Avat Shekoofa

Soybean ( Glycine max [L.] Merr.) productivity is often constrained by high flower abortion rates, especially under drought stress conditions, where up to 80% of flowers fail to develop into pods. This study aimed to assess the physiological and reproductive responses of eight soybean lines under controlled water‐deficit stress and recovery conditions to identify lines with improved flowers and pods retention. The experiment was conducted in a greenhouse using a dry‐down and rewatering protocol, followed by validation under field conditions across two growing seasons, 2023 and 2024. Eight lines were grown in a greenhouse where pots were sealed to prevent evaporation, and plants were allowed to gradually transpire the full amount of water in each pot before being re‐watered. The fraction of transpirable soil water (FTSW) and normalised transpiration rate (NTR) were monitored using a gravimetric method for all lines. Physiological parameters including stomatal conductance, transpiration rate, and quantum yield of fluorescence (ΦPSII) were recorded. Flower numbers and wilting scores were recorded daily, and pod numbers were assessed at harvest. Significant genotypic variation was observed in response to water‐deficit stress. PI506862 and PI423926 exhibited a strong stress adaptive response of early stomatal closure with high FTSW thresholds of 0.65 and 0.69, respectively, lower wilting scores, and rapid transpiration and ΦPSII activity during the rewatering recovery phase. PI506862 had high flower retention and pod setting during the recovery phase in greenhouse (17 pods/plant) and field trials (up to 146–193 pods/plant). In contrast, PI567638 had the lowest FTSW threshold (0.43), highest wilting scores, and poor recovery (4 out of 5 plants did not survive the dry‐down phase) and failed to produce pods after rewatering. These findings emphasise the presence of significant phenotypic variations in drought induced flower abortion and highlight PI506862 as a promising donor for breeding drought tolerant soybean line with enhanced productivity.

High temperature and water-deficit stresses are among the major limiting factors in cotton ( Gossypium hirsutum L.) production. Increasing atmospheric vapor pressure deficit (VPD, kPa) due to global warming further challenges crop productivity by altering plant water balance. This study aimed to assess the effects of different VPD conditions on whole-plant growth characteristics and physiological parameters of new cotton cultivars grown in a hydroponic system. The experiment was conducted from December 2022 to April 2023 at the West Tennessee Research and Education Center (WTREC), University of Tennessee, Jackson, TN. Two Conviron chambers were maintained at two VPD levels (chamber 1, 1.1 kPa and chamber 2, 2.1 kPa, both at 32 °C). Four cotton cultivars DP 2131 B3TXF (Thryvon technology), PHY 400 W3FE, PHY 1140A385–04 W3FE, and PHY 1140B373–04 W3FE were transplanted into hydroponic containers at the cotyledon stage. Cultivar DP 2131 B3TXF exhibited the highest plant height, root length, and total fresh and dry weight in both chambers compared to other cultivars. Under high VPD (2.1 kPa), DP 2131 B3TXF had significantly higher transpiration rate (TR) and stomatal conductance (gs) compared to PHY 400 W3FE. Interestingly, PHY 400 W3FE demonstrated higher intrinsic water use efficiency (iWUE) and significantly lower TR than DP 2131 B3TXF at the same VPD level. The same pattern was observed among cultivars for their stomatal density in chamber 2. These findings indicate that these new cotton cultivars performed differently when comparing TR, stomatal density, and root growth parameters under high VPD conditions. PHY 400 W3FE expressed the limited TR trait, while DP 2131 B3TXF exhibited greater biomass production and root length compared to other cultivars despite reduced root elongation under high VPD conditions.

This analysis assessed the partial net returns of a triazole, at-plant fungicide (i.e., Xyway LFR^@FMC) including no fungicide (control) and 1.11 L ha^-1 rate under three water scenarios in west Tennessee. In 2022, all water regimes and fungicide treatments had positive average partial net returns compared to rainfed (RF) with no fungicide treatment. However, in 2023 due to beneficial rainfall and low disease pressure during the growing season, low yield differences between treatments resulted in negative partial net returns for all treatments compared to RF with no fungicide treatment. The annualized capital recovery cost of the irrigation equipment was one of the reasons for the negative partial net returns across treatments and particularly water regimes for 2023. An additional factor that influenced the partial net returns analysis was the decline in corn prices between the 2022/23 and the 2023/24 marketing year. Although the Xyway LFR^@FMC fungicide application can be profitable for corn production, different environmental factors will determine yield and net return differences each year. Clearly, the investment in irrigation systems has a multiyear return on investment and the application of fungicide is completed before weather and disease pressure is known. As such, long-term weather variability will play an important role in the net returns of Xyway LFR^@FMC fungicide application.

A fungicide’s ingredients can play a physiological role in crop water-management decisions. Our greenhouse study in 2021 demonstrated that Xyway LFR^@FMC at-plant fungicide can significantly improve water-saving potential in corn. In 2022 and 2023, a field study was conducted to validate this finding. The 1.11 L ha⁻¹ of Xyway LFR^@FMC and no-fungicide/check were the main plot effects. Three water regimes, high (HI) and low (LO) numbers of irrigation events and rainfed (RF), were the subplot effect. Plants treated with Xyway LFR^@FMC had significantly higher plant height, stem diameter, and leaf water potential (LWP), and had 11.9, 13.4, and 18.3% higher yield under RF, LO, and HI, respectively, in 2022. In 2023, there were no significant differences for the yield components and growth parameters when the combined effect of fungicide treatments and water regimes was considered. However, plants treated with the fungicide had a higher number of rows per ear, kernel number per row, and cob diameter compared to the check. There was no significant separation for yield among the water regimes in 2023, but the crop yield was overall higher for the fungicide-treated plots. Our results indicate that Xyway LFR^@FMC fungicide has the potential to improve plant growth and protect the yield when limited water is applied.

