Indian Institute of Maize Research

Sustainability of contemporary crop establishment and management practices is questioned due to soil degradation, higher carbon emission and declining soil productivity. Hence, this study was conducted to address the impacts of conservation agriculture (CA) practices like permanent broad beds (PBB), permanent narrow beds (PNB) and zero tilled flat beds (ZT) with residue retention on soil organic carbon (SOC) protection within aggregates in the Indo-Gangetic Plains (IGP). Compared to conventionally tilled (CT) plots, the total SOC content was ∼27%–33% higher in the CA plots on equivalent mass basis. The soil physical properties, such as soil aggregation and mean weight diameter were considerably improved under the CA practices. The macroaggregates were ∼41, 37% and 27% higher in the PBB with residue (PBB + R), PNB with residue (PNB + R) and ZT with residue (ZT + R) plots (CA plots), respectively, than the CT plots in the surface soil (0–15 cm). The plots under PBB + R had ∼31% higher microaggregates within macroaggregates than the CT plots (24.4 g 100 g ⁻¹ ) soil. An increase in SOC content by ∼72, 55% and 69% was observed in the PBB + R, PNB + R and ZT + R plots over the CT plots in microaggregates within macroaggregates (3.02 Mg ha ⁻¹ ). However, plots under PBB + R, PNB + R and ZT + R had only ∼11, 3% and 23% more SOC within silt + clay fraction, respectively, than CT plots (5.85 Mg ha ⁻¹ ). Thus, SOC stabilization within microaggregates inside macroaggregates was the major mechanism, and not the chemical stabilization within silt + clay, of C sequestration under CA. As aggregate-associated carbon is an ecosystem property that strongly affects organic carbon stabilization, water holding capacity and resistance to erosion, growing maize/cotton–wheat system under PBB + R practice is a viable option for carbon sequestration in the IGP and similar agro-ecologies.

Introduction: Soil organic matter (SOM) plays a vital role in enhancing soil characteristics and promoting sustainable crop production. The active and passive components of SOM tend to be more effective indicators of soil changes than total SOM content. Methods: This study aimed to examine the impact of integrated nutrient management (INM) on the active and passive segments of SOM in maize during the kharif seasons of 2019 and 2020 at the Instructional Farm of Rajasthan College of Agriculture, Udaipur. A total of 11 treatments comprising of control (no application of manures/fertilizers/biofertilizers), different INM combinations, and application of inorganic fertilizers were laid in a randomized block design (RBD) with three replications tested in this study. Results: The use of INM through enriched phosphorus compost (EPC), biofertilizers, and chemical fertilizers significantly boosted both the active and passive constituents of the organic matter of the soil. In this study, a combination of 75% NPK fertilizers via soil test response (STR), EPC @ 5 t ha−1, an Azotobacter consortium, phosphorus solubilizing bacteria (PSB), and a foliar spray of 0.5% Zn considerably increased the active fraction of SOM than other treatments as indicated by microbial biomass carbon (251 mg kg−1), microbial biomass nitrogen (36.8mg kg−1), microbial biomass phosphorus (6.82 mg kg−1), water-soluble organic carbon (73.9 mg kg−1), water-soluble carbohydrates (43.8mg kg−1), presence of dehydrogenase in soil (6.82 µg TPF g−1 soil 24 h−1), and carbon mineralization (43.8mg CO2C kg−1 soil 24 h−1). This treatment was also found to increase the passive fraction as shown by the presence of humic acid (0.332%), fulvic acid (0.210%), hymatomelanic acid (0.052%), brown humic acid (0.252%), and humin (0.604%). Discussion: From this study, it can be concluded that the application of 75% NPK fertilizers as per STR + EPC + Azotobacter + PSB + 0.5% foliar Zn spray can improve soil health in maize-based cropping systems.

