Semi-arid Conditions Research Articles

Gas exchange in yellow passion fruit hybrids in the Semiarid region

Agronomic characterization and exploitation of the genetic variability in plants of the Passiflora can reveal important genetic resources because the Passiflora species grown under semiarid conditions make important contributions to breeding. The aim of this work was to evaluate the vegetative and physiological characteristics of fifteen yellow passion fruit hybrids in semiarid conditions. The experiment was conducted at IF Baiano – campus Guanambi, Bahia, Brazil. The 15 treatments were 10 genotypes: H09-10; GP09-02; H09-02; H09-14; H09-07; H09-09; FOP09; GP09-03; H09-30; FOP08 from the Active Germplasm Bank of the Genetic Breeding Program of Embrapa Cassava and Fruits, and five commercial hybrids: FB200; FB300; BRS SC; BRGA; BRS Rubi. The treatments were arranged in a randomized block design, with three replications and five observational units per plot. Vegetative characteristics (main branch length, number of functional leaves, number of nodes, and number of flower buds) were measured at full vegetative development, 90 days after transplanting (DAT). Hybrid H09-10 is the earliest in flowering, physiologically more efficient in the morning, closes stomata in the afternoon, regulates transpiration, and has lower leaf temperature, higher photosynthesis rate, and more efficient water use. Gas exchanges and photosynthesis rates, at 300 DAT, vary between hybrids and reading times: photosynthesis is higher in the morning while transpiration is greater in the afternoon. The reduction in carboxylation efficiency is related to non-stomatal factors. Gas exchange variables of the genotypes tend to be directly correlated with the photosynthetically active radiation incident on the leaf

Factors restraining youth involvement in fish farming business: Case study of Kamuthanga Village, Kenya

Fish farming serves as one of the important strategies for reducing unemployment and improving the standard of living for many households. However, in many African countries, including Kenya, a large number of young people tend to pursue administrative and white-collar jobs, resulting in a noticeable lack of youth participation in the fish farming sector. This trend underscores the challenge of attracting youth to agricultural enterprises like fish farming, despite its promising opportunities. This study explored the factors limiting youth participation in the fish farming business, targeting some individuals aged 18-35 in Kamuthanga village. The research follows a qualitative case study approach, with twenty-six (26) individuals interviewed. The study is grounded in the anthropological entrepreneurship theory, utilizing triangulation to ensure a holistic understanding. In-depth interviews and key informant interviews were employed to capture perceptions regarding barriers to youth involvement. The data was gathered through focus group discussions and in-depth interviews and analyzed using Qualitative Data Analysis (QDA) Miner Lite software. Data organization, coding, and theme development were conducted systematically to align with the study’s objectives. The findings revealed several challenges hindering youth involvement in fish farming, including the semi-arid conditions of Kamuthanga village, which lead to water scarcity; limited access to capital; insufficient technical knowledge; inadequate support structures; and some cultural barriers. These findings shed light on the critical factors that must be addressed to foster greater youth involvement in fish farming and ultimately unlock its potential for economic development and unemployment reduction in Kamuthanga village.

The efficacy of crossbreeding on reproductive and productive performance in New Zealand White and Flemish Giant rabbits

Crossbreeding is a well-established practice in livestock production aimed at improving reproductive and productive traits. This study evaluated the effects of crossbreeding on rabbits, focusing on comparisons between purebred Flemish Giant (n = 10), New Zealand White (n = 23), and their crossbred offspring (n = 27). Various parameters, including litter size, body weight, growth rate, and mortality, were assessed. The results demonstrated that crossbred rabbits presented a 15% faster growth rate than purebred rabbits, along with the lowest mortality rate and highest total meat output. This phenomenon, attributed to hybrid vigour, effectively blends the large frame of the Flemish Giant with the good litter size of the New Zealand White. Furthermore, statistical analyses, including ANOVA and Tukey‒Kramer’s honestly significant test, confirmed the significant effects of breed class on productivity, body weight, and carcass yield. Growth curves estimated using the Gompertz model highlighted the superior performance of crossbred rabbits under semiarid conditions. Notably, crossbreeding resulted in offspring with the highest dressing percentage and overall improved performance, offering potential advantages for rabbit producers worldwide.

