Impact of high temperature stress on floret fertility and individual grain weight of grain sorghum: sensitive stages and thresholds for temperature and duration

Citation: Prasad PVV, Djanaguiraman M, Perumal R and Ciampitti IA (2015) Impact of high temperature stress on floret fertility and individual grain weight of grain sorghum: sensitive stages and thresholds for temperature and duration. Front. Plant Sci. 6:820. doi: 10.3389/fpls.2015.00820Sorghum [Sorghum bicolor (L.) Moench] yield formation is severely affected by high temperature stress during reproductive stages. This study pursues to (i) identify the growth stage(s) most sensitive to high temperature stress during reproductive development, (ii) determine threshold temperature and duration of high temperature stress that decreases floret fertility and individual grain weight, and (iii) quantify impact of high daytime temperature during floret development, flowering and grain filling on reproductive traits and grain yield under field conditions. Periods between 10 and 5 d before anthesis; and between 5 d before- and 5 d after-anthesis were most sensitive to high temperatures causing maximum decreases in floret fertility. Mean daily temperatures >25°C quadratically decreased floret fertility (reaching 0% at 37°C) when imposed at the start of panicle emergence. Temperatures ranging from 25 to 37°C quadratically decreased individual grain weight when imposed at the start of grain filling. Both floret fertility and individual grain weights decreased quadratically with increasing duration (0–35 d or 49 d during floret development or grain filling stage, respectively) of high temperature stress. In field conditions, imposition of temperature stress (using heat tents) during floret development or grain filling stage also decreased floret fertility, individual grain weight, and grain weight per panicle

Effect of Bio sulphur granules (BSG) as fertilizer ingredient on different fractions of sulphur in calcareous soil cultivated with blackgram (Var.VBN-8)

The purpose of this study was to examine the various sulphur (S) fractions in experimental pot calcareous soil treated with Bio sulphur granules (BSG) in order to assess the impact of granular sulphur fertilization in S deficient calcareous soil using blackgram (Var. VBN-8) as a test crop.Factorial randomized block design with ten treatments (T1- Absolute control;T2-Recommended dose of NPK and S (Control);T3-Soil test based NPK; T4-T3 + S as Elemental Sulphur @ 40 kg S/ha; T5-T3 + S as BSGI@ 40 kg S/ha; T6-T3 + S as BSGII@ 40 kg S/ha;T7-T3 + Vermicompost @ 4 t ha-1; T8-T4  + Vermicompost @ 4 t ha-1;T9- T5 + Vermicompost @ 4 t ha-1; T10- T6+ Vermicompost @ 4 t ha-1 ) replicated thrice and 5 pots were maintained for each replication. The results of this study revealed that there was an upward trend in all S fractions in every treatment (T1 to T10), in the following order: organic > inorganic > water soluble > exchangeable S. The pot that received vermicompost coupled with BSG II (T10) (ES@ 40 kg ha-1 and MethylobacteriumthiocyanatumVRI7-A4 as S source) was found to have the greatest S-fraction and was higher than other treatments. Therefore, using BSG II in conjunction with vermicompost is necessary to preserve the availability of S nutrients in calcareous soil and increase the solubility of nutrients through S-oxidation

Influence of different types of soils on the growth and yield of Quinoa (Chenopodium quinoa Wild.)

Quinoa is a resilient high-yielding pseudo cereal, gaining attention because of its high nutritional value, strong growth potential, and tremendous source of essential amino acids, micronutrients, vitamins, phenolic compounds, and minerals. The main aim of this investigation was to find the best suitable soil type for maximizing the growth and yield of Quinoa. The pot study was undertaken at the Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore, during the Kharif 2022 season. Eight soil samples (clay loam soils of wetlands of TNAU, sandy loam soils of eastern block of TNAU, sandy loam soils of Mettupalayam, sandy clay loam soils of 36 B eastern block of TNAU, sandy clay loam soils of 37 B eastern block of TNAU, clay loam soils of Ooty, sandy clay loam soils of Govindanaickenpalayam and sandy clay loam soils of Annur) were collected round Coimbatore in Tamil Nadu and tested in a complete randomized design with three replications. The pot study results revealed that growth parameters viz. Plant height (81.5 cm), number of leaves plant-1 (164.8), leaf area (317.7 cm2), number of branches plant-1 (38.0) and dry matter production (22.78 g) were significantly higher in the clay loam soils of Ooty than all other soil types. Similarly, yield attributes such as the number of panicles plant-1 (21.7), panicle length (13.08 cm), number of grains panicle-1 (3050) and grain yield plant-1 (9.60 g) of Quinoa were also higher in the same clay loam soils followed by that in sandy clay loam soils of Govindanaickenpalayam. Red soils of Mettupalayam had shown the lowest growth, yield and yield attributes of Quinoa. Based on the above results, it was concluded that the clay loam soil of Ooty was the best suited for cultivating Quinoa crops

