DTA

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Tesi etd-04022020-124608

Type of thesis
Dottorato
Author
LAKEW, BASAZEN FANTAHUN
URN
etd-04022020-124608
Title
Genotypic and phenotypic diversity in Ethiopian barley (Hordeum vulgare ssp hordeum) farmer varieties based on morphologic and molecular markers
Scientific disciplinary sector
Istituto di Scienze della Vita
Course
SCIENZE AGRARIE E BIOTECNOLOGIE - AGROBIODIVERSITY
Committee
relatore Prof. PE', MARIO ENRICO
Tutor Prof. DELL'ACQUA, MATTEO
Keywords
  • barley
  • principal component
  • AUDPC
  • GWAS
  • QTL
  • SNP
Exam session start date
30/03/2021;
Availability
completa
Abstract
Barley as one of the founder crops in the world agriculture had gone through thousands of years<br>of cultivation and has been an important component of the world agriculture. It is a staple food for<br>human consumption in some parts of the world. It is also used in the beverage industries for the<br>production of alcoholic drinks and as a feed for animals. The production coverage for the crop is<br>showing a slight increase with a renewed interest for the crop associated with its health benefits<br>worldwide. In Ethiopia, the crop has been under cultivation for more than five thousand years and<br>hence adapted to the varied agro-ecologies of the country and in higher altitudes being the<br>dominant crop produced for human consumption.<br>Germplasms that can be used as a building block in crop breeding programs to complement a trait<br>lacking in a given variety are of the World’s valuable resources. The crop genetic resources<br>particularly the farmer varieties are reservoirs of important genes which can be used in an effort<br>to develop superior varieties that can best fit the prevailing biotic and biotic challenges. To date,<br>different factors such as population growth, climate change and damage caused by pest and<br>diseases are challenging crop production all over the World. Therefore, understanding of the extent<br>of diversity the crop genetic resources entail can be considered as a sound strategy to cope with<br>the challenge the world agriculture is facing. For barley to this end, the conservation more than<br>400 thousand landraces in gene banks across the World was found to be an opportunity to exploit<br>these resources with the application of the dynamic modern technologies. Besides, the resources<br>are conserved in the gene bank are not meant for conservation per se rather to sustainably utilize<br>them and derive benefits out their utilization.<br>As part of the effort to exploit the potential the barley genetic resources were composed of we have<br>phenotyped 320 barley lines and genotyped 501 lines of the core collection. The phenotyping and<br>the genotyping carried out clearly indicated the barley genotypes included in the study were<br>diverse. Interestingly, lines developed from farmers varieties showed excellent performance for<br>most of the quantitative traits studied with some difference over the test environments. For grain <br>122<br>yield in this case, comparing the performance on the two locations separately, it was found that<br>the line from famer variety Accn# 1826 at Arsi Negelle and Accn# 24970 at Holleta were the<br>highest yielding genotypes. Combined over all the test environments these genotypes were not<br>significantly less than the highest yielding cultivar HB-1307. On the other hand, the phenotyping<br>had revealed there were lines from farmer that can mature less than 85 days. These genotypes<br>though they were not in the list of high yielding genotypes they can be used in crossing block to<br>combine this desirable trait with the high yield genotypes. Especially for those locations which are<br>characterized by terminal moisture stress genotypes as early as line Accn#17254 will benefit the<br>most. Furthermore, the genotypes under study showed that there were 40 days difference between<br>the early and the late barley lines suggesting these genotypes can fit the varied agro-ecologies of<br>the country and elsewhere. The participatory evaluation we had with the two-farming community<br>justified development of superior varieties based on metric data mainly grain yield may not address<br>the framer’s preference. Besides, the it was revealed that in choice of a variety that best fits their<br>demand farmers consider traits other than grain yield and the choice of a variety by farmers from<br>the different community were different. Hence, this calls for the involvement of farmers in the<br>variety development activities carried out by the breeding programs.<br>With genotyping experiment, we identified 165 marker traits associations based on the phenotypic<br>data on 10 pheno-agronomic traits. Some of these association were overlapping suggesting a<br>particular QTL controlling more than one trait. Provided positive correlation between these QTL,<br>selection based on one trait may facilitate the selection of the other desirable trait controlled by the<br>overlapping QTL. Overall, the current study uncovered there were lines from farmer varieties than<br>can be directly used as in case of line Accn#1826 in environments like Arsi Negelle and others as<br>potential valuable genes for further improvement in Ethiopia and elsewhere. In addition, the<br>produced genotypic data can be combined to assess to as the performance of the genotypes in the<br>drought prone areas in the future.
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