Spike Yield Research Articles

A generalized model for accurate wheat spike detection and counting in complex scenarios

Wheat is a crucial crop worldwide, and accurate detection and counting of wheat spikes are vital for yield estimation and breeding. However, these tasks are daunting in complex field environments. To tackle this, we introduce RIA-SpikeNet, a model designed to detect and count wheat spikes in such conditions. First, we introduce an Implicit Decoupling Detection Head to incorporate more implicit knowledge, enabling the model to better distinguish visually similar wheat spikes. Second, Asymmetric Loss is employed as the confidence loss function, enhancing the learning weights of positive and hard samples, thus improving performance in complex scenes. Lastly, the backbone network is modified through reparameterization and the use of larger convolutional kernels, expanding the effective receptive field and improving shape information extraction. These enhancements significantly improve the model’s ability to detect and count wheat spikes accurately. RIA-SpikeNet outperforms the state-of-the-art YOLOv8 detection model, achieving a competitive 81.54% mAP and 90.29% R2. The model demonstrates superior performance in challenging scenarios, providing an effective tool for wheat spike yield estimation in field environments and valuable support for wheat production and breeding efforts.

Assessing the Management of Nitrogen Fertilizer Levels for Yield Values, Photosynthetic Characteristics and Non-Structural Carbohydrates in Rice

The interaction between the amount and frequencies of nitrogen application has always been a hot issue in improving crop yield and reducing environmental pollution. Photosynthesis and non-structural carbohydrates (NSCs) play an important role in the formation of rice yield. However, the research on photosynthetic characteristics and NSCs under nitrogen fertilizer management on rice yield is still insufficient. This work was a two-year field trial in China’s Hunan Province in 2020–2021. To analyze the photosynthetic characteristics and NSCs of the hybrid rice “Zhu Liangyou 819” (ZLY819), the experiment was set up with N application frequencies, specifically P1 (basal-tiller fertilizer at a ratio of 5:5), P2 (basal-tiller-spike fertilizer at a ratio of 4:3:3), and P3 (basal-tiller-spike-grain fertilizer at a ratio of 4:3:2:1). Additionally, three distinct amounts of N applications were utilized: N1 (90 kg ha−1), N2 (150 kg ha−1), and N3 (210 kg ha−1). The findings indicated that under the same N application amount, N2 increased the effective spike by 9.32–17.80% and the number of grains per spike by 12.21–13.28% compared with N1. Under the same N application frequency, P3 had the highest effective number of spikes and number of grains per spike, which were 320.83 × 104 ha−1 and 113.99–119.81, respectively. Under the same N application amount, the SPAD and photosynthetic rate (Pn) of N2 at the heading stage were increased by 5.61–5.68% and 11.73–13.81%, respectively, compared with that of N1; and at the maturity stage, the SPAD of N2 was increased by 14.79–17.21%. At the same N application frequency, SPAD and Pn were 5.40–6.78% and 4.70–12.85% higher in P3 compared to P1, respectively, at the heading stage. At maturity, SPAD showed 14.59–15.64% higher values in P3 compared to P1. The photosynthetically active radiations (PAR) and radiation use efficiency (RUE) of ZLY819 obtained the highest values under N2 or N3 as the differences between these both were nonsignificant. PAR and RUE tended to increase with the increase in the application frequency. NSC accumulation, output, and contribution rate to grains all exhibited a pattern of initial increase followed by a subsequent decline in response to escalating nitrogen application, i.e., it was highest under N2 treatment. A statistically significant positive correlation was observed between rice yield and effective number of spikes, number of grains per spike, SPAD, Pn RUE, output of NSCs, and contribution rate to grains. Appropriate amount and frequency of N application (P3N2) can significantly improve photosynthetic characteristics and NSCs of rice, thus increasing rice yield.

