Chapter 5: Tree Fruits & Nuts and Exotic Tree Fruits & Nuts


Chapter 5: Tree Fruits & Nuts and Exotic Tree Fruits & Nuts


CHESTNUT
Castanea spp., family Fagaceae

Chestnut trees are cultivated for their nuts or as ornamentals. Probably the most notable species was the large and graceful ornamental American chestnut (C. dentata (Marsh.) Borkh.) (fig. 73), which extended from Maine southwest to Arkansas (Munns 1938). It has been almost completely destroyed by blight. The Japanese chestnut (C. crenata Sieb. and Zucc.) and the Chinese chestnut (C. mollisima Blume) are both cultivated for their nuts.

[gfx]
FIGURE 73. - American chestnut tree. (Photograph taken in 1915.)

Plant:

Chestnut is a deciduous tree or shrub, which is cultivated in a similar manner to other deciduous nut trees. It bears brown nuts, about an inch in diameter, which are usually consumed after they are roasted. From one to nine nuts are produced in a spiny involucre or burr (fig. 74).

[gfx]
FIGURE 74.- Burrs and nuts of Chinese chestnuts.

Inflorescence:

The fragrant inflorescence is about 12 inches long (fig. 75). It consists of a group of catkins 4 to 8 inches long. Catkins bearing only staminate florets make up the bulk of the inflorescence. Those produced near the base bear both staminate and pistillate florets. The latter, near the base of the catkin, are few in number. Usually three pistillate florets make up an involucre, each floret capable of producing three nuts.

Bees visit the staminate flowers for both nectar and pollen (Hazslinszky 1955, McKay 1939, Pellett 1947*). the degree of visitation depending upon competition from other flowers. The bees do not intentionally visit the pistillate flowers, but may accidentally come in contact with them while visiting the staminate flowers.

[gfx]
FIGURE. - Chestnut inflorescence.

Pollination Requirements:

Reed (1941) concluded that chestnut is self-sterile. He noted that isolated trees bear few nuts or even a fair crop, but best results are invariably obtained from trees in a mixed orchard where good pollen is available. McKay (1939) reported finding a C. crenata tree that was completely male-sterile. Its nectar production was normal, and it produced a normal crop of nuts. He also reported male sterility in C. sativa Mill. and C. sativa X C. dentata. Later, McKay (1942) reported that when flowers of C. mollissima were self-pollinated only 1.3 percent of the flowers set fruit, when they were cross-pollinated 34.9 percent set, but when they were open-pollinated 68.1 percent set. This showed the need for transfer of pollen between plants.

Crane et al. (1937) stated: "As a rule all chestnuts are more or less self-sterile and they bear better when interplanted with other cultivars."

Kawagoe (1955) stated that the stigmas may remain receptive as much as 45 days and that cross-pollination was best effected 8 to 22 days after stigma emergence.

Ohno et al. (1958), considering the effect of rain on the pollination of chestnuts, tested the effect of water on the pollen. They found that 17 to 19 percent of their pollen germinated even after soaking in water in the laboratory for 9 hours. In the field, this pollen caused 48 to 50 percent set of fruit if cross-pollinated but only 3 to 9 percent set if it came from the same plant.

Watanabe et al. (1964) reported much higher bur-set on adjoining rows to the pollenizer row than on the (decreasing) 3d to 10th rows. They recommended that pollenizer cultivars be set in the ratio of 1 to 1 or 1 to 2 of the main cultivar.

Pollinators:

Crane et al. (1937) and Clapper (1954) stated that chestnut pollen is produced in great abundance and is carried by wind. However, J. W. McKay (personal commun., 1972) questioned this. He indicated that honey bees, rose chafers, and wild bees are highly beneficial to chestnut in the transfer of pollen, and they frequently visit the staminate flowers in large numbers. He also considered that for highest production on younger trees, a high population of pollinators is especially needed. If production of newer cultivars and hybrids expands, the value of insects in cross- pollination for maximum set should be more fully explored.

Pollination Recommendations and Practices:

There are no recommendations on the use of pollinating insects on chestnut although evidence shows they are needed.

LITERATURE CITED:

CLAPPER, R. B.
1954. CHESTNUT BREEDING, TECHNIQUES AND RESULTS. II. INHERITANCE OF CHARACTERS, BREEDING FOR VIGOR AND MUTATIONS Jour. Hered. 45: 201-208.

CRANE, H. L., REED, C. A., and WOOD, M. N.
1937. NUT BREEDING. U.S. Dept. Agr. Yearbook 1937: 827 - 889.

HAZSLINSZKY, B.
1955. [THE IMPORTANCE OF THE CHESTNUT TREE FOR BEEKEEPING.] Meheszet 3(6): 109 - 110. [ In Hungarian.] AA-171/57.

KAWAGOE, H.
1955. [STUDIES ON THE PERIOD DURING WHICH THE CAPACITY FOR FERTILIZATION OF THE CHESTNUT PERSISTS.] Okayama Nogaku Shikenjo Rinji Hokoku/Spec. Bul. Okayama Agr. Expt. stat 53: 141 - 154. [In Japanese.] Abs. in Plant Breed. 28(4): 826. 1958.

McKAY, J. W.
1939. MALE STERILITY IN CASTANEA. Amer. soc. Hort. Sci. Proc. 37: 509-510.

______ 1942. SELF-STERILITY IN THE CHINESE CHESTNUT (CASTANEA MELLISSIMA). Amer. Soc. Hort. Sci. Proc. 41: 156-160.

______ 1972. POLLINATION OF CHESTNUT BY HONEY BEES. North. Nut Growers' Assoc. Ann. Rpt. 63: 83-86.

MCKAY, J. W. and CRANE, H. L.
1953. CHINESE CHESTNUTS A PROMISING NEW ORCHARD CROP. Econ. Bot. 7(3): 228 - 242.

MUNNS, E. N.
1938. THE DISTRIBUTION OF IMPORTANT FOREST TREES OF THE UNITED STATES. U. S. Dept. Agr. Misc. Pub. 287, 176 pp.

OHNO M., SATO, s., and SAWABE, H.
1958. [THE STUDY OF CHESTNUT POLLINATION. 1. THE FRUIT SET OF CHESTNUTS WHICH WERE POLLINIZED BY THE WETTING POLLEN.l Chiba Univ. Faculty Hort. Tech. Bul. 6: 129-135. [In Japanese, English summary.]

REED, C. A.
1941. THE PRESENT STATUS OF CHESTNUT GROWING IN THE UNITED STATES. Amer. soc. Hort. Sci. Proc. 39: 147-152.

WATANABE, Y., ADACHI, M., and HIYAMA, H.
1964. [STUDIES ON THE POLLINATION IN CHESTNUT TREES. 1. INFLUENCE OF DISTANCE FROM THE POLLINIZER UPON BUR-SET IN VARIETY GINYOSE.] Ibaraki Hort. Expt. stat Bul. l: 7-12. [In Japanese, English summary.]


Capturé par MemoWeb ŕ partir de http://www.beeculture.com/content/pollination_handbook/chestnut.html  le 10/03/2006