Hessian fly (HF, Mayetiola destructor Say) is a major pest on wheat and can cause significant yield losses. Currently there are some HF resistance genes deployed, but mostly in hexaploid winter wheat (Triticum aestivum), with fewer resistance genes identified in durum wheat (Triticum turgidum ssp. durum L.) and other wheat wild relatives. Mapping of additional resistance genes, along with developing markers for these is needed to develop resistant germplasm. ARS researchers in Fargo, ND evaluated the BP025 population under greenhouse and growth chamber conditions to the Great Plains (GP) biotype of Hessian fly (HF, Mayetiola destructor Say). The BP025 population was developed by crossing Ben (PI 596557), a North Dakota hard amber durum variety, with PI 41025, a cultivated emmer (T. turgidum ssp. dicoccum) accession collected near Samara, Russia. The BP025 population consists of 200 RILs developed by single seed-descent and was advanced to the F7:8 generation. The BP025 population was evaluated for stunting score, larval mortality, and the percentage of resistant plants under growth chamber and greenhouse conditions in Fargo, ND (46.893273, -96.807319). Experimental plants were maintained in a greenhouse at 20 ± 2° C with an ambient relative humidity of between 40 and 70% and a 16:8 (L:D) photoperiod. Natural lighting was enhanced with the use of 430-watt high pressure sodium lamps. Individual seeds of the mapping population entries were planted in Ray Leach cone-tainer (4 cm diameter × 21 cm deep, Stuewe & Sons, Inc., Tangent, OR), held in racks (RL98). Plants were grown in potting media (SB100 Professional Growing Mix, Sungro Horticulture, Bellevue, WA), and fertilized at planting with Osmocote Plus 15-9-12 (N-P-K) standard release fertilizer. Each cone was considered an experimental unit. The BP025 population and the parental lines Ben and PI 41025 were screened for HF larval resistance over two greenhouse seasons. All plants were evaluated using a completely randomized design. For the infestations, seedling plants were exposed to egg-laying HF adult females (~ 1 female for each plant) for 24 h. Infestations were timed to occur when seedlings were at the two-leaf growth stage. Three days after exposure to adult females, plants were moved to a high humidity (50-75% RH) growth chamber. High humidity facilitates egg hatching and promotes the successful migration of neonate larvae down the leaf blade to feeding sites at the base of the plant. Following egg hatch, plants were returned to the greenhouse for 10 to 14 days. This provided time for virulent larvae to grow and be differentiated from the small presumably dead avirulent larvae. Detailed observations of plant quality and larval success provided each plant with a score of “resistant” or “susceptible.” Specifically, plants were scored for their growth, with information on the number of leaves and tillers being recorded. Plant health and appearance (i.e., severity of larval-induced stunting), was also scored for each plant. Normal healthy plants were given a score of 0, lightly stunted plants were scored as a 1, moderately stunted plants were given a 2, and severely stunted planted were given the score of 3. Each plant was also dissected using a stereo microscope. At the time of plant dissection, virulent (i.e., successful) larvae were expected to be large and white in color. The number of dead larvae (eg. large, medium, small, and neonate) and live larvae (eg. large, medium, and small) were recorded for each plant. Averages for the plant and insect measurements were derived from the mean score of the 12 to 14 plants evaluated for each entry in the population. Phenotypic data was analyzed using JMP version 15 (SAS Institute, 2015). Prior to analysis, homogeneity of variance was tested using an O-Brien test at p < 0.05 (O’Brien, 1979). The genotypic data used for further QTL analysis is available Peters Haugrud, Amanda; Saini Sharma, Jyoti; Zhang, Qijun; Green, Andrew J.; Xu, Steven S.; Faris, Justin D. (2023). Data from: Identification of robust yield QTL derived from cultivated emmer for durum wheat improvement. Ag Data Commons. Dataset. https://doi.org/10.15482/USDA.ADC/1529118.

1) Resource Title: Averages of the phenotypic data collected from the durum x cultivated emmer wheat recombinant inbred population BP025 infested with Great Plains biotype of Hessian fly. File name: Ben mapping population average phenotyping data.

Resource Description: In the data file, column headings indicate the line, entry # (seed source), total number of plants evaluated, stunting score (mean), Leaves (mean), tillers (mean), total dead larvae (mean), total live larvae (mean), total larvae (mean), larval mortality (%), R (resistant) plants %, and notes from observations during plant dissections. This data can be used for further QTL analysis and evaluating these lines for HF resistance and how HF infestations affect different traits in each genotype.

2) Resource Title: Individual plant phenotypic data collected from the durum x cultivated emmer wheat recombinant inbred population BP025 infested with Great Plains biotype of Hessian fly. File name: Ben mapping population individual plant phenotyping data.

Resource Description: In the data file, column headings indicate the planting date, infestation date, scoring date, line, entry # (seed source), Plant number for that genotype, stunting score, resistance score, Leaves, tillers, coleoptile tillers, number large dead larvae, number medium dead larvae, number small dead larvae, number neonate larvae, total dead larvae, number large living larvae, number medium living larvae, number small living larvae, total living larvae, and total number of larvae. These values can be used for individual replicates for further analysis.