EXHIBIT 99.1

           PURCHASE AGREEMENT AMONG MYCOGEN, AGRIGENETICS, INC. AND
             DELTA AND PINE LAND COMPANY, DATED FEBRUARY 15, 1995

                              PURCHASE AGREEMENT

This Purchase Agreement dated as of February 15, 1995, is made and entered into
by and between Mycogen Corporation ("Mycogen") and its subsidiary Agrigenetics,
Inc. doing business as Mycogen Plant Sciences ("MPS"), and Delta and Pine Land
Company ("DPL").
Mycogen and MPS desire to purchase DPL's corn and sorghum business for the
benefit of MPS and DPL desires to sell such business to MPS. The parties
contemplate consummating such a transaction in three components. One component
involves the exchange of certain facilities located in Lubbock, Texas owned by
MPS for certain facilities located in Plainview and Dumas, Texas owned by DPL.
Another component involves the acquisition by MPS of DPL's planting and
foundation seed germplasm and contracts associated with DPL's corn and sorghum
business. The final component involves an arrangement for the sale of DPL's
current corn and sorghum inventories.
NOW, THEREFORE, the parties hereby agree as follows:

                                   ARTICLE I

                            EXCHANGE OF FACILITIES

1.1   EXCHANGE OF PROPERTY. MPS and DPL hereby agree that on June 30, 1995
     (the "Property Closing Date"), MPS and DPL, subject to the terms and
     conditions set forth under this Article I, will consummate the exchange of
     the following properties (the "Exchange"):

     (i)     MPS will convey to DPL, MPS's facilities and, except as set forth
           on Schedule 1.1A, all fixed assets located at and used predominantly
           in connection with the operation of such facilities located at 624
           27th Street and 6201 Southeast Loop #289, Lubbock, Texas (the "MPS
           Property"); and

     (ii)    DPL will convey to MPS, DPL's facilities and, except as set forth
           on Schedule 1.1B, all fixed assets located at and used predominantly
           in connection with the operation of such facilities located at 3600
           North Columbia Street, Plainview, Texas, and Highway 152, Dumas,
           Texas (the "DPL Property").

     Each party will keep their own rolling stock and, as to be agreed upon by
     the parties, certain portable assets (such as furniture, computers,
     supplies, etc.). Each party will be responsible for removing all of their
     own rolling stock and agreed-upon portable assets from their facilities on
     or before the Property Closing Date.

1.2   OPERATION OF PROPERTIES PRIOR TO THE EXCHANGE. Prior to the Property
     Closing Date, each party will continue to operate its own facilities at its
     own cost.

1.3   MISCELLANEOUS COSTS.

      (a)    Each party will pay the cost of recording the warranty deed to the
           property being acquired by such party.

      (b)    Each party will pay (i) the cost of preparing its warranty deed to
           be delivered to the other party and any documentary transfer tax on
           its warranty deed, and (ii) the cost of an ALTA policy of title
           insurance as described in Section 1.4(b) hereof.

      (c)    Any other costs to effect the Exchange will be apportioned in a
           manner that is customary in the county where each of the MPS Property
           and the DPL Property, respectively, are located.


                                 EXHIBIT 99.1

 
1.4   CONDITIONS OF CLOSING. On the Property Closing Date, MPS (with respect
     to the MPS Property) and DPL (with respect to the DPL Property) will
     deliver to the other party the following items, which must be satisfied to
     effect the Exchange:

     (a)     Subject to any exceptions and limitations set forth in the title
           insurance policy accepted by the acquiring party in accordance with
           Section 1.4(b) and (c), a warranty deed conveying title to such
           property to the acquiring party.

     (b)     An ALTA standard policy of title insurance issued by a nationally
           recognized title company with liability in the amount of the value of
           the property as reflected in the financial records of MPS or, as the
           case may be, DPL showing title to such property as set forth in
           Section 1.1 above, subject only to:

           (i)     Nondelinquent real property taxes, assessments, and
                improvement bonds;

          (ii)     Utility, drainage and slope easements affecting such
                property that may be approved by the acquiring party in
                accordance with Section 1.4(c) below;

         (iii)     Such liens, licenses, easements, encumbrances, covenants,
                conditions and restrictions and other matters of record that may
                be approved by the acquiring party in accordance with Section
                1.4(c) below; and

          (iv)     A reservation of the mineral estate under such property so
                long as such reservation shall not include the right to use the
                surface of such property or the upper 500 feet of the land
                lying below the surface thereof; and

           (v)     Any other similar exceptions to title that do not interfere
                with the operation of the MPS Property and the DPL Property,
                respectively, as currently conducted.

