HYBRIDIZING BEGONIAS
Would you like to build a bigger better begonia or a smaller more compact one with red spots or silver stripes? Why not try? It's a lot of fun. A quick rundown on the procedure, select the parents, cross pollinate the flowers, wait until the seed sets, collect and sow the seed, raise the seedlings and select your new begonia.

A friend said to me ''I see you have the leaf shape from one parent and the colour from the other'' Sounds simple not really. The begonia he was talking about took about three years and dozens of different crosses to get what I wanted. Along with the plant, I was aiming for I got many other plants that were worth keeping as a bonus.

Some growers will tell you that the leaf shape comes from the female and the leaf colour from the male or is it the other way around I find there is no easy way, it depends on which parent is dominate. Some plants will have only a few characteristics that dominate e.g. habit of growth, leaf shape, or maybe texture. I have put together a list of plants that I have used in the past with their dominant characteristics it may be of help to someone starting out.

Rhizomatous X Cane	Rhizomatous X Thick-stem

NOTE the female parent is always written first in any cross.

• Cane type X rhizomatous or rhizomatous X cane type the cane type is usually dominant.
• Thick stem X rhizomatous or rhizomatous X thick stem the thick stem is usually dominant.
• Begonia glandulosa the leaf shape and texture is dominant which ever way you cross it.
• Begonia heracleifolia the leaf shape is dominant.
• Begonia manicata 'Crispa' the leaf colour is dominant the crested edge usually comes through in about 10 to 30% of the seedlings depending on the other parent.
• Begonia hydrocotylifolia the round succulent leaf is dominant.
• Begonia 'Morning mist' the silver leaf colour is fairly dominant depending on the other parent.
• Begonia 'Bedford Delight' the brown leaf stitching is fairly dominant the curled leaf bases usually turn up in about 20 to 50% of the seedlings if the other parent also has curled leaf bases the percentage will be higher.
• Begonia 'Joe Hayden' the black leaf colour is dominant.
• Begonia 'Baloo' the brown leaf colour is dominant.
• Begonia conchifolia var rubrimacula the red spot in the center of the leaf usually comes through in about 10 to 20% of the seedlings.
• Begonia 'Lowana' the yellow colour is dominant; also, the curled leaf bases will come through in about 20 to 50% of the seedlings depending on the other parent.
  

It sounds easy, for a yellow leaf use lowana for a brown leaf use baloo for a red spot in the middle use conchifolia var rubrimacula or for a star shaped leaf use heracleifolia the only trouble is it is you might get the leaf colour you want but not the leaf shape or the markings you want .It is fairly easy to predict the outcome of a cross between two species, a species being a plant occurring naturally in the wild. When you start crossing with hybrids a lot more factors come into it .The hybrid you are crossing with is probably crossed with other hybrids and all sorts of shapes and colours etc. can surface in the seedlings. Some of these shapes and colours may not show in the parent and only come out in a later generation. This is what makes hybridizing so interesting. There are hundreds of species and thousands of hybrids out there so why not try hybridizing, you never know what you will come up with.

There are different approaches to hybridizing I like to have a definite idea of what I am after, it may be a leaf shape of one parent, and the colour of another, or it could be some characteristic a few generations back in one of the parents. Another approach is the shotgun method where you cross every plant that is flowering in the shade house with whatever pollen is available .This works well if you only have a few plants. Before you start, a few things you need, your shade house needs to be insect free and sheltered from the wind. In addition, it is a good idea to spread your plants out; this will help to stop accidental pollinating. If you have garden plants you want to cross you can always tie a paper bag over the flower spike to prevent accidental pollination.

Begonias have separate male and female flowers, some Asian species have male and female plants, but you do not see these often .The male flower has a small bunch of yellow stamens then two or sometimes four petals, which join onto the flower stem. The female flower has three sets of knobby little bits called stigmas then the petals, which join onto a triangular seed case called the ovary.

Male and Female Flowers	Female Flower 'Red Amigo'	Male Flower 'Red Amigo'

To get started, keep an eye on your plants as they come into flower. Select the plants that you want to cross, remove the male flowers from the flower spike and as soon as the female flowers open their petals, pollinate them with the male flower that you have selected. I like to pollinate at least four to six flowers on a flower spike. To pollinate the flower pick the male flower, fold back the petals, and gently brush the stamens onto the stigmas of the female flower, one male flower should have enough pollen for three or four female flowers. Label the flowers in some way and record the cross. I like to use small sticky paper tags for labeling; you can buy them at newsagents in sheets. I write the cross on, female parent first then wrap them around the stem and stick together. Record the cross in a book with the date it was pollinated. After two days have a look at the flowers you have pollinated, if the stigmas have turned brown the flower has been pollinated. If they do not turn brown, repeat the pollinating procedure. Some flowers will close their petals when they have been pollinated. Some male flowers have very little pollen, it may help if you choose older male flowers that are ready to drop, they often have more pollen, and you could try picking the flower and leaving it for a day before pollinating. If you can't get the flower to pollinate after a few attempts, a hormone spray is sometimes helpful, I have tried a few different hormones for this and I have found coconut water the most convenient. I use a 10% solution, spray a few drops on the stigmas of the female flower, and then spread it around with the stamens of the male flower. The stigmas should turn brown the next day if pollination has been a success.

Cross Pollinating Flowers	Cross Pollinating Flowers

The seed cases should stay on the flower spike at least three to four weeks before they drop, if they fall off under two weeks there is little chance of them having viable seed. I like to mark the seed cases on the papery wings with coloured felt pens, I put the same colour on the paper tag with cross on it, then if the seed cases drop unexpectedly I can retrieve them from the shade house floor and work out where they came from. I let the seed cases hang on the flower spike until they are ready to drop, usually the stems dry out before the seed cases, then I pick them and put them in an open marg container to dry. If you have a few containers of seed drying at the same time space them out, as the seed sometimes gets flicked in the air as the seed cases dry out and may land in the container next door.

