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MN: Now you've done a lot of research on this guayule project.

GK: That's right.

MN: Can you give us the basics of this whole project that Manzanar... for example, what is the Intercontinental Rubber Company?

GK: The Intercontinental Rubber Company was set up to provide a domestic source of rubber for the United States. At the outbreak of the war, most of the rubber came from tree rubber, which is Hevea brasiliensis. And when imperial Japan took over Southeast Asia, the United States no longer had access to that tree rubber, and that was a serious problem for the United States. Because in order to wage a war, you need natural rubber, and you need it for airplane tires; you need it for truck tires; you need it for sealants; you need it for all sorts of important commodities that are required not only for domestic use but also for war. And without it, you can't really successfully wage a war. So it was an emergency commodity. U.S. Congress set aside thirty-seven million dollars to do research and grow the domestic source of natural rubber. And so what they decided to do was to purchase the Intercontinental Rubber Company that was centered in Salinas, California. And they were already growing the guayule rubber and the United States was already using some of that, but they wanted to ramp up production. They got high school kids and local communities involved, they bought up land in the Salinas Valley area and other places in order to raise the crops. So it was a huge industry that was brought into, brought together. Now, the Manzanar Guayule Project, sometimes it was called the Little Guayule Project, now, their goal was not to produce rubber. Their goal was to do research on improving the guayule plant so that they can find a strain of guayule that would grow better, that would grow on marginal lands, that would produce better rubber and things like that. And the other goal of the Manzanar Guayule Project was to see if they can produce the plant from cuttings, because that had not successfully been accomplished. Because if you have a rubber plant that had a high rubber yield, they would like to make cuttings from that plant so that they could grow more plants from that. If you depend on field pollination, you don't know what you're going to get. So even if you harvest a plant that has a high rubber yield, you don't necessarily, you're not necessarily going to have seeds that are going to grow into plants. But if you grow plants with cuttings from that plant, then you have a much better shot at finding a good quality plant that you can extract better rubber from.

MN: So what was one of the problems, though, that the Intercontinental Rubber scientists were having that the Manzanar people were able to overcome?

GK: Well, the Cal Tech scientists were actually wanting to work with the Intercontinental Rubber Company, the growers, to try to improve the quality of the plant. The Intercontinental Rubber Company, which was taken over by the U.S. Department of Agriculture, they wanted to just produce the rubber. They want to grow the crops, they didn't want to invest as much time and effort into improving quality because there was this emergency situation, it would take a couple years to get the crops grown to a size that would be harvestable. So they wanted to focus more on just production and not on research and development. So the Manzanar program was more like an R&D program. They did research, they studied the chromosomes structure of the plant that was done by Dr. Masuo Kodani from UC Berkeley, and he was at Manzanar studying the chromosome structure, and he also trained my dad to do the karyotype analysis, which is the chromosome analysis. And they worked on trying to hybridize guayule with other plants, larger plants, for example, to see if they can get the rubber produced in plants that were larger that would have a higher rubber yield and things like that. So these were some of the projects that they worked on. One of the challenges was to try to grow the rubber from cuttings, because it had not successfully been done before. And as I said, I think we got a plant that has an extraordinarily high rubber yield. If you can get cuttings and grow plants from those cuttings, then you can grow a large crop with all high rubber yielding plants. 'Cause some plants don't yield very much at all and others do. So this was another goal. And this work was done by Tomoichi Hata, sometimes he was nicknamed "Green Thumb Hata," and my dad both grew, they were able to develop techniques to grow these plants from cuttings.

MN: So once they found this high yield rubber plant, it had to get ground up, but they had the cuttings also? They saved the cuttings, and then didn't they ground up part of the plant, too?

GK: Yeah. The cuttings that they started off with came from plants that were kind of cut from, they were kind of mowed off the tops. These are plants, these cuttings were from the tops of plants that were kind of discarded because the leaves don't have very much rubber, okay? And so initially when Robert Emerson and Hugh Anderson went to Salinas to try to obtain some seed to start the project at Manzanar, they did not have enough seed to give them. So they, instead, they gave them some cuttings and they picked up gunnysacks of pretty much the mowed tops of plants, and parts that don't contain any rubber. And so they brought the gunnysacks to Manzanar, and the internees that were working on the guayule project, they carefully went through and examined the cuttings, the cut tops, and then they trimmed the side leaves and then they prepared them as cuttings and they were able to use some rooting hormone, which was a pretty recent discovery at that time. This is something that they were working on at Cal Tech, and they were able to get these cuttings to grow.

MN: Because the scientists at Intercontinental, they couldn't get any cuttings to grow, right?

GK: No, they didn't think that it was possible. But some workers in Mexico had earlier claimed to be able to do it, but they never really produced any big quantity of it. They claimed that they were able to, but the Intercontinental Rubber Company personnel, staff, they weren't able to duplicate those attempts. But they were successful at Manzanar. They were able to get eighty percent of the cuttings to take and grow roots, so they were very successful.

MN: So now, once they found a rubber plant, guayule plant that has a lot of rubber in it, what did they do with that? How do they get the rubber, and how did they improve the machine that you were sharing about?

GK: Okay, yeah. The other research projects involved the purification and extraction of the rubber once they grew the plants, and that's another improvement that they made at Manzanar. There was a man named Homer Kimura, and he was a mechanical engineer. And he designed a milling machine that was designed after a Jordan type paper mill, type of mill that could mash the fiber of the guayule to fine enough to where they can separate the rubber from the plant. Now, the difference between guayule and Hevea tree rubber is that in tree rubber, it's very easy to extract the rubber because all you have to do is score the trunk. You score the trunk like this, and the sap from the bark would just leak out, sort of like the way you harvest maple syrup. And then you just hang a bucket underneath that, and the sap just drips into the bucket. This is a labor-intensive procedure, but in places where it's grown, labor is very cheap. If we were to grow Hevea tree rubber here, and we were to pay minimum wage for the workers, we would not be able to afford that rubber, and then guayule would be very competitive that way. Because the advantage of guayule rubber is that it can be mechanically planted, harvested, everything can be mechanized. That's one big advantage of guayule rubber. And also it can be grown on marginal land so it doesn't compete with other commercial crops. So there are a lot of advantages.

MN: So that answers the questions of why Hevea rubber wasn't planted over here.

GK: Well, yeah, it's a tropical plant. And also during the war, Hevea brasiliensis, as the name implies, originated from South America. And so for a while we were getting South American tree rubber, but someone had the idea of, well, let's grow it in Southeast Asia. And it was a good thing they did that, because the South American crops, most of the crops were wiped out by a blight, which is a type of fungus. And so during World War II, we did not have access to South American rubber because the tree rubber in South America had been pretty much obliterated.

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