A new bacterial consortia for management of Fusarium head blight in wheat

Fusarium head blight (FHB) is a significantly important disease in cereals primarily caused by Fusarium species. FHB control is largely executed through chemical strategies, which are costlier to sustainable wheat production, resulting in leaning towards sustainable sources such as resistance breeding and biological control methods for FHB. The present investigation was aimed at evaluating newly identified bacterial consortium (BCM) as biocontrol agents for FHB and understanding the morpho-physiological traits associated with the disease resistance of spring wheat. Preliminary evaluation through antagonistic plate assay and in vivo assessment indicated that BCM effectively inhibited Fusarium growth in spring wheat, reducing area under disease progress curve (AUDPC) and deoxynivalenol (DON), potentially causing type II and V resistance, and improving single spike yield (SSPY). Endurance to FHB infection with the application of BCM is associated with better sustenance of spike photosynthetic performance by improving the light energy harvesting and its utilization. Correlation and path-coefficient analysis indicated that maximum quantum yield (QY_max) is directly influencing the improvement of SSPY and reduction of grain DON accumulation, which is corroborated by principal component analysis. The chlorophyll fluorescence traits identified in the present investigation might be applied as a phenotyping tool for the large-scale identification of wheat sensitivity to FHB.

Assessment of stability for some yield components in wheat under different fertilizations on saline soil

Salt-affected soils constrain wheat production in many countries. It is estimated that more than 831 million hectares (Mha) are salt affected globally, with 10 Mha of cultivated land lost annually. Salinity adversely affects wheat grain yield and grain quality traits. Wheat genotypes show wide variation for salinity stress tolerance. The main objective of this study was to evaluate the performance and stability of spike traits in 14 winter wheat varieties with different origin, in order to identify the varieties that can exploit the growing conditions of saline soils. The wheat material was tested in nine environments as a combination of three years and three fertilization treatments (urea, calcium nitrate, ammonium nitrate), using a split-plot design with three replications. At maturity plant height, spike length, grains number per spike, and spike yield were determined. The significant effect of genotype × environment interaction on the phenotypic expression of different traits indicates differential response of the genotypes across the testing environments, thus offering the possibility of identifying some genotypes of interest. The Romanian varieties ‘Alex’ and ‘Glosa’ present the highest productivity of spike associated with an average stability, being specifically adapted to favourable rainfall conditions, achieving above-average yields in less favourable conditions. The varieties ‘Cerere’, ‘Genesi’, ‘Alex’ and ‘Glosa’ can be selected for crossing and included in wheat breeding programs for the development of stable cultivars adapted to saline soils.

EXPLORING THE RELATIONSHIP BETWEEN PLANT HEIGHT AND YIELD-CONTRIBUTING ATTRIBUTES OF WHEAT IN DROUGHT CONDITIONS

Plant height is the most dynamic yield-affecting trait which has strong genetic and phenological associations with yield performance in wheat. The objective of the study was to explore the effect of plant height on spike yield by investigating the interrelationship between height and yield components of ninety wheat genotypes under a drought environment. Different statistical procedures including correlation, regression, path coefficient, principle component, biplot, and cluster analysis were performed to dissect the associative role of height and yield components in setting the yield potential of wheat plants. High positive correlation and direct effects are seen for spike yield from seed weight (r = 0.73) and seed number (r = 0.60) with a participatory contribution of 58% and 40%, respectively. But plant height is negatively associated with thousand seed weight (-0.22*) and spike yield (-0.15) in such a way that each additional unit (1cm) of height reduces 0.11 g thousand seed weight and 0.06 g spike yield due to negative regression. PC1 and PC2 associate height and yield components respectively and both types of traits moderately oppose each other for simultaneous improvement. Highly tall and short plants were observed with low yield potential under water-limited resources due to strong negative effects either on seed weight or number. An increase in height favors seed number but reduces enough seed weight to cause comparative losses. Intelligent allocation of plant resources to height or spike defines the plant yield potential. Plants with moderate height ranging from 74-83 cm were seen with the best yield potential among five different classes of height. Genotypes HM729, HM829, and HM644 belonged to this class and their better yield potential was due to the balance ratio of seed weight and number. This work would help direct our breeding programs for the improvement of the height-oriented yield potential of wheat.