Optimizing wheat supplementary irrigation: Integrating soil stress and crop water stress index for smart scheduling

A two-year field experiment was conducted to integrate soil moisture stress with the Crop Water Stress Index (CWSI) for optimizing irrigation in winter wheat (Triticum aestivum L.) under varying irrigation regimes. The study took place at the Water Technology Centre (WTC-02) of ICAR-IARI, New Delhi, where the climate shows a blend of monsoon-influenced humid subtropical and semi-arid conditions. Using a randomized block design (RBD), five irrigation treatments were applied: full irrigation and deficit irrigation (DI) at 15 %, 30 %, 45 %, and 60 % levels. Canopy and ambient air temperature data, along with vapor pressure deficit (VPD), were recorded using a developed integrated sensing device to empirically determine the lower baseline equations and upper threshold for CWSI computation at pre-heading and post-heading stages. The slope (m), intercept (c) of the lower baseline equation, and upper threshold (UL) for pre-heading and post-heading were found: m: −1.94, c: −1.33, UL: 1.92°C and m: −1.30, c: −2.37, UL: 2.0°C, respectively. Results showed that increasing water deficit levels led to significant reductions in grain yield, biomass production, and harvest index. A strong negative correlation (R² = 0.95 and 0.93) between mean seasonal CWSI and yield attributes highlighted the utility of CWSI in yield prediction under varying irrigation regimes. It is recommended to schedule irrigation based on the CWSI approach when CWSI ≥0.35 for optimum wheat yields. Integrating CWSI with soil moisture stress provides valuable real-time insights into crop water status, enabling more precise and smart irrigation scheduling.

Effectiveness of Diachasmimorpha longicaudata in Killing Ceratitis capitata Larvae Infesting Commercial Fruits in Dryland Agroecosystems of Western Argentina

Ceratitis capitata (Wiedemann) (medfly) strongly affects Argentinean fruit production and export. Augmentative biological control using the exotic parasitoid Diachasmimorpha longicaudata (Ashmead) is currently applied to this problem. The ability to find and parasitize medfly larvae on a wide diversity of fruit host species is a key issue that needs to be analyzed. This research assessed the effect of the physical features of fruit on the preference of foraging D. longicaudata females and the influence of varying release density on parasitoid performance as a pest mortality factor in three fruit species. Trials were performed inside field cages under semi-arid environmental conditions in Argentina’s central-western fruit-growing region. Sweet orange, peach, and fig were tested. The fruits were inoculated with third-instar larvae of the Vienna-8 temperature-sensitive lethal medfly strain. Naïve, 5 d-old mated D. longicaudata females were released in cages at 20, 40, 80, and 160 parasitoid densities. The highest levels of medfly mortality and parasitoid emergence were recorded in fig and peach, although D. longicaudata also induced mortality in orange, a fruit with few physical features favorable to parasitism. The medfly mortality in all fruit host species significantly increased with an increased number of parasitoid females released into the field cages. Diachsmimorpha longicaudata has high potential as a medfly biocontrol agent.

An elucidation on productivity, energetics, and carbon footprint of different forage land-use systems in semi-arid tropics of Karnataka, India

Forages are rapid biomass-generating crops that often demand intensive management. They necessitate a clear understanding of energy flow and carbon (C) footprinting which in turn helps in optimization of production resources and environmental impact assessment. Therefore, a field experiment was conducted for five consecutive years (2019–2023) to ascertain eight forage crops’ productivity, energetics, and C footprint. The crops under the annual monoculture system were maize and cowpea. While, Napier, Guinea, Rhodes, Green panic, Anjan grass, and Signal grasses were under perennial monoculture system. The results revealed that, the Napier grass was superior in biological productivity by recording 28%–50% higher green fodder yield over other forages. The energy analysis indicated that the Guinea grass consumed the highest energy (61,719 MJ ha−1 Year−1) during production, while Napier grass showed the highest energy output (32,5991 MJ ha−1 Year−1). Further, Napier grass outperformed the rest in terms of energy use efficiency (5.49), energy productivity (2.39 kg MJ−1), net energy gain (266,641 MJ ha−1 Year−1), energy profitability (4.49), nutrient energy ratio (14.7), and human energy profitability (558). Similar to energy input, Guinea grass production showed the highest C input (970 kg-CE ha−1 Year−1). Whereas, highest C output was observed with Napier grass (56,694 kg-CE ha−1 Year−1) due to its substantial C gain (55,805 kg-CE ha−1), C-efficiency ratio (63.79), and C-stability index (0.98). Consequently, Napier grass can be adopted as a productive, energy profitable, and C-efficient forage crop in semi-arid tropical conditions.

