Spikelets Spike-1 Research Articles

EVALUATION OF SPRING WHEAT GENOTYPES UNDER WATER STRESSED CONDITION

Pakistan faces severe challenges in wheat production annually due to the devastating effects of drought stress. Therefore, present research was carried out to evaluate 15 exotic bread wheat genotypes along with the local check variety, Khirman for their performance under drought stress. Analysis of variance revealed that all the traits were significantly different (P<0.01) among the cultivars. Based on mean performance, genotype V-18 showed better performance for all the studied characters, while genotype V-14 showed desirable performance for different traits such as early growth vigor, number of grains spikelet-1, number of grains spike-1, number of spikelets spike-1, spike length, peduncle length, and grain yield plant-1. The local check Khirman also produced desirable values for four different traits, namely early growth vigor, number of grains spike-1, peduncle length, and grain yield plant-1. The cluster analysis divided all the genotypes into three distinct clades. The first cluster comprises V-14, V-18, and the local check Khirman, which performed very well under drought conditions compared to the other genotypes. The presence of these genotypes with the local check Khirman is regarded as indicative of drought-tolerant genotypes. The second cluster comprises nine genotypes, namely V-10, V-11, V-12, V-13, V-16, V-19, V-20, and V-23, which performed moderately compared to the genotypes found in the drought-tolerant cluster. The last cluster comprises four genotypes, namely V-09, V-15, V-17, and V-22, which performed very poorly under drought conditions. Overall, the two exotic lines, V-14 and V-18, which were in the cluster with the drought-tolerant variety Khirman, performed very well and can be considered as drought-tolerant genotypes

Planting pattern and nitrogen management strategies: positive effect on yield and quality attributes of Triticum aestivum L. crop

Wheat (Triticum aestivum L.) is a staple food crop that plays a crucial role in global food security. A suitable planting pattern and optimum nitrogen (N) split management are efficient practices for improving wheat production. Therefore, an experiment was performed to explore the effect of N split management and sowing patterns on wheat at the Agronomy Research Farm, The University of Agriculture Peshawar, during rabi season 2020-21 and 2021-22. The treatments consisted of different nitrogen rates of 0, 80, 120, and 160 kg ha− 1 and planting patterns of W, M, broadcast and line sowing. The pooled analysis of both cropping seasons showed that application of 120 kg N ha− 1 increased spikelets spike− 1, grains spike− 1, 1000 grains weight, grain yield, grain N content, evapotranspiration and water use efficiency by 21.9, 16.7, 21.8, 70, 13, 19.9 and 40% as compared to control, respectively. In addition, W and M were observed the best management practices among all planting patterns. The M planting pattern enhanced chlorophyll a, b, carotenoids and evapotranspiration while W plating pattern improved yield components and yield of wheat as compared to broadcast planting patterns. The principal component analysis biplot showed a close association of M and W planting patterns with 120 kg N ha− 1 in most of the studied traits. Hence, it is concluded that split application of 120 kg N ha− 1 in W and M sowing patterns enhanced growth, biochemical traits and water use efficiency, reducing N fertilization from 160 to 120 kg ha− 1 while increasing grain yield of wheat. Hence, it is recommended that application of 120 kg N ha⁻¹ in combination with W and M planting patterns offer a sustainable approach to enhancing wheat production in the alkaline soil conditions of the Peshawar valley.

Genetic variability and trait associations in bread wheat (Triticum aestivum L.) genotypes under drought-stressed and well-watered conditions

