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                                                                  EXHIBIT 10.12


THIS WARRANT AND THE SHARES ISSUABLE HEREUNDER HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE SOLD, PLEDGED, OR
OTHERWISE TRANSFERRED WITHOUT AN EFFECTIVE REGISTRATION THEREOF UNDER SUCH ACT
OR PURSUANT TO RULE 144 OR AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE
CORPORATION AND ITS COUNSEL, THAT SUCH REGISTRATION IS NOT REQUIRED.

                            WARRANT TO PURCHASE STOCK

Corporation: DELTAGEN, INC., a Delaware corporation
Number of Shares: (see below)
Class of Stock: Series B Preferred
Initial Exercise Price: $1.75 per share
Issue Date: March 25, 1999
Expiration Date: March 25, 2006

         THIS WARRANT CERTIFIES THAT, for the agreed upon value of $1.00 and for
other good and valuable consideration, SILICON VALLEY BANK ("Holder") is
entitled to purchase the number of fully paid and nonassessable shares of the
class of securities (the "Shares") of the corporation (the "Company") at the
initial exercise price per Share (the `Warrant Price") all as set forth above
and as adjusted pursuant to Article 2 of this Warrant, subject to the provisions
and upon the terms and conditions set forth in this Warrant.

         For purposes of the foregoing:

         The Number of Shares shall be determined as follows: $1,500,000 divided
by the Initial Exercise Price multiplied by 2%.

                                   ARTICLE 1
                                    EXERCISE

         1.1 METHOD OF EXERCISE. Holder may exercise this Warrant by delivering
a duty executed Notice of Exercise in substantially the form attached as
Appendix 1 to the principal office of the Company. Unless Holder is exercising
the conversion right set forth in Section 1.2, Holder shall also deliver to the
Company a check for the aggregate Warrant Price for the Shares being purchased.

         1.2 CONVERSION RIGHT. In lieu of exercising this Warrant as specified
in Section 1.1, Holder may from time to time convert this Warrant, in whole or
in part, into a number of Shares determined by dividing (a) the aggregate fair
market value of the Shares or other securities otherwise issuable upon exercise
of this Warrant minus the aggregate Warrant Price of such Shares by (b) the fair
market value of one Share. The fair market value of the Shares shall be
determined pursuant to Section 1.4.

         1.3 INTENTIONALLY OMITTED.

         1.4 FAIR MARKET VALUE. If the Shares are traded in a public market, the
fair market value of the Shares shall be the closing price of the Shares (or the
closing price of the Company's


                                      -1-

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stock into which the Shares are convertible) reported for the business day
immediately before Holder delivers its Notice of Exercise to the Company. If
the Shares are not traded in a public market, the Board of Directors of the
Company shall determine fair market value in its reasonable good faith
judgment. The foregoing notwithstanding, if Holder advises the Board of
Directors in writing that Holder disagrees with such determination, then the
Company and Holder shall promptly agree upon a reputable investment banking
firm to undertake such valuation. If the valuation of such investment banking
firm is greater than that determined by the Board of Directors, then all fees
and expenses of such investment banking firm shall be paid by the Company. In
all other circumstances, such fees and expenses shall be paid by Holder.

         1.5 DELIVERY OF CERTIFICATE AND NEW WARRANT. Promptly after Holder
exercises or converts this Warrant, the Company shall deliver to Holder
certificates for the Shares acquired and, if this Warrant has not been fully
exercised or converted and has not expired, a new Warrant representing the
Shares not so acquired.

         1.6 REPLACEMENT OF WARRANTS. 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 reasonably satisfactory in form and amount 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.

         1.7 REPURCHASE ON SALE, MERGER, OR CONSOLIDATION OF THE COMPANY.

              1.7.1 "ACQUISITION". For the purpose of this Warrant,
"Acquisition" means any sale, license, or other disposition of all or
substantially all of the assets of the Company, or any reorganization,
consolidation, or merger of the Company where the holders of the Company's
securities before the transaction beneficially own less than 50% of the
outstanding voting securities of the surviving entity after the transaction.

              1.7.2 ASSUMPTION OF WARRANT. Upon the closing of any Acquisition
the successor entity shall assume the obligations of this Warrant, and this
Warrant shall be exercisable for the same securities, cash, and property as
would be payable for the Shares issuable upon exercise of the unexercised
portion of this Warrant as if such Shares were outstanding on the record date
for the Acquisition and subsequent closing. The Warrant Price shall be adjusted
accordingly.

              1.7.3 PURCHASE RIGHT. Notwithstanding the foregoing, at the
election of Holder, the Company shall purchase the unexercised portion of this
Warrant for cash upon the closing of any Acquisition for an amount equal to (a)
the fair market value of any consideration that would have been received by
Holder in consideration of the Shares had Holder exercised the unexercised
portion of this Warrant immediately before the record date for determining the
shareholders entitled to participate in the proceeds of the Acquisition, less
(b) the aggregate Warrant Price of the Shares, but in no event less than zero.