Maize (Zea mays) is the most important coarse cereal utilized as a major energy source for animal feed and humans. However, maize grains are deficient in methionine, an essential amino acid required for proper growth and development. Synthetic methionine has been used in animal feed, which is costlier and leads to adverse health effects on end-users. Bio-fortification of maize for methionine is, therefore, the most sustainable and environmental friendly approach. The zein proteins are responsible for methionine deposition in the form of δ-zein, which are major seed storage proteins of maize kernel. The present review summarizes various aspects of methionine including its importance and requirement for different subjects, its role in animal growth and performance, regulation of methionine content in maize and its utilization in human food. This review gives insight into improvement strategies including the selection of natural high-methionine mutants, molecular modulation of maize seed storage proteins and target key enzymes for sulphur metabolism and its flux towards the methionine synthesis, expression of synthetic genes, modifying gene codon and promoters employing genetic engineering approaches to enhance its expression. The compiled information on methionine and essential amino acids linked Quantitative Trait Loci in maize and orthologs cereals will give insight into the hotspot-linked genomic regions across the diverse range of maize germplasm through meta-QTL studies. The detailed information about candidate genes will provide the opportunity to target specific regions for gene editing to enhance methionine content in maize. Overall, this review will be helpful for researchers to design appropriate strategies to develop high-methionine maize.

Micronutrient malnutrition and suboptimal yields pose significant challenges in rainfed cropping systems worldwide. To address these issues, the implementation of climate-smart management strategies such as conservation agriculture (CA) and system intensification of millet cropping systems is crucial. In this study, we investigated the effects of different system intensification options, residue management, and contrasting tillage practices on pearl millet yield stability, biofortification, and the fatty acid profile of the pearl millet. ZT systems with intercropping of legumes (cluster bean, cowpea, and chickpea) significantly increased productivity (7–12.5%), micronutrient biofortification [Fe (12.5%), Zn (4.9–12.2%), Mn (3.1–6.7%), and Cu (8.3–16.7%)], protein content (2.2–9.9%), oil content (1.3%), and fatty acid profile of pearl millet grains compared to conventional tillage (CT)-based systems with sole cropping. The interactive effect of tillage, residue retention, and system intensification analyzed using GGE statistical analysis revealed that the best combination for achieving stable yields and micronutrient fortification was residue retention in both (wet and dry) seasons coupled with a ZT pearl millet + cowpea–mustard (both with and without barley intercropping) system. In conclusion, ZT combined with residue recycling and legume intercropping can be recommended as an effective approach to achieve stable yield levels and enhance the biofortification of pearl millet in rainfed agroecosystems of South Asia.

Conservation agriculture practices have been globally recognized for improving soil quality by enhancing soil organic carbon, mitigating climate change, and boosting resilience, thereby supporting food security. However, declining soil organic carbon (SOC) is reported as a significant issue in Indian soil, particularly in Indo-Gangetic Plain (IGP). In this investigation, the experiment was conducted to assess the impacts of crop residue retention under conservation agriculture practices with green seeker (GS)-based nitrogen (N) application. The finding of this study revealed that passive carbon pools were 25% and 22% higher in Zero Tillage with Residue Retention (ZTWR) than in Zero Tillage without Residue Retention (ZTWoR) during 2018 and 2019, respectively. Active carbon pools were found to increase, 5.47 g kg−1 in ZTWR plots and 4.34 g kg−1 in ZTWoR plots, while passive carbon pools were recorded at 7.46 g kg−1 in ZTWoR plots and 9.23 g kg−1 in ZTWR plots. The passive carbon pool was recorded as highest in ZTWR 50% N+GS treatment (8.61 g kg−1) and lowest in ZTWoR 70%N+GS treatment (8.15 g kg−1). 50%N+GS subplot treatment performed well in precision nitrogen management treatment under conservation agriculture, and it also improved various carbon pools; Overall, ZTWR performed better than ZTWoR plots, and 50%N+GS improved SOC pools in the subplot, it is followed by RDN, 33%N+GS and RDN subplot treatment. The soil organic pools are positively correlated with crop yields. Hence, the present study recommends that residue retention in conservation agriculture and optimized precision nitrogen management improve the soil organic carbon pools, ultimately improving soil fertility and sustainability.