Genetic Diversity Studies in Durum Wheat (Triticum durum L.) Accessions

Genetic diversity among durum wheat tetraploid species has a premium to understand the diversity within the genotypes. This study’s major objective was to learn more about the diversity and relationships between various durum genotypes. The experiment was design randomized complete block design with three replications. In this study, a total of eight durum advance lines, namely DW-1, DW-2, DW-3, DW-4, DW-5, DW-6, DW-7, and DW-8, were included with one Durum check wheat Miki3 and spring wheat Khirman to investigate the interrelationship and genetic diversity of quantitative traits and they ‘reaming these traits. For nearly all of the features, the analysis of variance revealed considerable variations among the durum advance lines, as evidenced by the significant mean squares at a probability level of P≤0.01. The mean performance results indicated variations in genotype performance DW8 exhibited maximum days to heading, tallest plant height (cm), and shortest peduncle length was measured in durum wheat. DW6 attained shorter plant height was recorded as compared to both check varieties. A notable variation was detected among the genotypes concerning the trait "number of tillers per m2". The genotype with the highest number of tillers appeared to be spring wheat and the minimum number of tillers was recorded in DW4, respectively. Significantly maximum number of spikelet’s, per spike-1,biological yield plant-1 and protein content % were observed in DW3, amount of grains spike-1 were significant in DW6, main spike yield per plant (g) was recorded in DW3. Whereas minimum grains spike-1and minimum spike yield was observed in DW9, respectively. Grain yield plot-1 (2.3333 kg) was observed significantly higher in DW6 and minimum Grain yield plot-1 (1.6667 kg) in DW10 was observed. Regards correlation, Grain yield plant-1 revealed there was a positive and significant correlation with respect to the trait "days to75% headline, days to 75% maturity, grains Spike-1, main spike yield-1 and 1000-Grain Weight (g) (r=0.500**, r=0.679**, r=0.316*, r=0.316*, r=0.533** and r=0.308*). Using UPGMA, two members of cluster 1 and cluster 2 were found to have closer relationship with different durum genotypes. However, miki 3 had closer relation with DW-8. The largest positive PCA loadings were observed in grains yield plant-1 and 1000 grains weight for the second, third, fourth and fifth PCA group. Hence, DW-8 was nearer relation with miki3, and DW-3, DW-10 and DW-6 considered the best genotypes according to performance.

Yield performance of four wheat cultivars under semi-arid conditions

The research was conducted at Kalar Technical College – Garmian Polytechnic University in Garmian region during the growing season 2023, using randomized complete block design (RCBD) with six replications, to evaluate yield performance of four wheat cultivars i.e, (Al-Rashi, Adana99, Wafia, and Deng) under semi-arid conditions. Analysis of variance showed a significant difference between genotypes for all traits measured in this experiment (P<0.05). . For grain yield and number of spikes per m2, there was no significant difference between Deng, Wafla and Adana 99 (max. 343.3 for Adana99), but they had significantly higher values than Al-Rashid (P<0.05), while in spike length Al-Rashid had the longest spike (13.53 cm; P<0.05). Adana 99 had significantly the highest number of seeds per spike (48.36; P<0.05). For the weight of 1000 seeds, Deng, Wafia and adana 99 (max. 45.04 gm for Deng) were also able to have significantly higher weights than the local wheat cultivar Al Rashid which displayed a comparatively lower average weight for this particular characteristic, which was (37.44 g). The research recommends that Adana wheat cultivar has superior performance compared to other cultivars, making it well-suited to be cultivated in Garmian area.

Pseudotyping Improves the Yield of Functional SARS-CoV-2 Virus-like Particles (VLPs) as Tools for Vaccine and Therapeutic Development.

