Major Cereal Crops Research Articles

Chemical Weed Management in Wheat- A review

Wheat (Triticum aestivum L.) is one of the major cereal food crops of the world and has very important role in attaining food security. Introduction of dwarf wheat varieties coupled with intensive input (assured irrigation and fertilizers) use after Green Revolution led to complex problem of both grassy and broad leaved weeds. Weed management is very important for achieving higher wheat production. Mechanical, cultural, biological and chemical methods can be adopted for weed management in wheat. Due to industrialization, labour is becoming scarce and costly. Among these methods, chemical weed control is more efficient, less costly and less time consuming. Pre-emergence herbicides cannot control the late flushes of weeds especially, grassy weeds. Post emergence herbicides are very effective against weeds in wheat. However, herbicides are effective against some weed groups due to mode of action and they do not kill other weeds. To control other weeds, another herbicide is needed which involves more cost, time and labour. To overcome this, sequential application of herbicides, herbicidal mixtures and herbicidal combinations are used. The herbicidal combinations could be very effective against both grassy as well as broad leaved weeds and help to reduce cost, time and labour. Application herbicidal combinations viz. clodinafop + metsulfuron (vesta) 60 g ha-1, sulfosulfuron + metsulfuron (total) 32 g ha-1 and mesosulfuron + iodosulfuron (atlantis) 14.4 g ha-1 as well as tank mixture of pinoxaden + carfentrazone (50 + 20 g ha-1) is the best way for managing complex weed flora in wheat as of now. Modification in application method like tank mixture with micronutrients also have potential of increasing the weed control efficiency of herbicides and yield of wheat. To give precise and concise information weed management in wheat, his article reviews the latest herbicides recommended for weed management in wheat. Recent advances in herbicidal mixture, combinations and application techniques are also being included in this review.

Use of Crop Wild Relatives (CWRs) of Wheat in Disease Resistance Breeding

Wheat (Triticum aestivum L.) is one of the three major cereal crops contributing 20% calories to the world population. The most serious constraints to wheat production are biotic stresses like rusts, blights, powdery mildew, bunts and smuts. Genetic or host plant resistance is the best way to control these diseases than use of chemical pesticides. Continuous search for novel genes is indispensable to counter the dynamic and rapidly evolving pathogen population. In case of some diseases like spot blotch, Karnal Bunt and Fusarium head blight development of resistant cultivars is not an easy task as the resistance to them found in the germplasm is not satisfactory and none of the commercial cultivars showed resistance. Hence, underutilized crop wild relatives prove to be valuable resource in the search for new disease resistance genes to combat wheat diseases.

Grain Yield and Nitrogen Use Efficiency Vary with Cereal Crop Type and Nitrogen Fertilizer Rate in Ethiopia: A Meta-Analysis

The crop production in Ethiopia is markedly constrained by soil nutrient depletion and limited fertilizer input. Nitrogen is among the most yield-limiting factors of cereal crops, especially in sub-Saharan Africa (SSA). A meta-analysis of 82 studies was carried out to evaluate the response of major cereal crops, viz. wheat, maize, barley, teff, and sorghum, to nitrogen fertilization in Ethiopia. The results showed that N-application significantly increased yields of all the five crops examined herein. The average yields of the treatment effects over controls for the five crops were 3775.8 kg∙ha−1 and 2593.3 kg∙ha−1, respectively. The overall yield response to nitrogen treatments for all the crops was 64.8% (wheat, 96.5%; maize, 40.65%; barley 84.36%; teff, 50.48%; and sorghum; 23%). Overall, nitrogen agronomic efficiency (AEN) and partial factor productivity (PFPN) were 18.2 and 71.81 kg∙kg−1, respectively. A downtrend of nitrogen use efficiency with an increase in N rate was realized. The yield response was higher for the nitrogen treatment effects of >100 kg∙N∙ha−1 (123.9%), clay soils (75.46%), low initial soil organic carbon (SOC) and available phosphorous (AP) (92.4% and 101.6%), respectively, Therefore, we recommend the application of nitrogen fertilizer (>100 kg∙N∙ha−1), especially on infertile soils for improved grain yield and NUE in aforementioned cereal crops in Ethiopia and similar regions in sub-Saharan Africa (SSA).

