Rootstock-Scion Interactions of Selected Annona Species

Home , Annona squamosa, Atemoya, Cherimoya, Custard apple, Soursop

22.2008

Rootstock-scionJ.Natn.Sci.Foundation interaction Sri Lanka in Annona 2009 species37 (1):71-75 71

SHORT COMMUNICATION

Rootstock-scion interactions of selected Annona species

H.M.S. Heenkenda*, B.L. Gunathilaka and J.P. Iswara 1 Horticultural Crops Research and Development Institute, Department of Agriculture, Gannoruwa, Peradeniya. 2 In-Service Training Institute, Department of Agriculture, Mahailuppallama. 3 Department of Crop Science, Faculty of Agriculture, University of Peradeniya, Peradeniya.

Revised: 11 August 2008 ; Accepted: 02 October 2008

Abstract: Annona species are commonly grown in home gardens vitamin C and minerals such as calcium, phosphorous of Sri Lanka. The nutritive value of Annona fruits and their and potassium, are consumed either fresh or processed1. value in the fruit processing sector have been realized recently. There is a potential for this fruit in the food processing This has increased the demand for planting material. Use of industry. Annona fruit, seed and many parts of the tree are seedlings as planting material generally resulted in extended used in traditional medicine. The green fruit and seeds vegetative growth, low productivity, inferior fruit quality and have effective vermicidal and insecticidal properties2. The inconsistency in yield and quality. Vegetatively propagated plants of superior varieties will solve some of these problems. potential of Annona species to produce nutritive fruits This study was therefore undertaken at the Horticultural indicates the need for research on varietal improvement, Research and Development Institute, Gannoruwa during Maha production of high quality planting material, large scale season 2006/2007, to identify suitable rootstock species for cultivation and value addition. some selected promising Annona accessions. Soursop (Annona muricata L.), cherimoya (A. cherimola Mill) and atemoya Soursop (A. muricata L.), cherimoya (A. cherimola (A. squamosa × A. cherimola) scion varieties were grafted on to Mill), custard apple (A. reticulata L.), and sweetsop soursop, cherimoya and sweetsop (A. squamosa L.) rootstocks. (A. squamosa L.) species of Annona are abundant The experimental design was based on two factor factorial set in home gardens in all agro-ecological regions of in Completely Randomized Design with three replications, Sri Lanka3. Atemoya (Annona squamosa × A. cherimola) with 15 plants in each treatment. Percentage success in grafting has been introduced to the island from Australia under was much less than the percentage bud take-on showing need for improvement of grafting. Atemoya and soursop were the FAO/UNDP/SRL Horticultural Project during the successfully grafted on to cherimoya rootstock (83.3 and 1983-1988 period. Annona is cultivated under a wide 73.3% respectively). Soursop scion grafted on to any one of range of ecological conditions with a minimum effort. the rootstock species showed the least successful combination Annona fruit is available in many months of the year (33%). The scion growth, indicated as length of the first shoot and is consumed as fresh fruit or as juice. Small and and leaf production (number of leaves/graft/week), depended medium scale fruit processing enterprises offer a market on the rootstock- scion combination. for these fruits. However, unavailability of quality fruits in large quantities regularly is a common problem for Keywords: Annona, grafting, interaction, rootstock species, development of the Annona industry in the island. scion. High quality planting material should be made INTRODUCTION available in line with expansion of cultivation of Annona. This can be achieved by selection of suitable The genus Annona (Annonaceae) includes more than 50 rootstock species to increase the efficiency of vegetative species widely distributed in different agro-ecological propagation techniques. Seedlings of Annona spp. take regions of Sri Lanka. Some of them are cultivated about five to six years from planting to attain the first for their edible fruits while others are cultivated for flowering stage while the grafts take about two and half ornamental purposes or to produce perfumes. Thus, years. The present study was undertaken to investigate they are multipurpose trees. The fruits, rich in energy, the interaction between common Annona species as