Optimizing nitrogen (N) inputs is crucial for maximizing wheat yield and ensuring environmental sustainability. Wheat’s economic significance in India calls for a comprehensive evaluation of its ecological implications to develop a resilient production system. This study aimed to identify and evaluate ten wheat cultivars for their yield and N-use efficiency under varying nitrogen inputs (control (N0), half of the recommended nitrogen (N75), and the recommended nitrogen (N150)) using the surface application of neem-oil-coated urea. All N inputs were applied in three splits, basal, crown root initiation, and tillering stages, and an experiment was conducted in a split-plot design. The application of N150 gave the highest dry matter accumulation (DMA) at harvesting stage (AHS) (871 g m−2), seed/spike (60), grain yield (GY = 7.4 t ha−1), straw yield (SY = 8.9 t ha−1), harvest index (HI = 45.2%), protein (12.5%), and total uptake of N (TUN) (223 kg ha−1) by the cultivar ‘HD 3249’, being closely followed by the cultivar ‘HD3117’. Six cultivars (‘HD 3298’, ‘HD 3117’, ‘HD 3249’, ‘PBW 550’, ‘HD 3086’, ‘HD 2967’) out of the ten cultivars evaluated responded well to different input treatments with respect to the grain yield efficiency index (GYEI ≥ 1). Regarding N input, N75 and N150 recorded the highest increases in plant height, AHS (16.5%; 21.2%), dry matter accumulation (DMA) at 30 days after sowing (DAS) (37.5%; 64%), DMA-60 DAS (42%; 53%), DMA-90 DAS (39.5%; 52.5%), TILL-30 DAS (19.8%; 26.4%), TILL-60 DAS (33.3%; 44%), TILL-90 DAS (37.2%; 47.2%), seed/spike (8%; 10%), 1000-grain weight (7.8%; 12.2%), and protein content (23.3%; and 33%) when compared with N0. Furthermore, the application of N75 and N150 improved GY (72.1%; 142.6%), SY (61.1%; 110.6%), BY (65.5%; 123%), and HI by 4.4% and 9%, respectively, over N0. Nitrogen addition (N75 and N150) also significantly increased total nitrogen uptake (104.7%; 205.6%), respectively, compared to N0. The correlation analysis revealed a positive association among most of the crop parameters. Overall, our research results suggest that the cultivars ‘HD 3249’ and ‘HD 3117’ have the potential to be effective options for improving N utilization efficiency, grain yield, and GYEI in North-West India.

Maize serves as a crucial nutrient reservoir for a significant portion of the global population.However, to effectively address the growing world population's hidden hunger, it is essential to focus on two key aspects: biofortification of maize and improving its yield potential through advanced breeding techniques. Moreover, the coordination of multiple targets within a single breeding program poses a complex challenge. This study compiled mapping studies conducted over the past decade, identifying quantitative trait loci (QTLs) associated with grain quality and yield related traits in maize. Meta-QTL analysis of 2,974 QTLs for 169 component traits (associated with quality and yield related traits) revealed 68 MQTLs across different genetic backgrounds and environments. Most of these MQTLs were further validated using the data from genome wide association studies (GWAS). Further, ten MQTLs, referred to as breedingfriendly MQTLs (BF-MQTLs), with a significant phenotypic variation explained (PVE) over 10% and confidence interval (CI) less than 2Mb, were shortlisted. BF-MQTLs were further used to identify potential candidate genes, including 59 genes encoding important proteins/products involved in essential metabolic pathways. Five BF-MQTLs associated with both quality and yield traits were also recommended to be utilized in future breeding programs.Synteny analysis with maize and rice genomes revealed conserved regions across the genomes, indicating these hotspot regions as validated targets for developing biofortified, high-yielding maize varieties in future breeding programs. After validation, the identified candidate genes (CGs) can also be utilized to effectively model the plant architecture and enhance desirable quality traits through various approaches such as marker-assisted breeding, genetic engineering, and genome editing.