Heading percentage estimation in proso millet (Panicum miliaceum L.) using aerial imagery and deep learning

AbstractProso millet (Panicum miliaceum L.), one of the major cultivated millets, serves as a complement to major cereal crops due to its drought tolerance and low input demands. Timing of heading is one of the key agronomic traits associated with its adaptation to a target environment and a major focus in breeding. Conventionally, heading percentage of a plot (genotype) was rated visually by breeders in field. Despite many successful studies reported in automatic head detections in other small grain species, little progress had been made to estimate heading percentage especially when multiple tillers exist. This study aimed to develop a method for automatic proso millet panicle detection and, more importantly, heading percentage estimation using regular red‐green‐blue images collected by an unmanned aerial vehicle. Aerial images of two dates were collected at heading stage in 2020 in Scottsbluff, NE. Faster regions with convolutional neural network models were trained to detect and count proso millet panicles in each plot. Then, using a sigmoid model, the number of detected panicles was converted to heading percentage without having the information of stand count and the number of tillers. Overall, the system achieved the highest coefficient of determination of 0.728 for proso millet heading percentage estimation, and an accuracy of 92.4% in determining whether a plot reached a certain threshold of heading (50% in this study). The methods developed in this study on heading percentage estimation can directly aid in decision making in proso millet breeding and can be ultimately incorporated into an automated proso millet high‐throughput phenotyping pipeline.

SNP genotyping of maize (Zea mays) hybrids and parental inbred lines for genetic purity testing using double digest restriction site-associated DNA sequencing

Maize (Zea mays) is the third major cereal crop in the Indian subcontinent, but the crop yields per hectare of Indian maize cultivars are less than half of the global average due to the impurity of seed lots supplied to farmers. In this study, we discovered high-quality Single Nucleotide Polymorphic markers (SNPs) in two widely cultivated maize hybrids and their parental inbreds. Paired-end double digest restriction site-associated DNA sequencing was used to discover SNPs and a total of 30,764,454 reads with a read length of 151 bp per sample were generated. Genotyping of SNPs for maize hybrids 'MAH 14-5' and 'Hema' revealed a total of 47,812 and 15,815 Genetic Purity Analysis markers, respectively, of which 44,388 and 12,391 were unique with 3,424 being common to both hybrids. Identified SNPs were used to develop primers for Kompetitive Allele-Specific PCR genotyping assays to determine the genetic purity of 10 seed lots and the results were found to correlate with Grow-out-Tests. Thus, the SNPs discovered in this study proved reliable to test the genetic purity of commercial seed lots. Advances in plant molecular breeding tools especially ddRADseq for SNP discovery offer new opportunities to genotype existing cultivars and accelerate the production of genetically pure seeds.

Unlocking Allelic Diversity for Sustainable Development of Salinity Stress Tolerance in Rice.

Rice is a major cereal crop, negatively impacted by soil-salinity, both in terms of plant growth as well as productivity. Salinity tolerant rice varieties have been developed using conventional breeding approaches, however, there has been limited success which is primarily due to the complexity of the trait, low yield, variable salt stress response and availability of genetic resources. Furthermore, the narrow genetic base is a hindrance for further improvement of the rice varieties. Therefore, there is a greater need to screen available donor germplasm in rice for salinity tolerance related genes and traits. In this regard, genomics based techniques are useful for exploring new gene resources and QTLs. In rice, the vast allelic diversity existing in the wild and cultivated germplasm needs to be explored for improving salt tolerance. In the present review, we provide an overview of the allelic diversity in the Quantitative Trait Loci (QTLs) like Saltol, qGR6.2, qSE3 and RNC4 as well as genes like OsHKT1;1, SKC1 (OsHKT1;5/HKT8) and OsSTL1 (salt tolerance level 1 gene) related to salt tolerance in rice. We have also discussed approaches for developing salt-tolerant cultivars by utilizing the effective QTLs or genes/alleles in rice.