*JournalCorresponding of the National author ([email protected]) Science Foundation of Sri Lanka 37 (1) March 2009 72 H.M.S. Heenkenda et al. rootstocks and scions, to identify the most effective when atemoya was grafted on to cherimoya rootstock rootstock-scion combinations for different species and to (83.3%). When the same scion species was grafted on make use of conventional wedge grafting efficiently. to sweetsop rootstock, the percentage of successful grafts achieved was 73.3% with a significant difference between them. The lowest percentage of successful METHODS AND MATERIALS grafts was recorded for the soursop grafted on to its own rootstock and on to sweetsop rootstock (36.7% and 33.3% This study was conducted at the Horticultural Research respectively). Soursop was more successful when grafted and Development Institute (HORDI), Gannoruwa, on to cherimoya rootstock (66.7%). All other rootstock- (WM agro-ecological region) during November 2006- 2b scion combinations resulted in moderate percentages of February 2007. The scion wood species of soursop, successful grafts (60-66.7%). Thus, cherimoya was the cherimoya (C-1: a local selection) and atemoya (var. most suitable rootstock for both atemoya and soursop. African Pride) were grafted on to the rootstock species of Soursop was the most suitable rootstock for cherimoya soursop, cherimoya (C-1: local selection) and sweetsop, in terms of percentage successful grafts (Figure 1). employing the conventional wedge grafting technique. Cherimoya is used as a rootstock for atemoya in Israel 4. The experiment was laid in Completely Randomized Soursop grafted on sweetsop rootstocks does not last long, Design with three replications and 15 plants (sub samples) which could be due to incompatibility 5. per treatment per replicate. Approximately 10-11 month old seedlings of uniform size were selected as rootstocks. There was no effect of rootstock on the time taken The scion wood, about 15 cm long, was extracted from for bud break (Figure 3). However, earliest bud break 10 year old fruiting trees of each species grown in the was observed in the soursop and atemoya grafts (15.5 orchard of the HORDI, Gannoruwa. The fresh grafts days after grafting) on cherimoya rootstock. Cherimoya were maintained under 70% shade during the study grafts on soursop rootstock took the longest time for bud period of 10 wks. The bud take-on indicates the possible break (20 days). The time taken for bud break depends fusing of scion and rootstock. Percentage bud take-on mostly on the condition of the scion. The first shoot in (successful healing of the graft union), successful grafts all grafts of the present experiment emerged three weeks (successfully established grafts with the scion grown up after grafting. to 30-35 cm in height), number of days taken for bud break after grafting, length of the first shoots emerging There was a difference in the length of the first shoot in from the grafts, number of leaves produced on the first different rootstock-scion combinations (Figure 4). Since shoots, position of the first shoot on the graft, total the interaction between scion and rootstock is significant, number of shoots emerging per graft and total number the scion growth is determined by the rootstock. Hence, of leaves produced per graft were recorded during the suitable rootstock species should be selected for the period of 10 wks after grafting. grafting of each scion species. The maximum length of the first shoot was recorded for cherimoya grafted on to RESULTS AND DISCUSSION soursop rootstock (8.2 cm) and cherimoya rootstock (6.2 cm). The length difference between them showed the There was a considerable effect of rootstock species and most suitable combinations for early emergence of scion. scion species on the percentage bud take-on in the grafts Shoots emerging from atemoya grafted on to soursop (Figures 1 and 2). The highest percentage bud take-on rootstock showed the least growth during the same period was recorded for atemoya grafted on to soursop rootstock (2.0 cm). (90%), cherimoya grafted on to cherimoya rootstock (90%) and atemoya grafted on to cherimoya rootstock The increase in shoot length of all combinations (86.7%) showing no significant difference among them were below 0.8 cm/week at five weeks after grafting in this respect. The lowest bud take-on was recorded for (Figure 4). Cherimoya grafted on to soursop and soursop soursop grafted on to its own rootstock and on to sweetsop grafted on to sweetsop showed relatively higher growth rootstock (40%). Grafting cherimoya on to soursop and (1.1 cm / week) at the beginning of this period and sweetsop rootstocks resulted in moderate percentage the shoot extension was less in other combinations. value of bud take-on (73.3%) while cherimoya rootstock The highest rate of growth of the first shoot during the for soursop grafting was less effective (66.7%). 7th and 9th week was recorded for cherimoya grafted on to cherimoya and soursop rootstocks, and soursop The percentage of successful grafts was lower scion on to sweetsop rootstocks. This showed that the than the percentage bud take-on showing the need for characteristics of the graft were influenced by both the improvement in grafting (Figures 1 and 2). However, stock and the scion.The rootstocks influenced the growth the highest percentage of successful grafts was achieved habit, flowering and yielding capacity of the graft6 .

March 2009 Journal of the National Science Foundation of Sri Lanka 37 (1)

Rootstock-scion interaction in Annona species 73

% Bud take on % Grafting sucess 100 90 % Bud Take on 80

% Grafting Success 70

percentage Success Success percentage 30

10 a b 0 Ss: soursop SS-CM SS-AM SS-SS CM-CM CM-AM CM-SS SwS-CM SwS-AM SwS-SS 25 Cm:cherimoya Treatments Sw:sweetsop Am: atemoya Fig. 1. Percentage of bud take on and grafting success 20 Figure 2: Percentage of bud take-on and grafting success

s Ss: soursop y a 25 Cm:cherimoya

10 Sw:sweetsop

Am: atemoya 20

s y a 0 D c Ss-Cm Ss-Am Ss-Ss C m-Cm Cm- Am dCm- Ss Sw-C m Sw-Am Sw-Ss 10

R ootstock-scion combinations

5 Fi g. 2. Da ys taken for bud break after gra fting Figure 1: Grafts of Annona species: a) fresh grafts in single

propagators; b) cherimoya grafted on to soursop rootstock; 0 c) soursop grafted on to cherimoya rootstock; d) atemoya Ss-Cm Ss-Am Ss-Ss C m-Cm Cm- Am Cm- Ss Sw-C m Sw-Am Sw-Ss

grafted on to cherimoya rootstock R ootstock-scion combinations

Fi g. 2. Da ys taken for bud break after gra fting Figure 3: Days taken for bud break after grafting