Virus-like particles (VLPs) have been proposed as an attractive tool in SARS-CoV-2 vaccine development, both as (1) a vaccine candidate with high immunogenicity and low reactogenicity and (2) a substitute for live virus in functional and neutralization assays. Though multiple SARS-CoV-2 VLP designs have already been explored in Sf9 insect cells, a key parameter ensuring VLPs are a viable platform is the VLP spike yield (i.e., spike protein content in VLP), which has largely been unreported. In this study, we show that the common strategy of producing SARS-CoV-2 VLPs by expressing spike protein in combination with the native coronavirus membrane and/or envelope protein forms VLPs, but at a critically low spike yield (~0.04-0.08 mg/L). In contrast, fusing the spike ectodomain to the influenza HA transmembrane domain and cytoplasmic tail and co-expressing M1 increased VLP spike yield to ~0.4 mg/L. More importantly, this increased yield translated to a greater VLP spike antigen density (~96 spike monomers/VLP) that more closely resembles that of native SARS-CoV-2 virus (~72-144 Spike monomers/virion). Pseudotyping further allowed for production of functional alpha (B.1.1.7), beta (B.1.351), delta (B.1.617.2), and omicron (B.1.1.529) SARS-CoV-2 VLPs that bound to the target ACE2 receptor. Finally, we demonstrated the utility of pseudotyped VLPs to test neutralizing antibody activity using a simple, acellular ELISA-based assay performed at biosafety level 1 (BSL-1). Taken together, this study highlights the advantage of pseudotyping over native SARS-CoV-2 VLP designs in achieving higher VLP spike yield and demonstrates the usefulness of pseudotyped VLPs as a surrogate for live virus in vaccine and therapeutic development against SARS-CoV-2 variants.

Multi-environment investigations using GGE biplot and regression model for higher spike yield and essential oil content in lavender (Lavandula angustifolia)

Lavender is a highly valuable medicinal and aromatic perennial shrub lacking superior and stable varieties for varied environments in the western Himalayas. In the present experiment, estimates of genotypic effects and their interaction with the environment under various conditions of Himachal Pradesh were investigated to identify superior and stable genotypes. For that, seven selections with a check were evaluated at four different locations in randomized block design with three replications during 2020 and 2021. The pooled analysis of variance showed that genotypic and environmental main effects were highly significant for all the traits under study while, G×E interaction was significant (p≤0.05) for plant height, spike length and spike yield. The highest mean performance for all the traits revealed that location-4 has favourable conditions for lavender cultivation, and LOH15141 followed by LOH15040 were the best performers over all the locations. These high-performing genotypes were clustered together with the check in a major cluster. The stability parameters of the Eberhart and Russell model showed that LOH15141 is stable and superior for both spike yield and essential oil content, further confirmed by GGE biplot analysis. GGE biplot analysis revealed that all the tested locations formed a single mega-environment. The strong positive yield contribution described through Pearson’s correlation coefficients and genotypic path diagram states that plant height, number of spikes and spike length were significant contributors to the spike yield and could be used as selection criteria to improve spike yield due to their high heritability and genetic advance.

Genetic Variability and Heritability of Tuberose (Polianthes tuberosa) Cultivars under Agro-Climatic Conditions of Prayagraj

The present study entitled “Genetic variability and heritability of Tuberose cultivars under agroclimatic conditions of Prayagraj” was made to identify the suitable variety for growing in Prayagraj, Uttar Pradesh. Fifteen varieties were laid out in Randomized Block Design with three replications during May 2022 to February 2023 at Departmental field of Horticulture, NAI, SHUATS, Prayagraj. The observations recorded on various growth, yield and quality contributing characters. The result from the present investigation revealed the genotypes Arka Suvasini, Mexican single and Hyderabad single are identified as higher spike yield per plot which indicated that these genotypes may be shown for higher yield at Prayagraj Agro-climatic condition. The PCV were higher than GCV for all the characters taken in to consideration. High magnitude of GCV and PCV was recorded for No. of bulblets per plant, weight of bulb per plant , yield of bulb per hectare and weight of bulb and least estimates for PCV and GCV was observed for no. of leaves at 6 month after planting. Heritability and genetic advance indicate that the additive nature of gene action and reliability of those characters for selection and emerged as ideal traits for improvement through selection.