Morphophysiological characterization of potato (Solanum tuberosum L.) genotypes prevailing in the core area of Punjab, Pakistan

Potato (Solanum tuberosum L.) is one of the most important vegetable crops and the fourth most important edible crop after the three major cereal crops. It is considered as an approximately complete diet food because of its nutritional value. Its center of origin is Peru, South America. In Punjab, Pakistan, the districts of Sahiwal and Okara serve as the core areas of potato cultivation. Thirty-three potato genotypes were collected from the core areas of Punjab for characterization. The genetic diversity of potato germplasm was assessed on the basis of morphophysiological traits. This experiment was conducted with a randomized complete block design and three replications. The data on 14 morphological and physiological traits were recorded. Analysis of variance indicated the presence of highly significant variation for each physiological and morphological trait. Correlation analysis showed that plant yield was highly correlated with the number of tubers per plant (0.484), tuber weight (0.648), and chlorophyll contents (0.365). By contrast, tuber dry matter exhibited a significant highly negative association with tuber moisture content (−0.753). Algorithmic hierarchical cluster analysis allocated the genotypes into four distinct clusters. Cluster 2, which was the largest cluster, comprised 18 genotypes. By contrast, cluster 4 was the smallest cluster and contained only two genotypes. The results of diversity analysis obtained through hierarchical clustering were further validated through principal component analysis (PCA). PCA provided five significant principal components that contributed 72.39% of the total variation. The principal components of the biplot explained 41.95% of the total variation, with tuber moisture content and tuber dry matter as distinct traits. Cultivars ‘SH-5’, ‘SH 7-18’, ‘Simply Red,’ and ‘Ruby’ were the vertex genotypes in the biplot. Results indicated the prevalence of significant variation in the tested germplasm. Furthermore, the assessment of diversity at the molecular level is recommended for the further validation of genetic diversity.

Seed priming with Salicylic Acid (SA) and Hydrogen Peroxide (H2O2) Improve Germination and Seedling Growth of Wheat (Triticum aestivum) under Salt Stress

Aim: Salinity is a major barrier to successful crop production. Seed priming and exogenous application of different signaling molecules can efficiently confer salinity tolerance. Wheat is a major cereal crop in the world and salinity drastically reduces the wheat seedling growth and yield. Therefore, the present study was conducted to explore the potentiality of different signaling molecules such as salicylic acid (SA) and H2O2 to alleviate the salinity-induced growth inhibition of wheat.
 Place and Duration of the Study: The study was conducted in the Department of Seed Science and Technology, Bangladesh Agricultural University, from September-October, 2021.
 Methodology: The wheat (cv. BARI-Gom 24) seeds were soaked in normal tap water (hydro-priming), 1 mM SA, 2 mM SA, 0.1 mM H2O2, and 0.15 mM H2O2 solutions for 30 minutes. The untreated seeds were used as control. Eventually, primed seeds were exposed to 150 mM NaCl in Petri dishes during germination. Primed and non-primed seedlings were grown for 15 days under 150 mM NaCl stress condition.
 Results: The result revealed that salt stress significantly reduced germination percentage (GP), germination index (GI), seed vigor index (SVI), shoot and root length. The results also exhibited that photosynthetic pigments, total chlorophyll, carotenoids, lycopene, and beta-carotene contents were significantly reduced by salt stress. Seed priming with SA and H2O2 and hydro-priming promoted the germination percentage, seedling growth (including shoot and root length), SVI, and photosynthetic pigments.
 Conclusion: Pretreatment with 1 mM SA and 0.1 mM H2O2 was observed to be relatively more efficient in conferring salinity tolerance of wheat compared with other treating conditions. Overall, this study suggests that wheat seed priming with SA and H2O2 and hydro-priming can improve salinity tolerance.
 Aim: Salinity is a major barrier to successful crop production. Seed priming and exogenous application of different signaling molecules can efficiently confer salinity tolerance. Wheat is a major cereal crop in the world and salinity drastically reduces the wheat seedling growth and yield. Therefore, the present study was conducted to explore the potentiality of different signaling molecules such as salicylic acid (SA) and H2O2 to alleviate the salinity-induced growth inhibition of wheat.
 Place and Duration of the Study: The study was conducted in the Department of Seed Science and Technology, Bangladesh Agricultural University, from September-October, 2021.
 Methodology: The wheat (cv. BARI-Gom 24) seeds were soaked in normal tap water (hydro-priming), 1 mM SA, 2 mM SA, 0.1 mM H2O2, and 0.15 mM H2O2 solutions for 30 minutes. The untreated seeds were used as control. Eventually, primed seeds were exposed to 150 mM NaCl in Petri dishes during germination. Primed and non-primed seedlings were grown for 15 days under 150 mM NaCl stress condition.
 Results: The result revealed that salt stress significantly reduced germination percentage (GP), germination index (GI), seed vigor index (SVI), shoot and root length. The results also exhibited that photosynthetic pigments, total chlorophyll, carotenoids, lycopene, and beta-carotene contents were significantly reduced by salt stress. Seed priming with SA and H2O2 and hydro-priming promoted the germination percentage, seedling growth (including shoot and root length), SVI, and photosynthetic pigments.
 Conclusion: Pretreatment with 1 mM SA and 0.1 mM H2O2 was observed to be relatively more efficient in conferring salinity tolerance of wheat compared with other treating conditions. Overall, this study suggests that wheat seed priming with SA and H2O2 and hydro-priming can improve salinity tolerance.

