<PAGE>

THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED (THE "ACT"). SUCH SECURITIES AND ANY SECURITIES OR
SHARES ISSUED HEREUNDER MAY NOT BE SOLD OR TRANSFERRED IN THE ABSENCE OF SUCH
REGISTRATION OR AN EXEMPTION THEREFROM UNDER SAID ACT OR IN ACCORDANCE WITH THE
PROVISIONS OF REGULATION S (SECTION 230.901 THROUGH 230.905, AND PRELIMINARY
NOTES) PROMULGATED UNDER THE ACT. HOLDER MAY NOT ENGAGE IN HEDGING TRANSACTIONS
WITH REGARD TO THE SECURITIES REPRESENTED HEREBY UNLESS IN COMPLIANCE WITH THE
ACT.

THIS WARRANT AND THE SECURITIES TO BE ISSUED UPON THE EXERCISE THEREOF HAVE NOT
BEEN REGISTERED UNDER THE ACT AND THIS WARRANT MAY NOT BE EXERCISED BY ANY U.S.
PERSON UNLESS REGISTERED UNDER THE ACT OR AN EXEMPTION FOR SUCH REGISTRATION IS
AVAILABLE.


No. W - C1                                       Warrant to Purchase
Date of Issuance: As of July 25, 2000 400,000 Shares of Series C Preferred Stock
                                               (subject to adjustment)

                       WARRANT TO PURCHASE PREFERRED STOCK
                                       OF
                                 DELTAGEN, INC.

          This certifies that, for value received, The Association for Research
at the Institut de Genetique et de Biologie Moleculaire et Cellulaire ("Holder")
is entitled, subject to the terms and conditions set forth below, to purchase
from Deltagen, Inc. (the "Company"), in whole or in part 400,000 fully paid and
nonassessable shares (the "Warrant Shares") of Series C Preferred Stock, par
value $.001 per share, (the "Preferred Stock") of the Company at a purchase
price per share equal to $3.58 per share (the "Exercise Price"). The number,
character and Exercise Price of such Warrant Shares are subject to adjustment as
provided below and all references to "Warrant Shares" and "Exercise Price"
herein shall be deemed to include any such adjustment or series of adjustments.
The term "Warrant" as used herein shall mean this Warrant, and any warrants
delivered in substitution or exchange therefor as provided herein.

          This Warrant is being issued in connection with services to be
provided to the Company pursuant to that certain consulting agreement between
the Company and the Holder, dated as of March 15, 2000 (the "Consulting
Agreement").

         1. TERM OF WARRANT. Subject to the terms and conditions set forth
herein, this Warrant shall be exercisable, in whole or in part, during the term
commencing on the four month anniversary of the Commencement Date (as defined
below) of the first project under the Consulting Agreement and ending at 5:00
p.m., Pacific time, on the earliest of the following: (i) the closing of a
merger, consolidation or other reorganization of the Company pursuant to which
the stockholders of the Company hold less than 50% of the voting securities of
the surviving entity, or a sale of all or substantially all of the assets of the
Company; or (ii) the third anniversary of the date hereof, and shall be void
thereafter (the "Exercise Period"). The "Commencement Date" shall mean the date
upon which Holder commences work on the first

                                      -1-
<PAGE>

project to be undertaken by Holder for the Company as jointly agreed in writing
as provided for under the Consulting Agreement (the "First Project"). Holder
shall provide written notice to the Company of the commencement of work on such
First Project.

         2. EXERCISE OF WARRANT.

         (a) CASH EXERCISE. This Warrant may be exercised by the Holder by (i)
the surrender of this Warrant to the Company, with the Notice of Exercise
annexed hereto duly completed and executed on behalf of the Holder, at the
office of the Company (or such other office or agency of the Company as it may
designate by notice in writing to the Holder at the address of the Holder
appearing on the books of the Company) during the Exercise Period and (ii) the
delivery of payment to the Company, for the account of the Company, by cash,
wire transfer of immediately available funds to a bank account specified by the
Company, or by certified or bank cashier's check, of the Exercise Price for the
number of Warrant Shares specified in the Exercise Form in lawful money of the
United States of America. The Company agrees that such Warrant Shares shall be
deemed to be issued to the Holder as the record holder of such Warrant Shares as
of the close of business on the date on which this Warrant shall have been
surrendered and payment made for the Warrant Shares as aforesaid. A stock
certificate or certificates for the Warrant Shares specified in the Exercise
Form shall be delivered to the Holder as promptly as practicable, and in any
event within 10 days, thereafter. If this Warrant shall have been exercised only
in part, the Company shall, at the time of delivery of the stock certificate or
certificates, deliver to the Holder a new Warrant evidencing the rights to
purchase the remaining Warrant Shares, which new Warrant shall in all other
respects be identical with this Warrant. No adjustments shall be made on Warrant
Shares issuable on the exercise of this Warrant for any cash dividends paid or
payable to holders of record of Common Stock prior to the date as of which the
Holder shall be deemed to be the record holder of such Warrant Shares.

