Chapter 9: Crop Plants and Exotic Plants


Chapter 9: Crop Plants and Exotic Plants


WHITE SAPOTE
Casimiroa edulis Llan. & Lex., family Rutaceae

Hoffman (1970) reported that although white sapote is a tropical plant it is becoming popular in the mild areas of California and Florida. Mowry et al. (1967*) stated that it was growing in scattered locations in these two States. Mortenson and Bullard (1968*) pointed out that this plant is not a true "sapote", which is in the family Sapotaceae, but a relative of the citrus. According to Mowry et al. (1967*), it is more common than any other plant known as sapote. (Also see, "Mamey Sapote," p. 253.)

Plant:

White sapote is a medium to large, erect to spreading, evergreen tree, with leaves 3 by 6 inches in size. It produces ovoid fruit up to 3 inches in diameter, with a greenish skin that becomes yellow at maturity. The creamy or yellowish juicy fruit, rich in vitamin C, has a distinctive sweet aroma. Each fruit has one to five large ovoid seeds imbedded in the flesh. The fruit is eaten out of hand or as a fruit dessert with cream and sugar (Mortensen and Bullard 1968*).

Inflorescence The small (5 mm), whitish-green flowers are produced in great numbers along the branchlets, but few ever produce mature fruit (fig. 196). Abundant nectar is produced from these flowers in southern Mexico, primarily in January and February (Ryerson 1925, Wulfrath and Speck no date). The individual flower has five pale-green, strongly reflexed pews with five short, stout, slightly reflexed stamens. Each stamen arises between two petals. The position of the pews and anthers leaves the globose green ovary exposed. The stigma is sessile, resting directly on the ovary, and leads directly to five ovules, which normally form the one to five seeds in the fruit. Nectar is secreted on the base of the petals next to the ovary.

[gfx] FIGURE 196. - Longitudinal section of 'Neysa' white sapote flower, x 15.

Pollination Requirements:

Mature fruits are sometimes irregular in shape from lack of seed development in one or more carpers, and heavy shed of immature fruit has been reported (Kennard and Winters 1960*). Although the flowers are hermaphrodite, Mustard (1954) showed that there is partial to total pollen sterility within the flower. He concluded that this factor was responsible for failure to set a good crop of fruit. Mortensen and Bullard (1968*) stated that in Florida the 'Dade' cv. must be cross-pollinated because it does not have "normal" pollen. Mustard (1954) reported that partial pollen sterility may be a factor in failure to obtain good sets of fruit. Pollinators The honey bees in visiting the flowers for nectar doubtless serve as pollinators of the plants, particularly if they are sufficiently concentrated in the area of the trees.

Pollination Recommendations and Practices:

None.

LITERATURE CITED:

HOFFMAN, L. E.
1970. THE SAPOTE TREE. Horticulture 48:3.

MUSTARD, M. J.
1954. POLLEN PRODUCTION AND SEED DEVELOPMENT IN THE WHITE SAPOTE. Bot. Gaz. 116:189-192.

RYERSON, H.
1925. THE WHITE SAPOTE OF CALIFORNIA. Calif. Univ. (Berkeley), College of Agr., Div. of Subtrop. Agr. Cir. 3, 2 pp.

WULFRATH, A., and SPECK, J. J.
(n.d.) ENCICLOPEDIA APICOLA. Folleto 28, Ed. 2, Ediciones Mexicanas, Mexico, D.F. 96 pp. [In Spanish.]


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