@article{sinclair_jafarikouhini_pradhan_2024, title={Unexpectedly, triple super phosphate fertilizer induces maize drought resilience}, ISSN={["1532-4087"]}, DOI={10.1080/01904167.2024.2325948}, abstractNote={Phosphorus fertilizer is commonly applied to soils in crop production as diammonium phosphate (DAP). To decrease ammonium addition to the environment, triple super phosphate (TSP) is being considered as a DAP replacement. This study was undertaken to compare the response of maize plants to soil fertilization with TSP vs. DAP under well-watered conditions, under soil-drying conditions, and root hydraulic conductance. It was found for well-watered conditions in a controlled environment that there was no difference in plant growth between DAP to TSP treatments. In soil dry-down experiments, however, the initiation of the decrease in transpiration rate was unexpectedly quite different between DAP and TSP treatments. The soil water content threshold for initiation of decrease in transpiration rate with DAP treatment (average fraction transpirable soil water for two experiments = 0.285) was consistent with common observations, but the threshold associated with TSP treatment occurred at an unusually high soil water content (average fraction transpirable soil water for two experiments = 0.545). The higher threshold with TSP resulted in an extended period of soil water use, i.e. soil water conservation. Soil water conservation resulting from the TSP treatment was associated with a 27% greater shoot mass accumulation following a 4-wk re-watering period after the water-deficit treatment than measured with the DAP treatment. The high threshold for decrease in transpiration resulting from TSP was consistent with measured lower root hydraulic conductance as compared to DAP treatment. The unexpected discovery of TSP-induced initiation of transpiration rate decrease at high soil water content is consistent with greater crop drought resilience.}, journal={JOURNAL OF PLANT NUTRITION}, author={Sinclair, Thomas R. and Jafarikouhini, Nahid and Pradhan, Deepti}, year={2024}, month={Feb} }
 @article{guiguitant_marrou_vile_sinclair_pradhan_ramirez_ghanem_2021, title={An exploration of the variability of physiological responses to soil drying in relation with C/N balance across three species of the under-utilized genus Vigna}, volume={172}, ISSN={["1399-3054"]}, DOI={10.1111/ppl.13224}, abstractNote={Abstract}, number={2}, journal={PHYSIOLOGIA PLANTARUM}, author={Guiguitant, Julie and Marrou, Helene and Vile, Denis and Sinclair, Thomas R. and Pradhan, Deepti and Ramirez, Martha and Ghanem, Michel Edmond}, year={2021}, month={Jun}, pages={477–486} }
 @article{chiango_jafarikouhini_pradhan_figueiredo_silva_sinclair_holland_2021, title={Drought resilience in CIMMYT maize lines adapted to Africa resulting from transpiration sensitivity to vapor pressure deficit and soil drying}, volume={8}, ISSN={["1542-7536"]}, DOI={10.1080/15427528.2021.1961334}, abstractNote={ABSTRACT Low rainfall limits crop yield, particularly for maize (Zea mays L.) in southern Africa. Consequently, there is a need to identify genetic sources of specific drought-related traits that can contribute to soil water conservation and increased yields under water-limited conditions. In this study, maize genotypes released for production in southern Africa were tested for expression of two soil water-conservation traits: limited transpiration under elevated vapor pressure deficit (VPD) and decreased transpiration rate at high soil water contents earlier in the soil drying cycle. Two genotypes, CML 590 and CML 593, were identified and confirmed to initiate expression of limited-transpiration rate at VPD above about 1.9 kPa. In the soil-drying experiment, Umbelu 8923 and Umbelu 8930 closed their stomata earliest in the soil drying cycle as compared to other tested genotypes. These four genotypes with specific physiological traits for superior response to water deficit are genetic resources for further study to improve maize drought resilience.}, journal={JOURNAL OF CROP IMPROVEMENT}, author={Chiango, H. and Jafarikouhini, N. and Pradhan, D. and Figueiredo, A. and Silva, J. and Sinclair, T. R. and Holland, J.}, year={2021}, month={Aug} }
 @article{pradhan_bertin_sinclair_nogueira_livingston_carter_2021, title={Microsphere stem blockage as a screen for nitrogen-fixation drought tolerance in soybean}, volume={172}, ISSN={["1399-3054"]}, DOI={10.1111/ppl.13281}, abstractNote={Abstract}, number={2}, journal={PHYSIOLOGIA PLANTARUM}, author={Pradhan, Deepti and Bertin, Diana and Sinclair, Thomas R. and Nogueira, Marco A. and Livingston, David and Carter, Thomas}, year={2021}, month={Jun}, pages={1376–1381} }
