ROOTSTOCK TRIALS FOR JABOTICABA

SCIENTIFIC NAME: Myrciaria cauliflora
FAMILY: Myrtaceae

INTERGENERIC AND INTERSPECIFIC ROOTSTOCK TRIALS FOR JABOTICABA , (MYRCIARIA CAULIFLORA (MART.) BERG) ¹

MARY ANN H. OGDEN
Fruit Crops Department, University of Florida,
IFAS, Gainesville, Florida 32611

CARL W. CAMPBELL
Agricultural Research and Education Center, University of Florida,
IFAS, Homestead, Florida, 33031

Additional index words. Myrtaceae, Eugenia, Calyptranthes, Myrcianthes, Syzygium, native plants, propagation, bud union.

Abstract. Jaboticaba is a slow-growing tree and it would be advantageous to graft jaboticaba scions onto vigorous native or edaphically-adapted rootstocks to induce precocity and scion vigor. Six genera and 10 species of native and exotic relatives were evaluated as potential rootstocks for jaboticaba. No satisfactory alternative rootstock was identified. Although several species formed unions, none survived for more than one year. A micro-cleft grafting technique is also described for jaboticaba.

Myrciaria cauliflora is native to Brazil and widely planted in southern Florida (1. 6, 8). The tree blooms in Florida 5 or 6 times yearly with fruit ripening in 20-30 days. The fruits are similar in appearance and flavour to a grape and are 2-3 cm in diameter with a tough black skin (4, 7, 8).

Most members of the family Myrtaceae are difficult to graft. Propagation of Myrciaria cauliflora is usually by seedage. The seeds are polyembryonic and usually come true to type (1, 3, 7). Because of slow growth of the seedlings and the long time it takes them to come into bearing, it would be advantageous to graft M. cauliflora to impart scion vigour and to induce precociousness (1, 8). Seedling trees under very good cultural conditions bear in 6-8 years: however, under poor growing conditions take up to 16 years to come into bearing (8). When grafted, they are usually inarched (1,7,8), or veneer grafted (8).

Materials and Methods
After a review of the taxonomic literature for potential rootstocks, several possibilities were found among the native and naturalized species (5). Final determination of which rootstock to use for experimentation was made by the availability of these plants from local sources.

Seedling stocks were obtained from native plant nurseries in south Florida, the U.S.D.A. Subtropical Horticulture Research Station in Miami, Florida, and some were grown at the University of Florida Agricultural Research and Education Center in Homestead, Florida. Some of the plants at 1-year-old were quite small with stems of 3-6 mm in diameter.

Three types of grafts were used depending on the size and condition of the stock plants: 1) micro-cleft for the very small stocks (3-6 mm); 2) veneer for the larger stocks; and 3) approach for the general test of compatibility.

Micro-cleft grafts were made with scalpels and forceps since grafting knives were too large and cumbersome. Parafilm was used to bind the small wounds because it is more adhesive and pliable than grafting tape (2). Small seedling tops and young terminal scions were used as scions in order to closely match the diameter of the stocks.

In many of the replications, plastic bags were placed over the entire plant which was then put in the shade to prevent moisture loss. In other tests the micro-grafts were put under the mist with and without plastic bags. The use of the mist was for cooling since the heat in the summer months caused the plants to wilt rapidly. Plants in plastic bags not in the mist had to be put in the shade to prevent a build-up of heat.

Veneer and approach graft wounds were made in the standard way but again using scalpels because of the small size of the stock plants. Parafilm was used to bind graft unions on the smaller stocks, and grafting tape split to 5 mm in width was used on the larger diameter stocks.

Budwood was prepared on the tree for the veneer grafts by using material from mature trees. Terminal buds were cut off and the leaves were removed leaving the petioles attached. When the petioles abscised, the buds were starting to swell and the bud sticks were then collected. When preparing the bud sticks for the graft, a shallow longitudinal cut was made removing only ¼ of the diameter of the bud wood leaving the scion ¾ of its original diameter. This retained as much food reserves as possible for the small scion to utilize while the graft union was forming.

Approach grafts were made by planting the stock and scion plants in the same pot, and waiting for 2 weeks for the plants to recover from the effects of transplanting. After the grafts were made the wounds were bound with parafilm for the smaller diameter combinations and for the larger ones, standard grafting tape was split to 5 mm in width. In the second year of the experiments standard 10 mm width grafting tape was used since the plants were larger.

Nine rootstocks were selected from available native and naturalized plants. The native species were: Calyptranthes pallens Griseb. (spicewood), C. zuzygium (L.) Sw. (myrtle of-the-river), Eugenia axillaris (Sw.) Willd. (white stopper), E. confusa DC (redberry stopper), E. foetida Pers. (Spanish stopper), Myrcianthes fragrans (Sw.) McVaugh (Simpson stopper). Exotic species include: E. uniflora L. (Surinam cherry), Pimenta dioica (L.) Merr. (allspice), and Syzygium cumini (L.) Skeels (Jambolan plum).