Long-Term Manuring and Fertilization Influence on Soil Properties and Wheat Productivity in Semi-Arid Regions

Information on the long-term effects of the addition of organics and fertilizers to wheat under the pearl millet–wheat cropping system with semi-arid conditions in north-western India is still lacking. The present research was conducted in an ongoing field experiment initiated during Rabi 1995 at the Research Farm of Chaudhary Charan Singh at Haryana Agricultural University, Hisar. After 25 years, the impacts of nutrient management practices on soil fertility and wheat productivity were evaluated. The experiment comprised a total of eight treatment combinations viz. half and full doses of recommended fertilizers (N and P), organic manures (FYM: farmyard manure, POM: poultry manure, and PRM: press mud) alone and in combination with NP fertilizers. The conjoint application of organic manure and chemical fertilizers resulted in a positive influx of nutrients via increasing total organic carbon (TOC), available N, P, K, and S, which ranged from 0.46 to 1.42%, 122.70 to 194.70, 15.66 to 74.92, 340.5 to 761.2, and 15.26 to 54.63 kg ha−1 in surface soil (0–15 cm), respectively. Carbon fractions and crop yield were significantly improved by adopting integrated nutrient management (INM). The TOC showed a positive and significant correlation with C fractions (r > 0.92) and with soil-available N, P, K, and S (r > 0.77) content. The data also revealed a strong relationship between TOC and soil-available (0–15 cm) nutrients i.e., available N (R2= 0.769), available P (R2 = 0.881), available K (R2 = 0.758), and available S (R2 = 0.914), respectively. Thus, practices that increased TOC were also beneficial in enhancing the availability of the nutrients in the soil. A positive and highly significant correlation was also found among wheat yield, nutrient (NPKS) content, and uptake. A polynomial relationship between grain yield and grain N (R2 = 0.962), P (R2 = 0.946), and K (R2 = 0.967) content, and between straw yield and straw N (R2 = 0.830), P (R2 = 0.541) and K (R2 = 0.976) content was obtained. Integrated use of PRM7.5 followed by FYM15 and POM5 coupled with NP fertilizers proved best, which could be beneficial for obtaining nutritious and highest wheat yield (grain: 6.01 t ha−1 and straw: 7.70 t ha−1) coupled with improved fertility within a sustained manner under the pearl millet–wheat sequence in prevailing semi-arid conditions of the North Indian state of Haryana.

Relations of the species wealth of adventive and aboriginal fractions of floras with the characteristics of climate and relief in the Middle Volga region

Overall, 34 local floras of vascular plants were analyzed at testing sites in the Middle Volga region with an area of 400 km2. Noticeable differences were revealed in the nature of correlations between the number of species of adventitious and native flora fractions and environmental factors: climate and relief. In the region, the number of native species is negatively related to air temperature, evaporation rates, and water deficit, while adventive species show a positive relationship with these characteristics. Adventive species are more often found in gently sloping lowlands in polygons characterized by increased elevation differences and drainage area. In general, adventitious species are more associated with semi-arid conditions in sites with relatively high ranges of environmental factors and standard deviation. Multiple regression showed that adventive species are more closely related to environmental factors than native species. In the region, adventive species are distributed predominantly in places (ecotopes) with increased environmental heterogeneity. An analysis of the relationships with environmental factors of the studied fractions may indicate that their distribution on the test sites is consistent, as a result of which they do not show opposition, which is also confirmed by the weak positive relationship between the richness of their species.

