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FlashCards por vfsf dsgrgr, atualizado more than 1 year ago
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Criado por vfsf dsgrgr
quase 6 anos atrás
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| Questão | Responda |
| what does shade light control? | temperature light intensity |
| nutrition is found in the... | dry matter |
| how does heat & light intensity affect a plant? | to preserve water, the stomates of the plant shut. which stops the C02 coming into the plant and therefore slows the photosynthetic process. may reach wilting |
| what are the MOST desirable traits in a plant? and why? | - short and thick stems =doesnt get lodging - salt tolerant =incre the area of which it can be planted -large size grain =so it doesn't get affected by machinery, in which it can slip or shatter through from being small -rustproof =resistnece to disease |
| how many traits can you place in a plant for a change? | MAX 2 |
| selective breeding for plants. describe the steps. | 1. select parent plant for desirable traits 2. transfer pollen from male onto the female stigma of another plant for fertilization 3. seed is collected from parent plants & taken to a trial site for further testing 4. more selections & eliminations are made 5. best-performing plants are tested for weight, protein, disease resistance, growth & performance 6. successful plants are replicated and their seeds are collected and passed onto farmers |
| name good traits of parent plants. | shallow roots = access to topsoil nutrients =will be affected by lodging tall stems = advantage to the sun = affect by lodging Dawf = uses less energy for growing, devotes energy to fruit = cannot compete with taller plants for sunlight higher yield = profit, success susceptible to lodging = higher yield |
| complete the equation - phenotype = ....+...... | (heritability) phenotype = genotype + environment |
| why is a bag used when selective breeding plants? | stop cross contamination |
| why are glasshouses be used when growing plants | it is a controlled environment: can control the -temperature - light intensity - moisture |
| how is the 'heritability' equation, *phenotype=genotype+environment* come in handy? useful? | it's useful to know what proportion of the observed yield is due to the genotype and the environment. the more that is due to the genotype, the faster the progress that can be made in improving a characteristic by selection and breeding |
| complete the heritability equation 1.0 = 7.0 + ? | environment = 3.0 |
| complete the heritability equation 1.0 = ? + 0.4 | genotype = 0.4 |
| how is the process of hybrid/crossbred varieties implemented? | OVERALL TAKES 10-15 YEARS 1) collecting and selecting specific varieties that have the desired characteristics 2) inbreed this plant for 8-10 generations (to produce true-breeding inbred lines -- recessive die out) 3) after, then cross breed the selected varieties to combine the favorable characteristics |
| what are some characteristics when it comes to the offspring that has resulted from the "inbreeding and crossbreeding" technique. | offspring display hybrid vigor - superior, uniform performance, higher yield |
| how is inbreeding an important part of the cross-breeding process | you need the plant/animal to be purebred to decrease the chances of an unfavorable(recessive) quality popping up in the next generations inbreed 8-10gen = then crossbreed |
| name the male and female sexual reproduction organs of a maize plant | male = tassle (pollen) female = silk (stigma) (hollow tube) |
| TRUE OR FALSE corn kernels are white when they aren't fertilised and yellow when they are fertilised | TRUE |
| define hybrid vigour | is the improved activity and survival of hybrid offspring |
| define a single-cross hybrid? | the crossing of 2 inbreds |
| what happens when a single-cross hybrid is allowed to open-pollinated, in relation to corn | aproximately half of the hybrid vigor is lost |
| what is genetic engineering? | when the genes are manipulated to create a new plant/animal with a whole new genetic makeup that would not have occurred naturally |
| what is the process(es) of genetic engineering? | -inserting genes from 1 species to another - removing a gene from a DNA sequence - removing a gene, reversing it and reinserting it into a DNA sequence |
| give an example of a process called 'revering sequence' | 1 ) A B C D = 2) A C B D |
| what is meant by the term " inbreeding then crossbreeding"? | is to produce parent lines that breed true and then cross-breeding, 2 inbred lines to produce hybrid vigor |
| give examples that farmers use the 'inbreeding and crossbreeding' technique on? | wheat, oats, sorghum, maize |
| define cross breeding? give examples of crops that have been experimented upon? | --the crossing of 2 varieties of plants -wheat,corn,grapes,roses,fruit trees |
| what are the objectives of plant breeding? | 1. Higher yield 2. Disease resistance 3. Flood resistance 4. Early to mature 5. Adaptability to a wide range of habitats 6. Resistance to alkaline and saline soil conditions -dormancy 7. Better quality 8. Drought resistance 9. Response to manuring 10. Insect and pest resistance |
| what is the advantages of maturity duration | -higher yield for a shorter time - shorter period = fewer materials used |
| define and explain the importance of soil pH | ==measure of acidity or basicity from a scale of 1-13 ==affects the reaction rates of microbial activity |
| under ACIDIC conditions what elements aren't available? | N, P, K, S, Ca, Mg, Mo are unavailible uner acidic conditions |
| under alkaline conditions what elements can become more SOLUBLE? | Fe, Bo, Mg, Cu, Zn become more SOLUBLE under alkaline conditions |
| define the term CEC (cation exchange capacity) | =measure the number of cation equivalent that an exchange between the soil and solution =indication of soil fertility (the ^ more fertile) |
| what is the importance of CEC? | =defines soil structure =fertile == high CECs (soils have the ability to attract ions to its surface =infertile ==low CECs (soils that do not allow nutrient ions to form) |
| Define the term soil carbon? ( organic matter) | the mixture of decayed and undecayed plant and animal matter which is broken down by microbes to release nutrients and energy |
| what is the importance of soil carbon | -decomposed OM releases nutrients back into the soil - OM particles are large in SA, which increases H20 and nutrients holding capacity -improves structure by binding soil particles together |
| name the major macronutrients | K, N, O, C, S, H, P, Ca, Mg |
| name the minor micronutrients | Fe, Zn, Cu, Mo, Cl, B, Co |
| define soil CO2 levels | measure the level of CO2 in the soil by a color changing test |
| what is the importance of soil CO2 levels | -an indication of microbial activity in the soil -increase microorganism the more fertile the soil, the faster the recycling of organic matter |
| define soil structure | the way in which solid particles and spaces(pores) are arranged within a soil |
| what is the importance of soil structure? | -it affects the root penetration (moisture, air, stability) -affects soil arratuib |
| dry sand = no structure wet sand = structure for a period of time mud = structure for a period of time |
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