         (b) NET ISSUE EXERCISE. In lieu of exercising this Warrant pursuant to
Section 2(a), this Warrant may be exercised by the Holder by the surrender of
this Warrant to the Company, with a duly executed Exercise Form marked to
reflect Net Issue Exercise and specifying the number of shares of Preferred
Stock to be purchased, during normal business hours on any Business Day during
the Exercise Period. The Company agrees that such shares of Preferred Stock
shall be deemed to be issued to the Holder as the record holder of such shares
of Preferred Stock as of the close of business on the date on which this Warrant
shall have been surrendered as aforesaid. Upon such exercise, the Holder shall
be entitled to receive shares equal to the value of this Warrant (or the portion
thereof being canceled) by surrender of this Warrant to the Company together
with notice of such election in which event the Company shall issue to Holder a
number of shares of Preferred Stock computed as of the date of surrender of this
Warrant to the Company using the following formula:


                  X = Y(A-B)
                     -------
                        A

       Where      X =      the number of shares of Preferred Stock to be issued
                           to Holder under this Section 2(b);

                  Y =      the number of shares of Preferred Stock otherwise
                           purchasable under this Warrant (as adjusted to the
                           date of such calculation);

                                      -2-
<PAGE>

                  A =      the fair market value of one share of the Preferred
                           Stock at the date of such calculation;

                  B =      the Exercise Price (as adjusted to the date of such
                           calculation).

         (c) FAIR MARKET VALUE. For purposes of Section 2(b), the fair market
value of one share of the Company's Preferred Stock shall be the price per share
which the Company could obtain from a willing buyer for the shares sold by the
Company from authorized but unissued shares, as such price shall be determined
in good faith by the Board of Directors of the Company.

         (d) EFFECTIVE TIME OF EXERCISE. This Warrant shall be deemed to have
been exercised immediately prior to the close of business on the date of its
surrender for exercise as provided above, and the person entitled to receive the
shares of Preferred Stock issuable upon such exercise shall be treated for all
purposes as the holder of record of such shares as of the close of business on
such date. As promptly as practicable on or after such date and in any event
within ten (10) days thereafter, the Company at its expense shall issue and
deliver to the person or persons entitled to receive the same a certificate or
certificates for the number of shares issuable upon such exercise. In the event
that this Warrant is exercised in part, the Company at its expense will execute
and deliver a new Warrant of like tenor exercisable for the number of shares for
which this Warrant may then be exercised.

         3. NO FRACTIONAL SHARES OR SCRIP. No fractional shares or scrip
representing fractional shares shall be issued upon the exercise of this
Warrant. In lieu of any fractional share to which the Holder would otherwise be
entitled, the Company shall make a cash payment equal to the product of the
Exercise Price multiplied by such fraction.

         4. REPLACEMENT OF WARRANT. On receipt of evidence reasonably
satisfactory to the Company of the loss, theft, destruction or mutilation of
this Warrant and, in the case of loss, theft or destruction, on delivery of an
indemnity agreement, with surety if reasonably required, in an amount reasonably
satisfactory to the Company, or in the case of mutilation, on surrender and
cancellation of this Warrant, the Company at its expense shall execute and
deliver, in lieu of this Warrant, a new warrant of like tenor and amount.