Pollinated Flower After 2 Days	Pollinated Flower After 4 Days	Pollinated Flower After 2 Weeks

The next job is to remove the seed and separate it from the unwanted rubbish .The seed is very small, there could be up to one hundred seeds in a seed case, you may need a magnifying glass to see it properly. Sometimes the seed case will split along the edges near the stem end, if this happens you can shake the seed out. If it does not split, crush the seed cases between your fingers, just enough to get the seed out, if you crush them up too much it is hard to separate the seed from the rubbish. To separate the seed from the rubbish I use a sheet of A4 white paper I put a fold through the center and then flatten it out, this makes the seed easy to pour. Put your seed on the paper and scrape off the rubbish with a piece of paper on edge then tip your sheet of paper so that the seed rolls away from the remaining rubbish, repeat this a few times until your seed is clean. The cleaner you can get your seed the better, if you have rubbish with your seed you will have problems with fungus growth latter on.

The next job is to store or sow the seed, usually it is late spring to early summer when the seed is collected, and I find this is the best time to sow it. If you want to store your seed, small paper envelopes are quite good; it will pay to sticky tape the bottom of the envelope as the seed can get out of the corners. It will keep a few years in the fridge.

I have tried quite a few different seed sowing mediums over the years and I have found sphagnum moss the most convenient to use for begonia seed. I rub the moss through a sieve to break it up into a fine texture, this is easy to do when the moss is dry, it will pay to put on a dust mask for this job as the dust can harm your lungs. Next put the sieved moss into a small pot, I use a 75 mm squat pot for this, and then pour boiling water over the moss. This will sterilize the moss and seal the small gaps on the surface of the moss. When this cools sow the seed, spread it evenly over the surface about fifty seeds are enough for a 75 mm pot, you will have to thin them later if you sow any more than this, do not cover the seed with moss. Label the pot and place in a plastic takeaway container with about 5 mm of water in the bottom, put on the lid. I use a 120 mm dia. X 100 mm high container for a 75 mm squat pot. Do not spray or mist the seed, this can encourage algae growth; there is plenty of humidity in the container to bring up the seeds. Put your containers on a bench in the shade house you can stack them on top of each other. If your seed is fresh, the seedlings should start to appear in about five days some will take longer. I have found that about 25% of my crosses do not set viable seed, I take note of these crosses, and try them next year, if they do not set seed again I try a different cross. You will need a min. day temperature in the twenties and min. night temperature above fifteen degrees C. to get the seed up, you may need some bottom heat if your temperatures are not high enough.

When your seedlings have leaves about 5 mm across start hardening them off, to do this open your takeaway container and leave a small gap for air to get in, increase this every few days until you leave the lid off after about ten days. You can start to give your seedlings a light misting of half strength soluble fertilizer, try it on a few leaves on the edge of the pot first, if it does not burn the leaves give them a spray about once a fortnight. You may start to notice a few markings on the leaves at this stage some may have silver spots, others may have dark brown markings, and some will be stronger growers than others. Keep a close eye on your seedlings for any fungus or mould it can cover a pot in a couple of days. I pick out any effected plants with a pair of tweezers then spray with fungicide, your plants may be overcrowded, if they are, thin them out. When the leaves are 8 mm to 10 mm across start picking them out into small pots, I use pots about 30 mm across and 30 mm deep for this. For the potting mix, I use half my normal mix and the other half-sieved sphagnum moss this gives the mix a better air content and lets you water your pots from the bottom. Pick out the biggest best looking plants from each pot; do not forget to label them. The plants left in the pot can be planted at a later date; they will stop growing after a few months. I keep mine for about twelve months and plant out any interesting looking plants that turn up. Put them in a polystyrene box with no drainage holes, put in about 5 mm of water and cover with glass. Put a piece of 50% or 70% shade cloth over the glass. After about a week start lifting the glass a little each day until you remove it completely and leave the shade cloth over the box. Do not water again until the water in the bottom of the box has dried out and the potting mix in the little pots has started to dry a little. When the seedlings start putting on growth, remove the shade cloth. If the plants have a silvery sheen on the leaves they may be getting too much light, put shade cloth back on for a while. As they start to get crowded, put them out into polystyrene trays about 50 mm deep, this will give them more light and stop them getting leggy, continue watering them from the bottom until they are ready to go into 75 mm squat pots in normal potting mix.

Hardning Off Seedlings	Hardning Off Seedlings	Hardning Off Seedlings

The next step I find the hardest, selecting what to keep and possibly name or what to throw out. If any plants have trouble with powdery mildew, these are the first to go. Don't be too hasty to throw them out when it comes to leaf colour and shape, it may take twelve months or more until the true shape and colour comes out. If you are growing for the flowers this may take even longer. Keep potting your plants on as they grow and throw out any that you don't like. Compare them to their parents are they different? Are they better? Or do they need composting? If you are not careful, you can end up with a shade house full of look-alikes. I was selling my latest begonia creations at a local market a few years ago when a woman walked up to me and told me she used to have all those begonias years ago, I tried to explain that these were my latest hybrids and there was nothing like them around, or was there?

Selection of Hybrid Seedlings	Selection of Hybrid Seedlings	Selection of Hybrid Seedlings

When you are sure, your new hybrids are different and better than anything on the market it is time to start selling them. How easy are they to propagate? If they are hard to propagate from leaf or cutting, they won't be around for long. In the end it all comes down to the market, it will decide what is a good begonia.