Role of healthy-looking banana and alternate hosts in the spread of banana bunchy top disease

Poster presented at Symposium of the Pest Management Council of the Philippines. 200

Catalogue of introduced and local banana cultivars in the Philippines: Results of a demonstration trial by the Institute of Plant Breeding, University of the Philippines, Los Baños

This catalogue provides information on the morphological and yield characteristics of 19 introduced and 8 local banana cultivars grown at the IPB-UPLB demonstration plot. It is intended to serve as a guide to help in identifying and selecting cultivars for further evaluation by researchers and planting by interested growers

Farmer's handbook on introduced and local banana cultivars in the Philippines

This manual provides information on the morphological and agronomic traits, fruit characteristics, reactions to common diseases, and uses of 21 introduced and 8 local cultivars based on field trials carried out through the Bioversity-DA-BAR-NRMDC programme. It is intended to serve as a useful guide in the identification and selection of cultivars for further evaluation by researchers and planting by interested banana growers

Gibberellic acid detection of dwarf offtypes in micropropagated Cavendish bananas

Detection of dwarf offtypes produced by micropropagation of Cavendish bananas (Musa spp.) cultivars New Guinea Cavendish and Williams was achieved by spraying gibberellic acid (GA(3)) solution (289 mu mol/L) onto deflasked plants and measuring various plantlet responses. The most useful identification criterion was elongation of the sheath of the first leaf to form after GA(3) application. Elongation of this structure was about 2-fold greater in normal plants than observed in dwarfs. Similar measurements taken earlier during in vitro culture or later during plant establishment in soil were not as useful in discriminating between normals and dwarfs as the measurements made at deflasking. The similar GA(3)-induced elongation response of the dwarf offtype and that of the naturally occurring dwarf cultivar Dwarf Parfitt suggests that the mechanism for dwarfism could be the same in the 2 cases

Use of a SCAR-based marker for the early detection of dwarf off-types in micropropagated Cavendish bananas

A PCR-based marker, termed sequence characterised amplified region (SCAR), has been developed to allow a more robust and reliable method for detecting dwarf off-types in micropropagated Cavendish bananas, as compared to a RAPD marker (Damasco, et al., 1996). This SCAR-based marker allows for the early in vitro detection of dwarfs. It has also been used as an early guide to investigate the factors that promote genetic instability during micropropagation. Dwarf off-types can arise early in the multiplication process and were detected as early as the 4th subculture after initiation of shoot tips. The results also strongly indicated that adventitious shoot multiplication is the main factor contributing to the formation of dwarf off-types. Adventitious buds are promoted by higher concentrations of the phytohormone, benzylaminopurine (BAP), by splitting of propagules longitudinally during micropropagation and by preferentially selecting bulbil-like structures as propagules for further multiplication. The inherent instability of the cultivar being micropropagated was another major factor influencing the production of dwarf off-types. It was found that New Guinea Cavendish produced dwarfs at a higher frequency than Williams. Furthermore the dwarf off-types were more stable in vitro, and the conditions that favoured the induction of dwarfism in control plants did not favour reversion to normal plants in the dwarfs