8th INTERNATIONAL WHEAT CONFERENCE

exPeCTed ReSPoNSe To SeLeCTIoN foR gRAIN yIeLd
ANd ITS ComPoNeNTS IN WheAT
G.Saeidi 1 , B. Heidari 2 , B. E. Sayed Tabatabaei 1 ,
1 Department of Agronomy and Plant Breeding and Department of Biotechnology, respectively,
College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111, Iran.
2 Department of Crop Production and Plant Breeding, School of Agriculture, The University
of Shiraz, Shiraz, Iran.
E-mail Address of presenting author: gsaeidi@cc.iut.ac.ir
The efficiency of any selection program is determined by the genetic gain obtained for
improvement of the target trait and prediction of response to selection is one of the most
important and useful concepts in genetic and breeding of quantitative traits. Developing
high yielding cultivars is one of the main objectives of wheat breeding programs, thus in
this study, response to selection was estimated for grain yield and yield components in
a wheat population of 107 doubled haploid lines derived from the cross of Oligoculm ×.
Fukuho-Kumogi. The lines were evaluated in a randomized complete block design with
three replications in two growing seasons at the Research Farm of Isfahan University of
Technology, Iran. The variance components were estimated based on the expected mean
squares and response to selection was predicted based on a selection intensity of 5%. The
results of combined analysis of variance over two years showed that there were significant
differences among the genotypes for the yield components, grain yield and harvest index.
Phenotypic coefficients of variation were calculated as 21.0, 19.2, 19.0, 10.3, 14.6, 14.0,
9.9% for grain weight/spike, grains/spike, spikes/m 2 , 1000-grain weight, grain yield, biological
yield and harvest index, respectively whereas their genetic coefficients of variation
were 19.2, 17.6, 14.1, 9.3, 8.5, 8.6 and 8.5%. The grain yield among the lines ranged from
461 to 1386 and from 266 to 829g/m 2 in the first and second growing seasons, respectively,
however, the corresponding range was from 295 to 1012 and from 196 to 1075 for
spikes/m 2 , from 30.8 to 102 and 37 to 124 for grains/spike and from 25.7 to 46.0g and 24.1
to 42.5g for 1000- grain weight The narrow-sense heritabilities were estimated 85.9, 87.3,
57.2, 82.7, 36.8, 38 and 76.3% for the traits of grain weight/spike, grains/spike, spikes/m 2 ,
1000- grain weight, grain yield/m 2 biological yield/m 2 and harvest index, respectively and
their expected response to selection were correspondingly calculated as 36.1, 33.3, 21.5,
17.0, 10.1, 11.0 and 14.2% of their population means (2.35g, 60.8, 569.8, 34.8g, 718.6g
1700g and 0.42, respectively). These results show there was genetic variation for the studied
traits in the population and appropriate selection programs can efficiently improve
grain yield and its components to develop high yielding cultivars of wheat.
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