     (c)     As soon as possible after the date of this Agreement, MPS (with
           respect to the MPS Property) and DPL (with respect to the DPL
           Property) will deliver to the other party the following items:

           (i)     A standard preliminary title commitment for a dollar amount
                equal to the book value of such property as reflected on the
                financial records of MPS and DPL, respectively (the "Title
                Commitment") issued by a nationally recognized title company
                showing the status of the title of such property;

          (ii)     A copy of all existing leases and management, maintenance,
                security and other contracts pertaining to such property
                ("Contracts"), which Contracts are listed on Schedule 1.4; and

         (iii)     Recorded tract map and other data pertaining to such
                property which are in the possession of, or are available
                without cost to, MPS or, as applicable, DPL.

     Within 30 days of each party's receipt of the other party's Title
           Commitment, the receiving party will notify the delivering party in
           writing of any unacceptable exceptions in the Title Commitment so
           that the receiving party may attempt to secure the removal thereof.
           Failure to disapprove in writing any such exceptions within said 30
           day period will be deemed approval thereof.

     Each party will use diligent efforts to remove within 60 days of
           disapproval any exceptions to title disapproved by the acquiring
           party. In the event that any such disapproved exceptions to title
           cannot be removed to the acquiring party's satisfaction within such
           60 day period, the parties will negotiate a mutually acceptable
           remedy to compensate and protect the acquiring party from risks
           associated with such disapproved exception to title.

     MPS will accept by assignment the DPL Contract listed on Schedule 1.4.
           There are no Contracts associated with the MPS Property to be
           assigned to DPL.

     (d)     Any other instruments and documents customary in the respective
           counties in Texas where the MPS Property and the DPL Property are
           located in order to effect the exchange.


                                 EXHIBIT 99.1

 
     (e)     A certificate duly executed by each party certifying that the
           representations and warranties of such party as set forth under
           Section 1.6 are true and correct as of the Property Closing Date.

     (f)     Satisfaction of the obligations with respect to environmental
           matters as set forth under Section 1.7.

1.5   POSSESSION, PRORATIONS AND CASUALTY.

     (a)     Each party will be entitled to possession of the property to be
           acquired by such party under the terms of this Agreement upon the
           exchange of deeds under Section 1.4(a) above.

     (b)     Real property taxes and assessments on each of the MPS Property and
           the DPL Property will be prorated as of the Property Closing Date.
           Said prorations to be based on a 30-day month and a 360-day year
           and the actual taxes for the most recent year available.

     (c)     In the event of any casualty to the MPS Property or the DPL
           Property, the acquiring party will have the right to elect to have
           the selling party repair and restore the damage caused by such
           casualty or to accept such damaged property with any insurance
           proceeds collectable with respect to such casualty.

1.6   REPRESENTATIONS, WARRANTIES AND COVENANTS.

     (a)     MPS, as the acquirer of the DPL Property, and DPL, as the acquirer
           of the MPS Property, hereby represent, warrant and covenant as
           follows:

           (i)     Each party represents that there have been no
                representations or warranties by the other party other than
                those specified in this Agreement concerning the property being
                acquired by such party under this Agreement, that such party is
                not relying in acquiring such property on any oral or written
                statement made by the other party except as provided herein, and
                that such party will rely on its own independent inspections of
                such property. It is understood that the MPS Property and the
                DPL Property will be conveyed in an "as is" condition, and no
                warranties or representations have been or will be made by or on
                behalf of the conveying party concerning the property or title
                thereto other than as provided in Section 1.6(b) hereof.

          (ii)     Each party is a corporation duly formed and existing under
                the laws of its state of incorporation. Each party has full
                legal right, power and authority to execute and fully perform
                its obligations under Article I of this Agreement, without the
                need for any further action.

     (b)     MPS, as the conveyer of the MPS Property, and DPL, as the conveyer
           of the DPL Property, hereby represent, warrant and covenant as
           follows:

           (i)     Each party is a corporation duly formed and existing under
                the laws of its state of incorporation. Each party has full
                legal right, power and authority to execute and fully perform
                its obligations under Article I of this Agreement, without the
                need for any further action.

          (ii)     To the best of MPS's knowledge, with respect to the MPS
                Property, and of DPL's knowledge, with respect to the DPL
                Property, there is no pending or threatened condemnation of such
                property, or of any portion thereof.

         (iii)     No claim, litigation, proceeding, or governmental
                investigation is pending or threatened against or relating to
                the property to be conveyed by such party under this Agreement,
                or affects such party's ability to fulfill all of its
                obligations under this Agreement. Each party is not aware of any
                basis for any such claim, litigation, other proceeding or
                governmental investigation.


                                 EXHIBIT 99.1

 
          (iv)     Each party has neither received notice nor has actual
                knowledge that any government authority, or any employee or
                agent thereof, considers the property to be conveyed by such
                party under this Agreement, or the current operation, use or
                ownership of the same to violate any ordinances, laws,
                regulations or orders of any governmental entity or any agency,
                body or subdivision thereof, or that any investigation has been
                commenced, or is contemplated, regarding such possible
                violation.