Impact of Zinc Application on Growth, Yield, and Quality of African Marigold in Semi-Arid Conditions

Marigold is a widely cultivated, hardy flower crop known for its adaptability. Among the various intercultural practices in marigold cultivation, foliar application of zinc plays a critical role in enhancing yield and quality, however, standardization of this practice is necessary to optimize commercial production. Hence, the investigation aimed to standardize foliar zinc application for improving productivity in African marigold (Pusa Narangi Gainda) at Rajasthan Agricultural Research Institute, Jaipur, during 2020-21, and 2021-22. Two concentrations of zinc sulphate (ZnSO₄), Z1 (0.2%), and Z2 (0.5%), were applied at 35 and 65 days after transplanting (DAT) in a factorial randomized block design with three replications. Results indicated that Z1 (ZnSO₄ 0.2%) was most effective in increasing plant height, and promoting early bud initiation, and flower opening, while Z2 (ZnSO₄ 0.5%) significantly enhanced plant spread, primary branching, leaf dimensions, plant biomass, root-to-shoot ratio, flower diameter, and yield parameters such as flower mass and number. Z2 also improved quality traits like chlorophyll and xanthophyll content. Statistical analysis revealed significant differences among treatments, suggesting that the application of ZnSO₄ at 0.5% may be recommended for optimizing growth, yield, and quality in commercial marigold cultivation, thereby enhancing productivity and profitability.

Unraveling the impact of high arsenic, fluoride and microbial population in community tubewell water around coal mines in a semiarid region: Insight from health hazards, and geographic information systems

High arsenic (As), fluoride (F-), and microbial pathogens coexist in semiarid conditions afflicting > 240 million people worldwide including Pakistan. Groundwater quality has declined due to geogenic and manmade activities providing suitable ground for ubiquity, bioavailability, and toxicity of contaminants. We tested the health hazard, distribution, and apportionment of As, F-, and microbes in groundwater around coal mines in Quetta, Pakistan. The range of As, and F- concentrations in groundwater were 0.2–16.6 µg/L, 0.4–18.5 mg/L. Both, As and F- correlate with high HCO3-, pH, Na+, SO42-, Fe, and Mn, and negatively with Ca2+ water. The coalfield showed many folds higher As 15.8–28.5 µg/L, and F- 10.8–34.5 mg/L compared to groundwater-wells. Geochemical phases revealed saturation of groundwater with calcite, dolomite, fluorite, gypsum, and undersaturation with halite-mirabilite, and arsenopyrite minerals. The positive matrix factorization (PMF) model assessed five-factor solutions: geogenic, industrial, coal mining, sulfide & fluoride-bearing mineral-dissolution, and agriculture pollution delivered As, F-, and microbial contamination. About 24.6 % and 64.4 % of groundwater samples exceeded the WHO guidelines of As 10 µg/L, F- 1.5 mg/L. The carcinogenicity, and non-carcinogenicity of As, and F- were higher in children than adults. Therefore, health hazards in children are of great concern in achieving sustainable management goals.

Growth performance, blood health, and antioxidant status of freshwater carp under brackish water rearing system: Sustainable aquaculture approach in arid and semi-arid conditions

Global warming, water salinization, and increased anthropogenic usage of freshwater sources have had severe effects on water sources and aquaculture practices, which is consequently putting pressure on aquatic fauna and fish production. Hence, brackish water can be used as an alternative and sustainable approach to meet the increasing food requirements. Four groups with triplicates were designed to evaluate the impact of brackish water on Cirrhinus mrigala (n = 100) for 180 days; T0: control group (freshwater), T1: (5.45 ppt salinity), T2: (8.45 ppt salinity) and T3 (12.45 ppt salinity). Little behavioural alterations and normal feeding were observed in all experimental groups as compared to control group, except group T3. Survival rate was 100 % in all groups excluding group T3, which had shown 88 % survival rate (P < 0.05), while mean weight gain and length gain were observed better with low FCR in T1 and T2 groups (P < 0.05) but best growth rate observed at 5 ppt salinity level. Significant reduction in haemoglobin (Hb), hematocrit (HCT), red blood cells (RBCs) and increase in white blood cells (WBCs) and platelets (PLTs) was observed in group T3 compared to other experimental groups (P < 0.05). ALT, AST, ALP, urea, creatinine, and triglycerides, exhibited significant changes in T3 group after 180 days (P < 0.05). Erythrocytes had shown morphological alterations as; micronuclei, notching, blebbing, pear-shaped nuclei and spherocytes in T3 group. Significant increase in DNA damage in various tissues had indicated potential genotoxic impact of highly saline brackish water. Oxidative stress markers were increased significantly and antioxidants reduced (P < 0.05) at high salinity level brackish water (T3) until 180 days. In conclusion, C. mrigala can potentially grow well in brackish water system at 5 ppt salinity whereas, rise in salinity level (12 ppt) is detrimental to freshwater fish health and growth.

