The triploid seeds are larger, and both types of seeds are planted in the same vicinity. When you buy seedless watermelon seeds, you get two kinds of seeds, one for the fertile diploid plant and one for the sterile triploid. With three sets of chromosomes, one set will not have a matching set to pair up with during meiosis.When flowers of this sterile triploid plant (called the seedless watermelon plant) are pollinated by a normal plant, seedless fruits develop. Triploids have three sets of chromosomes per cell (tri- means three). This triploid seed will germinate and grow into a triploid plant bearing triploid male and female flowers, but the flowers will not produce viable sperm-bearing pollen or eggs because of the odd number of chromosome sets (3). Since cells from each plant contribute half their chromosomes in the reproduction process, the result was a triploid plant. This watermelon, called a tetraploid, had four sets of chromosomes per cell (tetra- means four).įor Kihara, the next step was to cross-breed a tetraploid with a normal diploid as the pollinator. Since the purpose of seeds is reproduction, Kihara had to develop a watermelon that could not reproduce. The normal watermelon is called a diploid because it has two sets of chromosomes per cell (di- means two). By treating normal watermelon seedlings with Eigsti’s discovery, colchicine, Kihara produced watermelons with twice as many chromosomes in each cell. The seedless watermelon is a hybrid, a cross between two different kinds of watermelon. A Japanese scientist named Kihara used Eigsti’s chromosome-doubling process to produce the first seedless watermelon. Eigsti was a botanist and plant geneticist from Goshen, Indiana who discovered that colchicine, a chemical derived from crocus plants, could cause a plant to double its chromosomes. When fertilization takes place a single cell is formed with a complete set of 22 chromosomes. In the case of a watermelon, the male sperm cell and the female ovule each have 11 chromosomes. Meiosis is different than mitosis because it produces cells with only half the total number of chromosomes. Reproductive cells are produced through the process of meiosis. Meiosis differs from mitosis in that it only takes place in the reproductive organs to produce gametes, or reproductive cells. ![]() For this lesson student's understanding for sexual and asexual reproduction would be required for helping them gain an understanding for producing a hybrid such as seedless watermelons. Mitosis allows watermelon to grow from small to large. Mitosis divides cells allowing one cell to become two, two cells to become four, and so on. In the case of watermelons, they have 22 chromosomes. The chromosomes are threadlike structures found in the nucleus of living cells carrying genetic information, known as DNA, in the form of genes. ![]() Each cell has an exact and identical copy of DNA with a full set of chromosomes. One cell can divide into two cells, called daughter cells. Mitosis produces exact genetic copies of cells to allow growth as well as to replace worn out cells. Triploid: having or being a chromosome number three times the monoploid numberīoth mitosis and meiosis are processes that reproduce cells. Tetraploid: having or being a chromosome number four times the monoploid number ![]() Mitosis: a process that takes place in the nucleus of a dividing cell, involves typically a series of steps consisting of prophase, metaphase, anaphase, and telophase, and results in the formation of two new nuclei each having the same number of chromosomes as the parent nucleus Meiosis: the cellular process that results in the number of chromosomes in gamete-producing cells being reduced to one half and that involves a reduction division in which one of each pair of homologous chromosomes passes to each daughter cell and a mitotic division Hybrid: the offspring of two plants or animals of different species or varieties Adapt: to change so as to fit a new or specific use or situationĬhromosome: a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genesĬolchicine: a poisonous alkaloid c22H25No6 that inhibits mitosis, is extracted from the corms or seeds of the autumn crocus (colchicum autumnale), and is used especially in the treatment of gout and to produce polyploidy in plantsĭiploid: cells that have two complete sets of chromosomes, one from each parent
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