           (v)     No third party holds any option to purchase, right of first
                refusal or right to purchase the property to be conveyed by such
                party under this Agreement or any portion thereof. After the
                date of this Agreement, each party will not create any such
                liens, encumbrances, covenants, leases, licenses, occupancy
                agreements, options, rights or other exceptions to title to the
                property to be conveyed by such party under this Agreement
                without the acquiring party's prior written consent.

          (vi)     Except for fixed assets specifically excluded on Schedule
                1.1A (with respect to the MPS Property) and on Schedule 1.1B
                (with respect to the DPL Property), each such property is being
                conveyed with all fixed assets located at such property. As set
                forth under Section 1.1, each party will keep their own rolling
                stock and, as to be agreed upon by the parties, certain portable
                assets (such as furniture, computers, supplies, etc.) and will
                remove such items from their respective facilities on or before
                the Property Closing Date.

         (vii)     Except as set forth on Schedule 1.4, there are no leases
                or management, maintenance, security or other agreements
                (whether oral or written) affecting the property to be conveyed
                by such party under this Agreement, and no person has any right
                of possession to such property or any part thereof.

        (viii)     The Exchange will not violate any contract, agreement or
                instrument to which MPS (with respect to the MPS Property) or
                DPL (with respect to the DPL Property) is a party which affects
                such property or any part thereof.

1.7   ENVIRONMENTAL ASSESSMENTS.

     (a)     As promptly as possible after the date of this Agreement, the
           parties will have a Phase 1 environmental site assessment conducted
           with respect to the MPS Property located at 6201 Southeast Loop #289,
           Lubbock, Texas, the MPS Property located at 624 27th Street, Lubbock,
           Texas and the DPL Property located at 3600 North Columbia Street,
           Plainview, Texas. If the results of such Phase 1 assessments require
           a Phase 2 environmental site assessment with respect to any of such
           properties in order to adequately assess potential environmental
           liabilities, a Phase 2 assessment will be conducted on any such
           properties.

     (b)     The environmental site assessments will be conducted by an
           environmental firm selected by DPL. The costs of all assessments
           conducted under this Agreement will be shared 50/50 by DPL and MPS.

     (c)     Based on the environmental assessments of the above-referenced DPL
           Property and MPS Property, each selling party prior to the Property
           Closing Date (and as a condition precedent to consummating the
           Exchange) will remedy any environmental contamination not acceptable
           to the acquiring party to the reasonable satisfaction of the
           acquiring party. The Property Closing Date may be extended to permit
           sufficient time to remedy any such environmental contamination. In
           the event that the cost of any such remediation is unacceptably high
           to the selling party, such remediation will not be required and such
           contaminated property will not be included in the Exchange. In such
           event, the parties will negotiate (as a condition precedent to
           consummating the Exchange) mutually acceptable compensation for the
           party who will not receive all of the property contemplated by this
           Agreement to be received by such party in the Exchange. Each
           conveying party will 

                                 EXHIBIT 99.1

 
           indemnify and hold harmless the acquiring party from and against any
           and all liabilities, costs and expenses incurred by the acquiring
           party with respect to disposal of hazardous wastes on, or any
           violation prior to the Property Closing Date of environmental laws
           at, any property actually conveyed to the acquiring party as part of
           the Exchange. Each party may elect to have a third-party designee
           receive title and ownership of the property being acquired.

                                  ARTICLE II

             PURCHASE AND SALE OF DPL'S CORN AND SORGHUM BUSINESS

2.1   CONVEYANCE OF ASSETS.

     (a)     Effective as of the date of this Agreement, DPL hereby conveys,
           assigns and transfers to MPS, and MPS hereby accepts such conveyance,
           assignment and transfer of all of DPL's right, title and interest in
           and to the following DPL assets related to DPL's corn and sorghum
           business:

           (i)     All corn and sorghum foundation and parent seed germplasm
                (including, without limitation, all records and experimental
                seed stock related thereto); provided, however, that DPL will
                retain title to all existing corn and sorghum seed available for
                customer sales.

          (ii)     Subject to obtaining any legally required consent of third
                parties to such written agreements, all written agreements
                (including, without limitation, any and all licenses to corn and
                sorghum parent lines and varieties licensed by DPL from third
                parties) associated with DPL's corn and sorghum business.

     (b)     DPL represents and warrants that all written agreements associated
           with DPL's corn and sorghum business are set forth on Schedule 2.1 to
           this Agreement. Also, each agreement requiring such third-party
           consent is indicated on Schedule 2.1. Upon request by MPS, DPL will
           use diligent efforts to obtain as promptly as practical any and all
           third-party consents to assign to MPS the agreements set forth on
           Schedule 2.1, including, without limitation, the sorghum conditioning
           agreement with Asgrow, but specifically excluding the agreement
           relating to the supply and distribution of corn with Ciba Seeds. MPS
           will be solely responsible for conducting discussions with Ciba Seeds
           regarding any assignment and assumption of such agreement.