Genome sequencing and transcriptome analyses provide insights into the origin and domestication of water caltrop (Trapa spp., Lythraceae).

SummaryHumans have domesticated diverse species from across the plant kingdom; however, our current understanding of plant domestication is largely founded on major cereal crops. Here, we examine the evolutionary processes and genetic basis underlying the domestication of water caltrop (Trapa spp., Lythraceae), a traditional, yet presently underutilized non‐cereal crop that sustained early Chinese agriculturalists. We generated a chromosome‐level genome assembly of tetraploid T. natans, and then divided the allotetraploid genome into two subgenomes. Based on resequencing data from 57 accessions, representing cultivated diploid T. natans, wild T. natans (2x and 4x) and diploid T. incisa, we showed that water caltrop was likely first domesticated in the Yangtze River Valley as early as 6300 yr BP, and experienced a second improvement c. 800 years ago. We also provided strong support for an allotetraploid origin of T. natans within the past 230 000–310 000 years. By integrating selective sweep and transcriptome profiling analyses, we identified a number of genes potentially selected and/or differentially expressed during domestication, some of which likely contributed not only to larger fruit sizes but also to a more vigorous root system, facilitating nutrient uptake, environmental stress response and underwater photosynthesis. Our results shed light on the evolutionary and domestication history of water caltrop, one of the earliest domesticated crops in China. This study has implications for genomic‐assisted breeding of this presently underutilized aquatic plant, and improves our general understanding of plant domestication.

Evolution of the Ergot Alkaloid Biosynthetic Gene Cluster Results in Divergent Mycotoxin Profiles in Claviceps purpurea Sclerotia.

Research into ergot alkaloid production in major cereal cash crops is crucial for furthering our understanding of the potential toxicological impacts of Claviceps purpurea upon Canadian agriculture and to ensure consumer safety. An untargeted metabolomics approach profiling extracts of C. purpurea sclerotia from four different grain crops separated the C. purpurea strains into two distinct metabolomic classes based on ergot alkaloid content. Variances in C. purpurea alkaloid profiles were correlated to genetic differences within the lpsA gene of the ergot alkaloid biosynthetic gene cluster from previously published genomes and from newly sequenced, long-read genome assemblies of Canadian strains. Based on gene cluster composition and unique polymorphisms, we hypothesize that the alkaloid content of C. purpurea sclerotia is currently undergoing adaptation. The patterns of lpsA gene diversity described in this small subset of Canadian strains provides a remarkable framework for understanding accelerated evolution of ergot alkaloid production in Claviceps purpurea.

Minor Crops: A Path towards Crop Diversification

With passage of time, there has been paradigm shift observed in dietary intake of people henceforth disturb­ing the balance of nutrients required by the body. Due to the leap towards major cereal crops to feed the growing population, impetus towards minor crops have observed a continuous decline. This ap­proach have also led to emergence of various nutritional deficiencies. Though these crops are neglected but are treasure house of various nutrients needed for all-round development of an individual. This re­view examines and compares the nutritional aspects of major cereal crops to minor crops and also dis­cusses the abundant health benefits provided by few minor crops, as well their prevalence in context to Indian subcontinent.

Endomembrane mediated-trafficking of seed storage proteins: from Arabidopsis to cereal crops.