Drought is one of the most important yield-limiting abiotic stresses threatening wheat production and productivity. Development of wheat genotypes with enhanced grain yield under drought-stressed conditions depend on the extent of genetic variation present for drought tolerance-related traits. This study was carried out to determine the level of genetic variation and associations of yield and yield attributing traits among 196 bread wheat genotypes under drought-stressed and well-watered conditions. The genotypes were evaluated under greenhouse and field conditions and phenotyped for yield and yield-related traits. The genotypes varied significantly for the traits under both conditions. Grain yield ranged from 2.13 to 3.74 t ha−1 and from 2.52 to 5.06 t ha−1 under drought-stressed and well-watered conditions, respectively. Under both conditions, variances due to genotype were higher than environment and genotype × environment interaction variances for all the traits. Estimates of phenotypic coefficient of variation (PCV) were higher than genotypic coefficient of variation (GCV) for all the traits under both conditions, with both PCV and GCV being highest for kernel weight spike−1 and lowest for spike fertility. Under both conditions, broad-sense heritability estimates ranged from moderately high to very high, accompanied with high genetic advance as a percentage of the mean. Fertile spikelets spike−1, one thousand kernel weight, kernel weight spike−1, biomass yield and harvest index manifested high positive genotypic and phenotypic correlations and positive direct effects on grain yield under both conditions. The first five principal components accounted for 78.4% (well-watered) and 76.0% (drought-stressed) of the variation among the genotypes. The 196 genotypes were delineated into six major clusters under both water conditions, with clusters 3 (well-watered) and cluster 5 (drought-stressed) containing genotypes with the highest ability to tolerate drought stress. Genotypes Alidoro, Bolo, Dinknesh, ETBW8491 and ETBW172938 had high stable yields under both conditions. The identified traits and genotypes were drought tolerant and could be exploited to develop novel genotypes for drought stress tolerance.

Correlation and Path Analysis for Yield and Yield Component Traits on Bread Wheat (Triticum aestivum L.) Genotypes

The research was conducted at Kulumsa Agricultural Research Center Main Station, during July–November, 2021 (Main cropping season) to study the association among traits and estimate the direct and indirect effects of various traits on grain yield of bread wheat genotypes. A total of 64 bread wheat genotypes were evaluated for 16 traits in 8×8 simple lattice design. Grain yields showed positive and highly significant at (p<0.01) genotypic and phenotypic correlation with plant height, number of seeds spike-1, head weight, yield head-1, biomass yield, hectoliter weight, test weight and harvest index. Genotypic correlation coefficients were greater for all significantly correlated with grain yield studied traits than the corresponding phenotypic correlation coefficients, indicating inherent association of the characters, therefore, selection for these characters could improve grain yield. Genotypic path analysis of the direct effects revealed that days to maturity, number of spikelets spike-1, head weight, yield head-1, biomass yield, hectoliter weight, test weight and harvest index exerted direct positive effect on grain yield. Phenotypic path analysis of the direct effects showed that days to maturity, plant height, number of tillers plant-1, number of seeds spike-1, head height, yield head-1, biomass yield, test weight and harvest index had direct positive effect on grain yield. Therefore, these traits should be considered for bread wheat breeding program for yield improvement.

Effect Seed Soaking of Moringa Leaf Extract on Grain Yield and its Component of Three Bread Wheat Cultivars

The experiment was carried out at Research Station of College of Agriculture Engineering University of Baghdad/AL-Jadiriya during 2022-2023 season to study the effect of seed soaking with Moringa leaf extract (MLE) on grain yield and its component of three bread wheat cultivars. A split-plots arrangement according to RCBD was used with three replications. The first factor was bread wheat cultivars (Rasheed, Buhooth 22, Buhooth 10) as a main plots, and the second factor was soaking of wheat seeds with three concentrations (1%, 3%, 5% in addition to 0% tap water as control) as sub-plots. The results showed that cultivar Rasheed gave highest means for number of spikes (388m-2), number of spikelets (23.49 spikelets spike-1), weight of 1000 grain (40.55 g), and grain yield (4.012 t h-1). In addition, the results showed that soak wheat seeds with 3% gave highest means for number of spikelets (23.08 spikelets spike-1), number of grains per spike (51.07 grains spikes-1), weight of 1000 grain (41.71g) and grain yield (4.255 t h-1). The interaction between cultivars and MLE concentrations it was significant in all studied traits except for the number of spikes.

