R3104 UNDERSTANDING APPLIED PLANT PROPAGATION

Transcription

1 Including Examiner Comments R3104 UNDERSTANDING APPLIED PLANT PROPAGATION Level 3 Wednesday 10 February :45 16:35 Written Examination Candidate Number:. Candidate Name:. Centre Number/Name: IMPORTANT Please read carefully before commencing: i) The duration of this paper is 50 minutes; ii) iii) iv) ALL questions should be attempted; EACH question carries 10 marks; Write your answers legibly in the spaces provided. It is NOT necessary that all lined space is used in answering the questions; v) Use METRIC measurements only; vi) vii) viii) ix) Use black or blue ink only. Pencil may be used for drawing purposes only; Where plant names are required, they should include genus, species and where appropriate, cultivar; Where a question requires a specific number of answers; only the first answers given that meet the question requirement will be accepted, regardless of the number of answers offered; Please note, when the word distinct is used within a question, it means that the items have different characteristics or features. Ofqual Unit Code J/505/8534 Please turn over/..

2 ANSWER ALL QUESTIONS MARKS Q1 a) Explain the functions of the following in seed germination: i) endosperm; ii) hypocotyl. b) Describe a standard method for determining percentage germination. Please see over/..

3 c) Complete the following table by stating: i) TWO Reasons why viable seed of Fraxinus excelsior fails to germinate even in ideal conditions; ii) the appropriate treatment for EACH to encourage germination. i) Reason for non-germination ii) Appropriate treatment 1 Total Mark 3 Please turn over/..

4 Q Describe the production of a crop of Roses using a method of budding, under EACH of the following headings: i) NAMED root stock; ii) scion preparation; iii) the budding procedure Please see over/.. 4

5 ... Total Mark. Please turn over/.. 5

6 Q3 Describe the purpose of the following seed treatments giving a NAMED seed example for EACH: i) priming; ii) fluid sowing; iii) pesticide treatment; iv) pelleting Please see over/..

7 ... Total Mark 7 Please turn over/..

8 Q4 Describe the commercial production of a NAMED shrub under EACH of the following headings: i) preparation of cuttings; ii) propagation medium; iii) propagation environment; iv) weaning; v) potting. 8 Please see over/..

9 ... ******* Total Mark 9

10 R3104 UNDERSTANDING APPLIED PLANT PROPAGATION Level 3 Wednesday 10 February 016 Candidates Registered 45 Total Candidates Passed 6 7.% Candidates Entered 36 80% Passed with Commendation % Candidates Absent/Withdrawn % Passed % Candidates Deferred 4.44% Failed % Senior Examiner s Comments On the whole this paper was well answered with the majority of candidates attempting and completing all the questions. The following guidelines should be of help to future candidates. 1. Where named plant examples are asked for, full botanical names (genus and species) are required to achieve full marks. Common names will not be given a mark.. Use the command statements e.g. list or name (single words only), state (a few sentences), describe or explain (a fuller answer) together with the mark allocation, to judge the depth of the answer. Half marks are often allocated where the basic information given is correct but needs further qualification to gain the full mark. 3. Where a number of answers are specified in the question, the examiner will not select correct answers from a list e.g. if the question states State TWO plant names, only the first two names given will be marked. 4. Labels on diagrams should be correctly positioned to avoid ambiguity and diagrams should be clearly drawn and annotated. No marks will be awarded for artistic merit. 5. Candidates should use unambiguous plant examples as reference sources from, for example, the RHS Find a Plant Service available on the RHS Website. 10

11 Q1 a) Explain the functions of the following in seed germination: i) endosperm; ii) hypocotyl. MARKS b) c) Describe a standard method for determining percentage germination. Complete the following table by stating: i) TWO reasons why viable seed of Fraxinus excelsior fails to germinate even in ideal conditions; ii) the appropriate treatment for EACH to encourage germination. ii) Reason for nongermination ii) Appropriate treatment 1 11

12 a) The Examiners were looking for explanations of the functions of the endosperm and hypocotyl, so it was not necessary for candidates to include details of anatomy or the characteristics of the tissues. Essentially the endosperm is a store of food which maintains the embryo before germination and then sustains it during the germination processes before the seedling starts to photosynthesise. This was generally well stated, but some candidates overlooked these points and many were unclear about the role of the hypocotyl, showing confusion between hypocotyl and epicotyl and also hypogeal and epigeal germination. The role of the hypocotyl in epigeal germination is to expand and push the cotyledons above the surface of the growing medium into the light. In hypogeal germination expansion of the hypocotyl pushes the radicle further into the soil. The hypocotyl also has a role in conducting products of the cotyledon food store to the growing radicle. b) Candidates who stated that the application of optimal germination conditions to a set number of seeds over an appropriate time period will give a result of germinated seeds which can be expressed as a percentage, would have received maximum marks. Number of seeds germinated x 100 = n% Number of seeds in sample c) The failure of Fraxinus excelsior to germinate can be due to an immature embryo which requires time and warmth to develop. This was mentioned by most candidates as warm stratification ; the temperature and duration of the treatment also gained the mark. Similarly the presence of inhibitors in the seed can be dealt with by cold stratification, which follows the warm treatment. Again the appropriate temperature and duration of the treatment gained a mark. Scarification is not usually required. 1