Novel optimized models to enhance performance forecasting of grid-connected PERC PV string operating under semi-arid climate conditions

This study focuses on modeling and forecasting the performance of a grid-connected photovoltaic (PV) string, aiming to enhance the accuracy of output power prediction, which is crucial for the effective management and stability of the electrical grid. While previous research has extensively examined PV modules, there is a notable lack of studies specifically targeting PV string behaviors, especially in harsh climates prevailing in semi-arid regions. This study addresses this gap by investigating the modeling and performance prediction of a Passivated Emitter Rear Cell (PERC) PV string under semi-arid climate conditions using analytical and predictive approaches based on both implicit and explicit models as Single Diode Model (SDM), Das Model (DM), Boutana et al. Model (BM) and Power Law Model (PLM). New mathematical models of DM and BM shape parameters versus temperature and irradiance along with novel analytical formulas giving DM shape parameters as a function of PV metrics have been introduced. The proposed approaches are validated using real measurements of a PERC PV string incorporating 12 JKM405M-72H PV modules operating at Green Energy Park (GEP) research facility in Morocco. The reliability of these approaches is assessed by comparing I-V curves, P-V curves and peak power generated and predicted by SDM, DM, BM and PLM to actual measurements. The comparison reveals that generated and predicted outcomes align well with measured data, with an average value of Normalized Root Mean Square Error (NRMSE) not exceeding 4.16 % for all models throughout the day. The findings indicate that the proposed approaches effectively predict the performance of the PERC PV string, accounting for climatic influences and providing insights into optimizing PV system performance, thereby contributing to improved grid stability in semi-arid regions.

Genetic diversity in rye (Secale cereale L.) landraces based on agro-morphological traits under the semi-arid conditions of Iran

Genetic diversity in rye (Secale cereale L.) landraces based on agro-morphological traits under the semi-arid conditions of Iran

Dissipation and persistence behaviour of fipronil and its metabolites in chilli fruits using GC-ECD, confirmed by GC-MS, under semi-arid conditions

Chilli, one of the most popular vegetables in the world is infested by many insect-pests and diseases. Fipronil, a phenylpyrazole class insecticide is used to manage insect-pests on chilli. The present study aimed to analyze the dissipation patterns and residual concentrations of the fipronil and its metabolites in chilli fruits during the Kharif season of 2020–21, in semi-arid environment. In the study, fipronil was applied to the plants twice, with a 10-day gap between treatments, using a 5 % suspension concentrate. The applications were undertaken using two separate concentrations i.e. the lower dosage of 40 g a.i. ha−1 and higher dosage of 80 g a.i. ha−1. There were four sets of data for each concentration. The chilli crop was systematically sampled at predetermined intervals after the application of the second spray. The procedure encompassed utilizing the modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) technique for extraction and purification, followed by analyzing the resulting residues using Gas Chromatography Electron Capture Detector. Gas Chromatography- Mass Spectrometry was subsequently conducted for the confirmation of the findings. The research revealed that the mean initial deposit of fipronil and its metabolites (desulfinyl, sulphide, and sulfone) at the authorized dosage was determined to be 0.574, 0.123, 0.031, and 0.180 mg kg−1, respectively. In contrast, when administered at twice the prescribed dosage, the mean first deposit was 1.204, 0.230, 0.067, and 0.382 mg kg−1. The half-life values of these residues exhibited a range of 1.2–4.1 days for both dosages. A prudent waiting duration was determined for the doses, leading to the conclusion that an average interval of 7 days is deemed safe for harvesting chilli peppers. The significance of this discovery is related to the maximum residue limits of 0.001 mg kg−1 for fipronil in green chilli, as established by the Food Safety and Standards Authority of India. This study provides significant insights into fipronil's persistence and proper management in chilli plant cultivation, emphasizing the importance of following prescribed dosages and designated waiting intervals to ensure the safety of food products.

