Despite many investigations genotype by environment interaction remains
one of the least understood factors in plant improvement. Understanding genotypic
differences responsible for such interactions could assist in making more informed
breeding decisions. The components of yield being less complex than grain yield
per se may be useful for selection to improve adaptation of genotypes and enhance
grain quality. However, the potential compensatory response among the
components of yield could compromise their usefulness as selection criteria.
To evaluate this aspect fifteen cultivars, including Soft White, Hard White
and Hard Red wheats, were planted at three diverse locations over two growing
seasons. Genotypes were ranked based on measurements for specific traits in each
environment. The genotype by environment interaction for grain yield, protein
concentration and hardness were investigated according to the AMMI model.
Influence of environmental factors and genotype by environment interactions on
associations among selected traits were determined.
The results of this study showed that genotypic differences in adaptation to
the Pacific Northwest and resistance to Septoria spp. were responsible for
interactions for grain yield. However, no consistent patterns of response were found
among the similar cultivars for quality traits. Those environments that favored
expression of biomass and grain weight potential provided for enhanced
performance of the adapted cultivars. The environments with suppressed biomass
accumulation and grain filling interacted positively with the unadapted cultivars. A
large compensatory relationship between tillering and apical growth was detected.
No or low compensation was observed between grains per spike and thousand
kernel weight. Two different strategies were proposed for improvement of Soft and
Hard White wheat cultivars under the conditions of the Pacific Northwest. Both
strategies accentuate importance of increasing biomass while maintaining harvest
index. When selecting for higher yielding Soft White cultivars, plants with larger
leaves, stronger stems, larger spikes and heavier grains should be emphasized. For
Hard Whites - higher number of tillers and grains m����� is desired, as they provide for
harder grains with higher protein content. / Graduation date: 2000
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/33306 |
| Date | 14 June 1999 |
| Creators | Bedoshvili, David |
| Contributors | Kronstad, Warren E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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