MANGO
Mangifera indica L., family AnacardiaceaeSeveral hundred acres of mango are grown commercially in Hawaii in addition to numerous dooryard plantings (Yee 1958). Singh (1960) reported that mangos cover about 7,000 acres in Florida but D. O. Wolfenbarger (personal commun., 1970) estimated that there were only about 2,000 acres.
Mango is grown for the egg-shaped, 2- to 6-inch long, greenish or yellowish to reddish fruit, which has a skin slightly thicker than that of a peach. The juicy, sweet to acid flesh around the hard mono- or polyembryonic stone is a popular fruit for millions of people in the tropical and subtropical areas around the world.
Plant:
The mango is an erect, multibranched evergreen tree characterized by its dome-shaped canopy. It may reach 100 feet although most trees are less than half that height, and it may live 100 years or more. The tree grows in frost-free areas of the world from sea level to 4,000 feet. Heavy rains during flowering will drastically reduce fruit production. Mangoes have a decided tendency to biennial bearing, and many cultivars produce only one good crop in 3 to 4 years (Purseglove 1968*). On the other hand, some double or even triple cropping (the setting of fruit at two or three different times during the year) also occurs (Naik and Rao 1943).
Inflorescence:
The mango inflorescence is a branched terminal panicle, 4 to 24 inches long, with from a few hundred to several thousand individual flowers, requiring up to a month for all to open. The number of panicles may range from 200 to 3,000 per tree with 500 to 10,000 flowers per panicle - 100,000 to 30 million per tree. The proportion of perfect to staminate flowers may vary from 1:4 to 2:1 (Ochse et al. 1961*). Sometimes, the entire tree comes into bloom at one time, covering itself with sweet-scented flowers.
There are perfect and staminate flowers on the same panicle. The perfect flower, 5 to 8 mm long, has a globular ovary (rarely two or three) and a lateral style, which is absent in the staminate flower. Both generally have one, but sometimes two or even three, functional stamens and several sterile staminodes. There are usually five greenish-yellow sepals and three to nine, but usually five, cream-colored petals that take on a pinkish tinge before falling (Naik and Rao 1943). In the perfect or hermaphrodite flower, a nectar-secreting fleshy disk surrounds the ovary. The stamen is on the outer margin of this disk. The pistil and stamen are the same length; therefore, pollinating insects that feed on either nectar or pollen are likely to transfer pollen from the anther to the stigma (Juliano and Cuevas 1932, Sturrock 1966).
The flower opens early in the morning, and the stigma is immediately receptive. Maximum pollen shedding is from about 8 a.m. to noon. This delayed pollen shedding can result in inadequate stigma fertilization (Spencer and Kinnard 1956). When the flowers open, they secrete nectar in considerable quantity, which attracts a large number of insects (Mukherjee 1953); however, relatively little pollen is produced on the anther (Popenoe 1917).
Pollination Requirements:
There has been some lack of agreement on the pollination of mangos. Young (1942) made pollination studies on the 'Haden' mango in Florida, which he said made up 90 percent of the commercial plantings in that State (the 'Tommy Atkins' is the current popular cultivar), and found no significant difference between percentages of set in selfed and cross- pollinated flowers. Sturrock (1944) also considered the flowers self- fertile. This self-fertility was supported by the earlier work of Popenoe (1917), who stated that the mango is selffertile but cross-pollination increases fruit set. However, Singh et al. (1962) reported that crossed flowers set fruit whereas selfed ones did not, indicating a degree of self- sterility. The actual degree of self-fertility and sterility in individual cultivars has not been determined, but there is apparently some variation. Self-sterility is not, however, a major problem in fruit set.
Within the cultivar there is a definite need for transfer of pollen from anther to stigma by an outside agent. Popenoe (1917) stated that some of the embryos are capable of developement without fertilization; however, Naik and Rao (1943) obtained no parthenocarpic fruit set of more than 100,000 flowers studied. Fraser (1927) stated that friuit bud formation and pollination were the two big problems in growing mangos. He pointed out that in some cases only 2 to 3 percent of the flowers on a panicle are perfect - in others 60 to 70 percent. Wolfe (1962) concluded that getting flowers to set fruit was more of a problem than getting the trees to produce flowers.
The effect of cool weather adversly affects pollen tube growth, but this was not considered to be a factor of major importance by Young (1955). Chapman (1964*) and Ruehle and Ledin (1955) considered that the lack of efficient pollination might be responsible in part for the low yields of some Florida cultivars.
The studies indicate that the need for cross-pollination between mango cultivars is not critical, at least for most cultivars, but there is need for pollinating insects to transfer the pollen from anthers to stigma within the cultivar to obtain satisfactory crops of fruit.
Pollinators:
Several agents have been given credit as pollinators of mango. Wagle (1929) showed that there was some selfing and some wind pollination, but insects (bees, ants, and flies) played an important part.
Popenoe (1920) disagreed with other writers that the mango is wind pollinated. He pointed out that the flowers have none of the characteristics of a wind-pollinated flower, and he considdered the mango to be an insect-pollinated plant. Galang and Lazo (1937) and Singh (1969) agreed with him.
Recent studies in India29 showed that plants caged to exclude all insects set no fruit and gall-midges were ineffective as pollinators, but a plant caged with a colony of honey bees where harmful insects were excluded set a heavy crop.
Singh (1961) reported that over 65 percent of the perfect flowers were never pollinated- a strong indication that wind is not an efective pollinating agent. Complaints about lack of adequate fruit set in larger plantings particularly of monoclonal cultivars are frequent (Singh 1969). Fraser (1927) concluded that the important problem was finding out which insets were important as pollinators.