In the first year, there were 4 experiments (Table 1) and in the second year there were 2 experiments (Table 2). The number and size of available stock plants determined combinations of species. and the number of replications per experiment. M. cauliflora grows very slowly and takes 6 months to a year to reach 3-6 mm in diameter. Some of the natives used as rootstocks grew faster than M. cauliflora and the exotic rootstocks grew much faster than M. cauliflora or the native species.

Results
All species tested as rootstocks showed some degree of tissue mingling or graft unions. Some species demonstrated better healing and sprouting of buds than other species. The relative performance of the stocks is summarized In Table II. Even though all species showed sufficient affinity to permit mingling of tissues, none tested showed sufficient longevity to be considered as a rootstock for M. cauliflora.

Table 1. Summary of stock trials for Myrciaria cauliflora, 1979.

					Comments
Expt.	Stock	Date	Reps (no.)	Graft	1 month	2 months	Later observations
1	Calyptranthes pallens Griseb.	6/27	5^z	micro-cleft	4 alive	all dead	dead
1	Eugenia axillaris (Sw.) Willd.	6/27	5^z	micro-cleft	4 alive	1 alive	died 4 months
1	E. uniflora L.	7/6	5^z	approach	2 alive	all dead	dead
2	C. pallens	8/12	5^yw	approach	all alive	alive	wilted and died
2	C. pallens	8/12	5^yw	approach	all alive	alive	4 unions
2	C. zuzygium (L.) Sw.	8/12	5^yw	approach	all alive	alive	wilted and died
2	C. zuzygium (L.) Sw.	8/12	5^xw	approach	all alive	alive	4 unions
2	E. axillaris	8/12	5^yw	approach	all alive	alive	wilted and died
2	E. axillaris	8/12	5^xw	approach	all alive	alive	3 unions
2	E. confusa DC	8/12	5^yw	micro-cleft	all alive	alive	wilted and died
2	E. confusa DC	8/12	5^xw	micro-cleft	all alive	alive	1 union
2	E. uniflora	8/12	5^yw	micro-cleft	all alive	alive	wilted and died
2	E. uniflora	8/12	5^xw	micro-cleft	all alive	alive	3 unions
2	Myrciaria cauliflora (Mart.) Berg	8/12	5^yw	micro-cleft	all alive	alive	wilted and died
2	Myrciaria cauliflora (Mart.) Berg	8/12	10^x	micro-cleft	all alive	alive	10 unions and growing
3	E. axillaris	12/24	10^w	veneer	dead	dead	dead
3	E. axillaris	12/24	10^w	veneer	dead	dead	dead
3	E. uniflora	12/24	10^v	veneer	dead	dead	dead
3	E. uniflora	12/24	10^v	veneer	dead	dead	dead
3	M. cauliflora	12/24	10^w	veneer	dead	dead	dead
3	M. cauliflora	12/24	10^v	veneer	dead	dead	dead
4	C. pallens	12/28	1^w	approach	alive	died	tissue mingled
4	E. axillaris	12/28	1^w	approach	alive	died	tissue mingled
4	E. foetida Pers.	12/29	8^w	veneer	alive	died	pushed, tissue mingled
4	Myrcianthes fragrans (Sw.) McVaugh	12/29	5^w	veneer	alive	died	pushed, tissue mingled

4	Syzygium cumini (L.) Skeels	12/30	10^w	veneer	alive	pushing	stock outgrew the scion in 3 months

^z Shade with bag
^y Mist without bag.
^x Mist with bag.
^w With parafilm.
^v With grafting tape.

Because M. cauliflora is considered quite difficult to graft, it is commonly grown from seed, although approach grafts and veneer grafts are possible (3, 4, 8). One method not mentioned in the literature was micro-cleft grafting. It was found with the controls (M. cauliflora/M. cauliflora) in experiment 3 (Table 1) that by putting the grafted plants in a plastic bag under the mist that the grafts were uniformly successful. The plastic bag kept the plants from getting waterlogged, while the mist kept the plants cooler and not transpiring rapidly. The plants without the plastic bag became waterlogged and when removed from the mist, wilted and died.

Table 2. Summary of stock trials for Myrciaria cauliflora, 1980.