ASSESSMENT OF WHEAT GENOTYPES FOR THEIR LOW NITROGEN USE EFFICIENCY UNDER SEMI-ARID CONDITIONS OF PUNJAB, PAKISTAN

Nitrogen is one of the most important and critical macronutrients needed by plants for their optimal growth and development. The current experimental study was designed to examine the response of wheat variety Akbar-2019 under different nitrogen levels keeping the levels of phosphorus and potassium constant. The study was conducted in Chak No. 169/7.R Fort Abbas, District Bahawalnagar under the supervision of the Department of Soil Fertility (Field) during the crop year 2022-23. The experimental material was comprised of a wheat variety Akbar-2019 and five different treatments of nitrogen consisted of (i) N = 160 kg ha-1 (ii) N = 145 kg ha-1 (iii) N = 131 kg ha-1 (iv) N = 117 kg ha-1 and (v) N = 103 kg ha-1. The experiment was laid out under a randomized complete block design with three replications and 170 m² net plot size par treatment per replication. The results revealed the presence of highly significant variations among nitrogen treatments in wheat variety based on the agronomic and morpho-physiological parameters including flag leaf area, thousand-grain weight, grains per spike, relative water contents, stomatal conductance, net photosynthetic rate, biological yield and gain yield. Furthermore, the results also unveiled that treatments with higher nitrogen dosage produce better results for almost all the study parameters including grain yield. These results were also confirmed through correlation coefficient analysis and bar graph graphical representation based on mean data, where correlation coefficient analysis showed a strong positive correlation of grain yield with studied plant traits except biological yield for which the correlation was positive but non-significant. The results suggest that nitrogen in higher amounts up to a certain level is necessary for obtaining maximum output from wheat crops under semi-arid conditions.

Provenance, paleoweathering, sediment maturity, and depositional environment of intertrappean sediments in Angot–Gazo volcanic plateau, northeastern Ethiopia: Evidence from field mapping, petrography and geochemistry

Numerous intertrappean beds have been reported in different sections of the Ethiopian highlands; however, their detailed paleo-sedimentological characteristics have not been fully examined. This study investigates the source rock composition, tectonic setting, degree of past weathering, paleoclimatic conditions, sediment maturity, and depositional environments of the Angot–Gazo terrestrial sediments through geological mapping, mineralogical analysis, and geochemical approaches. Two terrestrial beds, consisting of mudrock and sandstone, were identified. The sandstone is characterized by massive, medium to coarse, and poorly sorted grains that range from sub-rounded to angular shapes. Minerallogically, the sandstone comprises quartz, feldspar, and lithic fragments grains with a proportional amounts of ash material. Both mineralogical (Q–F–R) and geochemical classification plots categorize the sandstone as arkosic to lithic greywacke. Felsic volcanic rocks are the main source material for the investigated sediments, as evidenced by multiple discrimination plots (DF1 vs. DF2, V–Ni–Th∗10, La–Th–Sc, Cr/Th–Th/Sc, La/Co–Th/Co, La/Sc–Th/Co and Y/Ni–Cr/V), LREE/HREE patterns, elemental ratios, and the appearance of abundant felsic-derived lithic fragments within the sandstone. A new bivariate discriminant function plot from DF1 vs. DF2 analysis, coupled with ternary diagrams of Zr/10–Th–Sc for the studied intertrappean sediments, revealed a continental rift setting, particularly a passive continental margin. Ternary diagram of A–CN–K, binary plots of Al₂O₃/Na₂O vs. average values of weathering indices (CIA, CIW, PIA, & MIA), and SiO2 vs. Al2O3+K2O + Na2O plot demonstrate slight to moderate degree of weathering for the sandstone, and deep weathering for the mudrock under semi-arid paleoclimatic conditions. The binary schemes of SiO2/Al2O3 and Ni–TiO2 ratio, along with the significant abundance of angular to sub-angular framework grains, reflect both immaturity and initial sediment recycling. Finally, the examined sediments were deposited in freshwater under oxic conditions, as evidenced by binary plots of Sr/Ba, Th/U, U/Th, and Ni/Co.

