CHRYSANTHEMUMS in ABERDEEN

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2001 Paul Barlow


Raising new chrysanthemums

Chrysanthemum breeding is a popular pastime and addition to the normal growing and showing activities of many growers. While this is not an activity that I am personally involved in at this time the techniques for breeding are relatively straightforward, are readily accessible in any number of non-specialist publications and can be explained in quite simple terms.

However, like most technical subjects, an overview such as this cannot (and is not intended to) give more than a very elementary view of the subject. There are many more detailed writings on this topic that should be consulted in order to fully understand the techniques involved in chrysanthemum cross-pollination.


Flower parts

The diagrams below show the parts of the flower involved in the process.

breed3a.jpg (6305 bytes)  

The pistil is the female reproductive organ consisting of
- the stigma
- the style, and
- the ovary.

The stigma is the top of the pistil and is the part that receives the pollen.

breed3b.jpg (13589 bytes)  

The anther is the part that produces the pollen and is part of the male reproductive set.

The corolla is the petal of the flower.

 

The process:

Essentially the process requires a male pollen donor (the anther) and a female pollen recipient (the stigma) and involves transferring the pollen from the male to the female in order to fertilize the seed (see diagrams below). Both participants in this transaction need to be at the correct stage of development and will probably have been pre-selected for particular charateristics that when combined through the breeding programme may create desirable results.The steps involved are described below.

Creating donor and recipient in the right condition:

  • Growth should be restricted by using a semi-starvation diet and stopping the plants several times in order to create many laterals. These laterals should bear single flowers with few petals (even though when grown under normal conditions the cultivar may be a double).

  • From June onwards the plants should be in complete darkness each day for about 15 hours (say 5pm to 8am next day). This will encourage production of buds.

The pollination process:

  • Pollination consists of transferring ripe pollen from the anthers of one cultivar to the stigma of another, this can be done using a soft brush (camel hair brushes are favoured by some breeders). The petals of the recipient bloom are first closely trimed to make the stigma accessible.

  • The recipient bloom should be prepared and made ready to recieve the pollen. If the recipient is a double type then the ray florets should be reduced gradually over a period of days until the tip of the pistil is seen. The stigma should then grow and elongate beyond the point to which the ray florets were cut back, pollination is then relatively straightforward.

  • If the recipient flower is a single or anemone type then treatment is slightly different. The entire centre of the bloom should be cut down so that all anthers are removed leaving only the ray florets for hybridisation.

  • When the tips of the stigma are curled back as shown in the diagram then this is the time to apply the pollen.

  • Pollination can be carried out in situ with the recipient bloom still on the plant and the pollen donor carefully carried to the recipient, alternatively both recipient and donor can be carried indoors and pollination carried out there. In each case it is a good idea to have labels ready to record details of the crossing and attach securely to the stem of the recipent.

  • If pollen is produced before the recipient bloom is in the required condition then it is possible to collect and store pollen provided the container is kept dry. Pollen collected in this way may remain usable for some weeks after.

Germination and seed collection:

  • Germination will be assisted by providing good light and warmth and making sure no insects interfere with the cross that has been made.

  • If successful, the seeds will take between 30 and 60 days (approximately) to ripen so we should not try to remove them from the seed head until the seed head is almost ready to fall to pieces. Each seed head can be collected intact in an envelope that is clearly marked with it's contents and retained there until it's time to sow the seed.

Seed sowing and seedling production:

  • There is no great rush to sow the new seeds, February is probably early enough to get started as this is when daylenth is beginning to improve. Compost can be either a light, sandy soil-based mix or a soilless compost, germination will be just as good in each medium. A temperature of around 16C will be adequate to get things moving while keeping the air a little on the moist side.

  • After the seeds have germinated then the newly emerged seedlings should be given good light conditions and when large enough to handle individually they can be pricked out into individual containers eg 3 inch pots.

  • Treatment from here on is similar to any chrysanthemum - moved through a series of pot sizes and compost strenghts until large enough to plant out (if earlies) or move into final pots (if lates). At all stages it is essential to keep the plants labelled with details of the cross or a number that can be referred to in the record book.

Growing the plant and producing the bloom:

  • Normal growing tasks follow - reducing flowering laterals, disbudding, feeding, bagging etc until eventually we see the success or failure of the fruits of our selected parents.

  • If it's good and looks promising then the stool will be marked and used for vegetative propagation next year and hopefully registered and released at some point in the future. It the cross is a failure then it will probably be consigned to the dust bin. 

Chysanthemum seeds created in this way will create a large number of variations based largely on the charateristics of the parents. Some of these variations will be successful in that they are commercially viable end results, others will be of no value to either exhibitor or cut flower trade and will be discarded.


If you would like further information or wish to comment on this publication please send your e-mail to: paul.barlow@chrysanthemums.info

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Last updated on 21 December, 2001