Exogenous melatonin improves seed germination and seedling growth in greengram under drought stress

Drought stress diminishes seedling germination and vigor by reducing water uptake, inhibiting plant growth and development. Most of the pulse growing areas are under rainfed ecosystems, which significantly reduces crop yield. Melatonin, a growth-regulating compound, is widely used to mitigate the negative effects of abiotic stresses in pulses. With this background, a laboratory experiment was conducted to standardize the optimum melatonin concentration for seed treatment and foliar application in greengram, to minimize the ill effects of drought stress. The experiment was arranged in a completely randomized design (CRD) with three replications for each treatment. The treatments consisted of soaking seeds with different melatonin concentrations, viz., 20, 40, 60, 80 and 100 μM. Seeds were sown in a perti dishes and the drought stress was imposed using poly ethylene glycol 6000 (PEG 6000) @ - 0.4 MPa, and plates were maintained at room temperature (24-30 °C). After the seedlings emerged, various seedling growth parameters like germination percentage, shoot length, root length, vigor index, promptness index, germination stress tolerance index, fresh and dry weight of the seedlings, plant height stress index and root length stress index were recorded. The experimental results showed that drought stress significantly reduced germination percentage and other growth-related parameters in greengram seedlings compared to the melatonin treatments. Among the melatonin treatments, seeds treated with @ 100 μM concentration recorded the highest germination percentage (99.67 %), promptness index (98.80), vigour index (1631.68), shoot and root length (8.9 cm and 7.5 cm), fresh and dry weight of the seedlings (3.249 and 0.147 mg seedling-1) under PEG induced drought stress condition

Growth and yield response of winter blackgram (Vigna mungo) under high temperature and elevated CO2 conditions

Blackgram is the most important legume crop grown throughout India. It is mostly cultivated during the rainy and winter seasons in central and southern India. An investigation was carried out during winter 2021 to evaluate the effect of High Day Temperature (ambient+3oC) and Elevated CO2 (600ppm) (HDT and eCO2) and High Day and Night Temperature (ambient+3oC) and Elevated CO2 (600ppm) (HDNT and eCO2) on growth and yield of blackgram (Vigna mungo) under soil plant atmospheric research (SPAR) and ambient conditions with eleven treatments (T1 to T11). The results revealed that significant (P=0.05) increase in photosynthetic rate, stomatal conductance, transpiration rate, number of pods per plant and grain yield by 22.3%, 80.6%, 29.2%, 28% and 41.3%, respectively, under HDT and eCO2 conditions from 46 to 60 DAS (days after sowing) in comparison with HDNT and eCO2 and ambient conditions. The increase in chlorophyll index under HDT and eCO2 during 16 to 30 DAS by 12.9%. The significant increase in the number of flowers per plant and biomass of the blackgram was increased under HDT and eCO2 during 31 to 45 DAS by 7% and 38.1%, respectively. However, the plant height and leaf area index of the blackgram were found to have significantly increased under HDT and eCO2 during the early stage (1 to 15 DAS) by 29.3% and 44.5%, respectively. This experiment indicated a significant increase in crop growth, leaf photosynthesis and yield of blackgram under HDT and eCO2 at flowering stage to pod development stage (31 to 60 DAS) followed by HDNT and eCO2 and ambient condition. The overall findings of the study showed that increased temperature and CO2 levels would result in greater biomass production and increased yield for the black gram.

