Somaclonal variation

Even though pineapple is not generally considered to have an unstable genotype, at least 30 mutants have been recorded in 'Smooth Cayenne' since the early 1920s (Collins and Kerns, 1938). Spiny leaves are commonly encountered during conventional pineapple propagation of 'Smooth Cayenne', and it is no surprise that spininess is also most commonly encountered during micro-

Table 4.1. Review of methods used for the micropropagafion of pineapple.

Stage I

Stage I

Explant Axillary and terminal buds from crown Medium Nitsch with 0.1 mg I-1 BA and 0.1 mg I-1 NAA

Explant Axillary buds from slips and suckers Medium MS, hormone-free

Explant Axillary bud from crown Medium MS with 25% coconut water

Explant Axillary bud from crown Medium MS with 2 mg MBA and 2 mg I-1 NAA

Medium MS with 2.0 mg M KIN, 2.0 mg M IBA and 1.8 mg M NAA 8 plantlets per month

Medium MS with 2.3 mg I-1 BA and 2.2 mg M KIN 50 plantlets per month (callus involved)

Medium MS with between 0.5 and 1.0 mg M BA 3 plantlets per month

Medium As for stage I, but liquid (shaken) cultures 17 plantlets per month for 'Smooth Cayenne'; 76 plantlets per month for 'Perolera'

Explant Axillary bud from crown Medium MS with 0.5 mg I-1 BAand 0.2 mg I-1 IAA

Medium MS with 0.5 mg I-1 BA 'Plantlets halved or quartered during subculture'

10 plantlets per month

Stage III

Stage IV

Reference

Medium MS with 0.1 mg M NAA 'Soil' and 0.4 mg M IBA

Mathews etat. (1976)

Not stated

Medium i MS, hormone-free Not stated

Zepeda and Sagawa (1981)

No roots

'Commercial DeWald et al. (1988)

Plantlets > 2.5 cm

Medium MS, hormone-free

'Peat/perlite mix' Cote et al. (1991) Plantlets 2-3 cm

Continued

Table 4.1. Continued

Stage I Stage II Stage III Stage IV Reference

Table 4.1. Continued

Stage I Stage II Stage III Stage IV Reference

Expiant

Axillary bud from crown

Medium

MT with 2.0 mg h1 KIN

Medium

MT with 1.0 mg h1 NAA

'Peat/perlite/sand'

Fitchet (1990)

Medium

MT with 2.0 mg h1 KIN,

and NAA

and 500 mg h1 malt

Fitchet-Purnell (1993)

IBA and NAA

14 plantlets per month

extract

Expiant

Axillary bud from stem

Medium

As for stage I

Medium

MS with 0.3 mg h1 IBA

Not stated

Osei-Kofi and Adachi

Medium

MS with 2.3 mg h1 BA

8 plantlets per month

and 0.1 mg M IAA

(1993)

and 0.6 mg M NAA

Expiant

In vitro plantlets

Medium

N6 with 5 mg h1 KIN

Medium

MS, hormone-free

'Soil'

Kiss etal. (1995)

Medium

MS with 2.0 mg h1 NAA in

and 4.5 mg h1 BA

Plantlets 8 cm

the dark

'Etiolated shoots placed

horizontally on medium'

60 plantlets per month

Expiant

Apical bud from crown

Medium

As for stage I, except

Medium

MS with 2.0 mg h1 IBA

Not stated

Devi etal. (1997)

Medium

MS with 1.0 mg h1 BA and

2.0 mg M BA

0.1 mg h1 NAA

'Regeneration from pro

liferating callus at base

of plantlets'

56 plantlets per month

BA, benzyladenine; IAA, indole acetic acid; IBA, indole butyric acid; KIN, kinetin; NAA, naphthalene acetic acid; MS, Murashige and Skoog (1962); MT, Murashige and Tucker (1969); N6, Chu (1978); Nitsch, Nitsch (1951).

propagation (Wakasa, 1979, 1989; Smith and Drew, 1990). Spiny variants have also been observed in micropropagated 'Red Spanish' (Liu et al., 1987). A range of other somaclonal variants have been described by Wakasa (1989), including variants for leaf colour, leaf shape, wax, foliage density and abnormal phyllotaxy. Spininess and dense-foliage variants were attributed to chimeras at the donor-plant level. However, most of the other variations were attributed to regeneration of plants from callus cultures, especially undifferentiated callus derived from the syn-carp. Further studies of this nature are needed to establish the explant sources and culture conditions required to minimize somaclonal variation during micropropagation and transformation.

Smith (1988) and Damasco et al. (1998) outlined a number of strategies for minimizing somaclonal variation in micropropagated bananas, and central to these approaches were regular initiations of cultures while providing limits to the number of plants multiplied from a single explant. While no data exist on this aspect in pineapple, commercial tissue-culture laboratories usually limit multiplication to 300-1000 plants per explant. Roguing of off-types, particularly during nursery establishment, is also essential to reduce the percentage of off-types reaching the grower. Many of the somaclonal variants recorded by Wakasa (1989) would lend themselves to easy identification and roguing while the plants are quite small. Other less obvious variants, such as those that produce small, malformed or cracked fruit, require a fruiting cycle for identification. It is particularly important to grow all plants arising from tissue culture through a cycle of fruiting to enable roguing of all somaclonal variants.

Was this article helpful?

0 0
Growing Soilless

Growing Soilless

This is an easy-to-follow, step-by-step guide to growing organic, healthy vegetable, herbs and house plants without soil. Clearly illustrated with black and white line drawings, the book covers every aspect of home hydroponic gardening.

Get My Free Ebook


Responses

  • sonja
    How to minimise somaclonal mutation in pineapple?
    1 year ago

Post a comment