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University of Nebraska-Lincoln (2017)

High and low yielding soybean lines from an irrigated selection environment : Performance evaluation in irrigated and droughted environments

Perez Arocho Jorge E.

Titre : High and low yielding soybean lines from an irrigated selection environment : Performance evaluation in irrigated and droughted environments

Auteur : Perez Arocho Jorge E.

Université de soutenance : University of Nebraska-Lincoln

Grade : Doctor of Philosophy (PhD) 2017

Résumé
Drought is the most significant abiotic stress affecting agricultural production. Improving seed yield under water stress is an important breeding objective. Soybean cultivars that tolerate water stress could help improve and stabilize production in water-stressed environments. “Drought” needs to be defined, because water stress can vary in intensity, timing, and duration. Other factors including ambient temperature, soil texture, depth, and fertility will influence the impact of limited water on crop productivity. This research addresses the impact of water stress on soybeans adapted to the north-central US, where the majority of soils are relatively deep, fertile silt loams or silty clay loams with good water-holding capacity. We hypothesized that selection for seed yield in a high-yielding environment without water stress would concordantly generate lines that also display improved seed yield in drought environments. To test this hypothesis, nine populations of 70 lines each from the NAM soybean collection were evaluated for yield in a single, high-yield, irrigated environment at the University of Nebraska Research Center at Clay Center, NE during 2011. The seven highest-yielding lines and seven lowest-yielding lines were selected from the respective high and low tails of each population. The selected recombinant inbred lines plus the parents from nine populations were evaluated during 2012 and 2013 in irrigated and water-stress environments. The high-yield selected group performed better than the low-yield selected group for grain yield, in both irrigated and dry environments. This result indicated that differences in yield between the two groups when selected in an irrigated environment retained a consistent high versus low-yield pattern in subsequent irrigated and drought environment tests. Average genotypic correlation for seed yield in non-stress and water-stress conditions was positive and significant (0.71±0.09), suggesting that selection for high yield in non-stress environments will result in simultaneous improvement of yields under water stress environments. On average, drought stress reduced soybean seed yield by 60.1%, 100-seed weight by 12.5%, plant height by 30%, lodging 64%, and days to maturity by 8 days. While some populations showed significant effects of water treatment on seed composition, overall, seed protein and oil concentration did not change with water treatment.

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Page publiée le 17 octobre 2017