Richard E. Litz

The mango: botany, production and uses

1. Botany and Importance S K Mukherjee (deceased) and R E Litz 2. Taxonomy and Systematics J M Bompard 3. Important Mango Cultivars and Their Descriptors R J Knight, Jr., R J Campbell and I Maguire 4. Breeding and Genetics C P A Iyer and R J Schnell 5. Reproductive Physiology T L Davenport 6. Ecophysiology B Schaffer, L Urban, P Lu and A W Whiley 7. Fruit Diseases D Prusky, I Kobiler, I Miyara and N Alkan 8. Foliar, Floral and Soilborne Diseases R C Ploetz and S Freeman 9. Physiological Disorders V Galan Sauco 10. Pests J E Pena, M Aluja and M Wysoki 11. Crop Production: Propagation S Ram (deceased) and R E Litz 12. Crop Production: Mineral Nutrition I S E Bally 13. Crop Production: Management J H Crane, S Salazar-Garcia, T-S Lin, A C de Queiroz Pinto and Z-H Shu 14. Postharvest Physiology J K Brecht and E M Yahia 15. Postharvest Technology and Quarantine Treatments G I Johnson and 16. P J Hofman 17. World Mango Trade and the Economics of Mango Production E A Evans and O J Mendoza 18. Fruit Processing L C Raymundo, M T Ombico and T M de Villa 19. Biotechnology R E Litz, M A Gomez Lim and U Lavi.

Biotechnology of fruit and nut crops.

Kiwifruit Cashew Soursop Coconut Papaya Cranberry Chestnut Pecan Avocado Fig Banana Guava Olive Carambola Passionfruit Strawberry Citrus Grape Mango Pistachio Atemoya Oil palm Date palm Pineapple Mangosteen Blueberry Walnut Jackfuit Prunus species Rubus species Pear Quince Apple Cacao Litchi Longan

Genetic transformation of perennial tropical fruits

SummaryGenetic transformation provides the means for modifying single horticultural traits in perennial plant cultivars without altering their phenotype. This capability is particularly valuable for perennial plants and tree species in which development of new cultivars is often hampered by their long generation time, high levels of heterozygosity, nucellar embryony, etc. Most of these conditions apply to many tropical and subtropical fruit crops. Targeting specific gene traits is predicated upon the ability to regenerate elite selections of what are generally trees from cell and tissue cultures. The integrity of the clone would thereby remain unchanged except for the altered trait. This review provides an overview of the genetic transformation of perennial tropical and subtropical fruit crops, i.e., citrus (Citrus spp.), banana and plantain (Musa groups AAA, AAB, ABB, etc.), mango (Mangifera indica L.), pineapple (Ananas comosus L.), avocado (Persea americana Mill.), passion fruit (Passiflora edulis L.), longan (Dimocarpus longan Lour.), and litchi (Litchi chinensis Sonn.).

Somatic embryos from culture ovules of polyembryonic Mangifera indica L.

Ovules were aseptically removed from 2 month old fruits of 9 naturally polyembryonic cultivars and 1 monoembryonic cultivar of mango (Mangifera indica L.). Ovules were placed into culture on solid Murashige and Skoog medium that had been modified by the addition of half strength major salts and chelated iron, 6% sucrose, 400 mg/l glutamine, 100 mg/l ascorbic acid with or without the following growth regulators: 20% (v/v) CW, 1 or 2 mg/1 BA. Somatic embryogenesis occurred from the nucellus excised from the ovules of 5 of the naturally polyembryonic cultivars after 1–2 months in culture. Somatic embryogenesis was not apparently affected by the growth regulator composition of the media; however, efficient somatic embryogenesis only occurred in liquid containing 20% CW.

Stable integration and expression of β-glucuronidase and NPT II genes in mango somatic embryos

SummarySomatic proembryos of mango (Mangifera indica L. cv. Hindi) were co-cultivated withAgrobacterium tumefaciens strain A208 harboring pTiT37-Se::pMON 9749 (9749 ASE). Transformed somatic proembryos capable of growing on selection medium containing 200 μg/ml kanamycin produced the characteristic indigo blue precipitate in the presence of 5-bromo-4-chloro-3-glucuronic acid. These proembryos were chimeral consisting of transformed (blue) and nontransformed (yellow/white) cells. A stepwise selection strategy was found necessary to eliminate chimeras. a) Initial screening at 200 μg/ml kanamycin to enable growth of transformed cells, b) further screening at 400 μg/ml kanamycin to reduce chimeras, and c) recovery of pure transformed clones of proembryos in liquid selection medium with 100 μg/ml kanamycin. The integration of the NPT II and GUS genes into mango genome was confirmed by Southern hybridization.