Host Plant Resistance (HPR) is the most important component for sustainable management of insect pests. The purpose of the present work was to understand the role of various morphological and biochemical factors as defense mechanism and their interaction on different biological parameters attributed to survival and development of pink stem borer (PSB), Sesamia inferens Walker in maize. The resistant and moderately resistant genotypes (DMRE 63, CM 500 and WNZ Exotic pool) suffered least leaf injury rating (LIR), dead hearts (DH%), percentage stem tunneling (ST%), number of entry/exit holes (E/EH) and showed deleterious effects on biological parameters of pink stem borer as compared to susceptible ones (CM 202 and BML 6). Resistance index among the genotypes varied from 0.11 to 0.46. The variation in morphological traits such as number of nodes, internode distance and stem diameter could not distinguish all the resistant genotypes from that of susceptible genotypes in terms of its mean value. Higher levels of biochemical constituents, viz ., p -Coumaric acid ( p -CA), ferulic acid (FA), acid detergent fibre (ADF) and acid detergent lignin (ADL) were observed in resistant genotypes compared to susceptible ones. Antibiosis was expressed in terms of reduced pupal weight when fed on WNZ Exotic pool, whereas larval weight and larval survival affected when fed on DMRE 63. Higher concentration of p -CA content in pith of resistant maize genotypes prolonged the pupal period of pink stem borer. Higher concentration of p -CA and FA contents in rind reduced the adult emergence, as they showed significant negative correlation between them. The larval period was prolonged with higher levels of ADF and ADL contents in maize genotypes either in rind or both rind and pith as both ADF and ADL content showed a significant positive correlation with the larval period. The Pearson correlation analysis of most of the biochemical constituents revealed significant negative correlation with damage parameters. The correlation coefficients between p -CA with DH (%), ST (%) and E/EH were r= -0.9642 ** , r= -0.9363 ** , and r= -0.9646 ** , respectively. Similarly, the correlation coefficients between FA with DH (%), ST (%) and E/EH were r= -0.9217 * , r= -0.9563 ** , and r= -0.9434 ** , respectively and ADF with DH (%), ST (%) and E/EH were r= -0.9506 ** , r= -0.9611 ** , and r= -0.9709 ** , respectively. The study confirms that stem damage parameters can also be used as selection criteria along with LIR to identify resistant genotypes against pink stem borer. Based on the correlation analysis it was concluded that resistance to pink stem borer in maize is the result of interaction of several morphological and biochemical traits rather than a single factor. The findings obtained from the present study can be utilised in pink stem borer resistance breeding programmes to enhance and diversify the basis of resistance.

Viral diseases substantially impact global maize production. Genetic resistance is the most feasible approach to combat losses caused by viral diseases. Various researchers have mapped several QTLs for viral disease resistance (VDR) in maize. The meta-QTL (MQTL) analysis is the best way to leverage such independent studies to find overlapping or common genomic regions governing target traits. Towards this direction, in the present study, the MQTL analysis was carried out using a total of 39 QTL mapping investigations on resistance against 14 viral diseases. 53 (27.04%) out of 196 QTLs could be projected on the maize genome. The study discovered 14 MQTLs for resistance against 11 viral diseases on chromosomes 1, 3 and 10. Marker trait associations (MTAs) in genome-wide association studies confirmed the role of two MQTLs (MQTL3_2 and MQTL10_2) for VDR. The identified MQTL regions harboured 1715 candidate genes. Further, the genes expressed constitutively in the MQTLs identified for VDR were analyzed for their involvement in metabolic pathways. The identified genes were found to be implicated in antiviral resistance, and thus, constitute a good resource for allele mining to decipher the mechanism of plant-virus interactions.

