Pollination effects of the sweat bee Lasioglossum villosulum trichopse (Hymenoptera: Halictidae) on genic male-sterile lettuce

Abstract

For development of an F 1 hybrid of lettuce cultivars, an efficient pollinator must be found. To evaluate pollination effects of a candidate pollinator, Lasioglossum villosulum trichopse, the foraging behavior and pollination ability of this sweat bee were investigated on the flowers of male-fertile (MF) and genic male-sterile (GMS) lettuce. Females of the sweet bee visited three lettuce cultivars for a short time corresponding to each cultivar's full blooming time and showed unique foraging behavior on the MF lettuce flower. The flower heads thus visited by a single pollen-gathering female sweat bee indicated a seed set as high as that of self-pollinated flower heads on a fine day. On the GMS lettuce, the rate of seed set was significantly lower in the bee-pollinated flower heads than that of hand-pollinated flower heads which bloomed on fine days. The low seed set was considered to be associated with weather conditions during the experimental period. This is the first report of successful F 1 hybrid seed production of lettuce using a pollinator insect.

Small sweat bees (Hymenoptera: Halictidae) as potential major pollinators of melon (Cucumis melo) in the Mediterranean

“…Among wild bees, members of the family Halictidae (sweat bees) have been shown to efficiently pollinate some crops around the world. For example, Nomia melanderi Cockerell is managed for alfalfa, Medicago sativa L., pollination in North America (Cane ), Macronomia rufipes (Smith) is an important pollinator of eggplant, Solanum melongena L., in East Africa (Gemmill‐Herren & Ochieng ), Lasioglossum villosulum trichopse (Strand) is crucial for lettuce, Lactuca sativa L., pollination in Japan (Goubara & Takasaki ) and a number of species from several genera were recorded in both Europe and America to be effective pollinators of tomato, Solanum lycopersicum L. (Harter et al . ; Teppner ).…”

Development of SCAR and CAPS markers linked to a recessive male sterility gene in lettuce (Lactuca sativa L.)

“…In Asteraceae, GMS was reported in sunflower (Chen et al 2006) and lettuce (Ryder 1967), and controlled by single recessive genes in both cases. Hybrid lettuce using GMS has already been successfully grown (Goubara and Takasaki 2004). However, the traditional breeding system using GMS is very laborious and time-consuming because visible characteristics linked to male sterility have not been found so far and the phenotype is recognized only after flowering.…”

Pollen‐mediated transgene flow in lettuce (Lactuca sativa L.)

“…Cleistogamy (pollen shedding before or/at the anthesis) strongly limits crosses: lettuce F 1 hybrid production can be achieved by emasculation and hand pollination (Nagata 1992) or, most frequently, by honey bee and fly pollination using two inbred lines, whereas the use of male sterile lines has been unsuccessful (commented by Goubara and Takasaki 2003). Hence, the selection of efficient flower visitors was performed in wild bee species (Goubara and Takasaki 2004). Lactuca sativa is sexually compatible with the ancestor Lactuca serriola , and the related saligna and virosa species (de Vries 1990, Koopman et al.…”