off-types
 

The use of shoot-tip culture for banana micropropagation, conservation and exchange of germplasm may be reduced by the occurrence of undesired somaclonal variants at high percentages. Dwarf variants which account for approximately 80% of the off-types among ‘Cavendish’ bananas are difficult to detect at the in vitro and nursery stages. A significant economic loss is caused when they are detected only at the production stage in the field.

In the present study the hypothesis that the rate of occurrence of dwarf variants among ‘Cavendish’ vitroplants is governed by clonal-inherent genetic factors was studied. For this purpose, a selection in favour of highly stable clone(s) was performed. Based on results obtained in an earlier study, 11 families of cv. ‘Williams’ were selected for further large-scale multiplication and evaluation. Six of the families that did not produce dwarf variants in the initial study are referred to as ‘stable’ families. Five of the families which did produce dwarf variants are referred to as ‘non-stable’ families.

At the first stage, a few hundred plants of each of the families were evaluated. All of the ‘non-stable’ families and four of the six ‘stable’ families produced dwarf variants. One of the ‘stable’ families produced a very low rate of dwarfs and one did not produce any dwarfs.

The two stable families were tested further, especially the one which exhibited the greatest stability. In that clone only five dwarf variants were recorded among more than 21 000 vitroplants over a span of 8 years. During that period plants for evaluation were regenerated from newly initiated cultures with primary explants of the clone. Some of the cultures were kept before evaluation for many cycles and for a longer period in vitro than the regular ones. The fact that plants of the clone remained stable with regard to restoring a negligible rate of dwarf variants with time, both in situ and in vitro, is attributed to a genetic trait that was revealed by the selection procedure employed.

The origin and causes of dwarf somaclonal variation in bananas is discussed. It is suggested that Cavendish banana shoot tips are of chimeric constitution. The dissociation of these chimeras may result in dwarf somaclonal variants.

Re: off-types
 

Do you have a link or citation so I can see the entire article?


As a side note, the most unstable variety I have come across has been Hua Moa.

Re: off-types
 

That was an old paper but if you're interested in it, contact one of the authors and they'll send it to you. Plus they'll usually discuss things that never made it into the paper, giving you a better insight of what they were dealing with at the time.



Bananas and plantains (Musa spp.) may flower at any time of the year but they show seasonal variation in flowering. To determine whether photoperiod contributed to this seasonal variation, we calculated the thermal development units (DT) from planting to bunch appearance (flowering) using data from published planting date experiments in the tropics and subtropics. Minimising the coefficient of variation in DT across planting dates was used to evaluate the contribution of photoperiod and soil water balance to time of flowering. Coefficients evaluating sensitivity to photoperiod were estimated in some datasets and validated on independent datasets. Data on the rate of bunch appearance from four locations over several years were analysed to establish correlations between this, photoperiod and temperature. The time of bunch initiation was matched against photoperiod to determine whether short photoperiods delayed bunch initiation. Long photoperiods in the mid-vegetative phase hastened flowering while soil water deficits delayed it. Cultivars of the Cavendish subgroup (AAA) were more sensitive to photoperiod than the Maricongo cultivar (False Horn-type plantain, AAB). Long photoperiods during the reproductive phase were correlated with an increased rate of bunch appearance some 8 to 11 weeks later. Musa spp. show a facultative long-day response to photoperiod.

Re: off-types
 

Which French-type or types have you tried to grow?

Re: off-types
 

Dwarf super plantain and I have a tall one that was a reversion of a false horn Giant Plantain. Also FHIA-21.

If you could put the author names down, that would be helpful in finding the articles. I have a file on banana somaclonal variation.

Re: off-types
 

Try to google

Six of the families that did not produce dwarf variants


The FHIA-21 was a waste of time.

What makes the Dwarf super plantain and the Tall super plantain super is that they have super in their names but without that they're not that super. If you want to grow a super French-type plantain then go with the Maiden or Red, large bunches with large fingers.

Re: off-types
 

I don't know what the tall one is that I have. There were 3 of them in a block of Giant Plantains. From the literature I know that false horns can revert back to French types. They made nice bunches. For my purposes though, I need dwarf plants. The wind takes down the tall ones. The tall ones make nice bunches but if it is laying on the ground it is pretty useless.

Re: off-types
 

What's a block of Giant Plantains?




What's your height difference between dwarf and normal?

The difference for the cultivars I grow is about 12 inches.

Re: off-types
 

In my original planting of bananas I planted each variety in a block. All the plants in a row were the same variety. Depending on the variety I might have multiple rows. For me the difference between dwarf and normal is 6-8 feet. I have to get on top of the bed of my truck to touch the bottom of a tall plantain.

Re: off-types
 

Thanks for the info, I don't want super tall plantains either. I want plantains shorter than the semi-dwarf Maricongo.

Your first statements sounds like you had a known false horn Giant Plantain that reverted to a tall French-type.

Now it sounds like it could have just been a seller error, either tc's or suckers from the org.

WOW 6-8 feet. The Red French-type have all flowered under 10 feet and the Maiden should be even shorter. The Dwarfs are a little under to a little over 9 feet.