The statement was made by Singh (L.B.) (1960) that honey bees do not visit mango flowers, but Singh (S.) (1954) listed this plant as a source of pollen and nectar for bees. Popenoe (1917) reported that honey bees were the most important hymenopterous insect visitor to the mango flowers, but the number present was variable, possible because of the location of apiaries or other relatively more attractive flora. This probably explained the low population of honey bees reported by Simao and Maranhao (1959).
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29 UNIVERSITY OF ALLAHABAD, INDIA. P. L. (PUBLIC LAW) 480 RESEARCH REPORT OF PROGRESS, PROJECT A-7-ENT-26, PERIOD 1-10-64 TO 31-3-65. From Dept. Zoology, Allahabad Univ., to U.S. Dept. Agr., Agr. Res. Serv., Foreign Res. and Tech. Rpts. Div., 1 p.Pollination Recommendations and Practices:
There is no indication that the recommendation by Young (1942) to place colonies of honey bees in mango groves has become an accepted practice; however, the chances are likely that such bee usage is needed today much more so than when his studies were made. The evidence is quite strong that concentration of colonies of honey bees within the mango grove would result in increased floral visitation and possibly more stabilized set of fruit, particularly in some years. The mango flowers do not appear to be overly attractive to honey bees, and they tend to open in large numbers at a time of year when many other flowers are also available, so visitation in commercial groves is likely to be far below that necessary for maximum floral visitation. If such is the case, a heavy concentration of colonies in the grove, possibly three to six per acre, may be necessary to obtain maximum fruit set.
LITERATURE CITED:
FRASER, S.
1927. AMERICAN FRUITS, THEIR PROPAGATION, CULTIVATION, HARVESTING AND DISTRIBUTION. 829 pp. Orange- Judd Publishing Co., Inc., New York.GALANG, F. G., and LAZO, F. D.
1937. THE SETTING OF CARABO MANGO FRUITS AS AFFECTED BY CERTAIN SPRAYS. Phillipine Jour. Agr. 8(2): 187-210.JULIANO, J. B. and CUEVAS, N. L.
1932. FLORAL MORPHOLOGY OF THE MANGO (MANGIFERA INDICA L. ) WITH SPECIAL REFERENCE TO THE PICO VARIETY. Phillipine Agr. 21: 449-472.MUKHERJEE, S.K.
1953. THE MANGO, ITS BOTANY, CULTIVATION, USES AND FUTURE IMPROVEMENT. Econ. Bot. 7(2): 130-162.NAIK, K.C., and RAO, M.M.
1943. STUDIES ON THE BLOSSOM BIOLOGY AND POLLINATION IN MANGOES (MANGIFERA INDICA L. ). Indian Jour. Hort. 1(2): 107-119.POPENOE, W.
1917. THE POLLINATION OF THE MANGO. U.S. Dept. Agr. Bul. 542, 20 pp._____1920. MANUAL OF TROPICAL AND SUBTROPICAL FRUITS. 474 pp. The Macmillan Co., New York.
RUEHLE, G. D., and LEDIN, R. B.
1955. MANGO GROWING IN FLORIDA. Fla. Agr. Expt. Sta. Bul. 574, 90 pp.SIMAO, S., and MARANHAO, Z. C.
1959. [INSECTS POLLINATING MANGO.] Anais Esc. sup. Agr. 'Luiz Queiroz' 16: 299-304. [In Portuguese, English Summary.]SINGH, L. B.
1960. POLLINATION. His the Mango: Botany, Cultivation, and Utilization, chap 3, pp. 42-43. Interscience Publishers, New York.SINGH L. B. STURROCK, D.
1969. MANGO. In Ferwerda, F. P., and Wit, F., eds., Outlines of Perennial Crop Breeding in the Tropics, pp. 309-327. H. Veenman and Zonen, N. V. Wageningen, The Netherlands.SINGH, S.
1954. HORTICULTURAL CROPS AS BEE PASTURE. Indian Jour. Hort. 11(2): [49]-52.SINGH, S. N.
1961. STUDIES ON THE MORPHOLOGY AND VIABILITY OF THE POLLEN GRAINS OF MANGO. Hort. Adv. 5: 121-144.SINGH, R. N., MAJUMDAR, P. K., and SHARMA, D. K.
1962. SELF-INCOMPATIBILITY IN MANGO (MANGIFERA INDICA L.) VAR. DASHEHARI. Cur. Sci. 31(5): 209.SPENCER, J. L., and KENNARD W. C.
1956. LIMITED STIGMATIC RECEPTIVITY MAY CONTRIBUTE TO LOW FRUIT SET IN THE MANGO (MANGIFERA INDICA L.). Amer. Soc. Hort. Sci. Proc. 67: 287-289.STURROCK, T. T.
1944. NOTES ON THE MANGO. Sturart Daily News, Inc., Sturart, Fla. 122 pp.STURROCK, T. T.
1966; THE MANGO INFLORESCENCE. Fla. State Hort. Soc. Proc. 79:- 366-369.WAGLE, P. V.
1929. A PRELIMINARY STUDY OF THE POLLINATION OF THE ALPHONSO MANGO. Agr. Jour. India 24(14): 259-263.WOLFE. H. S.
1962. THE MANGO IN FLORIDA 1887-1962. Fla. State Hort. Soc. Proc. 75: 387-391.YEE, W.
1958. THE MANGO IN HAWAII. Hawaii Agr. Ext. Sen. Cir. 388, 26 pp.YOUNG, T. W.
1942. INVESTIGATIONS OF THE UNFRUITFULNESS OF THE HADEN MANGO IN FLORIDA. Fla. State Hort. Soc. Proc. 55: 106-110.______ 1955. INFLUENCE OF TEMPERATURE ON GROWTH OF MANGO POLLEN. Fla. State Hort. Soc. Proc. 68: 308-313.
