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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower and Plant Biology Research » Research » Research Project #436660

Research Project: Assessing the Importance of Plant Spacing Heterogeneity (Skips, Doubles, Gaps) on Yield, and Heritability of Seedling Emergence in Field Conditions

Location: Sunflower and Plant Biology Research

Project Number: 3060-21000-043-24-N
Project Type: Non-Funded Cooperative Agreement

Start Date: Jul 1, 2019
End Date: Jun 30, 2024

Objective:
1. Observe the effects of stand heterogeneity on one oilseed hybrid and one confectionery hybrid, given a constant actual plant population, at three very different sites: Red River Valley (Minnesota); eastern Colorado; and the Texas High Plains. 2. Observe the effects of stand heterogeneity due to large gaps, where an ideal plant spacing situation is altered by creating a gap in one row (i.e. simulating planter malfunction, cutworm damage, or poor microenvironment for planting). Same three sites. 3. Use daily monitoring from 5 to 25 DAP to find differences among USDA testcross hybrids in days to emergence, and differences in early seedling vigor in the field. MN only.

Approach:
Objective 1. We propose to develop 4x replicated, 4 row plots, 30 feet in length with an oilseed and a confectionery hybrid (Red River Commodities 2215), in which the distribution of seeds is pulled from a multinomial statistical distribution but keeping total population constant. This will allow us to see the effects of seed spacing issues independent of population differences. We will have the following treatment levels: a) 100% proper singulation (control); b) 6.25% doubles, 87.5% singles, 6.25% skips; c) 12.5% doubles, 75% singles, 12.5% skips; d) 25% doubles, 50% singles, 25% skips; and e) 37.5% doubles, 25% singles, and 37.5% skips. The plots will be established near Glyndon, MN, Burlington, CO, and Plainview, TX, which are all sites with nearby agronomists to monitor the plots closely. The final plant density at the Minnesota site will be 22,000 plants per acre for oilseed and 16,000 for confectionery, and in Colorado and Texas, 17-18,000 plants per acre oilseed and 15,000 confectionery. To arrive at the appropriate spacing, seeds will be planted at 5x final density with an Almaco belt cone planter or similar equipment. At VE stage, plants will be purposely removed by hand to arrive at the final intended spacing. In Minnesota, plots will be monitored twice weekly by drone aircraft, with data taken on percentage of green cover on each plot and plant density changes due to death or competition among plants. Drone hardware will be supplied by USDA-ARS (DJI Matrice 100 with Zenmuse X3 camera and GPS guidance). In Colorado and Texas, manual stand observations will take place prior to bloom and before harvest to monitor plant death, competition effects, or pest damage. Yield will be taken by cutting heads in the two center rows and threshing with an Almaco LPR stationary thresher or similar equipment at each site, to reduce the chance of seed loss in combine equipment and increase precision. Objective 2. We will model stand gaps by developing properly singulated plots, like treatment (a) above, with the addition of significant gaps in one of the two central rows: f) 3 foot, g) 6 foot, and h) 9 foot. These plots will be randomized with the plots in Objective 1, following the same general guidance mentioned there. It is important to note that these plots will not be held at the same total plant density per plot, in contrast to Objective 1 plots. Objective 3. Breeders frequently have a poor understanding of heritable differences in days to emergence and vigor in early plant development for new hybrids in the field. Selecting for lines and hybrids that have rapid seed germination may help avoid issues caused by seedling pests. We will conduct daily drone flights, 5 to 25 DAP, over our USDA testcross yield trial at Glyndon, MN, to observe differences among testcross hybrids for days to emergence and early seedling vigor. The plots are replicated twice, with several hundred unique entries. The data collected will allow us to determine if heritable differences in emergence are present. If such differences exist, these data can be used in conjunction with genomic data on the hybrids to conduct mapping of the trait in the near future.