         5. NO RIGHTS AS STOCKHOLDER. Subject to Sections 8 and 10 of this
Warrant, the Holder shall not be entitled to vote or receive dividends or be
deemed the holder of Preferred Stock or any other securities of the Company that
may at any time be issuable on the exercise hereof for any purpose, nor shall
anything contained herein be construed to confer upon the Holder, as such, any
of the rights of a stockholder of the Company or any right to vote for the
election of directors or upon any matter submitted to stockholders at any
meeting thereof, or to give or withhold consent to any corporate action (whether
upon any recapitalization, issuance of stock, reclassification of stock, change
of par value, or change of stock to no par value, consolidation, merger,
conveyance, or otherwise) or to receive notice of meetings, or to receive
dividends or subscription rights or otherwise until the Warrant shall have been
exercised as provided herein.

         6. TRANSFER OF WARRANT. Neither this Warrant nor any of the rights,
interests or obligations hereunder may be transferred or assigned in whole or in
part.

         7. RESERVATION OF STOCK. The Company covenants that during the term
this Warrant is exercisable, the Company will reserve from its authorized and
unissued Preferred Stock a

                                      -3-
<PAGE>

sufficient number of shares to provide for the issuance of Preferred Stock upon
the exercise of this Warrant and, from time to time, will take all steps
necessary to amend its Amended and Restated Certificate of Incorporation (the
"Restated Articles") to provide sufficient reserves of shares of Preferred Stock
issuable upon exercise of the Warrant. The Company further covenants that all
shares that may be issued upon the exercise of rights represented by this
Warrant, upon exercise of the rights represented by this Warrant and payment of
the Exercise Price, all as set forth herein, will be free from all taxes, liens
and charges in respect of the issue thereof (other than taxes in respect of any
transfer occurring contemporaneously or otherwise specified herein).

         8. NOTICES.

         (a) Whenever the Exercise Price or number of shares purchasable
hereunder shall be adjusted pursuant to Section 10 hereof, the Company shall
issue a certificate signed by its Chief Financial Officer setting forth, in
reasonable detail, the event requiring the adjustment, the amount of the
adjustment, the method by which such adjustment was calculated, and the Exercise
Price and number of shares purchasable hereunder after giving effect to such
adjustment, and shall cause a copy of such certificate to be transmitted by
telex or facsimile, or mailed (by firstclass mail, postage prepaid) to the
Holder of this Warrant.

         (b) IN CASE:

                  (i) the Company shall take a record of the holders of its
         Preferred Stock (or other stock or securities at the time receivable
         upon the exercise of this Warrant) for the purpose of entitling them to
         receive any dividend or other distribution;

                  (ii) of any capital reorganization of the Company, any
         reclassification of the capital stock of the Company, any consolidation
         or merger of the Company with or into another corporation, or any
         conveyance of all or substantially all of the assets of the Company to
         another corporation; or

                  (iii) of any voluntary dissolution, liquidation or winding-up
         of the Company;

then, and in each such case, the Company will transmit by telex or facsimile, or
mail or cause to be mailed to the Holder or Holders a notice specifying, as the
case may be, (A) the date on which a record is to be taken for the purpose of
such dividend, distribution, and stating the amount and character of such
dividend, distribution or (B) the date on which such reorganization,
reclassification, consolidation, merger, conveyance, dissolution, liquidation or
winding-up is to take place, and the time, if any is to be fixed, as of which
the holders of record of Preferred Stock shall be entitled to exchange their
shares of Preferred Stock for securities or other property deliverable upon such
reorganization, reclassification, consolidation, merger, conveyance,
dissolution, liquidation or winding-up. Such notice shall be delivered at least
seven business (7) days prior to the date therein specified.

         (c) All such notices, advices and communications shall be deemed
effectively delivered upon deposit with a nationally recognized overnight
courier or upon transmission by facsimile (upon receipt of appropriate
confirmation of successful transmission).

                                      -4-
<PAGE>

         9. AMENDMENTS. This Warrant and any term hereof may be changed, waived,
discharged or terminated only by an instrument in writing executed by the
Company and the Holder.

