How to maximize characteristics of the parent plants in crossings
A first principle in making uncommon Astrophytum asterias is to start with excellent parent plants because Astrophytum asterias inherit parents' appearance and shape. It is important to remember that the father's genes more strongly influence the appearance of the offspring than the mother's, particularly, in Astrophytum asterias. For example, if you wish to make a new generation of variegated Astrophytum asterias by crossing, I recommend chosing a variegated parent plant for the father rather than the mother, which may be a normal Astrophytum asterias.
Why seedling-grafting?
If you wish to make red-flowered Astrophytum asterias, you should cross two or more Astrophyum asterias that have reddish/rosy flowers. Then, sow the seeds from this initial crossing to obtain seedlings. Next, select seedlings to cross with another reddish one. The point at issue is the amount of time it takes to complete this process. On plants grown on their own roots, the time is too long. We Japanese use seedling-grafting to shorten the time and avoid this problem. We use mostly 'SANKAKU-CHU' for stock. I cannot distinguish which species is 'SANKAKU-CHU'; Hylocereus undatus or Hylocereus guatemalensis. (I have seen a large colony of 'SANKAKU-CHU' in Honolulu, Hawaii.) This grafting method produces rapid growth and early flowering, so it reduces your time to achieve new cultivar. Typically, it will take only two or three years to make next generation.
Tips for seedling-grafting with 'SANKAKU-CHU'
The best stock will be plants
that are just starting new growth after breaking dormancy. They
will be thick.
Following three photos shows each apex and it express one's condition.
This stock is not fit for common
grafting but can use for seedling-grafting in the very limit
This stock is just fit for seedling-grafting
This stock is an older plants,
but still can use for seedling-grafting
-Try to graft on a rainy day. Then, keep them in the shade
for a few days.
-Cut stock as high up as possible.
-It is necessary that central core (cambrian) ring of stock is
smaller than scion diameter.
-Use very sharp-edged knife, thicker than a
razor blade.
-Large size of stock means rapid scion growth.
Selection of seedlings
This is the most important skill to develop uncommon caltivar, otherwise you must keep all seedlings untile they all grow up. Sometimes small seedlings will grow into an uncommon form. It is ture that variegated plant grow smaller that ordinary one. To my surprise, small seedlings of Astrophytum asterias Super-Kauto which has thin flecks, will appear nice flecks when it grow to a mature plants. Needless to say, I don't know all tips in this matter, so please find out new tips and make your splended plants. I hope you enjoy this wonderful hobby.
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