Seed storage proteins (SSPs) are of great importance in plant science and agriculture, particularly in cereal crops, due to their nutritional value and their impact on food properties. During seed maturation, massive amounts of SSPs are synthesized and deposited either within protein bodies derived from the endoplasmic reticulum, or into specialized protein storage vacuoles (PSVs). The processing and trafficking of SSPs vary among plant species, tissues, and even developmental stages, as well as being influenced by SSP composition. The different trafficking routes, which affect the amount of SSPs that seeds accumulate and their composition and modifications, rely on a highly dynamic and functionally specialized endomembrane system. Although the general steps in SSP trafficking have been studied in various plants, including cereals, the detailed underlying molecular and regulatory mechanisms are still elusive. In this review, we discuss the main endomembrane routes involved in SSP trafficking to the PSV in Arabidopsis and other eudicots, and compare and contrast the SSP trafficking pathways in major cereal crops, particularly in rice and maize. In addition, we explore the challenges and strategies for analyzing the endomembrane system in cereal crops.

The Adaptation and Tolerance of Major Cereals and Legumes to Important Abiotic Stresses.

Abiotic stresses, including drought, extreme temperatures, salinity, and waterlogging, are the major constraints in crop production. These abiotic stresses are likely to be amplified by climate change with varying temporal and spatial dimensions across the globe. The knowledge about the effects of abiotic stressors on major cereal and legume crops is essential for effective management in unfavorable agro-ecologies. These crops are critical components of cropping systems and the daily diets of millions across the globe. Major cereals like rice, wheat, and maize are highly vulnerable to abiotic stresses, while many grain legumes are grown in abiotic stress-prone areas. Despite extensive investigations, abiotic stress tolerance in crop plants is not fully understood. Current insights into the abiotic stress responses of plants have shown the potential to improve crop tolerance to abiotic stresses. Studies aimed at stress tolerance mechanisms have resulted in the elucidation of traits associated with tolerance in plants, in addition to the molecular control of stress-responsive genes. Some of these studies have paved the way for new opportunities to address the molecular basis of stress responses in plants and identify novel traits and associated genes for the genetic improvement of crop plants. The present review examines the responses of crops under abiotic stresses in terms of changes in morphology, physiology, and biochemistry, focusing on major cereals and legume crops. It also explores emerging opportunities to accelerate our efforts to identify desired traits and genes associated with stress tolerance.

Genome-editing in millets: current knowledge and future perspectives.

Millets are small seeded cereal crops predominantly cultivated and consumed by resource-poor farmers in the semi-arid tropics of Asia and Africa. Millets possess rich nutrients and a climate resilience property when compared to the other cereals such as rice and wheat. Millet improvement using modern genetic and genomic tools is falling behind other cereal crops due to their cultivation being restricted to less developed countries. Genome editing tools have been successfully applied to major cereal crops and, as a result, many key traits have been introduced into rice, wheat and maize. However, genome editing tools have not yet been used for most millets although they possess rich nutrients. The foxtail millet is the only millet utilised up to now for genome editing works. Limited genomic resources and lack of efficient transformation systems may slow down genome editing in millets. As millets possess many important traits of agricultural importance, high resolution studies with genome editing tools will help to understand the specific mechanism and transfer such traits to major cereals in the future. This review covers the current status of genome editing studies in millets and discusses the future prospects of genome editing in millets to understand key traits of nutrient fortification and develop climate resilient crops in the future.

Evaluation of Kenya Stem Rust Observation Nursery Wheat Genotypes for Yield and Yield Components under Artificial Rust Conditions