         10. ADIUSTMENTS. The Exercise Price and the number of shares
purchasable hereunder are subject to adjustment from time to time as follows:

         (a) STOCK CONVERSION OF PREFERRED STOCK. Should all of the Company's
Series C Preferred Stock, at any time prior to the expiration of this Warrant,
converted into shares of the Company's Common Stock in accordance with the
Company's Restated Certificate, then this Warrant shall immediately become
exercisable for that number of shares of the Company's Common Stock equal to the
number of shares of the Common Stock that would have been received if this
Warrant had been exercised in full and the Preferred Stock received thereupon
had been simultaneously converted immediately prior to such event, and the
Exercise Price shall be immediately adjusted to equal the quotient obtained by
dividing (x) the aggregate Exercise Price of the maximum number of shares of
Preferred Stock for which this Warrant was exercisable immediately prior to such
conversion, by (y) the number of shares of Common Stock for which this Warrant
is exercisable immediately after such conversion. For purposes of the foregoing,
the "Restated Certificate" shall mean the Certificate of Incorporation of the
Company as amended and/or restated and effective immediately prior to the
conversion of all of the Company's Series C Preferred Stock.

         (b) RECLASSIFICATION, ETC. If the Company, at any time while this
Warrant, or any portion thereof, remains outstanding and unexpired by
reclassification of securities or otherwise, shall change any of the securities
as to which purchase rights under this Warrant exist into the same or a
different number of securities of any other class or classes, this Warrant shall
thereafter .represent the right to acquire such number and kind of securities as
would have been issuable as the result of such change with respect to the
securities that were subject to the purchase rights under this Warrant
immediately prior to such reclassification or other change and the Exercise
Price therefor shall be appropriately adjusted, all subject to further
adjustment as provided in this Section 10. No adjustment shall be made pursuant
to this Section 10 (b), upon any conversion of the Preferred Stock which is the
subject of Section 10 (a).

         (c) SPLIT, SUBDIVISION OR COMBINATION OF SHARES. If the Company at any
time while this Warrant, or any portion thereof, remains outstanding and
unexpired shall split, subdivide or combine the securities as to which purchase
rights under this Warrant exist, into a different number of securities of the
same class, then (i) in the case of a split or subdivision, the Exercise Price
for such securities shall be proportionately decreased and the securities
issuable upon exercise of this Warrant shall be proportionately increased, and
(ii) in the case of a combination, the Exercise Price for such securities shall
be proportionately increased and the securities issuable upon exercise of this
Warrant shall be proportionately decreased.

         (d) ADJUSTMENTS FOR DIVIDENDS IN STOCK OR OTHER SECURITIES OR PROPERTY.
If while this Warrant, or any portion hereof, remains outstanding and unexpired
the holders of the securities as to which purchase rights under this Warrant
exist at the time shall have received, or, on or after the record date fixed for
the determination of eligible stockholders, shall have become entitled to
receive, without payment therefor, other or additional stock or other securities
or property (other than cash) of the Company by way of dividend, then and in
each case, this Warrant shall represent the right to acquire, in addition to the
number of shares of the security receivable upon exercise of this Warrant, and
without payment of any additional consideration

                                      -5-
<PAGE>

therefor, the amount of such other or additional stock or other securities or
property (other than cash) of the Company that such holder would hold on the
date of such exercise had it been the holder of record of the security
receivable upon exercise of this Warrant on the date hereof and had thereafter,
during the period from the date hereof to and including the date of such
exercise, retained such shares and/or all other additional stock available by it
as aforesaid during such period, giving effect to all adjustments called for
during such period by the provisions of this Section 10.

         (e) CERTIFICATE AS TO ADJUSTMENTS. Upon the occurrence of each
adjustment or readjustment pursuant to this Section 10, the Company at its
expense shall promptly compute such adjustment or readjustment in accordance
with the terms hereof and furnish to each Holder of this Warrant a certificate
setting forth such adjustment or readjustment and showing in detail the facts
upon which such adjustment or readjustment is based. The Company shall, upon the
written request, at any time, of any such Holder, furnish or cause to be
furnished to such Holder a like certificate setting forth: (i) such adjustments
and readjustments; (ii) the Exercise Price at the time in effect; and (iii) the
number of shares and the amount, if any, of other property that at the time
would be received upon the exercise of the Warrant.

         (f) NO IMPAIRMENT. The Company will not, by any voluntary action, avoid
or seek to avoid the observance or performance of any of the terms to be
observed or performed hereunder by the Company, but will at all times in good
faith assist in the carrying out of all the provisions of this Section 10 and in
the taking of all such action as may be necessary or appropriate in order to
protect the rights of the Holders of this Warrant against impairment.

