Libby, William J. : William J. Libby, Professor, Genetics, U.C., Berkeley.

Y 7 Cloning coast redwoods William J . Libby I n a redwood breeding program , time is a problem . Between germination ( or planting ) and harvest as a renewable sourceof wood , a Micropropagation of difficult - to - rootwhite spruce using tiny segments from redwood must survive and grow in a mini - genetically improved seeds aims for more mally managed environment for three to wood formation in a prolonged juvenile eight decades . Trees in park and amenity use on poor phase , and efficient nitrogen plantings may be expected to grow for cen - soil . turies , or even millenia . Redwood foresters thus , and properly , tend to be conservative . The first step in redwood breeding has Improving woody crops been to identify families or populations of trees that are well adapted to particular sites . Don J . Durzan This is based on the reasonable assumption that , having evolved on a site , they are Geneticist Bill Libby with his prized 14 - year - the Russell old coast redwood clones at adapted to it . Site adaptation is important Reservation test plantation near Berkeley . Genetic engineering and cell and tissue not only in California , in the native range of culture have already begun to influence the the redwood , Sequoiasempentirens , but also Some , but not yet all , of the superior trees breeding and vegetative propagation of su - in places likeFrance and New Zealand , where can now be propagated independently of the perior rootstocks and woody perennial trees as an ex - the redwood is gaining importance constraints of natural climatic cycles . Cherry , for efficient forestry systems and urban otic plantation tree . almond , and pistachio trees and tissues are plantings . In our laboratory , hard - to - root In most years , in the centralpart of the red - being reduced to cells so that multiple copies biomass species such as Douglas - fir , white wood's native range , demand for seedlings of each variety are available on a massive sprace , and jack pine have been cloned far exceeds the supply of local - origin seed . scale for performance tests in many environ - through micropropagation . The American One solution to this problem is to clone red - us to estimate ments . This technique permits elm has been ' propagated from cell suspen - woods native to the plantation region . We the total available genetic variation and to sion cultures . With similar methods being have four options with this approach . The sort out interactionsbetween geneticsand en - used for fruit and nut trees , valuable root - first is to find young native seedlings that vironment . Early screening to certify new stocks of Prunus and Pistacia species are at have successfullyestablished themselves and varieties for quality and trueness to type is the point of being cloned and modified to to bring cuttings from them into the green - becomingmore efficient . However , problems capture the maximum genetic variation avail - house . Since the trees are juvenile , their cut - with the control of growth and maturity of able . Currently , a considerably smaller pro - tings root easily , and a small collection of tissues still limit our approaches to tree im - portion is obtained through conventional known - origin clones can be expanded to provement . Nevertheless , members of the selection and breeding . thousands of young trees in two or three Department of Pomology have started to col - Problems with woody species based on years . lect and preserve valuable varieties as tissue their large size , age , complex natural prod - A second option is to take cuttings of out - cultures for our Germplasm Repository to be ucts , and elusive reproductive processes are standingmature trees . Such cuttingsare diffi - 1982 . opened in being bypassed with invigorated tissues , cult to root , and they frequently grow in Now that cell suspensionsof many woody which may double the genetic gains affecting branch form for many years when they do species can be established , application of re - productivity . Gains being sought through se - root . Such rooted cuttings planted together DNA technologies to protoplasts combinant lection , propagation , and engineeringinclude should produce a large amount of seed , is being evaluated . We are exploring how to resistance to insects and disease , production which could be used to establish new stands . fuse protoplasts , induce phase changes , and of of pathogen - free stocks , rapid growth However , there are stillproblemsin obtaining improve upon the biosynthetic potential of wood - producing tall trees , and inhibited abundant seed production in such seed - cells especially for the products of photosyn - wood production in small fruit trees to foster orchards , and the site - adaptation of the open - thesis and the building blocks of proteins . Ef - precocious fruiting and convenient mechani - pollinated offspring from a multi - parent forts are under way to scale - up low molecular cal harvesting . In our cloning experiments , seed - orchard is uncertain . weight transformations and the conversionof we are searching for trees less dependent on As a third option , outstanding parent trees biomass using immobilized cell and enzyme nitrogenous fertilizers , more responsive to are crossed in specific combinations , and systems . cultural practices , and able to grow in poor their juvenile seedling offspring are cloned and saline soils , on steep slopes , and in dry and tested . We are lookingnot only for adap - Don J . Durzan , Chairman , Pomology , U.C . , and harsh climates . Davis . tation to various sites but also for clones for - 34 CALIFORNIA AGRICULTURE , AUGUST 1982 Microphotograph of sporulated wine yeast strain shows unsporulated diploid vegetative cells and sporulated cells , which oThef contain four