each capsule, number of flowers per plant and number of capsule s. Salicylic acid singly affected number of branches. On the other hand in plants treated by flame pre harvest, weight of seed contained capsule and number of branches affected significantly. The interaction effect of honey bee and salicylic acid on measured parameters was not significant. In contrast to that, significant effect of interaction of honey bee and flame was observed on capsules. Also treating with both flame and salicylic acid affected plant height, weight of seed contained capsule, number of branches, length of capsule and seed yield. Simultaneous use of pollinator, flame and salicylic acid significantly affected weight of seed contained capsules, length of capsule s and seed yield.
Although investigations of this study determines that, primrose is self-pollinator and even clystogam, nevertheless result showed that pollinator plays an important role in increasing seed yield. Plant treating with flame one week before harvest as pre harvest treatments seems to stimulate the filling of seed via increasing the speed of nutrient transport to seed and fastened seed maturation. By stopping the plant growth via burning the stem by flame stops vegetative growth and stimulates the seed filling. As the highest quality of seed is expected at seed maturity, the high seed quality will be achievable by using mentioned treatments. It seems that, by using any way to inducing tension during seed ripening of evening primrose, an indeterminate plant, accelerates seed formation and reduces seed maturity period which results to a higher seed quality and quantity.