Step-by-Step Stevia Trial Manual

Transcription

1 Step-by-Step Stevia Trial Manual Contents Trial Brief... 1 Quick Overview... 2 Step 1: Propagating Candy Seeds (Day 1-14)... 3 Step 2: Curing/Hardening Off (Day 14-21)... 4 Step 3: Open Field (Day 21-90)... 4 Step 4: Harvest 1 & 2 (Day 90-91)... 4 Step 5: Analysis (Day 92)... 5 Water Requirements... 5 Fungi and Plagues... 5 Materials Overview... 5 Contacts... 5 Evaluation Form Trial Brief Objective: To test and validate the adaptation and performance of selected stevia varieties (4) in open field conditions in the North West region of Ghana. Methodology: Test are carried out in line with this protocol which is a result of recommendations from agronomist and plant material suppliers. To get a representative result we start by testing plants per variety. Time Frame: Initially test during 1 growth cycles which totals aprox. 90 days. An evaluation and site visit to will take place towards the end of the cycle. Outcome: Shortlist the best performing stevia varieties. The weighing of the best performing varieties is based on a variety of factors, including the adaptation of the plant in the region, biomass/dry leaf yield and most importantly TSG content. Based on the outcome decisions can be made in terms of the viability of commercial scale cultivation and/or whether further breeding programs are required. Management: Mr Henry Lommerse for agronomical queries. Mr Sadat acts as a regional executive and is responsible for execution of the trials. Mr Ike Mbamali oversees all Ghana operations and Mr Rogier Want maintains over responsibility. Reporting: Briefs will be held daily. Findings should be noted and reported and pictures should be taken and submitted daily (mon-fri).

2 Quick Overview The trial is made up of 5 phases. Step 1 is the propagation phase (Candy Only). Step 2 is the curing/hardening off phase and step 3 is the open field phase. Thereafter harvesting (step 4) takes place (2 times) after which the plant material is dried and shipped for analyses (step 5). The varieties we will test are Candy (seeds) and cuttings LB755615, LB and LB Step 1: Propagating Candy Seeds (Day 1-14) The plug trays (ph ) must filled with soil and dampened to almost the soil s limit of humidity for the reception of seeds. Apply light pressure using the palm of your hands to attach the seeds to the surface but do not cover them with sand. Stevia is a photoblastic species and needs sunlight for germination. Step 2: Curing/Hardening Off (Day 14-21) Both the cuttings and seedlings need to be hardened off. This is the process of moving seedlings outdoors for a portion of the day to gradually introduce them to direct sunlight and dry air. Step 3: Open Field (Day 21-90) When the plants are between 10-15cm high, with a minimum of 20 leaves and strong branches. When this is the case they are ready to be transplanted into the open field. 2 Step 4: Harvest 1 & 2 (Day 90-91) Initiate the harvest of stevia leaves when bud induction and development commences and when about 5% of the stevia flowers are open as at this time the leaves have their highest concentration of stevioside. Sun dry the leaves for up to 12 hours. Step 5: Analysis (Day 91-92) Unbiasedly select 2 batches of 40 grams of dried leaves per variety. Make sure to weigh this accurately and avoid any cross-contamination. Pack in re-sealable plastic bags and make sure to label each variety clearly. Ship for analysis.

3 Step 1: Propagating Candy Seeds (Day 1-14) The first step is to propagate the Candy seeds. This step will show us the germination rate and vigour of the seed lot. It will also provide us with the seedlings for transplant to the open field. Checklist: Candy Seeds, Plug Trays (100) - Soil/Coco Peat/Vermiculite Phosphorus Sieve - Watering Can - Labels & Pen. Ø Fill 90% of the plug trays (100) with sowing ground. The texture of the seedbed must be sandy, mixed with organic material and phosphorus. A fine sphagnum moss or coco peat (30 %) could be used. The soil must have a good aeration. Thereafter dampen the soil to almost the soil s limit of humidity for the reception of seeds. The temperature should preferable range between C. Ø Place 1 seed in each plug tray. Now fill to above the rim with a sieve; light and thin layer of vermiculite or equivalent. Do not cover them with sand! Stevia is a photoblastic species and needs sunlight for germination and will not germinate if covered with sand. This gives a micro-climate, oxygen, moisture and a degree of light to the germination process. Apply slight pressure on the surface to attach the seeds to the seedbed. Water carefully/with mystifying spraying top. Note sowing date! Ø Keep the plug trays in protected area against wind and dissection (shaded etc) until the plants are 1-2 cm high. Ø From day 1-14 check for germination speed, uniformity, quality and vigor. This should be documented with pictures daily for the duration of this process. Ø Also check for normal and abnormal seedlings. Tally up after day 7 and after 14 days. We may for example have a seed lot/batch with 70% germination but only end up with 40% normal seedlings and, therefore, poor stand establishment. This is likely to be the reality with stevia, thus it becomes more and more important to do proper evaluation of seed lots. From this we can determine whether the stevia seedlings are showing proper morphology. Depending on the results we may have to do a proper adjustment aimed at good seedlings and proper stand establishment. It is a key issue relating to production cost and productivity. 3