     (c)     MPS hereby assumes all liabilities and responsibilities of DPL as
           of the date of this Agreement under all contracts and agreements
           assigned or sublicensed to MPS under this Section 2.1, which, in the
           case of agreements that require third-party consent, will be deemed
           assigned to and assumed by MPS upon receipt of such third-party
           consent. To the extent that any such agreements prohibit an
           assignment of such agreement, but permit the sublicense of rights
           thereunder by DPL, DPL hereby exclusively sublicenses to MPS all of
           DPL's right, title and interest under any such agreement. MPS agrees
           to continue to supply Ciba Seeds with sorghum seed as historically
           supplied by DPL and to enter into a supply agreement mutually
           acceptable to MPS and Ciba Seeds for such purpose.

     (d)     Subject to obtaining the consent of Ciba-Geigy Corporation
           substantially in the form attached to this Agreement, DPL represents
           and warrants that (i) it has full power and authority to assign to
           MPS its ownership and irrevocable license to all sorghum germplasm
           owned or licensed by DPL without the need for any third party consent
           or approval; (ii) effective as of the date of this Agreement, all of
           DPL's right, title and interest in DPL's parent and foundation
           sorghum germplasm hereby is conveyed, assigned and transferred to
           MPS; and (iii) MPS has all the rights of DPL under DPL's sorghum
           germplasm license (as set forth in the excerpts to the Assets
           Purchase Agreement dated December 13, 1988 between DPL and Ciba Geigy
           attached as part of Schedule 2.1) subject only to the 


                                 EXHIBIT 99.1

 
           limitations to such license as set forth under the license grant
           provisions of such license agreement. This representation and
           warranty will survive the consummation of the transactions
           contemplated by this Agreement.

2.2   SALE OF EXISTING DPL CORN AND SORGHUM INVENTORY.

     (a)     DPL will retain title to all existing DPL corn and sorghum
           inventory until title is transferred to MPS in accordance with
           Section 2.2.(a)(iv) for sale to MPS customers. MPS and DPL hereby
           agree that DPL's existing corn and sorghum available seed (including
           fiscal 1995 production to come into inventory) will be marketed and
           sold during the 1995 through 1997 marketing years (through December
           1997) as follows:

           (i)     DPL, in 1995, and MPS, in 1996 and 1997, will use diligent
                efforts to market and sell DPL available corn and sorghum seed
                on a FIFO basis to the extent commercial quality standards can
                be satisfied. Such quality standards are set forth on Schedule
                2.2A by corn and sorghum hybrid. The quantity of corn and
                sorghum seed comprising DPL's available seed is set forth by
                hybrid, pedigree (to the extent DPL has pedigree information
                readily available) and, with respect to corn, by seed size on
                Schedule 2.2B.

          (ii)     DPL will be responsible for marketing and selling the DPL
                available corn and sorghum seed for the benefit and account of
                MPS in 1995. DPL also will be responsible for shipments,
                invoicings and collections in 1995. With respect to all order
                entry, bagging and rebagging, shipments, invoicing and
                collections for 1995, DPL will send out all documentation to
                customers under its computer system and provide such information
                to MPS. Each invoice will indicate that the sale is made for the
                benefit of MPS. DPL will be responsible for cash collections
                with respect to 1995 sales. MPS will be responsible for bad
                debts with respect to 1995 sales consummated after the date of
                this Agreement; provided, however, that Mycogen will be able to
                offset the amount of such bad debts against any repurchase of
                Mycogen stock from DPL under Section 3.5.

         (iii)     MPS will be responsible for marketing and selling the DPL
                available corn and sorghum seed in 1996 and 1997. MPS will also
                be responsible for order entry, bagging and rebagging,
                shipments, invoicing, and collections with respect to sales
                after 1995. In connection with marketing and selling DPL
                available corn seed, MPS will, in each of 1996 and 1997, sell
                (as a percentage of sales) a quantity of "small" or
                "undesirable" seed sizes of corn fitting the description of
                "small" or "undesirable" seed set forth on Schedule 2.2C equal
                to DPL's average annual quantity of small corn seed sizes sold
                by DPL (as a percentage of sales) over the last three years,
                which average annual quantity (as a percentage of sales) also is
                set forth on Schedule 2.2C. In each of 1996 and 1997, MPS will
                not sell any "small" or "undesirable" seed produced by MPS after
                the date of this Agreement until the annual average quantity (as
                a percentage of sales) of "small" or "undesirable" seed set
                forth on Schedule 2.2C has been sold in such year out of the DPL
                available seed. In the event that MPS fails to sell the annual
                average quantity of "small" or "undesirable" seed (as a
                percentage of sales) set forth on Schedule 2.2C in each of 1996
                and 1997, MPS will purchase any shortfall (the difference
                between the quantity of "small" or "undesirable" seed actually
                sold, as a percentage of sales, and the annual average quantity,
                as a percentage of sales, set forth on Schedule 2.2C) out of DPL
                available seed on or before August 15 of each of 1996 and 1997.

