Avanços na ciência e tecnologia agrícola

Abstrato

Genetic Variability and Divergence in Wheat

Takele Mitiku Abdeta*

This term paper is intended to assess genetic diversity and variability of wheat crop and its contribution for
traditional and modern farming system in Ethiopia.. Genetic diversity refers to the variation of genes or entire
genome within and between populations of organisms. The genetic diversity of wheat plant species depends on
different factors i.e. ecological, geographical, breeding system & anthropogenic effects, selection methods and
variety preference by user. Wheat is a major diet component due to the wheat plant’s agronomic adaptability, ease
of grain storage and ease of converting grain into flour for making edible, palatable, interesting and satisfying food.
The first cultivation of wheat occurred about 10, 000 years ago, as part of the ‘Neolithic Revolution’, which saw a
transition from hunting and gathering of food to settled agriculture. These earliest cultivated forms were diploid
(genome AA) (einkorn) and tetraploid (genome AABB) (emmer) wheats and their genetic relationships indicate that
they originated from the south-eastern part of Turkey. Ethiopia is one of the major center of diversity for many plant
species with its more than 60,000 accessions of different crops maintained in its gene bank. Durum wheat (Triticum
turgidum var durum Desf is among the most diversified crop species in Ethiopia accounting for about 12% (* 7000
accessions) of the national gene bank holdings. Traditionally, tetraploid wheats have been predominantly grown by
the Ethiopian farmers, and currently occupy more land than hexaploid wheat. Tetraploid wheat has been under
cultivation in Ethiopia for thousands of years, and has acquired a diverse set of characteristics that makes the
country a center of diversity for that species. Even though breeding program is to promote genetic makeup of plant
genetic diversity of crops renders more vulnerable to disease and insect epidemics and jeopardizes the potential for
sustained genetic improvement over the long term.