IMPACT OF VARIED AMOUNTS OF NITROGENOUS FERTILIZERS ON GRAIN YIELD AND RELATED AGRO-PHYSIOLOGICAL TRAITS IN SPRING WHEAT (TRITICUM AESTIVUM L.)

The application of nitrogen (N) is a critical factor influencing grain yield and agro-physiological traits in spring wheat (Triticum aestivum L.). This study aimed to evaluate the impact of varied nitrogen levels on grain yield and associated traits under field conditions. The study was conducted in Chak No. 136 / 6.R Haroonabad, District Bahawalnagar under the supervision of the Institute of Soil Fertility (Field) during the crop year 2022-23. A randomized complete block design (RCBD) was used, with five N treatments (160, 145, 131, 117 and 103 kg ha⁻¹) applied across three replicates. Key parameters, including flag leaf area, thousand-grain weight, spikelets per spike, number of grains per spike, chlorophyll a, stomatal conductance, net photosynthetic rate, biological yield and gain yield, were measured. The results showed a significant increase in flag leaf area, thousand-grain weight, spikelets per spike, number of grains per spike, chlorophyll a, stomatal conductance, net photosynthetic rate, biological yield and gain yield with increasing nitrogen application, with the highest yield observed at 160 kg ha⁻¹. The results unveiled the presence of highly significant variations among nitrogen treatments in wheat variety based on the agro-physiological parameters including flag leaf area, thousand-grain weight, number of spikelets per spike, number of grains per spike, chlorophyll a, stomatal conductance, net photosynthetic rate, biological yield and gain yield. Furthermore, the results also unveiled that treatments with higher nitrogen dosage produce better results for almost all the study parameters including grain yield. The correlation coefficient analysis also confirmed the results and suggested that any wheat breeding program aimed at improving wheat yield must select its parental genotypes based on traits having the highest correlation with yield i.e., flag leaf area, thousand-grain weight, number of grains per spike, chlorophyll a, stomatal conductance and net photosynthetic rate except the number of spikelets per spike and biological yield for which the correlation was positive but non-significant. The results suggest that nitrogen in higher amounts up to a certain level is necessary for obtaining maximum output from wheat crops under semi-arid conditions.

Protocol for Pre-Selection of Dwarf Garden Rose Varieties

Ornamental plant breeding enables the selection of cultivars with desired features from numerous genotypes; however, this process is time-consuming and resource-demanding. Aiming to establish a pre-selection protocol that can facilitate the selection of dwarf rose varieties, the connection between anatomical and histological characteristics and the vegetative growth of rose cultivars was examined. To assess the adaptive potential of the studied cultivars, intra-annual cambial dynamics were explored relative to the observed meteorological fluctuations during the growing season. The investigation included six garden rose cultivars from the ‘Reka’ and ‘Pixie’ collections, bred under semi-arid open-field conditions in Serbia. Plant height ranged from 20 to 68 cm, with differing growth habits and types. Vegetative growth was significantly correlated with the xylem/phloem ratio, the proportion of total vessel area relative to cross-sectional and xylem areas, vessel-related features, and porosity (correlation coefficients up to 0.78). Regeneration via cambial activity and the formation of false rings were observed in five of the six cultivars studied, with meteorological analysis suggesting that precipitation and temperature triggered cambial reactivation. This approach effectively targets key parameters in the selection of dwarf and climate-resilient rose cultivars, facilitating the development of reliable pre-selection criteria.