Enhancing iron concentration in bread wheat through Fe-EDTA fortification

Iron (Fe) malnutrition in humans is a global concern which can be revised by improved Fe density in staple crops. A field experiment was performed to evaluate the effect of chelated iron on growth, yield and iron concentration in bread wheat (cv. Moomal) at Tando Jam Pakistan. The treatments included, Control (No Fe-EDTA), Soil supplement of Fe-EDTA (@ 2 kg Fe ha-1), Soil + foliar supplement of Fe-EDTA (@ 2 kg ha-1 and 0.2% Fe at booting, flowering, and milky stage), and Foliar supplement of Fe-EDTA (@ 0.2% Fe at booting, flowering and milky stages). The defined growth and yield traits of wheat were increased with Fe-EDTA applications over control treatment. Among different Fe-EDTA application methods, there was no significant difference for most of the growth and yield parameters (excluding spike length, number of spikelets spike-1, and 1000 grain weight). The amount of Fe in wheat grains was significantly higher in all Fe-EDTA treatments over control, with maximum value (86.54 ± 5.57 mg kg-1) in the treatment where Fe-EDTA was applied in soil + foliar. Similarly, a high Fe build up in surface soil was obtained with treatment of Fe-EDTA in soil + foliar. Overall, with various Fe-EDTA treatments, an increase of 21.2 to 29.1% in grain yield and 1.9 to 4.3 times in Fe concentration of wheat grains was achieved in current study. It is suggested that the Fe should be included in wheat production technology to attain better yield and Fe concentration in grains.

GENETIC ANALYSIS IN VARIOUS GENOTYPES OF BREAD WHEAT UNDER NORMAL AND HEAT-STRESS ENVIRONMENTS

Abiotic stresses have brought the crops to a destructive position towards yield production of crops, especially wheat. The present study was investigated to compare the relationship between normal and heat stress conditions under two different sowing dates viz. normal and late sowing dates (25th Nov and 25th Dec). The correlation coefficients varied with both sowing dates (normal and late planting). In normal planting number of grains showed a significant positive correlation with grain weight spike-1 (r = 0.618**), grain yield plant-1 (r = 0.591**), seed index (r =0 .456**), biological yield plant-1 (r = 0.540**) and harvest index (r =0 .667**). Grains spike-1 contributed significant positive correlation with grains spike-1 (r=0.094**), grain yield plant-1 (r=0.844**), biological yield plant-1 (r=0.936**), harvest index (r=0.556**), leaf area (r=0.791**), relative water content (r=0.763**), chlorophyll content (r=0.853**), cell membrane stability (r=0.828**) and stomatal conductance (r=0.292**). Grain yield plant-1 exhibited a significant positive correlation under normal planting with the number of tillers plant-1, number of spikelets spike-1, grains spike-1, and grain weight spike-1 (r=0.695**,0.207*,0.591**and 0.950**), respectively. Whereas, late planting declared grains spike-1 revelaed signficant positive correlation with grains spike-1 (r=0.094**), grain yield plant-1 (r=0.844**), biological yield plant-1 (r=0.936**), harvest index (r=0.556**), leaf area (r=0.791**),relative water content (r=0.763**), chlorophyll content (r=0.853**), cell membrane stability (r=0.828**) and stolatal conductance (r=0.292**). Under late planting, Yield showed a significant positive correlation with spike length, grains spike-1, and grain weight spike-1 (r=0.343**,0.844**, and 0.964**), respectively

Exploring the recuperative potential of brassinosteroids and nano-biochar on growth, physiology, and yield of wheat under drought stress

Drought stress as a result of rapidly changing climatic conditions has a direct negative impact on crop production especially wheat which is the 2nd staple food crop. To fulfill the nutritional demand under rapidly declining water resources, there is a dire need to adopt a precise, and efficient approach in the form of different amendments. In this regard, the present study investigated the impact of nano-biochar (NBC) and brassinosteroids (BR) in enhancing the growth and productivity of wheat under different drought stress conditions. The field study comprised different combinations of amendments (control, NBC, BR, and NBC + BR) under three irrigation levels (D0, D1 and D2). Among different treatments, the synergistic approach (NBC + BR) resulted in the maximum increase in different growth and yield parameters under normal as well as drought stress conditions. With synergistic approach (NBC + BR), the maximum plant height (71.7 cm), spike length (17.1), number of fertile tillers m–2 (410), no. of spikelets spike–1 (19.1), no. of grains spike–1 (37.9), 1000 grain weight (37 g), grain yield (4079 kg ha–1), biological yield (10,502 kg ha–1), harvest index (43.5). In the case of physiological parameters such as leaf area index, relative water contents, chlorophyll contents, and stomatal conductance were maximally improved with the combined application of NBC and BR. The same treatment caused an increase of 54, 10, and 7% in N, P, and K contents in grains, respectively compared to the control treatment. Similarly, the antioxidant response was enhanced in wheat plants under drought stress with the combined application of NBC and BR. In conclusion, the combined application of NBC and BR caused a significant increase in the growth, physiological and yield attributes of wheat under drought stress.