Background Maize is an excellent fodder crop due to its high biomass, better palatability, succulency, and nutrition. Studies on morpho-physiological and biochemical characterization of fodder maize are limited. The present study aimed to explore the genetic variation in fodder maize landraces for various morpho-physiological traits and estimation of genetic relationship and population structure. Methods and results The study on 47 fodder maize landraces revealed significant variation for all morpho-physiological traits except leaf-stem ratio. Plant height, stem girth, leaf-width and number of leaves showed positive correlation with green fodder yield. Morpho-physiological traits-based clustering grouped the landraces into three major clusters, whereas neighbour joining cluster and population structure analysis using 40 SSR markers revealed four and five major groups, respectively. Most landraces of Northern Himalaya-Kashmir and Ludhiana fall into a single group, whereas rest groups mainly had landraces from North-Eastern Himalaya. A total of 101 alleles were generated with mean polymorphic information content value of 0.36 and major allele frequency of 0.68. The pair wise genetic dissimilarity between genotypes ranged from 0.21 to 0.67. Mantel test revealed weak but significant correlation between morphological and molecular distance. Biochemical characterisation of superior landraces revealed significant variation for neutral detergent fibre, acid detergent fibre, cellulose and lignin content. Conclusion Interestingly, significant, and positive correlation of SPAD with lignin content can be explored to bypass the costly affair of invitro quality assessment for digestibility parameters. The study identified superior landraces and demonstrated the use of molecular markers in genetic diversity assessment and grouping of genotypes for fodder maize improvement.

Plant diseases threaten global food security by reducing the production and quality of produce. Identification of disease resistance sources and their utilization in crop improvement is of paramount significance. However, constant evolution and occurrence of new, more aggressive and highly virulent pathotypes disintegrates the resistance of cultivars and hence demanding the steady stream of disease resistance cultivars as the most sustainable way of disease management. In this context, molecular tools and technologies facilitate an efficient and rational engineering of crops to develop cultivars having resistance to multiple pathogens and pathotypes. Puccinia spp. is biotrophic fungi that interrupt crucial junctions for causing infection, thus risking nutrient access of wheat plants and their subsequent growth. Sugar is a major carbon source taken from host cells by pathogens. Sugar transporters (STPs) are key players during wheat-rust interactions that regulate the transport, exchange, and allocation of sugar at plant-pathogen interfaces. Intense competition for accessing sugars decides fate of incompatibility or compatibility between host and the pathogen. The mechanism of transport, allocation, and signaling of sugar molecules and role of STPs and their regulatory switches in determining resistance/susceptibility to rusts in wheat is poorly understood. This review discusses the molecular mechanisms involving STPs in distribution of sugar molecules for determination of rust resistance/susceptibility in wheat. We also present perspective on how detailed insights on the STP's role in wheat-rust interaction will be helpful in devising efficient strategies for wheat rust management.

Maydis leaf blight (MLB) is a prevalent disease affecting maize worldwide, caused by the necrotrophic plant pathogen Bipolaris maydis (Nisikado and Miyake). Depending on environmental conditions, MLB can lead to yield losses of up to 40% or more. To combat this disease, various chemical and biocontrol/botanical agents have been developed and proven effective. This study aimed to assess the efficacy of different combinations of disease management components as an alternative approach. The effectiveness of three modules, namely organic, chemical, and IDM, was tested in hot spot locations, namely Ludhiana, Karnal, and Delhi, during 2019 and 2020. Results indicated that the chemical module demonstrated superior disease control, achieving percentages of 54.16 and 52.92 at Ludhiana and Karnal, respectively. The IDM module also showed promising results, with disease control percentages of 45.87 and 44.69 at Ludhiana and Karnal, respectively. Conversely, the organic module exhibited the least effectiveness. Notably, at the Delhi location, the standard control (Foliar spray with Mancozeb 75 WP @ 2.5 g / l water) proved most effective, achieving a disease control percentage of 64.29, followed by the IDM module at 50.00. The chemical module exhibited the highest percent increase in yield (PIY), with figures of 86.47 and 52.92 at Ludhiana and Karnal, respectively, compared to other treatments. This study highlights the superior efficacy of the chemical and IDM modules in comparison to the positive control (check). Consequently, these modules present alternative strategies for effectively managing MLB.

