Update:
Objectives 1 and 2 Highlights:
• The Chile nurseries were successful, and seed was received in time for normal planting in Iowa.
• New sources of resistance for disease resistance (including, soybean cyst nematode) and abiotic stresses were identified and used as parents in the 2017 crossing nurseries.
• Single plant selections were made in the breeding populations.
• Single plot selections were made in the short-row plots for incorporation in yield tests.
• Yield trials (small plot and regular yield plot) were grown, and selections will be made in Fall 2017.
• At the time of reporting, combine harvest is continuing but near completion; single plant pulls and pod picks have been completed.
• F1 seed of new populations, developed to meet our objectives, has been sent to Puerto Rico and Chile.
Thirty-nine populations were created in the 2016-2017 winter nursery. Over the 2017 season, 67 populations will be created in the 2017 summer and winter crossing blocks at Ames, IA, Juana Diaz, PR, and Rancagua, Chile.
In addition to high yield, parents in crossing blocks were selected for yield protection traits (tolerance/resistance to biotic and abiotic stresses), genetic diversity, abiotic stress tolerance, and seed compositional traits.
Bulk populations and short-row plots were grown in Chile winter nurseries (2016-2017). Visual selection was made among short-row progeny rows in off-season nurseries, and these selections were grown in multi-location yield tests in Iowa in 2017. Pod picks and individual plant pulls were made in Chile, and the seed returned was planted either in bulk populations or progeny rows for selection and continued yield testing. One-hundred twenty-five populations were planted in Ames, IA: 39 were from winter nursery in Puerto Rico; 79 were from winter nurseries in Chile; and 7 were early generation diversity populations (courtesy: Dr. Randy Nelson). Pod picks or single plant pulls were done on 124 populations in Fall 2017.
In 2017, 7620 small yield plots were planted at Ames, IA. The entries (6511) from 2016 bulk populations, winter nursery populations, and single plants from yield trials, were from 51 populations with yield protection traits (aphid tolerance, disease resistance), genetic diversity, and compositional traits. After selection for desirable agronomic traits, these will be grown in regular yield plots in 2018.
Selections from 2016 short-row yield trials and Chile progeny rows were advanced to long-row yield trials and planted in the US in multiple locations in 2017. The total number of entries was 1835 from 48 populations, and the total plot number was 8020. Traits in these populations were high-yield, genetic diversity, aphid tolerance, quality traits, and disease resistance/tolerance.
Thirteen entries from 2016 first-year, long-row yield trials were selected and planted in an advanced long-row yield test at multiple locations throughout Iowa in 2017. Eight populations created with stacked aphid resistance were grown in Chile in 2016-2017. Single plants were pulled, threshed, and planted in two-row, short-row yield tests in Iowa in 2017. Selections will be advanced to long-row yield trials at multi-locations in the US in 2018.
Objectives 3 and 4:
Susan Xu has been hired for molecular marker assisted selection breeding system and repository. Marker protocols for SCN, disease resistance and compositional traits are being standardized. These will be screened on selections from 1835 multi-location entries tested in 2017 season. This will be accomplished in fall 2017/spring 2018 as harvested was on-going at the time of reporting.
Seed density study has been completed and Race Higgins, PhD student, is now completing data analysis and writing the manuscript so results can be shared with the farmer and researcher communities. The residue traits studies to look at maximizing profitability in corn-soybean rotation. Race is scheduled to defend in spring 2018. Row width study has also been completed and PhD student Kyle Parmley is working on data analysis and manuscript writing. These results have been shared through presentation already (see section below on presentation).
View uploaded report