Pre-anthesis spike growth dynamics and its association to yield components among elite bread wheat cultivars (Triticum aestivum L. spp.) under Mediterranean climate

Wheat (Triticum spp.) grain yield (GY) is highly associated with grain number per unit area (GN m-2). Biomass accumulation and partitioning are essential to understand pre-anthesis spike growth dynamics which determines spike dry matter at anthesis (SDMa) - a GN determinant. Spike growth takes place during the stem elongation period (SE), from terminal spikelet to anthesis, following leaf and spikelet initiation (LS) from sowing to terminal spikelet. In this study, bread wheat cultivars were examined under Mediterranean semi-arid conditions to determine (i) the varietal differences in pre-anthesis phase duration, (ii) whether this variability influences biomass partitioning and spike-related traits, and (iii) to what extent, the genotypic variations in pre-anthesis phase duration and spike growth are associated with yield components. A panel of Israeli commercial bread wheat cultivars were grown in the field during 2016–17 (three environments) and 2017–18 (two environments) and characterized for pre-anthesis phases, floral conditions and spike fertility via histological measurements; spike traits, dry matter accumulation, partitioning at anthesis and maturity and for yield components. Significant variability in the timing of pre-anthesis phases was detected within the tested panel for both LS and SE phases. LS duration was positively associated with growing degree days (GDD) to anthesis across environments (0.72–0.90) while variation in SE was related with differences in GDD to anthesis but to a lesser extent and not in all environments (0.47–0.79). In addition, LS duration, and occasionally SE, were favourably related with a higher dry matter of fertile florets spike-1 (at anthesis) and SDM (at both anthesis and maturity). Principal component analysis (PCA) clearly separates environments and to a lesser extent cultivars within each environment. Two cultivar pairs 'Zahir-Yuval' and 'Negev-Gedera', which flowered concurrently, showed significant differences in the durations of LS and SE phases across most of the environments. Longer LS, in cultivars Zahir and Negev, exhibited increased spikelets spike-1, whereas longer SE (e.g., in Yuval and Gedera) enhanced spike fertility through improving the survival rate of floret primordia (FSR%) of central spikelets. However, there was a trade-off for FSR at the proximal and distal spike portions, resulting in lower grain set (%) leading to reduction of final GN (or GY) in cultivars with longer SE. In the tested panel and under our environmental conditions characterized by growing cycle and Mediterranean climate, the duration of both LS and SE contribute to spike fertility, but LS duration seemed a stronger driver than SE for GN and yield enhancement. Our results highlight the importance of pre-anthesis phases, especially the role of LS in wheat yield increment during the short growing cycle. The varietal combination with variable LS and SE duration could be implemented in breeding pipelines and used as pre-breeding materials for GN improvement. Furthermore, the findings will encourage pre-anthesis traits adoption in Mediterranean bread wheat future breeding programs.

Seed priming influences on yield and protein content of wheat sown at different time

The aim of this field experiment conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, was to investigate the impact of different seed priming techniques and sowing dates on the yield and quality of wheat. The study aimed to identify the most effective seed priming technique and optimal sowing date to enhance wheat productivity and minimize yield reduction. The experiment employed a split plot design with two factors: seed priming techniques (no priming, hydropriming with distilled water, osmopriming with PEG, and halopriming with CaCl2) and sowing dates (November 20, December 05, and December 20). The trial was conducted from November 2019 to April 2020 at the research field. The study consisted of three replications for each treatment combination. Osmopriming exhibited the most favorable results among all priming techniques, showing significantly higher values for effective tillers hill-1 (3.91), number of grains spike-1 (43.82), number of spikelets spike-1 (16.16), grain yield (3.87 tons hectare-1), biological yield (6.02 t ha-1), and harvest index (39.03%). No priming condition resulted in the highest protein content (12.11%), while osmopriming had the lowest protein content (11.77%). The sowing conducted on November 20 yielded the highest number of effective tillers hill-1 (3.57), number of grains spike-1 (42.49), number of spikelets spike-1 (15.75), grain yield (3.71 t ha-1), biological yield (9.70 t ha-1), and lowest protein content (11.74%). Sowing on December 20 resulted in the highest protein content (12.20%). Based on the study's findings, it can be concluded that the osmopriming technique, combined with sowing on November 20, offers the most promising approach to mitigate the yield reduction of wheat. This combination demonstrated the highest grain yield (4.23 t ha-1) compared to other treatments. Therefore, farmers and agricultural practitioners are recommended to adopt the osmopriming technique with a sowing date of November 20 for optimizing wheat production and enhancing overall crop quality.