Introduction: Soil organic matter (SOM) quality is the major driving force for nutrient cycles impacting the productivity of cropping systems. Identification of sensitive indicators and developing metrics to assess SOM quality is a major challenge under field conditions. Methods: Data from a continuing long-term experiment since 2005 at Modipuram, India, were analyzed with key objectives to 1) observe the long-term effect of vermicompost/crop residues alone or in conjunction with NPK chemical fertilizers on crop yield and quality of SOM, 2) identify and develop SOM quality indicators (SOMQI) by encompassing sensitive indicators, and 3) predict system productivity by using SOMQI under rice ( Oryza sativa L.)–potato ( Solanum tuberosum L.)–wheat ( Triticum aestivum L.) (RPW) and maize ( Zea mays L.)–potato–onion ( Allium cepa L.) (MPO) cropping systems. The treatments comprised of 100% NPK fertilizer; 100% N from vermicompost (N-VC); 50% NPK from fertilizer + 50% N from VC; 100% NPK from fertilizer + crop residue (CR); 100% N from VC + CR. Results: Results showed that continuous application of 100% N-VC and 100% N-VC+CR for eight years considerably increased the soil’s particulate organic matter carbon (POM-C), light fraction organic matter carbon (LFOM-C), and nitrogen (LFOM-N), dissolved organic carbon (DOC) and nitrogen (DON), as well as the available N (AN), available P (AP) and available S (AS) over control. Principal component analysis (PCA) identified AN, POM-C, LFOM-C: N, and DON in RPW and AN, POM-C, microbial biomass carbon (MBC), and LFOM-C: N in MPO cropping system as sensitive SOM quality indicators for the development of SOMQI. Under the MPO cropping system, results were more pronounced with 100% N-VC and 50% NPK+50% N-VC at 0–15 cm soil depth. Furthermore, at 15–30 cm depth, the effect was more prominent in 100% NPK + CR over other treatments. Discussion: Overall MPO cropping system exhibited better SOMQI than the RPW system. Rice, wheat, and maize yields increased significantly under different fertilizer treatments with organic or inorganic amendments. Substitution of fertilizer N with organic sources showed comparable yields obtained under 100% NPK treatment. Partial substitution of chemical fertilizers either by VC and/or CR enhanced the SOM quality and productivity under both cropping systems. The use of PCA-based SOMQI can be helpful in assessing SOM quality and predicting the productivity of cropping systems.