13 Q Describe the production of a crop of roses using a method of budding, under EACH of the following headings: i) NAMED root stock; ii) scion preparation; iii) the budding procedure i) The appropriate rose stock was named for the mark. Rosa canina was cited for bush rose production, alternatively Rosa rugosa was recommended for standard rose production. ii) The collection of the bud-stick, prior to the budding procedure, is vital to the operation. Candidates who mentioned points such as the time of year when taken, the condition of the material and trueness to type, the length, and state of maturity, gained the marks. The bundling of the scions, labelling and keeping them hydrated are equally important. The foliage removal leaving a short piece of petiole to assist with handling and de-thorning the bud-sticks were points noted in many answers. The preparation of the bud, be it for T Budding or Chip-Budding was well covered but too often the actual dimensions of the bud were inordinately large or in some very small. The removal of the bud or chip from the bud-stick was explained, in some instances using labelled diagrams. If the wood is to be removed from a T bud, this must be carefully done so as not to damage the bud. iii) In T budding the cuts on the stock plants are more usually done at or slightly below ground level, the base having been exposed and grafting point cleaned for the purpose. With chip budding the stocks are worked on at a higher point, but still require cleaning to remove dirt and algae. T-budding, on a large scale, is carried out in the field and the time of year is critical to the success. Most candidates specified the time as when the sap is freely moving in the stock, i.e. mid-summer or later. Some candidate s answers did not specify the size of the cuts. The actual fitting of the bud into the stock with the emphasis on cambium contact was stressed by candidates. The whole graft was then taped by some form of tie. Each technique has points specific to its success, in T-budding the bud is not covered, but the whole chip is covered in chipbudding. Further aftercare was not required in the answer. 13

14 Q3 Describe the purpose of the following seed treatments giving a NAMED seed example for EACH: i) priming; ii) fluid sowing; iii) pesticide treatment; iv) pelleting. 3 3 i) The main purpose of seed-priming is to enhance the germination time and increase percentage germination. This can be achieved by removing inhibitors in the seed and by softening the testa. This speeds up imbibition and thus enables more even germination. Many candidates referred to primed seeds being saved for a later sowing. Many examples were named, including Allium porrum and Lathyrus odoratus. ii) Fluid sowing of seeds can enhance the germination potential in soils that do not provide optimum conditions for germination. Sowing seeds in a fluid can give an even distribution as well as providing moisture to the seeds. These points were explained in full by most candidates. The most quoted example was Pastinaca sativa, where germination can be slow and erratic, especially in cold soils. iii) The most quoted seed example was Zea mays and the need for some protection of the seed was noted. However only a few answers actually named potential pests or diseases for the seed examples quoted. iv) The purpose of pelleting of seed was explained in great detail by most candidates. Its use with small seeds, such as that of Begonia semperflorens, allows for easier handling, due to increased size, and sowing, as the seed is more visible. Such treatment also facilitates mechanical sowing, a point noted by many candidates. The actual pelleting material can also contain other beneficial additives, such as fertiliser or pesticide, to assist in successful germination. 14

15 Q4 Describe the commercial production of a NAMED shrub under EACH of the following headings: i) preparation of cuttings; ii) propagation medium; iii) propagation environment; iv) weaning; v) potting. This question asked for details of commercial production of a named shrub; where a candidate named an inappropriate shrub i.e. one that was not propagated commercially by the method explained, the candidate would still gain marks if the method was correctly described for hardwood or softwood or semi-ripe cuttings. i) The preparation of the cuttings was understood and explained by most candidates. The actual type of cutting was not always stated and this affected the timing of the operation and the environment. The need for propagules to be hydrated and protected until insertion was stated. The size of the cutting was not apparent in many answers, but the need to reduce foliage and make nodal cuts for the soft and semi-ripe cuttings were covered by candidates as was maintaining the polarity of hardwood cuttings. The use of hormones to aid rooting was often mentioned. ii) iii) iv) The choice of medium was governed by the type of cutting being used and the requirements of moisture retention and drainage/air content were described fully by candidates. Where propagation by hardwood cuttings was described on an open or protected outdoors site, candidates included the use of grit in and on the bed to improve drainage. The choice of propagation environment was dependant on the type of propagation and this was appreciated by most of the candidates. The mist unit was the popular choice with the control of temperature and atmospheric moisture, particularly bottom heat for callusing and cool tops to reduce transpiration. Avoiding severe fluctuations of temperature and the sheltering of outdoors facilities were noted. In the main the choice of environment was suitable for the type of propagation mentioned. The importance of weaning, particularly from mist propagation, was not always appreciated. The gradual reduction of moisture and temperature is central to the whole process. Weaning is not just the hardening-off stated by many. Marks were also gained where the reduction of misting once cuttings had rooted was mentioned. v) The potting on of the rooted cuttings was stated well, and usually an appropriate compost to sustain growth was named. The size of container was not always stated. Since this is for a commercial operation usually a larger size is used to avoid an extra operation. Candidates who mentioned the inclusion of fertiliser, such as controlled release fertiliser, in the potting medium were credited. It was noted that some candidates stated that hardwood cuttings were to be lined out in the growing area. 15

16 These questions are the property of the Royal Horticultural Society. They must not be reproduced or sold. The Royal Horticultural Society, Wisley, Woking, Surrey GU3 6QB. Charity Registration Number: 879/SC