Farklı Çevrelerde Yetiştirilen Bazı Ekmeklik Buğday Çeşitlerinin (Triticum aestivum L.) Bazı Fizyolojik ve Verim Özelliklerinin Değerlendirilmesi

This study aimed to evaluate the performance of some bread wheat varieties in different environments, and to reveal the relationships between some physiological parameters and yield and yield components. Three bread wheat varieties, (Namely, Basribey 95, Alibey, and Kaşifbey 95), were used as plant materials. Field experiments were conducted during the 2009-2010 and 2010-2011 growing seasons in Aydın and Menemen locations. The experimental layout was a RCBD with three replications at each location and year. In the study, canopy temperature depression (CTD), chlorophyll content (CC), stomatal conductance (SC), grain yield (GY), plant height (PH), spike number per square meter (S/m2), thousand kernel weight (TKW), test weight (TW), grain number per spike (G/S), single spike yield (SSY), number of days to heading (DHE), were examined. CTD in ZGS 65 had a decisive role in gaining high grain yield. Also, CC in ZGS 65 and ZGS 71 might be defined as an important physiological traits. On the other hand, the contribution of the SC parameter determined in ZGS 55, ZGS 65 and ZGS 71 to the yield depends on the environment. Those parameters could be selection criteria for high-yield wheat breeding due to positive and significant correlations with grain yield. And also SC and CC parameters might be used in yield estimation on wheat.

Response of Durum wheat (Triticum turgidum L. var. Durum) to direct and indirect selection under semi-arid conditions in Algeria

In arid and semi-arid areas, drought is an important abiotic factor that limits Durum wheat production. Identifying genotypes tolerant to drought is a challenge for plant breeders. This study aimed to evaluate the effect of direct and indirect selection on Durum wheat under rain-fed conditions in the high plains of Sétif, Algeria. Four parental varieties (Ofanto, MBB, Mrb5, Waha), three crosses (Ofanto/MBB, Ofanto/Mrb5, Ofanto/Waha) representing the F5, F6, and F7 populations, and one cultivar (Bousselm, control) were cultivated. Pheno-morpho-physiological traits were measured at the heading stage and yield and its components at grain maturity. Our results showed that the response to direct selection was reflected in a significant increase in grain yield, economic yield, and number of spikes, suggesting that grain yield may be improved using one of these characteristics as the selection criterion. Selection by canopy temperature was affected by a significant decrease in the drought susceptibility index (-11.3 %), making it possible to obtain abiotic stress-resistant lines. The study of the relationships between F5, F6, and F7 populations has shown that grain yield, economic yield, and plant height correlate with each generation, indicating no effect of genotype-environment interaction, unlike others. Late selection revealed eight meaningful lines (L1, L8, L14, L28, L32, L35, L36, and L40) in the selection process, maintaining high production throughout different cropping seasons. These successful lines were selected based on traits related to productivity: Gr.YLD, Ec.YLD, NS. These characters provide the same information as breeding programs, according to our results.

Effect of Drought Stress on Bread Wheat (Triticum aestivum L.) Genotypes

Drought is one of the environmental stress factors and the most important factor limiting crop production, especially in rain-based agricultural areas. This research aimed to determine the effects of drought stress on some bread wheat genotypes and to determine drought tolerant genotypes among genotypes. In the research, 20 bread wheat genotypes were used as material. The experiment was carried out in fully controlled greenhouses belonging to the Faculty of Agriculture of Dicle University in 2022 according to the randomized blocks trial design with 4 replications. An artificial drought stress environment was constituted by irrigating the pots up to 40% of the field capacity. As a result of the research, as the plants belonging to five genotypes lost their vitality as a consequence of the drought effect, observations could not be taken and they were not subjected to statistical analysis. Among the investigated characteristics, the chlorophyll content (SPAD) value in the spiking stage, the chlorophyll content (SPAD) value in the flowering stage, the number of days spike, and the plant height were affected by the drought application at the level of 1%, while the spike height and the number of grains per spike were affected at the 5% level. It is noteworthy that line 6, which is the prominent genotype among the genotypes in terms of spike yield, is also the earliest, has the longest plant height, and is the genotype with the highest number of grains per spike.