Ss: soursop 8 Ss: soursop 9 ( c m ) Cm:cherimoya Cm:cherimoya 8 7 Sw:sweetsop Sw:sweetsop Am: atemoya 6 Am: atemoya 7 L e n g t h Ss-C m Ss-Cm 5 6 Ss-A m Ss-Am 59 4 Ss-Ss Ss-Ss Cm- C m Cm-Cm 48 Ss: soursop Cm- Am ( c m ) Cm-Am 3 Cm:cherimoya Cm- Ss 37 Cm-Ss of leaves Number Sw:sweetsop 2 Sw-C m Sw-Cm 26 Am: atemoya Sw-Am L e n g t h Sw-Am 1 Ss-C m Sw-Ss 15 Sw-Ss Ss-A m 0 04 Ss-Ss 4 5 6 7 8 9 Cm- C m 1 2 3 4 56 W eeks after grafting 3 Cm- Am Number of weeks from 21 days after grafting Cm- Ss 2 Sw-C m Fig. 3. Le ngth of the first s hoots emerged from the Fig. 4. Number of leaves of the first shoot on scion Sw-Am gFigurerafts 4: Length of the first shoots emerged from the grafts 1 Figure 5: Number of leaves of the first shoot on scion Sw-Ss 0 4 5 6 7 8 9 The mean number of leaves produced on the first shoot first shoot (6.3-6.7 leaves). The least number of leaves on of the grafts was influenced by the relationship between the first shootW eewasks a frecordedter grafting in the atemoya and soursop rootstock and scion species (Figure 5). The highest grafts Fig. 3made. Le ng tonh of soursopthe first s h orootstocksots emerged fr o(4.7m th eleaves). Though grafts number of leaves on the first shoot was recorded in cherimoya scion grows vigorously on all rootstock cherimoya on soursop rootstock and on its own rootstock species tested, cherimoya rootstock was more suitable (7.7 leaves). Soursop grafted on to cherimoya rootstock for atemoya. Sweetsop rootstock was more suitable for and sweetsop rootstock also showed vigorous growth as soursop, in terms of the number of leaves produced in the indicated by the second highest number of leaves on the first shoot of the graft.

Journal of the National Science Foundation of Sri Lanka 37 (1) March 2009

Ss: soursop 6 Cm:cherimoya

Sw:sweetsop Am: atemoya 5

1 scion shoot first on Position of 0 Ss-Cm Ss-Am Ss-Ss Cm-CmCm-AmCm-Ss Sw-CmSw-Am Sw-Ss Rootstock-scion combinations

Fig. 5. Position of the first shoot of the grafts

74 H.M.S. Heenkenda et al.

Ss: soursop 4.5 Ss: soursop 6 Cm:cherimoya Cm:cherimoya

Sw:sweetsop 4 Sw:sweetsop Am: atemoya 5 3.5 Am: atemoya

3 4

2.5

3 2

Number shootsNumber of 1.5 2 1 1 scion shoot first on Position of 0.5 0 0 Ss-Cm Ss-Am Ss-Ss Cm-CmCm-AmCm-Ss Sw-CmSw-Am Sw-Ss Ss-Cm Ss-Am Ss-Ss Cm-Cm Cm-Am Cm-Ss Sw-Cm Sw-Am Sw-Ss

Rootstock-scion combinations Rootstock-scion combinations

Fig. 5. Position of the first shoot of the grafts Figure 6: Position of the first shoot of the grafts Fig. 6.Figure Total number 7: Total of numbershoots emerged of shoots per emerged graft per graft

and the sequence of their maturity influenced by the 16 Ss: soursop Cm:cherimoya scion species. This suggests the importance of selection 14 Sw:sweetsop Am: atemoya of suitable lengths of the scion wood of different Annona 12 species for grafting. Ss-Cm 10 Ss-Am 8 4.5 Ss: soursop Ss-Ss The total number of shoots per scion did not vary Cm:cherimoya Cm-Cm 4 6 Sw:sweetsop Cm-Am significantly. The highest number of shoots (four shoots/ of Number leaves