Phytic acid (PA) acts as a storehouse for the majority of the mineral phosphorous (P) in maize; ~80% of the total P stored as phytate P is not available to monogastric animals and thereby causes eutrophication. In addition, phytic acid chelates positively charged minerals making them unavailable in the diet. The mutant lpa1-1 allele reduces PA more than the wild-type LPA1 allele. Further, mutant gene opaque2 (o2) enhances lysine and tryptophan and crtRB1 enhances provitamin-A (proA) more than wild-type O2 and CRTRB1 alleles, respectively. So far, the expression pattern of the mutant lpa1-1 allele has not been analysed in maize genotypes rich in lysine, tryptophan and proA. Here, we analysed the expression pattern of wild and mutant alleles of LPA1, O2 and CRTRB1 genes in inbreds with (i) mutant lpa1-1, o2 and crtRB1 alleles, (ii) wild-type LPA1 allele and mutant o2 and crtRB1 alleles and (iii) wild-type LPA1, O2 and CRTRB1 alleles at 15, 30 and 45 days after pollination (DAP). The average reduction of PA/total phosphorous (TP) in lpa1-1 mutant inbreds was 29.30% over wild-type LPA1 allele. The o2 and crtRB1-based inbreds possessed ~two-fold higher amounts of lysine and tryptophan, and four-fold higher amounts of proA compared to wild-type alleles. The transcript levels of lpa1-1, o2 and crtRB1 genes in lpa1-1-based inbreds were significantly lower than their wild-type versions across kernel development. The lpa1-1, o2 and crtRB1 genes reached their highest peak at 15 DAP. The correlation of transcript levels of lpa1-1 was positive for PA/TP (r = 0.980), whereas it was negative with inorganic phosphorous (iP) (r = −0.950). The o2 and crtRB1 transcripts showed negative correlations with lysine (r = −0.887) and tryptophan (r = −0.893), and proA (r = −0.940), respectively. This is the first comprehensive study on lpa1-1 expression in the maize inbreds during different kernel development stages. The information generated here offers great potential for comprehending the dynamics of phytic acid regulation in maize.

An understanding of the heterotic pattern in the active germplasm is the first and crucial step in any hybrid breeding program. Diallel and line × tester ( L × T ) mating designs were extensively followed to understand the heterotic pattern based on the combining ability information. The present study adopted GGE biplots, generated using the L × T matrix to understand the tropical maize germplasm's heterotic pattern and identify the best tester combinations for heterotic grouping. The L × T matrix and combining ability information was generated by evaluating 985 testcross, generated by crossing 110 diverse tropical inbred lines with 10 inbred testers at two geographically diverse locations. The stability of combining ability effects, the magnitude and direction of combining ability effects, and also the discrimination and representativeness of testers were considered for the identification of best tester combinations for heterotic grouping. The present investigation has shown the usefulness of GGE biplots’ effectiveness in understanding the heterotic pattern and identifying the best tester combinations for heterotic grouping. The results of the present investigation revealed the existing heterotic pattern in the elite tropical maize inbred lines that were extensively used in hybrid maize breeding. The findings of the present study are of immense practical significance, which not only guides different hybrid maize breeding programs but also helps to identify the best testers in their respective hybrid breeding programs. The study showed that the GGE biplot method can be adopted to understand the active germplasm's heterotic pattern and organize the germplasm into different heterotic groups.

Root system architecture (RSA), also known as root morphology, is critical in plant acquisition of soil resources, plant growth, and yield formation. Many QTLs associated with RSA or root traits in maize have been identified using several bi-parental populations, particularly in response to various environmental factors. In the present study, a meta-analysis of QTLs associated with root traits was performed in maize using 917 QTLs retrieved from 43 mapping studies published from 1998 to 2020. A total of 631 QTLs were projected onto a consensus map involving 19,714 markers, which led to the prediction of 68 meta-QTLs (MQTLs). Among these 68 MQTLs, 36 MQTLs were validated with the marker-trait associations available from previous genome-wide association studies for root traits. The use of comparative genomics approaches revealed several gene models conserved among the maize, sorghum, and rice genomes. Among the conserved genomic regions, the ortho-MQTL analysis uncovered 20 maize MQTLs syntenic to 27 rice MQTLs for root traits. Functional analysis of some high-confidence MQTL regions revealed 442 gene models, which were then subjected to in silico expression analysis, yielding 235 gene models with significant expression in various tissues. Furthermore, 16 known genes viz., DXS2, PHT, RTP1, TUA4, YUC3, YUC6, RTCS1, NSA1, EIN2, NHX1, CPPS4, BIGE1, RCP1, SKUS13, YUC5, and AW330564 associated with various root traits were present within or near the MQTL regions. These results could aid in QTL cloning and pyramiding in developing new maize varieties with specific root architecture for proper plant growth and development under optimum and abiotic stress conditions.