ascospores . diploid cells have two sets chromosomes in each nucleus ; the ascospores have only one . The spores result from meiotic similar to those divisions in nearly all higher occurring plants and animals . tuitously combiningmany of the best traits of a problem . It their parents . Again , time is takes time for characteristics of the bole , branches , and wood to develop to a point where evaluation is appropriate . Each year , some clones are disqualified , while the rest are used with increasing confidence . plast fusion also can be applied . These tech - A fourth option is now becoming possible . niques open the door to the use of genetic Tissues from outstanding mature trees may engineering methods in yeast improvement . be cultured in nutrient medium , becoming In my laboratory we are working on one such Genetic akrati0n Of undifferentiated masses of cells project , the introduction of a gene from a Fragments of the calluscan be induced to dif - yeast bacterial strain into a wine yeast strain . ferentiate into small plants resembling seed - This gene codes for the structure of an en - lings , and when these have become large Richard Snow zyme that converts malic acid ( the principal enough , juvenile cuttings can be taken from grape acid ) into lactic acid - the process of them . An important aspect of this method is malolactic fermentation . This conversion is manipulation of the developmental , or ma - of importance in preventing wine spoilage turation , state of a clone . Early promising Yeast is one of the major industrial micro - and in cases where the grape must is too acid . results in rejuvenating redwood clones have organisms , used in the brewing , baking , and To cause malolactic fermentation , wine become available from the tissue - culturelab - wine industries . Most improvements in wine makers eitherhold the must under conditions E . Ball and Professor oratories of Professor making have resulted from better grape varie - that encourage the bacteria naturally present T . Murashige , at the University of Califor - ties ( such as Ruby Cabernet developed at to multiply , or they inoculate with a starter niaâ??s Santa Cruz , Irvine , and Riverside cam - or from im - University of California , Davis ) culture of the desired bacteria . It would be puses , and from France . provements in fermentation practices . Not desirable to have a yeast strain that could There is one report of a hybrid between much attention has been given to planned im - carry out both the malolactic and the alco - coast redwood and giant sequoia . We and provement of the other organism on which holic fermentations at the same time . others have not been able to repeat it by the wine industry is based , the wine yeast . We have been able to isolatethe malolactic normal controlled - pollination crosses . Inter - Yeast has many favorable characteristics gene from a species of lactic acid bacteria by specific hybrids with giant sequoia or other making it one of the best organismsto use for cloning it on a plasmid . A plasmid carrying speciesmay someday be created by cell fusion basic genetics research , and as a result , our Es - the gene has been put into the bacterium in culture , followed by recovery and cloning geneticunderstanding of it has reached an ex - cherichia coli ( a widely used genetic organ - of the hybrid plants . tremely high level . ism ) and into a laboratory yeast strain . In As a general principle , the more the newly Yeast is classified scientifically with the both cases , the recipient organisms acquired selected redwoods are like previously tested fungi , the same group to which the common the malolactic function , indicating that the trees , the quicker they can be used for large - mushroom and manyplant diseaseorganisms gene is working in its new hosts . At present its scale reforestation . Conversely , if the new belong . Bakerâ??s , brewerâ??s , and wine yeasts expression in yeast is too low to be of use to trees are radically different genetically , they Saccharomyces belong to the same species , wine makers , but we expect to be able to in - must properly be tested in many conditions cerevisiae.Surveysof many wine yeast strains crease its activity greatly . for many decadesbefore their widespread use have been made for characteristicsof interest The selective introduction of genes from is appropriate . Some new techniques will be to the wine maker , and in every case they one organism into another will be important immediately valuable , for example , in reju - of variability , in - have uncovered a great deal in future plant breeding , and in many cases venating tested trees or clones , or rapidly ex - dicating considerable genetic heterogeneity will circumvent laborious ( or impossible ) panding clones of known families . But the that could be exploited by appropriate breed - breeding programs . The malolactic case is great promise of the new techniques for pro - ing programs . one example : yeast and bacteria cannot be ducing radically new trees must be tempered of crossing The standard breeding method crossed directly . What we learn about in - by the need to be sure those trees can survive strains and selecting desirable recombinant of our bacterial gene creasing the expression and perform well , for many decades , in the progeny can be applied to yeast , just as it can in yeast should also have direct applicationto of our varied and uncertain environments to most other agriculturallyimportant plants many other cases of agricultural importance . forests . of the most attractive and animals . But one features of yeast is that the new techniques of William J . Libby , Professor , Genetics , U.C . , Richard Snow , Chairperson and Professor , Ge - Berkeley . transformation with foreign DNA and proto - netics , U.C . , Davis . CALIFORNIA AGRICULTURE , AUGUST 1982 35