Efficacy of seaweed and neemcake on growth and flowering attributes of tuberose (Polianthes tuberosa L.) in the plains of West Bengal

An experiment was carried to evaluate the effect of combined application of seaweed and neem cake on growth and flowering of tuberose (Polianthes tuberosa)cv. Prajwal. The study was laid out under Randomized Block Design (RBD) with eleven treatments and three replications where different combinations of neem cake and seaweed were compared with control. The result of the experiment revealed that the application of neem cake and seaweed significantly affected the quantitative and qualitative characters of tuberose. Among all the treatments, treatment T11 (Seaweed 4g/m2 + Neem cake 0.4 kg/m2 ) was found most effective regarding the growth and flowering attributes in comparison to control. The treatment T11 (Seaweed 4g/m2 + Neem cake 0.4 kg/m2 ) also gave most promising result regarding vase life and spike yield.

Ekmeklik buğdayda (Triticum aestivum L.) 15N izotopu kullanılarak çiçeklenme sonrası kuraklığın azot mobilizasyonu ve gelişimine etkileri

Water and nitrogen shortage are one of the main limiting factors of crop productivity such as wheat and cereals. Increased variation and changes in climate conditions are expected to dominate yield potential of wheat. Nitrogen isotope technique widely used in recent years provides useful information about mobilization and nitrogen use efficiency under environmental constraints. This study aimed to determine the effects of drought conditions applied during different growing periods on nitrogen uptake by using stable 15N isotope, yield and quality properties and stomatal conductivity of bread wheat. Environmental variation was obtained by designing 4 artificial practices (irrigated condition, rainfed condition, early drought (flowering-harvest) and late drought (grain filling-harvest) by rainout shelter with covering progress about drought in different growing periods. Number of grains per spike, 1000 grain weight, single spike yield, spike numbers per square meter, plant height, grain yield, biomass yield, stomatal conductance, protein, ash content and stem δ15N (‰), flag leaf δ15N (‰), grain δ15N (‰) values were determined. The drought period from the beginning of flowering till harvest of plants had adverse impact on grain yield and yield components. The results clearly indicated the practices that may cause drought stress in the generative period should be avoided. In addition, nitrogen use efficiency of bread wheat was disrupted with the decrease in the amount and efficiency of plant water use during drought periods. The results also revealed that contribution of nitrogen to crop yield decreased due to less consumption of nitrogen in plant metabolic activities during drought periods. Based on the results additional water supply decreased δ15N content in mature grains from 13420 ‰ to 9278 ‰. Nitrogen applied in stem elongation period had greater contribution to grain δ15N content (15269 ‰) compared to tillering growth stage (8975 ‰). Nitrogenous fertilizer application time suggested not to be delayed to improve nitrogen contribution in metabolic activities and to prevent postponing the tillering and stem elongation periods. The application of nitrogen improved mobilization and efficiency of nitrogen contribution to different plant parts during generative development stages of bread wheat.

Pleiotropic Effect of the compactum Gene and Its Combined Effects with Other Loci for Spike and Grain-Related Traits in Wheat.

Club wheat (Triticum aestivum ssp. compactum) with a distinctly compact spike morphology was conditioned by the dominant compactum (C) locus on chromosome 2D and resulted in a redistribution of spike yield components. The disclosure of the genetic basis of club wheat was a prerequisite for the development of widely adapted, agronomically competitive club wheat cultivars. In this study, we used a recombinant inbred line population derived from a cross between club wheat Hiller and modern cultivar Yangmai 158 to construct a genetic linkage map and identify quantitative trait loci associated with 15 morphological traits. The club allele acted in a semi-dominant manner and the C gene was mapped to 370.12–406.29 Mb physical region on the long arm of 2D. Apart from compact spikes, C exhibited a pleiotropic effect on ten other agronomic traits, including plant height, three spike-related traits and six grain-related traits. The compact spike phenotype was correlated with decreased grain size and weight, but with an increase in floret fertility and grain number. These pleiotropic effects make club wheat have compatible spike weight with a normal spike from common wheat. The genetic effects of various gene combinations of C with four yield-related genes, including Ppd-D1, Vrn-D3, Rht-B1b and Rht8, were evaluated. C had no epistatic interaction with any of these genes, indicating that their combinations would have an additive effect on other agronomically important traits. Our research provided a theoretical foundation for the potentially effective deployment of C gene into modern breeding varieties in combination with other favorable alleles.