3.5 Cm-Ss 4 Am: atemoya Sw-Cm scion) emerged from soursop scions grafted on to

3 Sw-Am 2 cherimoya rootstock. Three shoots emerged on cherimoya 2.5 Sw-Ss 0 grafted on to soursop rootstock, cherimoya grafted on to 122 3 4 5 6 cherimoya rootstock, atemoya grafted on to cherimoya shootsNumber of 1.5 Number of weeks from 21 days after grafting rootstock and soursop grafted on to sweetsop rootstock 1 (Figure 7). This could be attributed to the status of the Figure 8: Total number of leaves on the scion 0.5 scion wood, mostly the length and number of nodes 0 (number of mature axillary buds) present on the scion. The rate of leafSs-Cm emergence Ss-Am Ss-Ss on Cm-Cm theCm-Am firstCm-Ss shoot Sw-Cm Sw-Am of the Sw-Ss Rootstock-scion combinations grafts was below one leaf /week until the 6th week The total number of leaves produced on a graft varied after graftingFig. 6. but Total increased number of shoots thereafter emerged per (Figure graft 5). The among different rootstock-scion combinations showing first shoot of the cherimoya graft made on soursop and the effect of interaction between the rootstock and scion cherimoya rootstocks showed a higher leaf emergence on leaf production (Figure 8). Cherimoya grafts made on rate throughout the period. Soursop and atemoya grafted soursop and cherimoya rootstocks produced the highest on to sweetsop rootstock also showed a similar rate of number of leaves of 15. This shows that cherimoya leaf emergence. on soursop and cherimoya rootstocks are compatible combinations for vigorous growth of cherimoya scions. The sequence of the shoots emerging from the graft However, atemoya grafted on to soursop rootstock indicates the future shape and architecture of the tree and produced the least number of leaves (7.7 leaves) and the total number of shoots that continue to grow. The soursop grafted on to its own rootstock had a slightly position of the first shoot (number of nodes away from higher number of leaves per graft (8.7 leaves) indicating graft union) also influences the position and growth of that these combinations are not suitable to develop a the subsequent shoots and thereby the framework of the strong canopy. tree. The position of the first shoot was not significantly affected by rootstock species (Figure 6). However, the The highest rate of leaf emergence in the grafts position of this shoot seemed to vary according to the was recorded in the 4th week after grafting (2.2 leaves/ scion species. Almost all the first shoots emerged at week) (Figure 5). Thereafter, this rate was maintained 3rd, 4th or 5th node of the scion wood but most atemoya at a slightly lower level (1.4 – 1.7 leaves / week) but th grafts produced the first shoot at the 5 node. In most declined in the 9th week after grafting. This could be due of soursop grafts, the first shoot was produced at about to maturity of the emerged leaves. Cherimoya grafted on 3 nodes above the graft union. The emergence of first cherimoya and soursop grafted on cherimoya rootstock shoot may depend on the development of axillary buds achieved higher rates of leaf emergence in most weeks,

March 2009 Journal of the National Science Foundation of Sri Lanka 37 (1) Rootstock-scion interaction in Annona species 75 though their total leaf production was slightly less than References that of cherimoya grafted on to soursop rootstock. The lowest rate of leaf emergence was continually recorded 1. Anonymous (2002). Fruits for the future. Fact sheet for atemoya grafted on to soursop rootstock. number 05, International Centre for Underutilized Crops, University of Southampton, U.K. CONCLUSION 2. Rayes F.R. & Santos A.C. (1931). The isolation of annonaine from Annona squamosa L. Philippine Suitable rootstocks should be selected to graft different Agriculturist 26 (5): 425-445. Annona species. Scion species on its own rootstock is not 3. Anonymous (2005). Exploration. collection, conservation the best combination. Length of the scion of each species and characterization of underutilized fruits. HORDI Annual Report, Horticultural Research and Development determined the growth of the first bud as indicated by Institute, Gannoruwa, Peradeniya. the position of the first shoot emerging from the scion. 4. Morton J. (1987). Atemoya. In: Fruits of Warm Climates. Cherimoya was the most suitable rootstock for atemoya (Ed. F.J. Morton). pp.72-75. Creative Resource Systems, and soursop scions, when grafted using the wedge grafting Inc., Winterville N.C. 28590, Miami, Florida, U S A. technique. Soursop was the most suitable rootstock for 5. Morton J. (1987). Cherimoya. In: Fruits of Warm Climates. cherimoya. These grafts established well and grew faster (Ed. F.J. Morton). pp. 65-69. Creative Resource System resulting in a dense canopy during the first nine weeks Inc., Winterville, N.C. 28590, Miami, Florida, U S A. after grafting. Other Annona spp. not included into this 6. Nanda K.K. & Kochhar V.K. (1995). Vegetative study, should also be tested in reciprocal combinations Propagation of Plants. Kalyani Publishers, New Delhi, in future. India.

Journal of the National Science Foundation of Sri Lanka 37 (1) March 2009