Soybean cyst nematode (SCN), Heterodera glycines, is the most economically important soybean (Glycine max [L.] Merr) pathogen in North America. More than $1.5 billion in yield losses are attributed...

The glyphosate‐tolerant soybean [Glycine max (L.) Merr.] line ‘TN16‐520R1’ (Reg. no. CV‐560, PI 703273) was released as a high‐yielding cultivar by University of Tennessee Agricultural Research in 2018. TN16‐520R1 is a BC₄F₂ cultivar derived from the recurrent parent ‘Ellis’, with drought tolerance and a maturity group (MG) of V‐early. It has white flowers, gray pubescence, tan podwall, and a determinate growth habit. The seed has buff hila, is yellow with smooth seed coat, and contains 40% protein and 22% oil on a dry weight basis. TN16‐520R1 has good resistance to lodging and good seed quality (1.8 and 1.6, respectively, on 1–5 scale), and a seed size of 11.8 g per 100 seed. Like Ellis, TN16‐520R1 has performed competitively throughout much of the mid‐South United States over several years, with testing occurring over a 6‐year period in 100 environments. Further, TN16‐520R1 is remarkably like the recurrent parent Ellis for yield, maturity, lodging, height, protein, and oil. Also, like Ellis, TN16‐520R1 is resistant to stem canker [caused by Diaporthe phaseolorum (Cooke & Ellis) Sacc. var. caulivora K.L. Athow & R.M. Caldwell] and southern root‐knot nematode [Meloidogyne incognita (Kofoid and White) Chitwood] and has field tolerance to frogeye leafspot [caused by Cercospora sojina (Hara)]. This combination of beneficial traits and broad adaptability make TN16‐520R1 an excellent choice as a soybean cultivar for producers or a crossing parent for breeders.

Irrigated cropland continues to increase in Tennessee to sustain yield when seasonal temperatures are high and water deficit occurs. Corn (Zea mays L.) production is directly related to water availability. Inefficient irrigation scheduling can result in excessive or inadequate water applications. The objective of this study was to optimize profitable corn yield using soil water sensors to improve irrigation scheduling. Three irrigation regimes plus a rainfed/check were evaluated in a field study at the University of Tennessee Milan Research and Education Center in 2020 and 2021. Soil water level was monitored with Meter Inc. Teros 21 matric potential sensors and ZL6 soil‐water loggers. Irrigation‐scheduling decisions were based on rainfall, plant growth stages, and soil water sensors. An optimal irrigation schedule was determined within this study that increased yield by 13.0% and 3.0%, respectively, in 2020 and 2021 while also having the lowest cost among irrigation treatments. Results indicate that irrigation scheduling can improve yield, conserve water, and increase economic returns.

Drought conditions exhibit various physiological and morphological changes in crops and thus reduce crop growth and yield. In order to mitigate the negative impacts of drought stress on soybean (Glycine max L. Merr.) production, identification and selection of genotypes that are best adapted to limited water availability in a specific environmental condition can be an effective strategy. This study aimed to assess the inheritance of early stomatal closure traits in soybeans using a population of recombinant inbred lines (RILs) derived from a cross between N09-13890 and Ellis. Thirty soybean lines were subjected to progressive water-deficit stress using a dry-down experiment. The experiment was conducted from June to November 2022 at the West Tennessee Research and Education Center (WTREC), University of Tennessee in Jackson, TN, under controlled environment conditions. This study identified significant differences among soybean lines in their early stomatal closure thresholds. The fraction of transpirable soil water (FTSW) thresholds among 30 tested lines ranged from 0.18 to 0.80, at which the decline in transpiration with soil drying was observed. Almost 65% of the RILs had FTSW threshold values between 0.41 to 0.80. These results, indicating inheritance, are supportive of the expression of early stomatal closure trait in progeny lines at a high level in cultivar development for water-deficit stress conditions. Thus, identifying the differences in genotypes of water use and their response to water-deficit stress conditions can provide a foundation for selecting new cultivars that are best adapted to arid and semi-arid agricultural production systems.

Background: Cotton (Gossypium hirsutum L.) is often grown in locations characterized by high atmospheric evaporative demand. It has been hypothesized that plants which resist hydraulic flow under this condition will limit water use and conserve soil water. Therefore, in a series of controlled environment experiments ten cotton cultivars were exposed to two different temperature and vapor pressure deficit (VPD) conditions (i.e., 38 °C, > 3 kPa and 32 °C, 1∼1.5 kPa) as well as a progressive soil drying. Then, individual differences in shoot hydraulic conductance (K_shoot) was measured using a hydraulic conductance flow meter (HCFM). Physiological parameters were reported included leaf area, dry leaf weight, stomatal conductance (g_s), and water use efficiency coefficient (WUE_k). Results: Differences were observed in K_shoot among cultivars under the 38 °C, > 3 kPa but not the 32 °C, 1∼1.5 kPa environment. Under the 38 °C, > 3 kPa environment, correlations were found between K_shoot, stomatal conductance (g_s), VPD breakpoint, WUE_k, total leaf area, dry leaf weight, fraction transpirable soil water (FTSW) threshold, and slope of TR decline after FTSW threshold. Conclusion: Results show that the ability of some cotton cultivars to restrict water loss under high evaporative demand through early stomatal closure is associated with the cultivars’ K_shoot. The K_shoot is influential in the limitation of TR trait under high temperature and VPD.