Performance of dual-purpose sorghum (Sorghum bicolor) under different sowing windows and crop geometry

India is one of the most vulnerable countries to climate change and its impact on agricultural production and livestock. Sorghum (Sorghum bicolor) is an important food crop of India cultivated in tropical and subtropical climates, especially the semiarid tropics; varying environmental attributes significantly affect its duration and yield. Therefore, the present research aimed to evaluate the potential of dual-purpose sorghum under varying sowing windows and crop geometry. The experiment was conducted in Eastern block farm of Tamil Nadu Agricultural University during the summer season- 2022. The experiment was laid out in strip plot design with three different dates of sowing in the main plot, i.e., D1 - First fortnight of February, D2 - First fortnight of March and D3 - First fortnight of April and six different crop geometries in the subplot viz., 45 x 15 cm (S1),45 x 10 cm(S2), 45 x 5 cm (S3), 30 x 15 cm (S4),30 x 10 cm (S5) and 30 x 5 cm (S6) and replicated thrice.The results revealed that sowing during the first fortnight (I FN)  of April with a spacing of 45x 15 cm resulted in maximum grain yield(2585 kg/ha) and for fodder yield, April I FN sowing with a crop geometry of 30x 5 cm resulted in maximum green biomass (43.6 t/ha) as well as dry matter production. So, spacing of 30x 5 cm helps in better utilization of resources along with maximum fodder yield

Implications of high temperature and elevated CO2on flowering time in plants

Citation: Jagadish, S. V. K., Bahuguna, R. N., Djanaguiraman, M., Gamuyao, R., Prasad, P. V. V., & Craufurd, P. Q. (2016). Implications of high temperature and elevated CO2on flowering time in plants. Frontiers in Plant Science, 7. doi:10.3389/fpls.2016.00913Flowering is a crucial determinant for plant reproductive success and seed-set. Increasing temperature and elevated carbon-dioxide (e[CO2]) are key climate change factors that could affect plant fitness and flowering related events. Addressing the effect of these environmental factors on flowering events such as time of day of anthesis (TOA) and flowering time (duration from germination till flowering) is critical to understand the adaptation of plants/crops to changing climate and is the major aim of this review. Increasing ambient temperature is the major climatic factor that advances flowering time in crops and other plants, with a modest effect of e[CO2]. Integrated environmental stimuli such as photoperiod, temperature and e[CO2] regulating flowering time is discussed. The critical role of plant tissue temperature influencing TOA is highlighted and crop models need to substitute ambient air temperature with canopy or floral tissue temperature to improve predictions. A complex signaling network of flowering regulation with change in ambient temperature involving different transcription factors (PIF4, PIF5), flowering suppressors (HvODDSOC2, SVP, FLC) and autonomous pathway (FCA, FVE) genes, mainly from Arabidopsis, provides a promising avenue to improve our understanding of the dynamics of flowering time under changing climate. Elevated CO2mediated changes in tissue sugar status and a direct [CO2]-driven regulatory pathway involving a key flowering gene, MOTHER OF FT AND TFL1 (MFT), are emerging evidence for the role of e[CO2] in flowering time regulation. © 2016 Jagadish, Bahuguna, Djanaguiraman, Gamuyao, Prasad and Craufurd

Genotypic variation in sorghum [Sorghum bicolor (L.) Moench] exotic germplasm collections for drought and disease tolerance

