Barley is the world’s fourth most important cereal crop after wheat. maize
and rice. It is the most widely cultivated cereal and is probably grown over a
broader environmental range than any other crop. It is grown from 70 north in
Scandinavia to the equator; from the humid regions of Europe and Japan to the arid
deserts of Africa and Asia; from below sea level in Israel to high up in the
Himalayan, East African and South American mountains. It is more tolerant to
drought and saline and/or alkaline soils than the other cereals (Briggs, 1978).
Breeding barley cultivars start by merely descendants of selections made from the
wild barley Hordeum vu! gare sp. spontaneuin (Zohary. 1971).
Several reviews of barley breeding and improvement have been published
from the middle 1800’s until now. Planned crosses began to be made in the late
1800’s and were handled as equivalents to land races. Plant breeding can be
devided into two distinct phases: generating variition and exploitation of the
variation. Iii the broad sense, pedigree breeding is te exploitation of variation by
selecting plants from a heterozygous or heterogeneous source and growing their
progenies until relative homozygosity is reached. In regard to the 1u phase of plant
breeding (generating variation), Smith and Lamben (1968) concluded that yield
testing the bulked F2 generation was useful in identif’ing crosses from which high-
yielding segregants could be obtained. but theے questioned the predictive value Qf
yield tests of lines in early generations. Their suggestion was to make many crosses
among adapted and high-yielding parental genotypes, evaluate the F2 diallel set and
selecting 25-30% as the best families for the following generation.
The value of prediction based on early generation performance will be
highest when the genetic variance of the studied character is relatively free of non-
additive effects. The pedigree breeding can utilize only that segment of the total
genetic variability resulting from the action of additive genes and those epistatic |
