Re: Hybrids

From: "Julius Boos" ju-bo at email.msn.com> on 2000.04.30 at 18:29:04(4484) To All Friends, My little bit of input into this--no one has as yet touched deeply on Mother Nature`s strategies for PREVENTING hybrids, this is what interests me, and investigations on this aspect should be continued. It is obvious that hybrids are not occurring as 'regularly' as they should be among species that occur naturally and in close proximity to each other in nature, and that there are STRONG barriers that prevent this, such as different pollen structure/size (as in Xanthosoma/Caladium/Chlorospatha), with the unanswered question of pollenators thrown into this mix for good measure). As a boy I`ll never forget discussing the 'why' of orchid hybrids with one of my early mentors, Dr Jack Price, a Canadian who 'went native' and lived in a shack near to a river in the hills, hand-to-mouth at times, working at the Virus Lab at others. He grew some orchids, and the genus Catasetum was one I liked. On Trinidad we have two species, C. macrocarpum and C. barbatum, hybrids of these have not been found in the wild state, but a simple hand pollination will result in a seed pod with viable seed, and Jack had grown some hybrid seed in flasks, the offspring as expected were 1/2 way between the parents. Then another Catasetum researcher arrived, and I was helping him find these two species growing in the wild, when I asked how come they do not cross in nature. With a smug smile he took two small bottles of liquid from his back pack, then pinned two small squares of blotting paper only feet apart on neighboring trees. He applied a drop of liquid on each square from each bottle. In seconds there were groups of small stingless bees around the squares, but it was quite clear that the two groups of bees were of different colors and differed slightly in size!! The liquid was artificial lab-produced scent of each of the two species, and he was investigating the artificial production of orchid scents in the Lab. What he had put out was the lab-produced scents of the two Catasetum sps in question, and the bees were specifically attracted ONLY to the scent of that specific orchid! NO hybrids of those in the wild! Now I know this does not always hold true, that obvious hybrids are sometimes and rarely found in the wild, the obvious one in Trinidad is the very rare orchid Oncidium 'haematocyllum' (spelling?) a plant that was initially described as a species, but turned out to be a naturally occurring hybrid between our 'Cedros bee' and the 'brown bee' orchids. In aroids we need to study the pollinators and scents that PREVENT the crossing of species that occur close together, such as Amorphophallus, this may lead to a better understanding of the species concept. In Urospatha, the scents of plants that I grew differed from each other, and though all were or seemed 'fruity'. One from the Orinoco Delta smelt of slightly 'off/old' fruit salad, while the one from Costa Rica smelt of cantaloupe or the old dried skins/remains of mangoes. These were easily 'crossed' with a little help of a wet brush and a helping hand, and the offspring were 1/2 way between 'mum' and 'dad'. I would love a field researcher to investigate the species/groups of this genus that may occur close together in nature, and check the scents they produce and the pollinators involved which keep them apart, and recognizable as different species, the same in the genus Dracontium, where several species occur together, some with tall petioles and wide open spathes, others with close-to-the-ground, partially closed spathes. Some smell of OLD rotten meat, others of just newer, just slightly 'off' meat, others smell of fish, etc., which we could speculate attract different pollinators, meat wasps to some, blow flies to others, etc.. Just one more piece of the giant jig-saw puzzle of life. Cheers and good growing, Julius +More > Just don' t see a point why human beings should "improve" plants in > only few years what nature has developed in millions of years ... I > enjoy nature the way it is and so hopefully my children will have the > opportunity ... > > To all a nice weekend, > > Bj?rn Malkmus >>There are many, many ,many 'points' why humans should and do "improve" plants on mother nature. Nature is not perfect. Some examples of why people have and do produce hybrids ALL VALID. The most valuable use of hybrids to humans is undoubtedly agricultural. I like my corn on the cob to be bigger than my thumb! Some times a plant that is desirable is not easily grown. Sometimes some of these desirable traits may be crossed onto a kindred species which is easier to grow. ( Anth. dressleri is hard to grow in Florida, but it's hybrids are grown very well there) Curiosity is a good enough reason to make cut flowers last longer, to make vegetables bigger, tastier, and or more productive and resistant to desease. Even though someone said this is 'old hat' , hybrids can be used to show inter specific or intergeneric relationships. The list can go on but I think my point is clear. the improvement of plants through hybridization is a valid , and even necessary part of our existence. I too enjoy nature the way it is and personally prefer to collect species.....but I believe there are many valid opinions for and against hybridization. I just don't see that these opinions should be mutually exclusive of each other. People are going to hybridize plants because they can and I doubt that it will ever, ever stop. As John Banta always points out......The genes of some species now only exist in the hybrids they parented. The recombination of genes happens in the course of nature.....I don't separate the actions of humans from nature. Humans and their actions are inseparable from nature. I have never understood why people think that our actions and brains separate us from nature. We are just as answerable to natures laws as every other thing. Neil<<

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