Two Genotypes of Tomato Cultivated in Gobi Agriculture System Show a Varying Response to Deficit Drip Irrigation under Semi-Arid Conditions

Water-saving irrigation is of extraordinary importance for tomato production in semi-arid areas of northwest China. For this purpose, we conducted a two-season trial in a solar greenhouse of two tomato genotypes named ‘181’ and ‘Mao Fen 802’ and cultivated with substrate, under four irrigation regimes, i.e., well-watered (WW), low (LWD, 80% WW), moderate (MWD, 60% WW) and high (HWD, 40% WW) water deficit. The substrate water content of WW treatment was 75%θf to 90%θf (where θf is the field capacity). The study results showed that the single fruit weight and yield of tomato were significantly declined with an increasing water deficit degree. Compared to WW treatment, the fruit weight and yield were decreased about 34.45% and 20.35% for ‘181’ and ‘Mao Fen 802’ under HWD treatment, respectively. Conversely, water deficit treatment led to an obvious promotion of WUE and showed an upward trend as the water deficit level increased. In addition, compared to WW treatment, the water deficit significantly decreased the total flavonoids of the ‘181’ tomato by 24.4–93.1%, whereas there was no significant impact on that of ‘Mao Fen 802’. Nonetheless, different individual polyphenols were increased by suitable deficit irrigation for two tomato cultivars. Gallic acid, 3,4-dihydroxybenzoic acid, and naringin of ‘181’tomato were increased by 128.4–195.2%, 8.6–43.7%, and 31–73-fold, respectively, under water deficit compared to WW treatment. Further, under water deficit treatment, p-coumaric acid, benzoic acid, and 3,4-dihydroxybenzoic acid of ‘Mao Fen 802’ were increased by 36.2–49.2%, 59.1–189.7%, and 36.3–106.4% compared to WW treatment. As the main carotenoid component, the lycopene content of tomato fruit exhibited a significant rise of 7.84–20.02% and 20.55–32.13% for ‘181’ and ‘Mao Fen 802’ under three degrees of water deficit compared to WW treatment. Linear regression showed a significantly positive relationship between irrigation amounts and yield, and total polyphenols, whereas there was a significantly negative relationship between irrigation amounts and WUE, and total carotenoids. Based on correlation and PCA, WW and LWD, and MWD and HWD, were gathered together for ‘181’, while LWD, MWD, and HWD, were gathered, and only WW scattered for ‘Mao Fen 802’, along the PC1 direction. It was proposed that ‘Mao Fen 802’ was more sensitive to water deficit than the ‘181’ tomato. In conclusion, water deficit is conductive to water-saving cultivation of the greenhouse tomato and the tomato genotypes, and water deficit level is a key factor necessary for consideration.

Extreme drought events and land surface temperature variations on the northeastern Tibetan Plateau over the last 350 ka

The northeastern Tibetan Plateau (NETP) is located in the ecologically vulnerable northwestern China, with semi-humid and semi-arid conditions. Long-term paleo-hydrological and paleo-temperature variations and their mechanisms over the NETP remain ambiguous, primarily due to the limited availability of well-dated, long-term depositional archives and suitable proxies. In this paper, we investigate climate variations and their underlying mechanisms in the region using Glycerol Dialkyl Glycerol Tetraethers (GDGTs) spanning the last 350 ka. Our results suggest that the NETP underwent substantial drying during glacial periods, with the driest period occurring during the last glacial period. The intensity of drought during glacial periods is comparable to that in the Westerlies-dominated region but differs from that in the East Asian monsoon region. This suggests that the influence of the Westerlies surpassed that of the East Asian summer monsoon (EASM), becoming the major driver of warm-season drought events on the NETP during glacial periods. Additionally, the peaks of aridity events coincide with summer insolation maxima during glacial periods, which may be related to the direct influence of local insolation on regulating evaporation. The reconstructed land surface temperatures were about 6.7 °C during interglacial periods and 2.6 °C during glacial periods, which may be linked to a combination of variations in insolation, CO2 levels, and other internal feedback mechanisms. However, an unusual warming occurred during the last glaciation, with an average temperature of about 4.8 °C. This warming may be related to variations in soil moisture and vegetation resulting from extreme drought. Our study highlights the sensitivity of hydrological variations over the NETP to insolation and Westerlies, as well as the critical roles of soil moisture and vegetation in land surface temperature variations.