 @article{sanchez_sinclair_pradhan_2021, title={Transpiration response to vapor pressure deficit and soil drying among quinoa genotypes (Chenopodium quinoa Willd.)}, volume={35}, ISSN={["1542-7536"]}, DOI={10.1080/15427528.2020.1817221}, abstractNote={ABSTRACT Water-deficit conditions limit increasing crop yield around the world. In order to improve crop yield it has been proposed to decrease water use early in the season so more water will be available later in the season to support seed growth during reproductive development. To achieve this, there are two water-conservation traits of special interest: partial stomatal closure under high vapor pressure deficit (VPD) and early in the soil drying cycle. Quinoa (Chenopodium quinoa Willd.) is well known for its ability to grow in poor soils and extreme climatic environments. Therefore, quinoa may especially benefit from expression of water-conservation for water-limited conditions. These traits have not been previously studied in quinoa. This study reported the response of eight quinoa genotypes. Genotypes Red head, CICA-17, Salcedo, Ollague, Good Afternoon, and Pasankalla expressed a VPD breakpoint (BP) but Titicaca and French Vanilla not. All genotypes expressed a FTSW threshold with soil drying as expected. French Vanilla had the highest threshold, so it would be a candidate as a water-conserving genotype. The results of this study can be applied directly in field tests comparing cultivars under water-deficit conditions, and selection of genotypes to be used in breeding for improved cultivars specifically for drought.}, number={2}, journal={JOURNAL OF CROP IMPROVEMENT}, author={Sanchez, Maria and Sinclair, Thomas R. and Pradhan, Deepti}, year={2021}, month={Mar}, pages={291–302} }
 @article{jafarikouhini_pradhan_sinclair_2020, title={Basis of limited-transpiration rate under elevated vapor pressure deficit and high temperature among sweet corn cultivars}, volume={179}, ISBN={1873-7307}, DOI={10.1016/j.envexpbot.2020.104205}, abstractNote={One plant trait that has been developed in several crop species to increase the effectiveness in water use through the cropping season is limited-transpiration under elevated atmospheric vapor pressure deficit (VPD). This trait allows water conservation early in the season so that there is more soil water available late in the season for sustained physiological activity during seed development. In sweet corn (Zea mays L. saccharata), where the quality of the kernels is important, this trait could prove to be especially beneficial. The background objective of this study was to explore 16 sweet corn cultivars for expression of the limited-transpiration trait. It was found at 32 °C that 13 of the 16 cultivars expressed the trait. It was found in a subset of eight of these cultivars, however, only half retained the limited-transpiration trait at 38 °C. The additional objectives were to explore the hypotheses that expression of the limited-transpiration trait was related to plant hydraulic conductance, and to the abundance of silver-sensitive aquaporins in the leaves. In cultivars that lost expression of the limited-transpiration trait at 38 °C there were large increases in plant hydraulic conductance at 38 °C as compared to 32 °C. Abundance of silver-sensitive aquaporins was related to the transpiration rate under low VPD conditions. That is, those cultivars with more abundant silver-sensitive aquaporins had greater transpiration rates as a result of greater stomatal conductance. These results showed that while expression of the limited-transpiration trait in sweet corn at 32 °C was common, differences in expression of the trait at 38 °C were observed due to differences in plant hydraulic conductance and stomatal conductance.}, journal={ENVIRONMENTAL AND EXPERIMENTAL BOTANY}, author={Jafarikouhini, Nahid and Pradhan, Deepti and Sinclair, Thomas R.}, year={2020}, month={Nov} }
 @article{pradhan_dunne_ramirez_sinclair_2020, title={Nitrogen-fixation drought tolerance in virginia-type peanut}, volume={34}, ISSN={["1542-7536"]}, DOI={10.1080/15427528.2020.1740903}, abstractNote={ABSTRACT Symbiotic nitrogen-fixation activity of grain legumes commonly does not exhibit tolerance to soil drying, including in peanut (Arachis hypogaea L.). Since the demand for nitrogen of peanut is large in the synthesis of seeds with high protein concentration, loss of nitrogen-fixation activity can result in major yield decreases. The objective of this study was to search the germplasm of virginia-type peanut for sources of nitrogen-fixation drought tolerance. The first phase was a field screen in one growing season of 100 lines from which leaves were harvested and nitrogen concentration measured. Research in soybean had shown that low leaf-nitrogen concentration was associated with nitrogen-fixation drought tolerance. A wide range of leaf nitrogen concentrations was observed, and 10 lines of low leaf nitrogen (23.1 to 26.4 mg N g−1) were identified for the second phase of study. The second phase of study was done in a greenhouse with 5-week old plants sealed in pots subjected to a 2-week dry down. Each day, the plants were briefly exposed to acetylene to measure acetylene reduction activity as an indicator of nitrogen-fixation activity. The soil water content, at which a decline in nitrogen fixation was initiated, was not different among seven lines. Three of the lines exhibited high sensitivity of nitrogen fixation to soil drying. None of the lines, however, exhibited substantial tolerance of nitrogen fixation to soil drying, indicating a need to search an even more diverse population of peanut to identify a genetic source for tolerance.}, number={4}, journal={JOURNAL OF CROP IMPROVEMENT}, author={Pradhan, Deepti and Dunne, Jeffrey and Ramirez, Martha and Sinclair, Thomas R.}, year={2020}, month={Jul}, pages={540–548} }
