An Effective Plant Field Cage to Increase the Production of Genetically Pure Chile (Capsicum spp.) Seed

Chile (Capsicum annuum L.) plants are considered a self-pollinating crop (Allard, 1960); however, out-crossing rates (7% to 91%) recorded by several investigators suggest that Capsicum is a facultative cross-pollinating species infield research (Franceschetti, 1971; Odland and Porter, 1941; Tanksley, 1984). Although the amount of out-crossing varied among the investigations, it was sufficient to impede progress in breeding programs (Odland and Porter, 1941; Tanksley, 1984). The out-crossing is associated with natural insect pollinators, not rain or wind (Odland and Porter, 1941; Tanksley, 1984). The amount of cross-pollination affects the precautions needed to produce seed and the breeding methodologies used by the plant breeder. Natural pollinators such as insects must be excluded to ensure self-pollination. To produce large amounts of genetically pure seed, seed certification programs have isolation requirements to control pollination (New Mexico Crop Improvement Association, 1992). Isolation distances range from 1.6 km for foundation seed to 0.4 km for certified seed. Breeding programs also require isolation during seed production. Thus, space for isolation becomes limited. To ensure self-pollination, a simple and effective plant isolation cage was needed. This paper describes such an enclosure (Fig. 1). The cage consists of nylon fabric draped on a frame constructed of conduit piping (Fig. 1A). A 3.05-m section of 19-mm-diameter galvanized electrical conduit pipe is bent in two places, making two “legs,” each 1.22 m long (Fig. 1B). The cage netting material is a white polyester fabric (NK82P, Apex Mills, New York). A green fabric has been used successfully. With either color, no effects on plant growth, fruit set, or seed production have been observed in the southern New Mexico climate. The fabric is 1.73 m wide and comes