          (iv)     All sales of the DPL available corn and sorghum seed will
                be made for the account of MPS. Immediately prior to shipping
                seed to fill each customer order, the amount of seed required to
                fill such order automatically will be deemed to be assigned,
                conveyed and transferred to MPS at a transfer price equal to
                DPL's cost of such seed, less reserve for returns of 40% for
                sorghum and 35% for corn, for

                                 EXHIBIT 99.1

 
                delivery on behalf of MPS to such customer. MPS and DPL hereby
                agree that for all purposes under this Section 2.2, DPL's costs
                of its available corn and sorghum seed for 1995, 1996 and 1997
                is set forth on Schedule 2.2D. Within five business days after
                each calendar quarter ending March and June of 1995, 1996 and
                1997 and on August 15 of each of 1995, 1996 and 1997, MPS will
                pay DPL for all DPL available seed shipped to customers during
                such calendar quarter and during the period of July 1 to August
                15 of each such year.

           (v)     With respect to all sales of the DPL available corn and
                sorghum seed, DPL will receive (1) 85% of total gross margins on
                all sales in 1995, (2) 50% of total gross margins on all sales
                in 1996, and (3) 30% of total gross margins on all sales in
                1997. MPS will retain the balance of such gross margins. The
                costs (calculated on a basis consistent with prior periods) and
                the projected domestic selling prices of DPL sorghum and corn
                seed are set forth on Schedule 2.2D. Gross margin will be
                calculated based on total sales less cost of goods sold (as set
                forth on Schedule 2.2D), third-party commissions, discounts and
                rebates actually allowed. Payment of gross margin to reflect the
                sharing arrangement described above, together with an adjusting
                payment to reflect any difference between actual returns and
                reserve for returns, will be made between DPL and MPS on August
                15 of each of 1995, 1996 and 1997. All customer returns of seed
                from DPL's existing corn and sorghum inventory will be returned
                to, and owned entirely by, DPL.

          (vi)     At the end of 1997, DPL will be responsible for the
                disposal of any remaining DPL available corn and sorghum seed
                not sold by MPS in accordance with this Section 2.2 as of
                December 31, 1997. DPL will not sell such remaining seed in the
                United States as planting seed. DPL will market and sell any
                such remaining seed in the international retail or wholesale
                market or as grain (and not as planting seed) in the U.S.
                wholesale market. On or before March 30, 1998, DPL will remove,
                at its cost, all remaining DPL available seed located in MPS
                warehouses as of the end of 1997.

         (vii)     DPL will continue, at DPL's cost, its Special DPL
                Salesman Incentive Program for current employee-salespersons for
                1995 for sales of corn and sorghum. The cost of DPL's incentive
                program for 1995 will not be included in the calculation of
                gross margin in connection with the sharing of gross margins
                between DPL and MPS as set forth above.

        (viii)     Any new production of corn and sorghum or new corn and
                sorghum hybrids (i.e., any sale of corn or sorghum other than
                out of DPL's existing inventory) will be owned and sold by MPS
                entirely for MPS's account. Sales by MPS of any new production
                of corn and sorghum will be made by hybrid on a FIFO basis
                consistent with Section 2.2(a)(i) so as to market and sell the
                DPL available seed (on a hybrid-by-hybrid basis) that satisfies
                the quality standards set forth on Schedule 2.2A prior to the
                sale of any newly produced seed.

          (ix)     The DPL available corn and sorghum seed will be marketed
                and sold in DPL bags for the 1995 season. MPS will have the
                right, but not the obligation, to continue selling such
                inventory in DPL bags through 1997; provided, that if such
                inventory is sold in DPL bags after 1995, MPS hereby indemnifies
                and holds DPL harmless from and against any and all liabilities,
                costs and expenses related to any customer claims made against
                DPL with respect to such seed sold in DPL bags. In connection
                with MPS's right to sell DPL available corn and sorghum seed in
                1996 and 1997 in DPL bags, DPL grants MPS a license,
                specifically limited to such sales, to use DPL's trademarks that
                are on DPL's sorghum and corn seed bags. DPL will have the right
                to inspect any DPL available seed bagged in DPL bags to insure
                that the seed in such bags satisfies the quality standards set
                forth on Schedule 2.2A and that the appearance of the filled
                bags are suitable for customer delivery and are not

                                 EXHIBIT 99.1

 
                tattered or torn. DPL reserves the right to revoke the rights
                granted to MPS under this Section 2.2(a)(ix) if seed sold in
                such bags does not satisfy the quality standards set forth on
                Schedule 2.2A or if filled bags for customer delivery are
                tattered and torn so as not to be suitable for delivery. Upon
                reasonable advance notice from MPS, DPL will supply MPS on a
                timely basis with DPL bags for the purpose of selling DPL's
                existing corn and sorghum inventory in accordance with this
                Section 2.2(a)(ix). MPS will purchase such bags at prices equal
                to DPL's cost to produce the bags.