         11. MISCELLANEOUS.

         (a) This Warrant shall constitute a contract under the laws of the
State of Delaware and for all purposes shall be construed in accordance with and
governed by the laws of said state, without regard to the conflicts of law
provisions thereof.

         (b) In the event of a dispute with regard to the interpretation of this
Warrant, the prevailing party may collect the cost of attorney's fees,
litigation expenses or such other expenses as may be incurred in the enforcement
of the prevailing party's rights hereunder.

         (c) This Warrant shall be exercisable as provided for herein, except
that in the event that the expiration date of this Warrant shall fall on a
Saturday, Sunday and or United States federally recognized Holiday, this
expiration date for this Warrant shall be extended to 5:00 p.m. Pacific time on
the business day following such Saturday, Sunday or recognized Holiday.

         IN WITNESS WHEREOF, DELTAGEN, INC. has caused this Warrant to be
executed by its officers thereunto duly authorized.

          Date:  July 25, 2000

                                     COMPANY:

                                     DELTAGEN, INC.



                                     By  /s/ Augustine Yee
                                       ----------------------------------------

                                      -6-
<PAGE>

                                      Name:  Augustine Yee
                                           ------------------------------------
                                      Title:   Vice President
                                            -----------------------------------


         The undersigned Holder hereby certifies to the Deltagen, Inc. as
         follows:

         1.       Holder is not a U.S. person and is not acquiring the Warrant
                  or Series C Preferred Stock issuable upon exercise of the
                  Warrant (or Common Stock issuable upon conversion of such
                  Series C Preferred Stock) (collectively, the "Securities") for
                  the account or benefit of any U.S. person.
          2.      Holder will resell such Securities only in accordance with the
                  provisions of Regulation S promulgated under the Securities
                  Act of 1933, as amended (the "Act"), pursuant to an available
                  exemption from the registration requirements of the Act, or
                  pursuant to registration under the Act.




                                      -7-
<PAGE>

          3.      Holder will not engage in hedging transactions with regard to
                  the Securities unless in compliance with the Act.

                                  HOLDER:

                                  THE ASSOCIATION FOR RESEARCH AT INSTITUT DE
                                  GENETIQUE ET DE BIOLOGIE MOLECULAIRE ET
                                  CELLULAIRE


                                  BY:   Pierre Chambon
                                     ------------------------------------------
                                  Name:  Professor Pierre Chambon
                                       ----------------------------------------
                                  Title:   President
                                        ---------------------------------------

                                  Address:     Parc d'innovation
                                               1, rue Laurant Fries
                                               67404 ILLKIRCH
                                               c.u. de Strasbourg, FRANCE



                                      -8-
<PAGE>

                               NOTICE OF EXERCISE


To: DELTAGEN, INC.

         (1) The undersigned hereby elects to purchase ______________ shares of
Series C Preferred Stock of DELTAGEN, INC., pursuant to the terms of the
attached Warrant, and ____ tenders herewith payment of the purchase price for
such shares in full or ____ elects to exercise such Warrant pursuant to the net
issue exercise provisions provided for in Section 2(b) thereof (PLEASE CHECK THE
APPROPRIATE FORM OF PAYMENT).


         (2) In exercising this Warrant, the undersigned hereby confirms and
acknowledges that (A) the undersigned is not a U.S. person and this Warrant is
not being exercise on behalf of a U.S. person and (B) the shares of Series C
Preferred Stock and/or other securities to be issued upon exercise thereof are
being acquired solely for the account of the undersigned and not as a nominee
for any other party, or for investment, and (C) the undersigned will not offer,
sell or otherwise dispose of any such shares of Preferred Stock except under
circumstances that will not result in a violation of the Securities Act of 1933,
as amended, or any applicable state securities laws.

         (3) Please issue a certificate or certificates representing said shares
of Series C Preferred Stock in the name of the undersigned or in such other name
as is specified below, which persons are not U.S. persons:


                                        -----------------------------------
                                                    (Name)

                                        -----------------------------------
                                                    (Name)



         (4) Please issue a new Warrant for the unexercised portion of the
attached Warrant in the name of the undersigned:


                                        -----------------------------------
                                                    (Name)


-----------------------------------     -----------------------------------
             (Date)                              (Signature)