STABILITY ANALYSIS OF WHEAT THROUGH GENOTYPE BY ENVIRONMENT INTERACTION IN THREE REGIONS OF KHYBER PAKHTUNKHWA, PAKISTAN

Genotype-by-environment (GEI) interaction provides the basic information that helps breeders to select stable and superior genotypes for targeted environments. Climate change also alters the recommendations of the genotype for a specific condition. The field study carried out during the cropping seasons of 2015–2016 determined the performance of 16 wheat genotypes (13 lines and three cultivars) at three different locations: The University of Agriculture, Peshawar (UAP), Nuclear Institute of Food and Agriculture, Peshawar (NIFA), and Cereal Crops Research Institute (CCRI), Pirsabak-Nowshera, Khyber Pakhtunkhwa, Pakistan. Data on yield contributing parameters (days to heading, spike length, spikelets spike-1, grain weight spike-1, 1000-grain weight, and grain yield) were collected and analysed using analysis of variance (ANOVA) and stability analysis. Mean square values revealed highly significant results for all the traits under consideration for genotypes (G) and locations (L). Likewise, interactions (GEI) were highly significant for all the traits except grain weight spike-1. The performance of genotypes under different locations indicated no similarity. However, the overall performance of genotypes displayed better under environmental conditions of the Cereal Crops Research Institute (CCRI- Location No: 03). According to the Eberhart and Russell approach, the genotypes K-87, PR-113, Pak-13, PR-112, NR-449, and KT-338 were confirmed stable under tested locations for yield contributing traits as their regression coefficient (bi) value exhibited close to unity. Correlations of grain yield with yield contributing traits considered were significant and positive except for days to heading.

Seed-Primed and Foliar Oxozinc Nanofiber Application Increased Wheat Production and Zn Biofortification in Calcareous-Alkaline Soil

Low Zinc (Zn) availability in alkaline calcareous soil is one of the major causes of low cereal yield and quality. Conventional application of Zn sulfate (ZnSO4) fertilizer through soil application attains minimal Zn efficiency as it is readily fixed in such soils. Oxozinc nanofiber (ZnONF) was evaluated for wheat Zn biofortification using different application methods to tackle this issue. Pots in triplicate (each with 7 kg soil) were arranged in a completely randomized design with a control treatment without Zn application. The conventional ZnSO4 fertilizer recommended dose (5.5 µg Zn kg−1 of soil) was used for comparison and applied through soil addition, foliar spray, and seed priming, while the ZnONF was applied through foliar spray, seed coating, and seed priming (@ 0.5 kg ha−1) either alone or in combination with ½ZnSO4 applied to the soil. The application of ZnONF significantly improved wheat plant growth as evidenced by increased plant height (14.5%), spikelets per spike (13.7%), and Zn use efficacy (611%) regardless of application methods as compared to control. The highest Zn uptake efficiency (34%) for nanofibers was obtained for theseed primed, followed by seed coating (23%) and foiar application (7%), respectively. Moreover, at the combined ZnONF and ½ZnSO4 application, further improvements for spike length, number of spikelets spike−1, grain, leaf, root, and stem Zn concentrations, as well as their respective Zn contents, were noted. These results elucidated that Zn nutrition with ZnONF was either at par with or higher than the conventional ZnSO4 fertilizer application despite significantly reduced ZnONF quantity, irrespective of the application method used. Additionally, the combined ZnONF and ½ZnSO4 (foliar spray, seed coating, or seed priming) maximized the crop Zn accumulation, wherein the ½ZnSO4 + ZnONF through foliar application exceeded grain Zn biofortification. Thus, various Oxozinc nanofibers application modes may be recommended for wheat biofortification either separately or in combination with ZnSO4 in Zn deficient calcareous soils for improved Zn nourishment.