<PAGE>

                                   ARTICLE 2
                            ADJUSTMENTS TO THE SHARES

         2.1 STOCK DIVIDENDS. SPLITS ETC.. If the Company declares or pays a
dividend on its common stock (or the Shares if the Shares are securities other
than common stock) payable in common stock, or other securities, subdivides the
outstanding common stock into a greater amount of common stock, or, if the
Shares are securities other than common stock, subdivides the Shares in a
transaction that increases the amount of common stock into which the Shares are
convertible, then upon exercise of this Warrant, for each Share acquired, Holder
shall receive, without cost to Holder, the total number and kind of securities
to which Holder would have been entitled had Holder owned the Shares of record
as of the date the dividend or subdivision occurred.

         2.2 RECLASSIFICATION. EXCHANGE OR SUBSTITUTION. Upon any
reclassification, exchange, substitution, or other event that results in a
change of the number and/or class of the securities issuable upon exercise or
conversion of this Warrant, Holder shall be entitled to receive, upon exercise
or conversion of this Warrant the number and kind of securities and property
that Holder would have received for the Shares if this Warrant had been
exercised immediately before such reclassification, exchange, substitution, or
other event. Such an event shall include any automatic conversion of the
outstanding or issuable securities of the Company of the same class or series as
the Shares to common stock pursuant to the terms of the Company's Articles of
Incorporation upon the closing of a registered public offering of the Company's
common stock. The Company or its successor shall promptly issue to Holder a new
Warrant for such new securities or other property. he new Warrant shall provide
for adjustments which shall be as nearly equivalent as may be practicable to the
adjustments provided for in this Article 2 including, without limitation,
adjustments to the Warrant Price and to the number of securities or property
issuable upon exercise of the new Warrant. The provisions of this Section 2.2
shall similarly apply to successive reclassifications, exchanges, substitutions,
or other events.

         2.3 ADJUSTMENTS FOR COMBINATIONS, ETC.. If the outstanding Shares are
combined or consolidated, by reclassification or otherwise, into a lesser number
of shares, the Warrant Price shall be proportionately increased.

         2.4 ADJUSTMENTS FOR DILUTING ISSUANCES. The Warrant Price and the
number of Shares issuable upon exercise of this Warrant or, if the Shares are
Preferred Stock, the number of shares of common stock issuable upon conversion
of the Shares, shall be subject to adjustment, from time to time in the manner
set forth on Exhibit A in the event of Diluting Issuances (as defined on Exhibit
A).

         2.5 NO IMPAIRMENT. The Company shall not, by amendment of its Articles
of incorporation or through a reorganization, transfer of assets, consolidation,
merger, dissolution, issue, or sale of securities or any other voluntary action,
avoid or seek to avoid the observance or performance of any of the terms to be
observed or performed under this Warrant by the Company, but shall at all times
in good faith assist in carrying out of all the provisions of this Article 2 and
in taking all such action as may be necessary or appropriate to protect Holder's
rights under this Article against impairment. If the Company takes any action
affecting the Shares or its common stock other than as described above that
adversely affects Holder's rights


                                       -3-

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under this Warrant the Warrant Price shall be adjusted downward and the
number of Shares issuable upon exercise of this Warrant shall be adjusted
upward in such a manner that the aggregate Warrant Price of this Warrant is
unchanged.

         2.6 FRACTIONAL SHARES. No fractional Shares shall be issuable upon
exercise or conversion of the Warrant and the number of Shares to be issued
shall be rounded down to the nearest whole Share. If a fractional share interest
arises upon any exercise or conversion of the Warrant, the Company shall
eliminate such fractional share interest by paying Holder amount computed by
multiplying the fractional interest by the fair market value of a full Share.

         2.7 CERTIFICATE AS TO ADJUSTMENTS. Upon each adjustment of the Warrant
Price, the Company at its expense shall promptly compute such adjustment, and
furnish Holder with a certificate of its Chief Financial Officer setting forth
such adjustment and the facts upon which such adjustment is based. The Company
shall, upon written request, furnish Holder a certificate setting forth the
Warrant Price in effect upon the date thereof and the series of adjustments
leading to such Warrant Price.

                                   ARTICLE 3
                  REPRESENTATIONS AND COVENANTS OF THE COMPANY

         3.1 REPRESENTATIONS AND WARRANTIES. The Company hereby represents and
warrants to the Holder as follows:

              (a) The initial Warrant Price referenced on the first page of this
Warrant is not greater than (i) the price per share at which the Shares were
last issued in an arms-length transaction in which at least $500,000 of the
Shares were sold and (ii) the fair market value of the Shares as of the date of
this Warrant.