Common wheat (Triticum aestivum L.) is a major cereal crop contributing to global food and nutrition which necessitates the deployment of wheat genotypes that are high yielding and resistant to prevailing diseases. The objective of this study was to evaluate Kenya stem rust observation nursery (KSRON) wheat genotypes for grain yield, yield components and stem rust resistance. A 3-season field experiment was set up in a 25 × 7 alpha lattice design at Kenya Agricultural and Livestock Research Organization (KALRO), Njoro (35°56′60′′ E; 0°20′60′′ S). Significant (p ≤ 0.001) differences due to seasons, genotype and genotype × season interaction was observed for all the traits except days to heading (DH) and number of seeds per spike (SS). Seasons, genotype and genotype × season interaction explained 48.2%, 25.23% and 26.67% of the total variability in grain yield (GY), respectively. Significant (p ≤ 0.05) variation of means between seasons for all the traits were higher in the 2019 main season than the 2019 and 2020 off-seasons except for 1000-kernel weight (TKW). Heritability (H2) estimates ranged from 49.58% for GY to 94.11% for DH. GY had a positive genetic and phenotypic correlation with all the traits except for DH (rg = −0.13, rp = −0.09), stem rust (SR) (rg = −0.53 ***, rp = −0.38 ***) and yellow rust (YR) (rg = −0.28 ***, rp = −0.19 *) severity. SR caused 22%, 14% and 13% reduction in TKW, GY and biomass (BM), respectively. YR caused 2% and 4% reduction in GY and BM. This study identified KSRON 13, KSRON 31, KSRON 40, KSRON 52, KSRON 53, KSRON 78, KSRON 80 and KSRON 144 as the best high GY (8.43–7.79 t ha−1) as well as resistant to SR and YR.

Impacts of Temperature Trends and SPEI on Yields of Major Cereal Crops in the Gambia

Variations in the climate constitute a significant threat to the productivity of food crops in the Gambia. A good understanding of the influence of climate variability on crop production is vital for climate resilience and improved food security. This study examined the trends, relationships, and the extent to which growing season temperatures and the SPEI (Standardized Precipitation and Evapotranspiration Index) impacted sorghum, millet, maize, and rice yields in three agro-ecological regions of the Gambia during 1990–2019. Mean temperatures and the SPEI exhibited increasing trends while observed yields showed a decline across all regions. The SPEI had a significant positive relationship with yields, and temperatures were negatively associated with yields. Though yield response to climate variability differs among regions, 20% to 62% of variations in the four crop yields were due to climate trends. The combined effect of the SPEI and temperatures decreased yields from 3.6 kg ha−1 year−1 to 29.4 kg ha−1 year−1, with the most severe decline observed in rice and maize yields in the Sahelian zone. Although uncertainties might arise from not considering related extreme climate events, this study highlights how past climate trends affect cereal yields in the Gambia; thus, any unfavorable change in the local climate could have severe repercussions on the country’s food security. There is a need for concerted efforts to increase investments in adaptation strategies to lessen the effects of the climate for improved crop productivity.

Transcriptome based identification and validation of heat stress transcription factors in wheat progenitor species Aegilops speltoides

Wheat, one of the major cereal crops worldwide, get adversely affected by rising global temperature. We have identified the diploid B genome progenitor of wheat, Aegilops speltoides (SS), as a potential donor for heat stress tolerance. Therefore, the present work was planned to study the total transcriptome profile of heat stress-tolerant Ae. speltoides accession pau3809 (AS3809) and compare with that of tetraploid and hexaploid wheat cultivars PDW274 and PBW725, respectively. The comparative transcriptome was utilized to identify and validate heat stress transcription factors (HSFs), the key genes involved in imparting heat stress tolerance. Transcriptome analysis led to the identification of a total of 74 K, 68 K, and 76 K genes in AS3809, PDW274, and PBW725, respectively. There was a high uniformity of GO profiles under the biological, molecular, and cellular functions across the three wheat transcriptomes, suggesting the conservation of gene function. Twelve HSFs having the highest FPKM value were identified in the AS3809 transcriptome data, while six of these HSFs namely HSFA3, HSFA5, HSFA9, HSFB2a, HSFB2b, and HSFC1b, were validated with qRT PCR. These six HSFs were identified as an important component of thermotolerance in AS3809 as evident from their comparative higher expression under heat stress.

Bread wheat genotypes phenotypic characterization under late sowing heat stress and genetic diversity analysis of selected heat tolerant genotypes