           (x)     MPS agrees that it will not market and sell the DPL
                available corn and sorghum seed at prices greater than DPL's
                suggested retail selling price by hybrid as set forth on
                Schedule 2.2D plus a year-to-year annual five percent increase
                thereon in each of 1996 and 1997.

     (b)     DPL and MPS agree that casualty and risk of loss of the DPL
           available corn and sorghum seed (including any and all customer
           returns) will remain with DPL until such time as seed is shipped to
           customer or unless such casualty or loss is caused by the negligence
           of MPS.

2.3   DPL NON-COMPETE IN CORN AND SORGHUM UNTIL THE YEAR 2000. From the date
     of this Agreement until January 1, 2000, DPL will not engage in the
     development, marketing or sale of corn or sorghum hybrids in the regions of
     the United States where DPL currently markets and sells corn and sorghum;
     provided, however, that this Section 2.3 automatically will terminate
     earlier than January 1, 2000 in the event (and effective upon the
     occurrence) that prior to such time a seed company engaged in the business
     of producing and selling corn and sorghum acquires a majority of the
     outstanding shares of capital stock of DPL or substantially all of the
     assets of DPL.

                                  ARTICLE III

                       ISSUANCE OF MYCOGEN STOCK TO DPL

3.1   ISSUANCE OF MYCOGEN STOCK. On the date of this Agreement, Mycogen will
     issue 153,846 shares of Mycogen common stock as part of the consideration
     for the transactions under this Agreement.

3.2   REGISTRATION OF MYCOGEN SHARES. As promptly as practicable, and within
     30 days of the date of this Agreement, Mycogen will file a registration
     statement on Form S-3 with the Securities and Exchange Commission to permit
     DPL to sell the Mycogen shares delivered under this Agreement under such
     registration statement. Mycogen will maintain such registration statement
     in full force and effect until the earlier to occur of (i) the sales of all
     such shares by DPL (whether by repurchase of such shares by Mycogen under
     Section 3.5 below or otherwise) or (ii) three years after the date of this
     Agreement so as to enable DPL to sell the Mycogen shares in the public
     market from the date of this Agreement until three years after the date of
     this Agreement.

3.3   REGISTRATION EXPENSES. Mycogen will pay all out-of-pocket expenses
     related to the registration of the shares of Mycogen common stock delivered
     to DPL under this Agreement, including, without limitation, NASD
     registration and filing fees, all fees and expenses incurred in complying
     with securities or blue sky laws, all printing, messenger and delivery
     expenses, the fees and disbursements of counsel to Mycogen and of its
     independent public accountants, and all registration, filing and
     qualification fees of the Securities and Exchange Commission and state
     securities or blue sky commissions.

3.4   INDEMNIFICATION BY MYCOGEN. Mycogen will indemnify, to the fullest
     extent permitted by law, DPL and its officers, directors and employees and
     each person who controls DPL (within the


                                 EXHIBIT 99.1

 
     meaning of the Securities Act of 1933, as amended, or the Security Exchange
     Act of 1934, as amended) from and against any losses, claims, damages,
     liabilities and expenses (including reasonable attorneys' fees) arising out
     of or based upon any untrue, or alleged untrue, statement of a material
     fact contained, or incorporated by reference, in the Form S-3 registration
     statement referred to above as originally filed and subsequently amended
     covering any sale or distribution by DPL of the shares of Mycogen common
     stock issued to DPL under this Agreement, or arising out of or based upon
     any omission or alleged omission to state a material fact required to be
     stated therein or necessary to make the statements therein not misleading,
     except insofar as the same are caused by, or contained in, any information
     furnished in writing to Mycogen by DPL expressly for use in such
     registration statement.

3.5   MYCOGEN PURCHASE OPTION. DPL hereby grants to Mycogen an option
     exercisable at any time after January 1, 1996 and ending on December 31,
     1997 to purchase from DPL 153,846 shares of Mycogen common stock for a cash
     payment of $1.35 million minus the amount, if any, of bad debts incurred by
     MPS from sales out of DPL inventory in 1995 pursuant to Section 2.2(a)(ii).

                                  ARTICLE IV

                                 MISCELLANEOUS

4.1   FORCE MAJEURE. "Force Majeure" will mean any event that is beyond the
     control of the parties, that is unforeseen, unavoidable or insurmountable,
     that arises after the execution of this Agreement and that prevents total
     or partial performance by one or more of the parties. Such events will
     include, without limitation, government regulations, war, strike, act of
     God, or other similar circumstances. If an event of Force Majeure occurs, a
     party's contractual obligations affected by such event will be suspended
     during the period of delay caused by the Force Majeure. A party claiming
     Force Majeure will promptly inform the other party in writing of the
     occurrence and the expected duration of such Force Majeure. The party
     claiming Force Majeure will use reasonable efforts to terminate the Force
     Majeure. In the event of Force Majeure, each party will remain obligated to
     perform all obligations that it is able to perform, the Force Majeure
     notwithstanding. The parties will immediately consult with each other in
     order to find an equitable solution and will use reasonable efforts to
     minimize the consequences of such Force Majeure, including amendments to
     this Agreement that are valid and legal and, to the maximum extent
     possible, carry out the original intent of the parties.