              (b) All Shares which may be issued upon the exercise of the
purchase right represented by this Warrant, and all securities, if any, issuable
upon conversion of the Shares, shall, upon issuance, be duty authorized, validly
issued, fully paid and nonassessable, and free of any liens and encumbrances
except for restrictions on transfer provided for herein or under applicable
federal and state securities laws.

              (c) The Capitalization table attached hereto is true and correct.

         3.2 NOTICE OF CERTAIN EVENTS. If the Company proposes at any time (a)
to declare any dividend or distribution upon its common stock, whether in cash,
property, stock, or other securities and whether or not a regular cash dividend;
(b) to offer for subscription pro rata to the holders of any class or series of
its stock any additional shares of stock of any class or series or other rights;
(c) to effect any reclassification or recapitalization of common stock; (d) to
merge or consolidate with or into any other corporation, or sell, lease,
license, or convey all or substantially all of its assets, or to liquidate,
dissolve or wind up; or (e) offer holders of registration rights the opportunity
to participate in an underwritten public offering of the company's securities
for cash, then, in connection with each such event the Company shall give Holder
(1) at least 20 days prior written notice of the date on which a record will be
taken for such dividend, distribution, or subscription rights (and specifying
the date on which the holders of common stock will be entitled thereto) or for
determining rights to vote, if any, in respect of


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the matters referred to in (c) and (d) above; (2) in the case of the matters
referred to in (c) and (d) above at least 20 days prior written notice of the
date when the same will take place (and specifying the date on which the
holders of common stock will be entitled to exchange their common stock for
securities or other property deliverable upon the occurrence of such event);
and (3) in the case of the matter referred to in (e) above, the same notice
as is given to the holders of such registration rights.

         3.3 INFORMATION RIGHTS. So long as the Holder holds this Warrant and/or
any of the Shares, the Company shall deliver to the Holder (a) promptly after
mailing, copies of all notices or other written communications to the
shareholders of the Company, (b) within ninety (90) days after the end of each
fiscal year of the Company, the annual audited financial statements of the
Company certified by independent public accountants of recognized standing and
(c) such other financial statements required under and in accordance with any
loan documents between Holder and the Company (or if there are no such
requirements [or if the subject loan(s) no longer are outstanding]), then within
forty-five (45) days after the end of each of the first three quarters of each
fiscal year, the Company's quarterly, unaudited financial statements.

         3.4 REGISTRATION UNDER SECURITIES ACT OF 1933 AS AMENDED. The Company
agrees that the Shares or, if the Shares are convertible into common stock of
the Company, such common stock, shall be subject to the registration rights set
forth on Exhibit B, if attached.

                                    ARTICLE 4
                                  MISCELLANEOUS

         4.1 TERM; NOTICE OF EXPIRATION. This Warrant is exercisable, in whole
or in part, at any time and from time to time on or before the Expiration Date
set forth above.

         4.2 LEGENDS. This Warrant and the Shares (and the securities
issuable, directly or indirectly, upon conversion of the Shares, if any)
shall be imprinted with a legend in substantially the following form:

             THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT
             OF 1933, AS AMENDED, AND MAY NOT BE SOLD, PLEDGED OR OTHERWISE
             TRANSFERRED WITHOUT AN EFFECTIVE REGISTRATION THEREOF UNDER
             SUCH ACT OR PURSUANT TO RULE 144 OR AN OPINION OF COUNSEL
             REASONABLY SATISFACTORY TO THE CORPORATION AND ITS COUNSEL
             THAT SUCH REGISTRATION IS NOT REQUIRED.

         4.3 COMPLIANCE WITH SECURITIES LAWS ON TRANSFER. This Warrant and the
Shares issuable upon exercise this Warrant (and the securities issuable,
directly or indirectly, upon conversion of the Shares, if any) may not be
transferred or assigned in whole or in part without compliance with applicable
federal and state securities laws by the transferor and the transferee
(including, without limitation, the delivery of investment representation
letters and legal opinions reasonably satisfactory to the Company, as reasonably
requested by the Company). The Company shall not require Holder to provide an
opinion of counsel if the transfer is to an


                                      -5-

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affiliate of Holder if there is no material question as to the availability
of current information as referenced in Rule 144(c), Holder represents that
it has complied with Rule 144(d) and (e) in reasonable detail, the selling
broker represents that it has complied with Rule 144(f), and the Company is
provided with a copy of Holder s notice of proposed sale.