EXOTIC WHEAT GENOTYPES RESPONSE TO WATER-STRESS CONDITIONS

Drought is the most devastating abiotic stress which has significantly threatened global wheat production. The recent study was designed to evaluate the performance of eight exotic wheat lines through the Drought Spring Bread Wheat Yield Trial (DSBWYT), along with a local drought-tolerant check cultivar, Khirman, under water-stressed conditions based on agronomic and yield-related traits. The experiment was conducted during cropping season 2019–2020 in a randomized complete block design with three replications at the Nuclear Institute of Agriculture (NIA), Tando Jam, Pakistan. The analysis of variance revealed that there was a significant difference among the genotypes for all studied traits. The genotype DSBWYT-8 possessed better agronomic traits and growth features like early growth vigor and early ground cover. On the other hand, the genotype DSBWYT-4 performed better in yield and yield-related traits like main spike yield, grains per spike, and 1000-grains weight. Both genotype revealed excellent plot grain yield and harvest index and were not significantly different from each other. The cluster analysis grouped all the genotypes into three clades. The drought-tolerant local check cultivar Khirman clustered with genotypes DSBWYT-2, DSBWYT-4, and DSBWYT-8 thus, this clade can be regarded as drought tolerant. The second cluster comprised of two genotypes, i.e., DSBWYT-1 and DSBWYT-5, which performed relatively low as compared to genotypes present in the drought-tolerant cluster, whereas the genotypes DSBWYT-3, DSBWYT-6, and DSBWYT-7 clustered together to represent low yielding genotypes under drought condition as compared with the check cultivar Khirman. Based on these results, the genotypes DSBWYT-2, DSBWYT-4, and DSBWYT-8 can be recommended as the drought-tolerant genotypes.

Post-flowering Soil Waterlogging Curtails Grain Yield Formation by Restricting Assimilates Supplies to Developing Grains.

Soil waterlogging is among the major factors limiting the grain yield of winter wheat crops in many parts of the world, including the middle and lower reaches of the Yangtze River China. In a field study, we investigated the relationship between leaf physiology and grain development under a varying duration of post-flowering waterlogging. A winter wheat cultivar Ningmai 13 was exposed to soil waterlogging for 0 (W0), 3 (W3), 6 (W6), and 9 d (W9) at anthesis. Increasing waterlogging duration significantly reduced flag leaf SPAD (soil plant analysis development) values and net photosynthetic rate (Pn). There was a linear reduction in flag leaf Pn and SPAD as plant growth progressed under all treatments; however, the speed of damage was greater in the waterlogged leaves. For example, compared with their respective control (W0), flag leaves of W9 treatment have experienced 46% more reduction in Pn at 21 d after anthesis (DAA) than at 7 DAA. Increasing waterlogging duration also induced oxidative damage in flag leaves, measured as malondialdehyde (MDA) contents. The capacity to overcome this oxidative damage was limited by the poor performance of antioxidant enzymes in wheat leaves. Inhibited leaf Pn and capacity to sustain assimilate synthesis under waterlogged environments reduced grain development. Compared with W0, W6 and W9 plants experienced a 20 and 22% reduction in thousand grain weight (TGW) in response to W6 and W9, respectively at 7 DAA and 11 and 19%, respectively at 28 DAA. Sustained waterlogging also significantly reduced grain number per spike and final grain yield. Averaged across two years of study, W9 plants produced 28% lesser final grain yield than W0 plants. Our study suggested that wheat crops are highly sensitive to soil waterlogging during reproductive and grain filling phases due to their poor capacity to recover from oxidative injury to photosynthesis. Management strategies such as planting time, fertilization and genotype selection should be considered for the areas experiencing frequent waterlogging problems.