 @article{pradhan_shekoofa_sinclair_2019, title={Temperature effect on peanut (Arachis hypogaea L.) transpiration response to vapor pressure deficit and its recovery}, volume={33}, ISSN={["1542-7536"]}, DOI={10.1080/15427528.2018.1552900}, abstractNote={ABSTRACT Partial stomata closure under high atmospheric vapor pressure deficit (VPD) has been identified as a means to conserve soil water to allow sustained crop physiological activity late in the growing season, especially during reproductive growth. This trait has been identified as potentially being particularly important in peanut (Arachis hypogaea L.) since peanut is commonly grown on sandy soils under variable rainfall conditions. While 11 peanut genotypes had been previously identified as expressing limited-transpiration trait (TRlim) at 32°C, there is no information on their response to VPD at higher temperatures to which peanut may be exposed. This study documented the response of these 11 genotypes to VPD when subjected to increasing temperatures at 2°C intervals from 32°C to 38°C. Nine of the 11 genotypes lost expression of the TRlim trait within this temperature range. Only two genotypes (N013042ol and G644) were able to sustain the TRlim trait at 38°C. Recovery of expression of the TRlim trait following the loss of the trait at high temperature also varied among genotypes. Three genotypes that lost expression of TRlim at 36°C were returned to 32°C to determine the ability to recover the trait. Two genotypes showed full recovery of TRlim within 1 or 2 days, whereas the third showed no recovery across 3 days. This study provides useful information on genotypic variability in transpiration response to VPD under high temperatures that can be applied in developing cultivars that are better suited to water-limited conditions.}, number={2}, journal={JOURNAL OF CROP IMPROVEMENT}, author={Pradhan, Deepti and Shekoofa, Avat and Sinclair, Thomas R.}, year={2019}, month={Mar}, pages={177–186} }
 @article{sinclair_pradhan_shekoofa_2018, title={Inheritance of limited-transpiration trait in peanut: an update}, volume={32}, ISSN={["1542-7536"]}, DOI={10.1080/15427528.2017.1420000}, abstractNote={ABSTRACT Peanut (Arachis Hypogeae L.) is commonly grown on sandy soil and in environments with intermittent rainfall, both of which can lead to soil water-deficit. Limited transpiration (LT) under elevated vapor pressure deficit (VPD) can result in water conservation, allowing sustained physiological activity later in the season during reproductive development. The objective of this study was to expand the number of progeny lines phenotyped for expression of the LT trait from the mating of Tifrunner (LT trait not expressed) × NC 3033 (LT trait expressed) to allow a preliminary examination of inheritance. Half of the 24 phenotyped lines expressed LT with their VPD threshold ranging from 2.16 to 3.38 kPa. Six of the 12 genotypes expressing LT had a threshold at 2.65 kPa or less, which is the range likely to be relevant in most peanut environments. These results, indicating epistatic inheritance, are supportive of LT expression in progeny lines at a reasonable frequency for relevant use in cultivar development for water-deficit conditions.}, number={2}, journal={JOURNAL OF CROP IMPROVEMENT}, author={Sinclair, Thomas R. and Pradhan, Deepti and Shekoofa, Avat}, year={2018}, pages={281–286} }
 @article{pradhan_sinclair_alijani_2018, title={Nitrogen Fixation Establishment during Initial Growth of Grain Legume Species}, volume={32}, ISSN={["1542-7536"]}, DOI={10.1080/15427528.2017.1393648}, abstractNote={ABSTRACT Atmospheric nitrogen fixation as a result of the symbiosis between bacteria and legume species, can result in major advantages in providing host plants with organic nitrogen. The objective of the present study was to evaluate the physiological potential during early seedling development for initiation of nodulation and nitrogen fixation activity of four grain legumes species: soybean [Glycine max (L.)], cowpea [Vigna unguiculate (L.) Walp], common bean [Phaseolus vulgaris (L.)], and peanut [Arachis hypogaea (L.)]. Seedlings were grown on a hydroponic solution so that nodule development could be readily observed until about 3 weeks after germination. Nodules developed in all cases. Acetylene reduction activity (ARA) by soybean and cowpea was also found early in seedling development. In contrast, peanut and common bean showed little or no development of ARA during seedling development. The results provided insight into differences in physiological potential among grain legumes in establishing symbiotic nitrogen fixation during crop establishment. These results indicate those species/cultivars that are candidates for readily establishing nitrogen fixation activity during the seedling stage of plant development.}, number={1}, journal={JOURNAL OF CROP IMPROVEMENT}, author={Pradhan, Deepti and Sinclair, Thomas R. and Alijani, Khadijeh}, year={2018}, pages={50–58} }