Inter-section crosses in Dendrobium

[catwalker808]

Calvin. nice thread you started ... on primary inter-sectional crosses. There have been a number of these primaries made ... but there also have been some notable complex hybrids made

The latouria x phalaenanthe cross you are thinking about is probably Den. Big Alex = (alexandrae x bigibbum), registered by H&R 8-10 years ago. It's a very prolific and early bloomer ... an exception among intersectional hybrids, which tend to have low seed production and/or require many many years to blooming.

H&R probably has done the most concerted breeding using the latouria section, largely because of the longevity of the flowers, the evergreen qualities of the plants and tolerance to wide ranges of climatic and cultural conditions. One of the mainstay plants in this breeding has been a hybrid which has been mentioned several times in the posts above ... (atroviolaceum x johnsoniae) = Den Roy Tokunaga, the namesake of the maker of the hybrid. As a whole, this and related lines of breeding have been very successful.

For Isurus ... the secondary hybrid, Den Frank Thrall is not latouria 67% x phalaenanthe 33%. One parent is all latouria = (atroviolaceum x johnsoniae). The other parent is all phalaenanthe = bigibbum. Therefore, Frank Thrall is 50% latouria and 50% phalaenanthe. However, because the Den Roy Tokunaga is 4N, it exerts a greater influence on the hybrid. Den Rising Star (atroviolaceum x johnsoniae) x (phalaenopsis x gouldii, a spatulata) may very well also involve a 4N Den Roy Tokunaga. The use of 4Ns in this line of breeding seems to have stabilized the quality of the crosses.

This thread's going in other directions also. But history seems to have demonstrated some general trends among intersectional hybrids: low fertility and low seed count, sometimes very low vigor and/or reluctance to bloom or prolonged periods to reach blooming maturity, which can sometimes mean VERY large plants. Den Omni and Den Violet Yamaji are examples of complex hybrids with very good flowers, but which take 6-7 years to blooming (in sunbelt climates and probably longer elsewhere)

Orchid Wiz can probably give some indication of what can be crossed (registered hybrids). On the other hand, you can only assume that with the easy availability of the parent species,many other combinations that are not listed may have been attempted but ended in failure.

Isurus, the most troublesome thing about den intersectional crosses is not necessarily the making of the seed. After that, you have to grow the plants. But being 28 gives you a lot of time to make intersectional crosses and grow the offspring.