A network modeling approach provides insights into the environment-specific yield architecture of wheat.

Wheat (Triticum aestivum) yield is impacted by a diversity of developmental processes which interact with the environment during plant growth. This complex genetic architecture complicates identifying quantitative trait loci that can be used to improve yield. Trait data collected on individual processes or components of yield have simpler genetic bases and can be used to model how quantitative trait loci generate yield variation. The objectives of this experiment were to identify quantitative trait loci affecting spike yield, evaluate how their effects on spike yield proceed from effects on component phenotypes, and to understand how the genetic basis of spike yield variation changes between environments. A 358 F5:6 recombinant inbred line population developed from the cross of LA-95135 and SS-MPV-57 was evaluated in 2 replications at 5 locations over the 2018 and 2019 seasons. The parents were 2 soft red winter wheat cultivars differing in flowering, plant height, and yield component characters. Data on yield components and plant growth were used to assemble a structural equation model to characterize the relationships between quantitative trait loci, yield components, and overall spike yield. The effects of major quantitative trait loci on spike yield varied by environment, and their effects on total spike yield were proportionally smaller than their effects on component traits. This typically resulted from contrasting effects on component traits, where an increase in traits associated with kernel number was generally associated with a decrease in traits related to kernel size. In all, the complete set of identified quantitative trait loci was sufficient to explain most of the spike yield variation observed within each environment. Still, the relative importance of individual quantitative trait loci varied dramatically. Path analysis based on coefficients estimated through structural equation model demonstrated that these variations in effects resulted from both different effects of quantitative trait loci on phenotypes and environment-by-environment differences in the effects of phenotypes on one another, providing a conceptual model for yield genotype-by-environment interactions in wheat.

Effect of gravity-fed drip irrigation and nitrogen management on flowering quality, yield, water and nutrient dynamics of gladiolus in an Indian inceptisol

Gladiolus is a promising flower crop during winter season and its popularity is growing fast due to its higher price in the market. However, the productivity and quality of the crop in resource-scarce region are constrained by improper irrigation and nitrogen management practices. Based on this presumption, the current study has been developed with the precise objectives of examining the effect of gravity-fed drip irrigation scheduling coupled with integrated nitrogen management on growth, yield, water productivity and macronutrients distribution in soil and plant system of gladiolus. The field experiment accommodating four irrigation levels (surface irrigation I1, and gravity drip irrigation at 1.0, 0.8 and 0.6 (I2, I3 and I4) of pan evaporation replenishment) and three levels of nitrogen management (100% recommended dose of nitrogen (RDN) as vermicompost, 50% RDN as vermicompost + 50% RDN as fertilizer and 100% RDN as fertilizer, respectively N1, N2 and N3) was conducted during three consecutive rabi seasons on gladiolus. I2N2 furnished highest spike/plot (72.9), florets/spike (10.6), longest spike length (66.7 cm), greatest spike weight (43.0 g) and maximum spike yield (10458 kg ha−1) which were at par with I2N2. Highest crop water productivity (CWP) of 9.06 kg m−3 was accomplished in I4N2 followed by I3N2 (8.84 kg m−3). Drip irrigation, on average, could save water by 20.6% for I2, 36.6% for I3 and 52.4% for I4 and improve CWP by 50.2% for I2, 65.2% for I3 and 65.2% for I4 as compared with I1. Two predictive models were developed based on flower yield vs. I and ETa. Ky for total growing season was estimated at 0.66 (R2= 0.91). Maximum soil water storage was accumulated in the surface layer and well distributed down the layers underneath in drip irrigation system, while the reverse trend was noticed in the surface irrigation. Higher availability of soil N and leaf N concentrations were obtained with I2N2 and I3N2 and lower with I1N1. Based on maximum spike yield, water productivity, substantial water saving and N economy, I2N2 and I3N2 emerged superior for the selected inceptisol.