Peach palm - World Agroforestry Centre

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4 2 Peach palm. Bactris gasipaes Kunth (gibberellic acid, 6-benzyl amino purine, hydrated cyanamide, ethaphon) have not been successful or have given inconsistent results (Villalobos 1991; Villalobos and Herrera 1991; Villalobos et al. 1992a, 1992b; Clement and Dudley 1995). Seedlings require about 6-9 months in the nursery before transplanting. Proper fertilization with adequate phosphorus is critical to seedling growth and resistance to anthracnose (Clement and Habte 1994). Vesicular-arbuscular mycorrhizal symbioses enhance uptake of phosphorus and other nutrients (Janos 1977; Ruíz 1993; Clement and Habte 1995), thereby reducing time to transplant and increasing survival in the field (Ruiz 1993). A foliar antitranspirant (or molasses solution) should be applied the day before transplanting, especially for bare-root seedlings. Transplanting should be done when the soil is humid and potential evapotranspiration rate is low (cloudy with little wind). 8.3 Asexual propagation There are two potential means for asexual propagation of peach palm: offshoots and tissue culture. Neither of these has been developed into a widespread commercial practice. Basal offshoots can be propagated but survival after transplanting in the field is generally low (Sattler 1986; Pinedo-Panduro and Meléndez-Torres 1993). The most common method in Peru is to partially sever the basal connection between an older shoot or stem and a young offshoot with preformed roots (20-40 cm tall), allow the young offshoot to further develop its roots in place for several weeks, then completely sever the connection, transplant the rooted offshoot into nursery containers, allow it to develop in the nursery for several (2-7) months, and then transplant it into the field. Alternatively, offshoots without preformed roots can be rooted in non-mist propagators for 2-3 months (with or without plant growth regulators), transplanted to nursery pots, allowed to develop for 2-3 months under shade and 1 month in full sunlight, then transplanted to the field (J.C. Weber, H. Jaenicke and C. Sotelo-Montes, unpublished data). Survival of offshoots is high while they are still semi-attached to older shoots or stems (or in non-mist propagators), but this is deceiving, since it decreases dramatically after removal and transplanting. For example, 78% of offshoots survived for 45 days while still partially connected to older shoots (Pinedo-Panduro and Tanchiva, unpublished data). In another study, 3-month-old rooted offshoots were transplanted to the field: 63% survived for 3 months, but only 9% survived for 9 months (Pinedo-Panduro and Meléndez-Torres 1993). Application of IBA (Indole- 3-butyric acid) increased the offshoot’s root production, which provided better survival after transplanting in the field, but the IBA application was associated with lower aboveground growth rate in the field (Pinedo-Panduro and Meléndez- Torres 1993). As mentioned in Section 6.3, some ‘viviparous’ phenotypes also develop vegetative shoots on the stem, and these are relatively easy to propagate. Sattler (1986) found that offshoots in the transition stage from bifid to pinnate leaves and with well-developed root systems gave the best results, but still only
Promoting the conservation and use of underutilized and neglected crops. 20. 43 found 63% survival after 70 days. Survival in the field can be improved to 90% by careful attention to details (R. Chumbimune, unpublished data): select plants with vigorous offshoots 30-60 cm tall; dissect the root mass with offshoots 2-3 months after harvesting the heart-of-palm; isolate and mound up soil around offshoots; allow 2 months for the root-mass sections to recuperate before transplanting to the field; and carry out all steps during the rainy season. Mora-Urpí (unpublished data) follows a modification of the methods described: selecting the entire cluster of mature heart-of-palm carrying large offshoots (each over 50 cm high), and taking along most of their well-developed root systems when transplanting. This method has been successfully used to fill empty spaces in commercial palm plantations. This method is not practical when dealing with full-grown fruit-producing trees because of the large size, hard wood and long roots of the cluster. More research on vegetative propagation of offshoots is required. Improving survival of rooted offshoots is clearly needed. In addition, the limited number of offshoots per plant (1-4 per year) does not allow rapid multiplication of selected germplasm (Blaak 1980). Simple methods to stimulate offshoot development are being investigated (H. Jaenicke, J.C. Weber and C. Sotelo-Montes, unpublished data). Tissue culture would be the most efficient means for mass propagation of selected peach palms. After more than 15 years of research, a commercial method has finally been developed. Historically, attempts to culture various tissues did produce some plants (Pinedo-Panduro 1987), but often with unreproducible results (Arias and Huete 1983; Arias 1985; Valverde and Arias 1986; Pinedo- Panduro 1987; Valverde et al. 1987; Stein 1988; Fisse 1990; Pinedo-Panduro and Díaz-Jamara 1993; Almeida 1994). Pinedo-Panduro (1987) tried direct organogenesis from cultured stem apices and was able to develop some vegetative shoots from meristematic buds. Almeida (1994) improved this method. No somaclonal variation is expected with this procedure since it involves direct development from meristematic axillary buds. The University of Costa Rica has now developed a repeatable tissue culture procedure for commercial application (L. Gómez and R. Vargas, unpublished data). The greatest commercial limitation was production time: more than 2 years were necessary to develop a rooted plant from the explant stage, and another year was necessary for acclimatization and growth in the nursery. Now these problems have been overcome and multiplication is possible. With an efficient tissue culture method the screening of selected genotypes is underway; this is necessary because not all genotypes are equally easy to propagate. Now clonal variety trials under different ecological conditions can be carried out. Some individuals may produce apomictic seeds coming from fruits that appear parthenocarpic (smaller, later maturing within a bunch) (J. Mora-Urpí, pers. observ.), but genetic evidence of apomixis in peach palm has not been demonstrated (e.g. mother plant and progeny with identical isozyme or DNA fingerprints). In addition, fruits appear parthenocarpic (smaller, later maturing than normal fruits) but they contain seeds with a fully developed embryo.
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Peach palm - World Agroforestry Centre

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