Background: Maize is an excellent fodder crop due to its high biomass, better palatability, succulency, and nutrition. Studies on morpho-physiological and biochemical characterization of fodder maize are limited. The present study aimed to explore the genetic variation in fodder maize landraces for various morpho-physiological traits and estimation of genetic relationship and population structure. Methods and Results: The study in 47 fodder maize landraces revealed significant variation for all morpho-physiological traits except leaf-stem ratio. Plant height, stem girth, leaf-width and number of leaves showed positive correlation with green fodder yield. Morpho-physiological traits-based clustering grouped the landraces into three major clusters, whereas neighbour joining cluster and population structure analysis using 40 SSR markers revealed four and five major groups, respectively. Most landraces of Northern Himalaya-Kashmir and Ludhiana fall into a single group, whereas rest groups mainly had landraces from North-Eastern Himalaya. A total of 101alleles were generated with mean polymorphic information content value of 0.36 and major allele frequency of 0.68. The pair wise genetic dissimilarity between genotypes ranged from 0.21 and 0.67. Mantel test revealed weak but significant correlation between morphological and molecular distance. Biochemical characterisation of superior landraces revealed significant variation for neutral detergent fiber, acid detergent fiber, cellulose and lignin content. Conclusion: Interestingly, significant, and positive correlation of SPAD with lignin content can be explored to bypass the costly affair of invitro quality assessment for digestibility parameters. The study identified superior landraces and demonstrated the use of molecular markers in genetic diversity assessment and grouping of genotypes for fodder maize improvement.

Te experiment was laid out in alpha-lattice design with two replicates of each genotype which comprised twenty-three heat-tolerant maize hybrids received from CIMMYT-Mexico and three check varieties. Tese treatment genotypes were evaluated at the Agronomy farm, Gokuleshwor College, Baitadi, Nepal, during the spring season of 2021. ZH191065 and ZH191158 were found to be the tallest (307.2 cm) and the shortest (227.6 cm) genotypes, respectively. High heritability (>60%) with high genetic advances in most traits, ensures the predominance diference of the genetic components observed among accessions. Te presence of diferences among genotypes showed that selection is possible by evaluating the days of 50% anthesis, days of 50% silking, anthesis-silking interval, number of ears per plant, number of grains per row, number of rows per cob, cob length, cob diameter, and grain yield; most of these evaluated morphological traits were found highly correlated with grain yield of varieties, suggesting that indirect selection achieves improvement for high yield. Based on yield ranks, ZH 19782, ZH 19961, and DKC 9108 could be promoted as potential higher-yielding heat-tolerant maize hybrids for Nepal.

The spotted stem borer, Chilo partellus (Lepidoptera: Crambidae) is the major insect pest of maize and sorghum crops during the rainy season. The pheromone released by adult virgin females has been reported to consist of (Z)-11-hexadecenal (Z11–16:Ald) as major component and (Z)-11-hexadecenol (Z11–16OH) as minor component. The latter has been reported to reduce the efficiency of major component to trap the male moths. We studied the electrophysiological and behavioral response of male C. partellus moths to Z11–16:Ald, Z11–16OH, their E-isomers (E)-11-hexadecenal and (E)-11-hexadecen-1-ol, and blends. Electroantennogram (EAG) studies revealed that male C. partellus antennae elicited significantly greater responses to both (Z)-11-hexadecenal and (Z)-11-hexadecenol compared to their respective E-isomers. Behavioral response studies through wind tunnel and cage bioassay showed that blends of Z11–16:Ald and Z11–16OH in the proportion of 100:100 and 100:95 elicited significantly higher responses from male moths. The attractiveness of these pheromone components and blends in field also revealed that traps baited with 100:100 proportion was most effective. Our studies clearly showed that the minor alcohol component Z11–16OH is important for enhancing attractiveness of the pheromone and provides a more effective blend for monitoring of this pest.