4.2   RESTRICTION ON ASSIGNMENT. Neither Mycogen, MPS nor DPL may assign its
     rights or obligations under this Agreement to any third party without the
     prior written consent of the other party; provided, however, that this
     restriction on assignment will not apply to an assignment to any entity
     that succeeds to the either party's position by merger, consolidation, or
     other corporate reorganization.

4.3   GOVERNING LAW; ENTIRE AGREEMENT. This Agreement will be governed by
     the laws of the State of Delaware, without the application of any choice of
     law statutes or regulations. This Agreement and the attached Schedules
     contain the entire agreement among the parties with respect to the purchase
     and sale of DPL's corn and sorghum business and the exchange of MPS and DPL
     facilities as contemplated hereunder, and supersedes all prior arrangements
     or understandings with respect thereto, whether written or oral. No
     modification or waiver of any provision of this Agreement will be effective
     unless made in writing and signed by all parties to this Agreement. The
     terms and conditions of this Agreement will inure to the benefit of and be
     binding upon the parties and their respective successors and permitted
     assigns.

                                 EXHIBIT 99.1

 
4.4   ADDITIONAL DOCUMENTS. The parties hereby agree to execute and deliver
     any additional instruments or documents, in form and substance mutually
     acceptable to the parties, to effect or evidence the transactions
     contemplated by this Agreement.

4.5   COUNTERPARTS. This Agreement may be executed in two or more
     counterparts, which, taken together, will constitute one and the same
     instrument.

4.6   PUBLIC ANNOUNCEMENT. Except for documents that are required to be
     flied with a government agency under applicable laws and regulations,
     neither party will make any press release, public announcement or public
     confirmation concerning the terms of this Agreement without prior written
     approval of the other party; provided, however, that once public disclosure
     is made in accordance with this Section 4.6, each party can make subsequent
     public disclosures consistent with such prior public disclosure without
     obtaining the prior approval of the other party.

4.7   MYCOGEN GUARANTY. By executing and delivering this Agreement, Mycogen
     guarantees the performance by MPS of all of MPS's obligations to DPL under
     this Agreement.

IN WITNESS WHEREOF, the parties have caused this Agreement to be effective as of
the date first above written.

MYCOGEN CORPORATION                    DELTA AND PINE LAND COMPANY

By:         /s/ J.R. Glynn             By:     /s/  Murray Robinson
   --------------------------------       ----------------------------------
     
Title:  Executive Vice President       Title:        President
      -----------------------------          -------------------------------
     
AGRIGENETICS, INC. d/b/a
Mycogen Plant Sciences

By:         /s/ Carlton J. Eibl
   -------------------------------- 

Title:       Vice President
      -----------------------------


                                 EXHIBIT 99.1

 
                        SCHEDULES TO PURCHASE AGREEMENT

     Schedule 1.1A    MPS Excluded Fixed Assets
     Schedule 1.1B    DPL Excluded Fixed Assets
     Schedule 1.4     Leases, Property Maintenance, Management and Security
                         Contracts (if any)
     Schedule 2.1     DPL Agreements and Germplasm Licenses Related to Corn and
                         Sorghum Business
     Schedule 2.2A    Seed Quality Standards
     Schedule 2.2B    Quantity of DPL Inventory (Detailed)
     Schedule 2.2C    Definition and Annual Sales of Small or Undesirable Seed
                         Sizes
     Schedule 2.2D    Projected Selling Price and Cost of DPL Corn and Sorghum
                         Product Line


                                EXHIBIT 99.1  

 
Purchase Agreement                                             Schedules
- --------------------------------------------------------------------------------


Schedule 1.1A

      MPS Excluded Fixed Assets and Rolling Stock - Attached

Schedule 1.1B
 
      DPL Excluded Fixed Assets and Rolling Stock - Still Pending

      Note:  Both parties have verbally agreed that portable equipment, such as
trucks, computers, etc., will remain with the current owners. Other fixed assets
which will be exchanged as part of this agreement will be determined by Randy
Dismuke of DPL and Larry Price of MPS after the transaction is announced.

                                 EXHIBIT 99.1

 
Purchase Agreement                                                 Schedules
- -----------------------------------------------------------------------------


Schedule 1.4

     MPS leases, Property Maintenance, Management and Security Contracts (if
any):


          None

     DPL Leases, Property Maintenance, Management and Security Contracts (if
any):

          National Guardian Alarm service agreement attached.