Wheat is one of the earliest cultivated plants and second major cereal crop of the world that contains human food essentials. Due to climatic variations, crop is exposed to severe environmental conditions. Rising global temperature is expected to result in severe climate shift in future. High temperature exerts negative effects on wheat phenology and grain production. Selection of heat tolerant wheat germplasm is the best stress management strategy. Present research was planned to conduct field-based evaluation of 100 wheat genotypes under normal and heat stress conditions. The data of twelve phenotypic traits was recorded under control and heat stress trials. There were diverse variations observed among genotypes for morphological characters. The high yielding selected wheat lines 68.111-56, CHEN-84, CHEN-74, IWA8611400-65, CHEN-95, CHEN-96, CHEN-86, CHEN-80, 68.111-60 and CHEN-92 were subjected to DNA fingerprinting with Simple Sequence Repeat markers viz; WMC 18, CFA2129, WMC 367, CFD 48, WMC44 and WMC 798. The genetic diversity ranged from 0 to 0.25 with an average value of 0.06. Unweighted pair group of arithmetic means cluster analysis grouped these lines into clusters. Most of the genetic diversity was observed for CHEN-74 and CHEN-96 in cluster. The study has identified genetically diverse, heat tolerant and high yielding wheat genotypes with possible exploitation in development of climate smart wheat varieties.

Contribution of Awns to Seed Yield and Seed Shattering in Siberian Wildrye Grown under Irrigated and Rainfed Environments

The seed yield of grass species is greatly dependent on inflorescence morphological traits, starting with spikelets per inflorescence and seeds per spikelet, to kernel size, and then to awns. Previous studies have attempted to estimate the contribution of these traits on the harvested yield of major cereal crops, but little information can be accessed on the influence of awns on seed yield of forage grass species. Siberian wildrye (Elymus sibiricus L.) is a widely important perennial forage grass used to increase forage production in arid and semi-arid grasslands. The grass has long inflorescences with long awns developed at the tip end of the lemmas in the florets. In order to evaluate the effect of awns on Siberian wildrye seed production, awn excision analyses from 10 accessions were performed at flowering stage under irrigated and rainfed regimes. Overall, awn excision reduced thousand-seed weight and seed size under both irrigated and rainfed regimes, which decreased final seed yield per plant. De-awned plants produced significantly more seeds per inflorescence, but spikelets per inflorescence was not influenced by awn excision in either condition. Moreover, histological analyses showed a high degradation of the abscission layer in the awned plants than de-awned ones, and awn excision evidently improved average seed breaking tensile strength (BTS), and thus decreased the degree of seed shattering. In conclusion, the observed significant impact of awn excision on different yield-related traits mirrored the impact of awns on the performance of Siberian wildrye under diverse growing conditions. These results provide useful information for plant breeders, seed producers, and researchers to efficiently improve seed production in Siberian wildrye.

Effect of Blended (NPSB) Fertilizer Rates and Plant Population on Yield and Yield Components of Maize (Zea mays L.) at Bako, Oromia National Regional State, Ethiopia

Maize (Zea mays L.) is the major cereal crop in Ethiopia and plays a crucial role in ensuring food security. However, its productivity is constrained by a number of problems, among which use of high or low plant population and poor soil fertility management are the most critical once. Therefore, a field experiment was undertaken to determine the optimal NPSB fertilizer rate and plant population for maize at Bako. The experiment was laid out in split plot design distributing three levels of plant population [53,333 plants ha -1 (25 x75 cm), 66,666 plants ha -1 (60x25cm) and 76923 plants ha -1 (65x20cm)] in the main plots and five levels of NPSB fertilizer rates (0,100,150,200 and 250 kg NPSB ha -1 ) and recommended NP rates as sub-plots. The interaction of plant population and NPSB rates influenced significantly (P<5 %) leaf area index, number of cobs plot -1 , number of kernel cob -1 , dry biomass and thousand kernel weight. The highest leaf area index 6.661 was recorded on the combination of 66,666 plants ha -1 with 200 kg NPSB fertilizer rate. The highest number of cob plot -1 (115.3) and dry biomass yield 28,299 kg ha -1 were recorded from 66,666 plant ha -1 with 150 kg NPSB ha -1 , and 53,333 plant ha -1 with standard check 92/69 kg NP ha -1 , respectively. The highest grain yield 9954 kg ha -1 with net profit of 76,038 Birr with marginal rate of return 598% was obtained from 150 kg NPSB ha -1 with 66666 plants ha -1 (60 cmx25 cm). Therefore, application of 150 kg NPSB ha -1 with 66666 plants ha -1 for farmers in the study area and with similar agro-ecology can use and can improve maize productivity. However, the experiment need to be further verified in multi-locations for better usage at different agro-ecologies. Keywords: plant population, blended fertilizer, maize, yield DOI: 10.7176/JNSR/12-21-04 Publication date: November 30 th 2021