INFLUENCE OF NITROGEN RATES ON THE PERFORMANCE OF WHEAT (Triticum aestivum L.) VARIETIES IN NORTHERN GUINEA SAVANNA ECOLOGICAL ZONE OF TARABA STATE NIGERIA

Influence of nitrogen rates on the performance of Wheat varieties were investigated to determine the effects of nitrogen rates on growth and yield of wheat (Triticum aestivum) in the study area. The experiments were laid out in split plot design with seven nitrogen rates. The treatments were replicated three times. The sub plot size was 3 m x 2 m. The crop was planted in the middle of November, at the beginning of the dry season. Half of each nitrogen rate was applied at sowing and the other half splited into two and top dressed at early tilling and flowering stage. Data were collected on number of tillers, Plant height, number of spikelets spike-1, number of grains spike1, weight of 1000 grain, biomass yield, grain yield and harvest index. All the data collected were subjected to Analysis of Variance (ANOVA) and Least Significant Difference (LSD) using Genstat version 4.0. The results revealed that nitrogen fertilization had significant effect (P<0.05) on wheat yield and yield components. Number of tillers was highest at 180 kg N ha-1 and variety Linfen. Similarly, Plant height was best at 180 kg N ha-1 and variety Reyna-28 while number of spikelets spike-1 was highest at 150 kg N ha-1 and variety Reyna-28 which was at par with Linfen. All the yield characters and final grain yield performed best at 120 kg N ha-1 and Reyna-28. These results indicate that, Nitrogen rate of 120 kg N ha-1 and Reyna-28 proved to be the best rate and variety for higher grain yield. Thus it is recommended that 120 kg N ha-1 and Reyna-28 be used for irrigated wheat production in the study area.

ESTIMATION OF COMBINING ABILITY AND HETEROSIS IN WHEAT

The study used a half-diallel mating fashion to identify combining ability (GCA and SCA) and heterosis of six wheat (Triticum aestivum L.) genotypes and their 15 F1 hybrids for morpho-physiological, yield, and yield-contributing traits. The present study was carried out in a randomized complete block design with three replications. The studied characters are heading days, maturity days, chlorophyll content, Plant height, Effective tillers plant-1, Total tillers plant-1, Spikes plant-1, Spike length, Filled spikelets spike-1, Unfilled spikelets spike-1, Grains spike-1, Thousand grain weight, Grain yield plant-1, Biological yield plant-1, and Harvest index Highly significant differences were observed among genotypes (parents and F1 hybrids) for all characters studied. The results also showed that the mean squares due to general (GCA) and specific (SCA) combining abilities were highly significant for all studied characters except harvest index, indicating the magnitude of both additive and non-additive gene effects in governing these traits. GCA/SCA ratios were greater than one for all characters except filled spikelets spike-1 and harvests index, indicating the dominance of additive gene effects, which play important roles in the inheritance of these characters. While the non-additive effect of the gene predominated in the inheritance of filled spikelets (spike-1) and harvests index, The parent BARI GOM-30 emerged as the best general combiner for total tillers plant-1, filled spikelets spike-1, grains spike-1, thousand-grain weight, grain yield plant-1, and harvest index. Bari Gom-28 was the best general combiner for heading days and maturity days, and Sourav was the best for effective tillers plant-1, spikes plant-1, and biological yield plant-1. The cross BARI GOM-30 SOURAV was the best specific combiner for effective tillers plant-1, total tillers plant-1, spikes plant-1, and PRODIP SOURAV for filled spikelets spike-1. Bari GOM-33 Sourav emerged as the best specific combiner for grain yield plant-1 and Prodip Ayt-5 for grain spike-1. Concerning heterotic effects in comparison to the midparent, the F1 hybrid BARI GOM-28 BARI GOM-33 showed maximum significant positive heterosis for chlorophyll content and biological yield plant-1 and BARI GOM-33 SOURAV for effective tillers plant-1, spikes plant-1, and grain yield plant-1. These parents and cross combinations could be used for the breeding program of wheat for potential yield.

Estimation of Heritability and Genetic Variability in Hexaploid Wheat (Triticum aestivum L.)

