(a) Define the terms budding and grafting (b) List four materials required for budding (c) Give two reasons why the improvement of crops by selection may not produce the desired results (d) State four disadvantages of asexual reproduction and four advantages of sexual reproduction in crop plants.
Explanation
(a)(i) Budding: Budding is the act of uniting a bud from one plant with the stock of another plant of the same or different specie. (ii) Grafting is the act of joining a scion .stem of one plant to the stock of another plant from the same genus.
(b) Materials for carrying out budding: (i) budding knives (ii) polythene sheets (iii) wax (iv) bud material (v) stock material (vi) secateur/ saw.
(c)Reasons why selection may not produce desired results: (i) since pollination of crops is random and uncontrolled, the offspring of selected crops may carry different genotypes (ii) the crop phenotype may not be a true reflection of the genotype (iii) environment influence may impede the performance of selected crops.
(d)(i) Disadvantage of asexual reproduction: (i) vegetation materials, are costly especially tree crops (ii) process involved in the preparation of the vegetative material may be time consuming. (iii) Requires special skill/expertise; (iv) Planting materials may transmit disease pathogens (v) Planting materials cannot be stored for a long period of time without losing their viability. (vi) Vegetative materials are generally bulky making their transportation and handling, difficult (vii) There is no hybridization or variability in them leading to all plants suffering to the same extent when adverse conditions are encountered.
(ii) Advantages of sexual production: (i) It is cheaper or less costly (ii) Seeds can be stored for a longer period of adverse conditions are encountered. time without losing their viability when compared with vegetative materials (iii) Seeds are light in weight making handling and transportation easier (iv) It is the surest means of crop improvement through breeding. (v) Easier to establish (or sow)