Citation: Kapanigowda, M., . . . & Little, C. (2013). Genotypic variation in sorghum [Sorghum bicolor (L.) Moench] exotic germplasm collections for drought and disease tolerance. SpringerPlus, 2, 650. https://doi.org/10.1186/2193-1801-2-650Sorghum [Sorghum bicolor (L.) Moench] grain yield is severely affected by abiotic and biotic stresses during post-flowering stages, which has been aggravated by climate change. New parental lines having genes for various biotic and abiotic stress tolerances have the potential to mitigate this negative effect. Field studies were conducted under irrigated and dryland conditions with 128 exotic germplasm and 12 adapted lines to evaluate and identify potential sources for post-flowering drought tolerance and stalk and charcoal rot tolerances. The various physiological and disease related traits were recorded under irrigated and dryland conditions. Under dryland conditions, chlorophyll content (SPAD), grain yield and HI were decreased by 9, 44 and 16%, respectively, compared to irrigated conditions. Genotype RTx7000 and PI475432 had higher leaf temperature and grain yield, however, genotype PI570895 had lower leaf temperature and higher grain yield under dryland conditions. Increased grain yield and optimum leaf temperature was observed in PI510898, IS1212 and PI533946 compared to BTx642 (B35). However, IS14290, IS12945 and IS1219 had decreased grain yield and optimum leaf temperature under dryland conditions. Under irrigated conditions, stalk and charcoal rot disease severity was higher than under dryland conditions. Genotypes IS30562 and 1790E R had tolerance to both stalk rot and charcoal rot respectively and IS12706 was the most susceptible to both diseases. PI510898 showed combined tolerance to drought and Fusarium stalk rot under dryland conditions. The genotypes identified in this study are potential sources of drought and disease tolerance and will be used to develop better adaptable parental lines followed by high yielding hybrids

Alien chromosome segment from Aegilops speltoides and Dasypyrum villosum increases drought tolerance in wheat via profuse and deep root system

BackgroundRecurrent drought associated with climate change is a major constraint to wheat (Triticum aestivum L.) productivity. This study aimed to (i) quantify the effects of addition/substitution/translocation of chromosome segments from wild relatives of wheat on the root, physiological and yield traits of hexaploid wheat under drought, and (ii) understand the mechanism(s) associated with drought tolerance or susceptibility in wheat-alien chromosome lines.MethodsA set of 48 wheat-alien chromosome lines (addition/substitution/translocation lines) with Chinese Spring background were used. Seedling root traits were studied on solid agar medium. To understand the influence of drought on the root system of adult plants, these 48 lines were grown in 150-cm columns for 65 d under full irrigation or withholding water for 58 d. To quantify the effect of drought on physiological and yield traits, the 48 lines were grown in pots under full irrigation until anthesis; after that, half of the plants were drought stressed by withholding water for 16 d before recording physiological and yield-associated traits.ResultsThe alien chromosome lines exhibited altered root architecture and decreased photochemical efficiency and seed yield and its components under drought. The wheat-alien chromosome lines T5DS5S#3L (TA5088) with a chromosome segment from Aegilops speltoides (5S) and T5DL(.)5V#3S (TA5638) with a chromosome segment from Dasypyrum villosum (5V) were identified as drought tolerant, and the drought tolerance mechanism was associated with a deep, thin and profuse root system.ConclusionsThe two germplasm lines (TA5088 and TA5638) could be used in wheat breeding programs to improve drought tolerance in wheat and understand the underlying molecular genetic mechanisms of root architecture and drought tolerance

Quantifying pearl millet response to high temperature stress: thresholds, sensitive stages, genetic variability and relative sensitivity of pollen and pistil

The objectives were to (1) quantify high temperature (HT) stress impacts at different growth stages (season long, booting to seed-set and booting to maturity) on various yield components; (2) identify the most sensitive stage(s) to short episodes of HT stress during reproductive development; (3) understand the genetic variations for HT stress tolerance based on cardinal temperatures for pollen germination; and (4) determine relative sensitivity of pollen and pistil to HT stress and associated tolerance or susceptible mechanisms in pearl millet. High temperature stress (≥36/26°C) imposed at different stages and durations caused decrease in number of seeds, individual seed weight and seed yield. Two periods (10–12 days and 2–0 days before anthesis) were identified as most sensitive to short episodes of stress, causing maximum decreases in pollen germination percentage and seeds numbers. HT stresses of ≥36/26°C results in floret sterility. Pistils were relatively more sensitive than pollen grains, causing decreased number of seeds and seed yield. HT stress increased the reactive oxygen species contents and decreased the activity of the antioxidant enzymes in both pollen and pistils. Under HT stress, pistils had relatively higher reactive oxygen species and lower antioxidant enzymes activity compared with pollen grains, which explains greater susceptibility of pistils