					Comments
Expt.	Stock	Date	Reps (no.)	Graft	1 month	2 months	Later observations
1	Syzygium cumini (L.) Skeels	3/27	10	veneer	all pushing	9 of 10 alive	3 months stock outgrew scion all died
2	Calyptranthes pallens Griseb.	7/26	10	approach	wilt	died	dead
2	Eugenia axillaris (Sw.) Willd.	7/26	10	approach	wilt	died	dead
2	E. foetida Pers.	7/26	10	approach	wilt	died	dead
2	E. uniflora L.	7/26	10	approach	wilt	died	dead
2	Myrciaria cauliflora (Mart.) Berg	7/25	10	approach	wilt	all alive	growing*

2	Pimenta dioica (L.) Merr.	7/26	10	approach	wilt	died	dead

*All alive as of June 1981, graft union healed so well it was difficult to find later.

Micro-cleft grafting techniques can be used on much younger plants than can approach grafting, and it is a more conservative use of propagating material. The controls that were grafted with this method in 1979 were still growing in the fall of 1982.

All species were micro-cleft grafted and placed under mist with and without bags, including the controls. Those without bags including the controls, wilted and died. The bagged micro-cleft grafts placed under the mist lived longer after removal. Living plants were sectioned free hand and graft unions were examined visually under a dissecting microscope. Some of the bagged micro-cleft grafts placed under mist had successful unions.

The larger approach grafts in the second year were successful only with the controls. None of the other species tested grew and thrived after they were separated. The species that died, lived only a few weeks and then went into wilt, although in all cases the wood was green 2 weeks after cutting the stock and scion apart.

None of the veneer grafts were successful including the controls. M. cauliflora on Syzygium cumini grew for a longer period of time than the other species tested; it grew and sprouted new leaves before the stock overgrew the scion. S. cumini is a rapidly growing tree and the results indicated the stocks were too vigorous for the scions.

No satisfactory alternative rootstock was developed for M. cauliflora; the use of parafilm on the small (3-6 mm) grafts instead of grafting tape made the technique of micro-cleft grafting easier and kept the miniature grafts in place. The parafilm technique used on grafted plants placed in plastic bags under the mist was a successful technique for grafting M. cauliflora scions on M. cauliflora rootstocks.

Table 3. Performance of rootstocks for Myrciaria cauliflora.

Performance*
Stock	1	2	3	4
Calyptranthes pallens Griseb.		XX
C. zuzygium (L.) Sw		XX
Eugenia axillaris (Sw.) Willd.		XX
E. confusa DC		XX
E. foetida Pers.			XX
E. uniflora L.		XX
Myrcianthes fragrans (Sw.) McVaugh			XX
Myrciaria cauliflora (Mart.) Berg				XX
Pimenta dioica (L.) Merr.		XX
Syzygium cumini (L.) Skeels			XX

* 1) No callus from stock or scion; 2) Some mingling of tissues but no water conduction; 3) Buds pushing bud did not live long; 4) Made union, continued growing, growth flushes.

¹ Florida Agricultural Experiment Stations Journal Series No. 4251. This work sponsored in part by the Rare Fruit Council International, Inc., Sam Mauro Fellowship and the Dade County Agri-Council-Dennis Carpenter Memorial Fellowship. Proc. Fla. State Hort. Soc 95: 1982.

Literature Cited
1. Argles, G. J., 1976. Myrciaria cauliflora and related species - jaboticaba. p. 513-517. In: R.J. Garner and S. A. Chaudri (eds.) Propagation of Tropical Fruit Trees. Hort. Rev. No. 4. Commonwealth Bur. Hort. Plantation Crops. East Malling, England.

2. Beineke, W. F. 1978. Parafilm:a new way to wrap grafts. HortScience 13:284.

3. Campbell, C. W. 1977. Cultivation of tropical fruits of the Myrtaceae in southern Florida. Proc. Trop. Reg. Amer. Soc. Hort. Sci. 21:3-7.

4. Mowry, H., I. R. Tov,and H. S. Wolfe. 1967. Miscellaneous tropical and subtropical fruits. Bul. 156A, Fla. Coop. Ext. Serv. Univ. Florida, Gainesville.

5. Ogden, M. A. H. and C. W. Campbell. 1979. Tropical fruits and their indigenous re1atives in southern Florida. Proc. Fla. State Hort. Soc. 92:294-298.

6. Ogden, M. A. H., I. K. Jackson, and C. W. Campbell. 1981. Florida tropical fruit culture via Master Gardener. Proc. Fla. State Hort. Soc. 94:222-224.

7. Phillips. R. I. and S. Goldweber. l978. The jaboticaba. Fruit Crops Fact Sheet FC-39. Fla. Coop, Ext. Serv. Univ. Florida, Gainesville.

8. Popenoe, W. 1920. Manual of tropical and subtropical fruits. Chap, IX, Hafner Press, New York.

Reprinted from Proc. Fla. State Hort. Soc. 95:119-121 1982

DATE: November 1983

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