The field experiment was carried out during Rabi season in 2019-20, 2020-21 at Mata Gujri College, Fatehgarh Sahib’s Experimental Farm,Department of Agriculture. Experimental materials comprising 15 F1s using half diallel mating design involving six parents were grownin randomized block design. High heritability estimates involving broad sense along with high genetic advance as a percent of meanwas observed for number of grain plant-1, harvest index (%), plant height (cm) and grain yield plant-1 (g). The high genotype coefficientof variation (GCV) and phenotype coefficient of variation (PCV) were observed for grain yield/plant and test weight whereas, moderatevalues for PCV and GCV was recorded for no. of spikelets spike-1, no. of grain spike-1, and spike length (cm) indicating prevalence ofgenetic variability, which can successfully be used for improvement of seed yield genetically in wheat.

Heterosis and correlation studies in F1 hybrids of hexaploid wheat (Triticum aestivum L.) cultivars

The goal of the study was to determine whether the heterotic influence and phenotypic link between a numbers of yield variables in F1 hexaploid wheat hybrids could be controlled (Triticum aestivum L.). Our research trail was held at the Botanical Garden of Sindh Agricultural University's Department of Plant Breeding and Genetics in Tandojam, Pakistan. Six parental varieties (Sunhri, PBGST2, Sarsabz, TD1, TJ83, and Moomal) and nine F1 hybrids (TJ83 x TD1, PBGST2 x TD1, TJ83 x Moomal, TD1 x Moomal, TD1 x Sarsabz, Sarsabz x Sunhri, and TJ83) were supplied with material seed by the Department of Plant Breeding. After eight characters were evaluated, the experimental fields were selected and put into a randomised complete block design with four repetitions. The hybrids differed considerably (P 0.01) for every trait examined with the exception of plant height and maturity up to 75% of the time, whereas the parents showed no differences in grain yield. There was significant heterosis in the F1 hybrids, as seen by the mean square of the parent and the hybrid. Overall, maturity was important up to 75% of the time, even if it was negatively correlated with the majority of production metrics, meaning that genotypes with early maturation produced lower yields. The spikelets spike-1, seed index, and harvest index in plant-1 were all adversely connected with plant height, however grain yield was significantly and favourably correlated with all yield indices. These findings showed that choosing plants that produce more grain could be based on one or more yield components.

Effect of Water Stress on Growth and Yield Performance of Wheat Genotypes

Climate change is one of the major threats to wheat cultivation globally. Among abiotic stress, imposed by climate change, drought stress causes a drastic effect on yield and productivity of wheat. Based on this context, research was carried out on eight genotypes including WS-I (Water stress), WS-II, WS-III, WS-IV, WS-V, WS-VI, WS-VII and Khirman (check variety) to check the effect of water stress at the experimental field of Nuclear Institute of Agriculture, Tandojam. The experiment was laid-out in a split-plot design (SPD) with factorial arrangement having four treatments i.e., T1 (normal six irrigations), T2 (one irrigation), T3 (two irrigations) and T4 (three irrigations) and three replications during Rabi season, 2019-2020 in order to assess the response of wheat genotypes under different water regimes conditions for vegetative, yield and yield-related traits. The results of analysis of variance results showed that genotypes were significantly different for all traits except spike length (cm). Similarly, a significant difference was observed among the treatments for all the traits except harvest index (%). While genotype x treatments interaction showed a significance level for most of the yield associated traits except few characters such as days to 75% heading, grain filling period, plant height (cm), peduncle length (cm), spikelets spike-1 and grains spike-1 indicating that genotypes perform similarly over the treatment. Maximum mean performance for all the traits was recorded under T3 treatment compared to the T2 and T1. Among the genotypes, WS-1V perform best for grains spike-1, grain weight spike-1 (g), 1000-grain weight (g), grain yield plot-1 and harvest index (%) under all treatments. However, WS-III also performed consistently under T2 and T3 treatment. Thus, genotypes like WS-III and WS-IV could be preferred for growing in those areas where growers face the problem of water shortage. Also, WS-III and WS-IV can be used as donor genotypes for developing drought tolerant varieties.

