Dry Bean (Phaseolus vulgaris L.) Crop Water Production Functions and Yield Response Factors in an Arid to Semi-Arid Climate

HighlightsDeficit irrigation negatively affected dry bean yield and yield components.Excess irrigation increased crop ETc but not dry bean yield.Soil moisture fluctuation was greater in the top 0.3 m of the soil profile compared to deeper depths.Crop water production function had a slope of 18.9 kg ha-1 mm-1 and threshold crop evapotranspiration of 171 mm.Dry bean crop was found to be sensitive to water stress (yield response factor Ky = 1.94).Abstract. Under changing climate conditions and declining water resources, understanding crop response to water stress is critical for effective irrigation management. The objectives of this study were to quantify dry bean (Phaseolus vulgaris L., cv. Othello) soil moisture dynamics, crop evapotranspiration (ETc), and yield response factor and to develop dry bean irrigation and crop water production functions (IWPF and CWPF). Five irrigation treatments, i.e., full irrigation (FIT), 75% FIT, 50% FIT, 25% FIT, and 125% FIT, were evaluated using a randomized complete block design (RCBD) with three replications for three years (2017, 2018, and 2019) in the arid to semi-arid intermountain region of Powell, Wyoming. The results showed a significant influence of irrigation on dry bean soil moisture dynamics and ETc. The dry bean crop showed a greater soil moisture fluctuation in the top 0.3 m of the soil profile compared to 0.6 m and at 0.9 m. ETc ranged from 187 to 438 mm, from 190 to 409 mm, and from 217 to 398 mm in the 2017, 2018, and 2019 growing seasons, respectively. A positive two-segment relationship was observed between dry bean seed yield and cumulative irrigation water applied. The average cumulative seasonal irrigation of 310 mm resulted in maximum seed yield. For all three years, the seed yield increased linearly with ETc. Combining the data from the three years resulted in a CWPF with a slope of 18.9 kg ha-1 mm-1 and an offset of 171 mm of ETc (i.e., the ETc required for crop establishment before any seed yield is produced, or threshold ETc). Moreover, the dry bean crop was found to be sensitive to water stress (Ky = 1.94). These results indicated that under the typical semi-arid to arid climate conditions of the intermountain region of Wyoming, deficit irrigation of dry bean may not be a viable strategy because the yield loss outweighs water-saving benefits. Keywords: Dry bean, Crop evapotranspiration, Crop production function, Irrigation water production function.

Phenotypic and molecular screening of dry bean (Phaseolus vulgaris L.) breeding lines for resistance to bean common mosaic virus and bean common mosaic necrosis virus

Bean common mosaic virus (BCMV) and bean common mosaic necrosis virus (BCMNV) are among the most economically important virus species infecting common bean. The use of resistant plant cultivars is the most effective way to control these viruses. National dry bean breeding studies have been conducted by seven different governmental agricultural research institutes in Turkey, and advanced breeding lines have been developed by using the selected local dry bean populations and crossing studies. In this study, 204 breeding lines were tested for resistance levels to BCMV and BCMNV. Initially, BCMNV NL-3 and BCMV NL-4 strains were individually sap-inoculated onto the leaves of bean plants belonging to each breeding lines with 10 replications, and the reactions of plants were evaluated for symptomatic appearance of virus infection 21 days after inoculation. Additionally, phenotypic evaluation was confirmed by molecular markers linked to resistance genes. As a result of the study, 153 breeding lines were found to involve the dominant I gene whereas four and five of the tested lines had the recessive genes bc-1² and bc-2², respectively. In conclusion, it was emphasized that these breeding lines could be registered after evaluating them in terms of yield and quality. Also, the use of seeds of the resistant lines to supply the source of virus-resistance in breeding studies and maintaining their seeds at the national genebank were recommended.

Critical Timing of Weed Removal in Dry Bean as Influenced by the Use of Preemergence Herbicides

The critical timing of weed removal (CTWR) is the point in crop development when weed control must be initiated to prevent crop yield loss due to weed competition. A field study was conducted in 2018 and 2020 near Scottsbluff, NE to determine how the use of preemergence herbicides impacts the CTWR in dry bean. The experiment was arranged as a split-plot, with herbicide treatment and weed removal timing as main and sub plot factors, respectively. Herbicide treatment consisted of no-preemergence, or pendimethalin (1070 g ai ha–1) + dimethenamid-P (790 g ai ha–1) applied preemergence. Sub-plot treatments included season-long weed-free, weed removal at: V1, V3, V6, R2, and R5 dry bean growth stages, and a season-long weedy control. A four-parameter logistic model was used to estimate the impact of time of weed removal, for all response variables including dry bean yield, dry bean plants m–1 row, pods plant–1, seeds pod–1, and seed weight. The CTWR based on 5% yield reduction was estimated to range from the V1 growth stage [(16 d after emergence (DAE)] to the R1 growth stage (39 DAE) in the no-PRE herbicide treatment. In the PRE-applied treatment, the CTWR began at the R2 growth stage (47 DAE). Dry bean plants m–1 row was reduced in the no-preemergence treatment when weed removal was delayed beyond the R2 growth stage in the 2020 field season. The use of preemergence-applied herbicides prevented a reduction in the number of pods plant–1 in 2020, and the number of seeds pod–1 in 2018 and 2020. In 2018, the number of pods plant–1 was reduced by 73% when no-preemergence was applied, compared to 26% in the preemergence-applied treatment. The use of preemergence-applied soil active herbicides in dry bean delayed the CTWR and preserved yield potential.