hey guys plz help with all the questions
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Answers
Answer (1) : Sometimes old and traditional varieties of crops do not give desired results to the farmers. Using new genetically modified crops helps to obtain better yields and overcome restrained environmental conditions. Hence it comes to the rescue of farmers.
Answer (2) : Crop variety improvement is done for the following factors :-
- Higher yield - The main aim of crop improvement is to improve the productivity of economic produce, e.g., grain, vegetables and fodder. Quality seeds of improved varieties are used for their commercial production.
- Improved quality - Quality consuderations of crop products varies from crop to crop, e.g., baking quality im wheat, protein quality in pulses, oil quality in oil seeds and preserving quality of fruits and vegetables.
- Biotic and abiotic resistance - Under different situations crop suffer due to biotic stresses (such as diseases, insects and nematodes) and abiotic stresses (such as drought, salinity, water logging, heat, cold and frost) If we develop crop varieties which are resistant to these stresses, then we can improve significantly the crop production.
Answer (3) : Desirable characteristics can be incorporated by two methods :
- Hybridisation - This is a genetical technique. The crossing between genetically dissimilar plants to produce a new kind (hybrid) is called hybridisation. Crossing may be between two different varieties (intervarietal cross-breeding), between two different species of the same genus (interspecific cross-breeding) and between different genera (intergeneric cross-breeding). This method incorporates the desired characteristics of both parents in one variery.
- Genetic manipulation - This is the another way of improving the crop is by introducing a gene that would provide the desired characteristic. This results in genetically modified crops.
Answer (4) : Intercropping is a practice of growing two or more crops simultaneously in a same field in definite row patterns with the objective of increasing productivity per unit area.
Crops are selected for intercropping on the basis of different nutrient requirement and different sowing and reaping (harvesting) times, e.g., soyabean and maize.
Answer (5) : There are three different sources from where a plant gets the 16 essential nutrients. These sources are air, water and soil.
- Air supplies carbon and oxygen to plants.
- Hydrogen comes from water.
- Soil supplies the other thirteen nutrients to plants.
6. Give reasons -
Answer (1) : Farmers using good quality seeds, adopting irrigation, using fertilizers, and using crop protection measures will derive most benefits because all these conditions are required for good crop production.
- The use of good quality seeds increases the total crop production. If a farmer is using good quality seeds, then a majority of the seeds will germinate properly, and will grow into a healthy plant.
- Proper irrigation methods improve the water availability to crops.
- Fertilizers ensure healthy growth and development in plants by providing the essential nutrients such as nitrogen, phosphorus, potassium, etc.
- Crop protection measures include various methods to control weeds, pests, and infectious agents. If all these necessary measures are taken by a farmer, then the overall production of crops will increase.
Answer (2) : Preventive measures and biological control methods should be preferred for protecting crops because excessive use of chemicals leads to environmental problems. These chemicals are also poisonous for plants and animals. Preventive measures include proper soil and seed preparation, timely sowing of seeds, intercropping and mixed cropping, usage of resistant varieties of crops, etc. On the other hand, biological control methods include the usage of bio-pesticides that are less toxic for the environment. An example of bio-pesticides is Bacillus thuringenesis,which is an insect pathogen that kills a wide range of insect larvae. Therefore, both preventive measures and biological control methods are considered eco- friendly methods of crop protection.