Delineation of Physiological, Agronomic and Genetic Responses of Different Wheat Genotypes under Drought Condition

Abioticstress such as drought is a potential threat posing a severe challenge to wheat production across the globe. The current study comparatively delineated the performance of elite Pakistani bread wheat genotypes at physiological (chlorophyll, canopy temperature, cell membrane percentage stability and leaf relative water content), agronomic (plant height, tillers plant−1, flag leaf area, spike length, spikelets spike−1, grains spike−1, grain yield spike−1, thousand grain weight and plant biomass) and genetic (TaDREB1A, TaGROS-A, TaLEA3, TaHSFA1a, TaWRKY44 and TaEXPA2) levels. Atri-replicate experiment was conducted in a two factorial arrangement using RCBD, and data were analyzed statistically using the computer-based programsStatistix8.1 and R-studio. In general, all wheat genotypes illustrated significant (p ≤ 0.05) alterations in physiological and agronomic traits under drought stress as compared to the control; however, this alteration was significantly (p ≤ 0.05) different among all genotypes owing to their varying genetic potential. Furthermore, these genotypes were evaluated for the extent of the association of physiological and agronomic traits using PCA, correlation and heatmap analysis, which proved statistically significant variation in the paired association of traits among all genotypes during drought stress as compared to the control. In addition, based on statistical evaluations, the genotypes Pakistan-13, Shahkar-13, AAS-11, Chakwal-86, Chakwal-50 and AUR-09 were found to be tolerant, while genotypes Anmol-97, Chakwal-97, Bhakkar-02 and BWP-97 were comparatively susceptible. Furthermore, these screened genotypes showed differential expression of drought-related genes, with relatively high expression in tolerant genotypes compared to susceptible genotypes. The current study concluded that physiological, agronomic and molecular characteristics are significantly interconnected, and these associations determine the end productivity of wheat genotypes during abiotic stress. Therefore, their integrated study can enhance the pace of wheat breeding for drought tolerance in the near future.

Comparative Analysis of Canopy Cooling in Wheat under High Temperature and Drought Stress

The size and the weight of wheat grains vary across the length of each spike (Triticum aestivum L.). High temperature and water scarcity often reduce the single grain weight, and this reduction also varies across the spike length. Plants tend to cope with high temperature and drought stress through inherent mechanisms such ascanopy cooling through transpiration, which can contribute to yield stability. The effect of canopy cooling on the average grain weight at different positions in spike is still unknown. In this study, we planned to assess the role of canopy temperature, yield-related traits, and spike shape in final grain weight. For two years (2017–2018 and 2018–2019), fifteen diverse genotypes released for cultivation in different environmental conditions were grown in the field. They were examined for canopy temperature, spikelets spike−1, grain number spike−1, grain yield spike−1, and grain weight of the spike’s basal, median, and distal regions. The Pearson correlation coefficient (r) was obtained for all pair-wise combinations of traits under different treatments and spike shapes. The results indicated that cooler canopy is correlated to grain weight in normal spike shape at all three positions within the spike irrespective of stress. The advantage of the cooler canopy in improving grain-filling at basal, median, and distal regions was more conspicuous in the high temperature stress conditions compared to non-stressed and drought conditions.

Evaluation of Some Advanced Bread Wheat (Triticum aestivum L.) Lines for Agronomic Traits Under Kırklareli and Tekirdağ Conditions

This study was carried out to determine grain yield and yield components of five bread wheat genotypes and 20 advanced lines at Kırklareli and Tekirdağ locations in 2017-2018 cropping year. The experiments were arranged in a randomized complete block design with four replications. In the study, grain yield (GY), plant height (PH), spike length (SL), number of spikelets/spike (SS), number of grains/spike (KS), grain weight/spike (KWS), test weight (TW) and thousand kernel weight (TKW) were investigated. Bread wheat genotypes were found statistically significant for all investigated traits according to the data obtained from two locations. According to the results of two locations the investigated traits such as GY ranked from 423.8 to 572.5 kg da-1, PH 85.3 to 116.2 cm, SL 8.8 to 12.2 cm, SS 16.5 to 21.6, KS 39.4 to 65.6, KWS 1.30 to 2.91 g, TW 65.9 to 75.6 and TKW 32.6 to 44.7 g. Relationship between GY and SS, KS and KWS were found positive and significant. In addition, relationship between PH and SL (r=0.39*), SS and KS (r=0.39*), SS and KWS (r=0.42*), TW and KS (r=0.42), TW and KWS (r=0.44*), KS and KWS (r=0.64**) were significant and positive. The highest grain yield was obtained from SME9 bread wheat advanced line at both Kırklareli and Tekirdağ, which was concluded as promising.