Induction and growth characteristics of embryogenic avocado cultures

Embryogenic cultures were induced from immature avocado zygotic embryos representing different botanical races and complex hybrids. The optimum induction medium consisted of B5 major salts, MS minor salts, 0.4 mg l−1 thiamine HCl, 100 mg l−1 myo-inositol, 30 g l−1 sucrose, 0.41 μM picloram and 8 g l−1 TC agar. Somatic embryogenesis occurred directly from the explants on induction medium, and secondary embryos and proembryonic masses proliferated in liquid and on semisolid maintenance medium. Embryogenic culture maintainance was optimized in liquid, filter-sterilized MS medium, supplemented with 30–50 mg l−1 sucrose, 4 mg l−1 thiamine HCl and 0.41 μM picloram. Two types of embryogenic cultures were recognized: –genotypes that proliferated as proembryonic masses in the presence of auxin (PEM-type) and; –genotypes in which the heart stage and later stages of somatic embryos developed in the presence of auxin(SE-type). Embryogenic suspension cultures became increasingly disorganized over time, and this was associated with progressive loss of embryogenic potential.

Somatic embryogenesis in mango (Mangifera indica L.)

The mango Mangifera indica L. is considered to be one of the most important fruit crops of the world (Fig. 1). Its annual production is exceeded only by Musa (bananas and plantains), citrus, grapes and apples (FAO Production Yearbook, 1990). Currently, it is the most important fruit crop of Asia. Mango is in the Anacardiaceae family, which includes several other tropical and subtropical tree species of economic importance, e.g., cashew Anacardium occidentale, pistachio Pistachia vera, and several Spondias species, including S. cytherea, S. mombin and S. purpurea. The center of diversity for the genus Mangifera is in southeast Asia, with the greatest number of species being found on the island of Borneo. According to Mukherjee (1985), there are 39 currently recognized Mangifera species. The mango is the most widely cultivated species within the genus, and has a natural distribution throughout outheast Asia. It is found in forests as far west as the Indo-Burman region (Assam). There appear to be two distinct geographical races of the species: a polyembryonic race that occurs in the tropical rainforest of southeast Asia and a monoembryonic race that is associated with India. Some taxonomists have suggested that the mango originated in India, because of the ancient association between Indian culture and religion with this fruit. It has also been noted that the word for mango used throughout Asia is derived from the Tamil “maanga”.

In vitro somatic embryogenesis from Mangifera indica L. callus

Abstract The nucellus and globular adventitious proembryos were removed from 2-month-old fruits of mango (Mangifera indica L.) cultivars ‘Ono’ and ‘Chino’, and were cultured on sterile, solid Murashige and Skoog (MS) medium that had been modified as follows: half-strength major salts and chelated iron; 20% (v/v) coconut water (CW); 6% sucrose; 100 mg l−1 ascorbic acid and 400 mg l−1 glutamine. Embryogenic explants were sub-cultured after 4–6 weeks in liquid modified MS medium containing 2 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) instead of CW. Rapidly growing cultures were established and were sub-cultured monthly. Somatic embryogenesis was induced following sub-culture from MS medium with 2,4-D to MS without growth regulators and with or without activated charcoal (0.5%). Germination of somatic embryos appeared to be enhanced by 1 mg l−1 benzyladenine (BA); however, most of the germinating embryos became embryogenic.

Micrografting and ex vitro grafting for somatic embryo rescue and plant recovery in avocado (Persea americana)

The efficient recovery of plants from avocado somatic embryos has been difficult to achieve by manipulating maturation and conversion conditions in vitro. The production of morphologically normal, bipolar somatic embryos occurs at low frequency, usually < 2, and conversion is sporadic. In order to utilize the embryogenic system for improving avocado by genetic transformation and in vitro mutagenesis, different protocols for rescuing the shoots that develop from somatic embryos were evaluated. Shoots derived either from somatic embryos or from shoot tip and nodal cultures were either micrografted or grafted ex vitro onto seedling rootstocks. Depending on scion type, micrografting was 59–100 successful. For ex vitro grafting, several genotypes derived from shoot tip/nodal cultures were used as scions with either top slit or side grafting. Plant recovery after ex vitro grafting was 52–76, and flushing generally occurred 20–25 days after grafting. Top slit and side grafting were equally successful (68–72); however, the former resulted in earlier flushing (21 versus 29 days). These grafting procedures have been adopted for routine rescue of avocado regenerants from somatic embryos.

In vitro shoot proliferation and production of sets from garlic and shallot

A procedure is described to regenerate shoots and bulbs in vitro with high frequency from shoot tips of garlic and shallot plants using benzyladenine or thidiazuron. Regenerated shoots were induced to form bulbs in Murashige and Skoog medium (1962) containing 5 g l-1 activated charcoal and 120 g l-1 sucrose under a long-day photoperiod. Bulbs formed in vitro were transferred to soil without acclimatization and produced viable plants. This method could be useful to produce low-cost bulbs, which are easy to handle and store until needed.