                               EXHIBIT 99.1     

 
Purchase Agreement                                                   Schedules
- ------------------------------------------------------------------------------
      

                                 SCHEDULE 2.1
     DPL AGREEMENTS AND GERMPLASM LICENSES RELATED TO CORN AND SORGHUM BUSINESS



ITEM   DESCRIPTION                                EXPIRATION    ASSIGNABLE?
- --------------------------------------------------------------------------------
                                                    
1.     Sorghum Purchase Agreement
       (Buyer: DPL; Seller: Ciba (Funk)
  
2.     Asgrow Conditioning Agreement              6/30/95        Silent
  
3.     Weaver Popcorn Storage Agreement           8/31/95      Yes; see p. 
                                                                 4, #13
  
4.     Carter Processing Storage                  3/23/95
       Agreement
  
5.     Northrup King Storage Agreement            6/1/95         Silent
  
6.     D&PL General Distributor Policy                           Silent
       (list of distributors to be
       provided at closing)
  
7.     Ciba Corn Distributorship             1 Yr. Notice      Only with 
       Agreement                             2 Yr. Sales      consent (p. 22)



                                 EXHIBIT 99.1

 
Purchase Agreement                                                     Schedules
- --------------------------------------------------------------------------------


Schedule 2.2A

     Seed Quality Standards

     Attached are MPS quality standards for corn and sorghum. These standards
will apply to DPL FIFO inventory, except that acceptable warm and cold test
standards for corn will be as follows:

          Warm Test:  92%
          Cold Test:  80%



                                 EXHIBIT 99.1

 
Purchase Agreement                                                Schedules
- --------------------------------------------------------------------------------

                                 SCHEDULE 2.2B
                              D&PL AVAILABLE SEED




                                 EXHIBIT 99.1

 
Purchase Agreement                                                     Schedules
- --------------------------------------------------------------------------------


Schedule 2.2C

     Definition and Annual Sales of Small or Undesirable Seed Sizes

     Definition of Undesirable Seed Sizes:

     Small Flat       F16 or Smaller
     Small Round      R25 or Smaller
     Large Flat       F12 or Larger
     Large Round      R22 or Larger
     Plateless        PP1 or PP2

     Summary showing inventory and 3-year average attached, with
supporting detail.




                                 EXHIBIT 99.1

 
                                 SCHEDULE 2.2C
                          SMALL/UNDESIRABLE SEED SIZE
        The plate sizes below are defined as "small" or "undesirable".



 
                                                         THREE-YEAR AVERAGE
                                                             ANNUAL SALES
                                PLATE SIZE/1/             (as a percentage of 
                                                         average total annual
                                                                sales)/2/
                                                   
   ---------------------------------------------------------------------------
   Small Flat                   B9 or smaller
                                    B190
   -----------------------------------------------
   Small Round                       B3                    (see attached
                                     B30                     material)
                                     B25
   -----------------------------------------------
   Large Flat                   B5 or larger
                                     B8
   -----------------------------------------------
   Large Round                       B0
                                     B54

_____________________________
/1/   The stated plate standard or comparable standard of any other plate
    size manufacturer.
/2/   Based on average annual sales by DPL during 1992, 1993 and 1994 of
    corn seed by hybrid of the referenced small or undesirable size.



                                 EXHIBIT 99.1

 
Purchase Agreement                                                     Schedules
- --------------------------------------------------------------------------------


                                 SCHEDULE 2.2D
                       PROJECTED SELLING PRICE AND COST
                            OF DPL CORN AND SORGHUM
                                 PRODUCT LINE



 
                           PROJECTED NET                                       1995
                             DOMESTIC       1995 COST/1,3/    1996/1997      SUGGESTED
                           SELLING PRICE                      COST/2,3/    RETAIL PRICES 
                                                                             
                                                               
==========================================================================================
Corn                          $49.25          $39.94           $34.24         See the
- -------------------------------------------------------------------------
Grain Sorghum                  33.73           21.99            14.33         attached
- -------------------------------------------------------------------------
Sudan Sorghum                  10.40            7.54             7.10        1995 price
- -------------------------------------------------------------------------
Forage Sorghum                 27.11           21.96            21.79          list.
- -------------------------------------------------------------------------
Sweet G90Corn                  71.30           51.10            48.47

_____________________________
/1/   Includes budgeted inventory cost, reprocessing cost and certain write
    off cost. Only adjustments will include cost of current year conditioning
    and bagging. Actual cost will not vary by more than 5% from stated cost.
/2/   Includes inventory cost and will be adjusted only for the cost of
    additional seed added to inventory from 1995 seed production. No obsolete
    seed or other write off of inventory will impact this cost. Actual cost will
    not vary by more than 5% from stated cost.
/3/   Costs  exclude the cost of warehousing inventory.





                                 EXHIBIT 99.1