4 Step 2: Curing/Hardening Off (Day 14-21) Both the cuttings and seedling need to be hardened off. This is the process of moving seedlings outdoors for a portion of the day to gradually introduce them to direct sunlight and dry air. Below are step-by-step instructions on how this should be done. Checklist: Propagated Candy Seeds, cuttings , and , shade room, watering can. Ø Harden off gradually so that seedlings become accustomed to strong sunlight, cool nights and less-frequent watering over a 7-14 day period. Ø Start with 2-3 hours of sun in a sheltered location (shade room). Ø Protect seedlings from strong sun, wind, hard rain and cool temperatures. Ø Increase exposure to sunlight a few additional hours at a time and gradually reduce frequency of watering, but do not allow seedlings to wilt. Avoid fertilizing under bright sun circumstances. Ø The young plants are ready to be transplanted into the open field after 1-2 weeks when they are between 10-15cm high, with a minimum of 20 leaves and strong branches. Step 3: Open Field (Day 21-90) Checklist: Hardened Candy Seeds, Hardened cuttings LB755615, LB and LB755015, prepped land, spade, watering can. 4 Ø Once in the field only water the roots. Monitor and document plant development using the evaluation form as a guide. Step 4: Harvest 1 & 2 (Day 90-91) Checklist: Cutter, Drying Nets, Watering Can. Ø Initiate the harvest of stevia leaves when bud induction and development commences. When about 5% of the stevia flowers are open the leaves have their highest concentration of steviosides. Cut the plants above the land to preserve the roots and start collecting the leaves. Harvest the leaves by stripping the stem. Ø Sun dry the leaves for up to 12 hours. Best is to place the leaves on a screen or net. Drying times longer than that will lower the stevioside content of the final product so please monitor the process every few hours. Once it is dry, store the leaves in a cool and dry place. Ø Post-harvest water the land daily for 2 weeks. Thereafter repeat this twice a week. Ø For the second harvest we will use the same batch and await regrowth of the plant. Initiate the second collection days after the first harvest. Therefore repeat step 4-5.

5 Step 5: Analysis (Day 92) Checklist: Weigher, resealable plastic bags, pen. Please avoid any cross-contamination between varieties and ensure correct labelling. Ø Unbiasedly select 2 batches of 40 grams of dry plant material per variety (total 8). Make sure to weigh this accurately and avoid any cross-contamination. Ø Pack in re-sealable plastic bags and make sure to label each variety clearly. Ø Post FAO of Annelies Schulte to ExPlant, J.H. Oortweg 21, 2333 CH Leiden, The Netherlands. Water Requirements Water stevia daily with small amounts of water. Any kind of watering system can be used. Water the soil daily the first 2 weeks after transplant date. Make sure the water is distributed efficiently. Fungi and Plagues Stevia is prone to fungi. The damage is almost always minimum, therefore, it is not necessary the use chemical agents. In exceptional cases, when the damage is significant, benomil metiltiofenate is used. Report immediately to Henry Lommerse ) if this becomes an issue. Notes a. The website provides background information on the cultivation of stevia. In addition, a separate section trail Ghana/Stevia in which additional information such as videos photos et cetera is available. b. Test are carried out in multiple locations. Information can and will be exchanged mutually. c. See also the evaluation forms which must be accurately maintained. d. Background info e. Have a look at this test/protocol which has been published in a science magazine. Materials Overview ü Seeds & Cuttings (Candy Seeds and Cuttings LB755615, LB and LB755015) ü Plug Trays or Seedbox (100) ü Pots (plastic bags or pots) ü Potting Soil/Vermiculite (10 1 ltr Bags) ü Sieve (1) ü Fertilizer (Phosphorus) ü Watering Can (1) ü Prepped land/digging Tools (45 m2) ü Shaded Area (45 m2) ü Labels and Pens ü Phone to take pictures with and with 5 Contacts Anwar Sadat X / / anwar.sadat@exelenti.com Ike Mbamali ike.mbamali@exelenti.com Henry Lommerse info@lommersebreeding.nl Rogier Want rogier.want@exelenti.com

6 Evaluation Form STEVIA REBAUDIANA Supplier Genesis Seeds Lommerse Lommerse Lommerse Variety Cadndy LB LB LB Date (week) Germination (up to day 7) 6 Date (week) Germination (up to day 14) Date (week) Transplanting Date (week) Planting field Comments process from seed to field (attachment)

7 Plant: Vegetative Growth Habit Leaf: Intensity of Green Colour Width/Plant Diameter High Taste Flowering / First week of Flowering Cut Regeneration Time 7 Comments on Growth Process Test Result 1st Sample Test Result 2nd Sample