         4.4 TRANSFER PROCEDURE. Subject to the provisions of Section 4.3 Holder
may transfer all or part of this Warrant or the Shares issuable upon exercise of
this Warrant (or the securities issuable, directly or indirectly, upon
conversion of the Shares, if any) at any time to Silicon Valley Bancshares or
The Silicon Valley Bank Foundation , or, to any other transferree by giving the
Company notice of the portion of the Warrant being transferred setting forth the
name, address and taxpayer identification number of the transferee and
surrendering this Warrant to the Company for reissuance to the transferee(s)
(and Holder if applicable). Unless the Company is filing financial information
with the SEC pursuant to the Securities Exchange Act of 1934, the Company shall
have the right to refuse to transfer any portion of this Warrant to any person
who directly competes with the Company. Notwithstanding the foregoing, any
single transfer of a portion of this Warrant or the Shares issuable upon
exercise of this Warrant shall not comprise less than 10% of the original Number
of Shares.

         4.5 NOTICES. All notices and other communications from the Company to
the Holder, or vice versa, shall be deemed delivered and effective when given
personally or mailed by first-class registered or certified mail, postage
prepaid, at such address as may have been furnished to the Company or the
Holder, as the case may be, in writing by the Company or such holder from time
to time.

         4.6 WAIVE. This Warrant and any term hereof may be changed, waived,
discharged or terminated only by an instrument in writing signed by the party
against which enforcement of such change, waiver, discharge or termination is
sought.

         4.7 ATTORNEYS. In the event of any dispute between the parties
concerning the terms and provisions of this Warrant, the party prevailing in
such dispute shall be entitled to collect from the other party all costs
incurred in such dispute, including reasonable attorneys' fees.


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         4.8 GOVERNING LAW. This Warrant shall be governed by and construed in
accordance with the laws of the State of California, without giving effect to
its principles regarding conflicts of law.

                          "COMPANY"

                          DELTAGEN, INC.



                          By:     /S/ AUGUSTINE YEE, VICE PRESIDENT

                          Name:   AUGUSTINE YEE

                          Title:  Chairman of the Board, President or
                                  Vice President


                          By:     MARK W. MOORE

                          Name:   MARK W. MOORE / CSO

                          Title:  Chief Financial Officer, Secretary,
                                  Assistant Treasurer or Assistant Secretary


                                      -7-


<PAGE>

                                   APPENDIX 1

                               NOTICE OF EXERCISE


         1. The undersigned hereby elects to purchase _______ shares of the
Common/Preferred Series ____ [Strike one] Stock of DELTAGEN, INC. pursuant to
the terms of the attached Warrant, and tenders herewith payment of the purchase
price of such shares in full.

         2. The undersigned hereby elects to convert the attached Warrant into
Shares/cash [strike one] in the manner specified in the Warrant. This conversion
is exercised with respect to ________________ of the Shares covered by the
Warrant.

         [Strike paragraph that does not apply.)

         3. Please issue a certificate or certificates representing said shares
in the name of the undersigned or in such other name as is specified below:

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

         -----------------------------------------------

         ------------------------------------------------
         (Address)

         4. The undersigned represents it is acquiring the shares solely for
its own account and not as a nominee for any other party and not with a view
toward the resale or distribution thereof except in compliance with
applicable securities laws.

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

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


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                                    EXHIBIT A

                            Anti-Dilution Provisions
     (FOR PREFERRRED STOCK WARRANTS WITH EXISTING ANTI-DILUTION PROTECTION)


         In the event of the issuance (a "Diluting Issuance") by the Company,
after the Issue Date of the Warrant, of securities at a price per share less
than the Warrant Price, then the number of shares of common stock issuable upon
conversion of the Shares shall be adjusted in accordance with those provisions
(the "Provisions!') of the Company's Articles (Certificate) of Incorporation
which apply to Diluting Issuances.

         The Company agrees that the Provisions, as in effect on the Issue Date,
shall be deemed to remain in full force and effect during the term of the
Warrant notwithstanding any subsequent amendment, waiver or termination thereof
by the Company's shareholders, unless such subsequent amendment, waiver or
termination thereof applies to each and every shareholder of Preferred Stock (as
defined in that certain Investors' Rights Agreement dated may 27, 1999) of the
Company.

         Under no circumstances shall the aggregate Warrant Price payable by the
Holder upon exercise of the Warrant increase as a result of any adjustment
arising from a Diluting Issuance.




                                      -9-

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                                    EXHIBIT B

                               REGISTRATION RIGHTS

         The Shares (if common stock) or the common stock issuable upon
conversion of the Shares, shall be deemed "registrable securities" or otherwise
entitled to "piggy back" registration rights in accordance with the terms of
Section 1 of the following agreement (the "Agreement") between the Company and
its investor(s):

                  Investors' Rights Agreement dated May 27, 1999 by and among
                  Deltagen, Inc. and the investors listed on Schedule A attached
                  thereto.

         The Company agrees that no amendments will be made to the Agreement
which would have an adverse impact on Holder's registration rights thereunder,
in a different manner from other holders of registrable securities under the
Agreement without the consent of Holder. By acceptance of the Warrant to which
this Exhibit B is attached, Holder shall be deemed to be a party to the
Agreement.


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