Improvement Of Grain Yield Research Articles

Diallel analysis of popcorn populations for yield, popping expansion and resistance to fall armyworm

ABSTRACT The objective of this study was to estimate the varietal and heterotic effects related to grain yield, popping expansion and resistance of popcorn against fall armyworm. Twelve open-pollinated varieties were intercrossed in a complete diallel mating scheme. The 66 experimental hybrids, together with their parents and controls Zapalote Chico, BRS 1030 and IAC 125, resulted in a total of 81 treatments, evaluated in an experiment in a 9x9 triple-square lattice design, in Maringa-PR and Araruna-PR. The data were analyzed according to the diallel model of Gardner and Eberhart (1966). The following traits were evaluated: grain yield (GR); mean plant height (PH) and insertion height of the highest ear in the stem (EI); silking (SIL); final plant density (FD) and popping expansion (PE). Variety PR 023 is indicated for intrapopulation improvement for grain yield. Regarding popping expansion, the results indicated cross SAM x UNB 2U C5 for recurrent reciprocal selection. In relation to resistance to fall armyworm, the varieties PARA 172, PA 091, PR 023, and SE 013 were selected for intrapopulation improvement. On the other hand, the crosses PARA 172 x BOZM 260, PA 091 x BOYA 462 and SAM x UNB 2U C5 can be indicated for interpopulation improvement.

Identifying rice grains with premium nutritional quality among on-farm germplasm in the highlands of Northern Thailand

Local rice varieties with premium nutritional quality grains are beneficial to consumers, and their genetic traits may be deployed in breeding programmes for many purposes. This study explores grain quality characteristics with health implications of rice germplasm maintained and used by farmers in the highlands of Northern Thailand. Concentrations of iron (Fe), zinc (Zn), phenols and anthocyanin and anti-oxidative capacity were determined in the caryopsis without husk of 77 samples of rice seed collected from farmers. Entries with the highest grain quality characteristics identified were grown together with four standard check varieties at two different elevations in a farmer’s field at Mae Wang District of Chiang Mai province (800 m above mean sea level), as well as in pots at Chiang Mai University (CMU) (330 m above mean sea level). The grain quality characteristics were determined at maturity, separately for 10 individual plants grown at CMU. A wide variation in all the grain quality characteristics was found among samples grown in the farmer’s field. There were approximately twofold differences in the lowest and highest Fe and Zn concentrations, especially high variation in contents of phenols and anthocyanin and anti-oxidative capacity found in grain with purple pericarp. The top entries identified from the farmer’s seed had significantly higher anthocyanin concentration and anti-oxidative capacity than the check varieties when grown together at Mae Wang and CMU, in spite of the strong locality specific effects on these characteristics. Further variation was found in the grain quality characteristics within each of the selected farmer’s seed samples. Quality improvement could thus be made by either eliminating the poorest performing lines or development of single-seed descent lines from the top-performing plants. The desirable genetic traits can also be used in breeding programme for improvement of grain yield as well as cooking and nutritional quality.

Variability, correlation and path studies in coloured rice

The present investigation was undertaken with 33 coloured and white rice genotypes to study the variability and genetic parameters in addition to character associations and path effects for yield and quality parameters. The study involved seven red pericarp, eight black pericarp and 17 white rice genotypes, in addition to the check, BPT 5204. The results revealed high genotypic and phenotypic coefficient of variability, heritability and genetic advance as per cent mean for grains per panicle, grain yield per plant, alkali spreading value, protein content, total phenol content, total antioxidant activity, zinc and iron content indicating the effectiveness of selection for these traits. The results on character associations revealed positive and significant association of grain yield with panicle length, grains per panicle and test weight; and the quality traits, namely, alkali spreading value, protein content, total antioxidant activity, zinc and iron content, indicating scope for simultaneous improvement of yield and quality traits through selection. Among these, grains per panicle, protein content and zinc content had also recorded high and positive direct effects on grain yield per plant, indicating the effectiveness of these traits in improvement of grain yield per plant towards development of high yielding genotypes with good nutritional quality.

A combination of linkage mapping and GWAS brings new elements on the genetic basis of yield-related traits in maize across multiple environments.

Using GWAS and QTL mapping identified 100 QTL and 138 SNPs, which control yield-related traits in maize. The candidate gene GRMZM2G098557 was further validated to regulate ear row number by using a segregation population. Understanding the genetic basis of yield-related traits contributes to the improvement of grain yield in maize. This study used an inter-mated B73 × Mo17 (IBM) Syn10 doubled-haploid (DH) population and an association panel to identify the genetic loci responsible for nine yield-related traits in maize. Using quantitative trait loci (QTL) mapping, 100 QTL influencing these traits were detected across different environments in the IBM Syn10 DH population, with 25 co-detected in multiple environments. Using a genome-wide association study (GWAS), 138 single-nucleotide polymorphisms (SNPs) were identified as correlated with these traits (P < 2.04E-06) in the association panel. Twenty-one pleiotropic QTL/SNPs were identified to control different traits in both populations. A combination of QTL mapping and GWAS uncovered eight significant SNPs (PZE-101097575, PZE-103169263, ZM011204-0763, PZE-104044017, PZE-104123110, SYN8062, PZE-108060911, and PZE-102043341) that were co-located within seven QTL confidence intervals. According to the eight co-localized SNPs by the two populations, 52 candidate genes were identified, among which the ear row number (ERN)-associated SNP SYN8062 was closely linked to SBP-transcription factor 7 (GRMZM2G098557). Several SBP-transcription factors were previously demonstrated to modulate maize ERN. We then validated the phenotypic effects of SYN8062 in the IBM Syn10 DH population, indicating that the ERN of the lines with the A-allele in SYN8062 was significantly (P < 0.05) larger than that of the lines with the G-allele in SYN8062 in each environment. These findings provide valuable information for understanding the genetic mechanisms of maize grain yield formation and for improving molecular marker-assisted selection for the high-yield breeding of maize.

Zinc Application in Combination with Zinc Solubilizing Enterobacter sp. MN17 Improved Productivity, Profitability, Zinc Efficiency, and Quality of Desi Chickpea

Chickpea is mostly grown in sandy loam soils having receding soil moisture and Zn deficiency, which limits the chickpea productivity. Zn solubilizing plant growth-promoting bacteria (PGPB) may improve the availability and uptake of Zn in these soils. This 2-year field study was conducted to evaluate the interactive effects of pre-optimized Zn application methods and Zn solubilizing PGPB (i.e., endophyte Enterobacter sp. MN17) on the productivity and quality of desi chickpea during 2016–2017 and 2017–2018. Zn was delivered through osmopriming (0.001 M Zn solution), seed coating (5 mg Zn kg−1 seed), foliar application (0.025 M Zn solution), and soil application (10 kg Zn ha−1) with or without Zn solubilizing PGPB, while hydroprimed seeds were taken as control. Zn application through either method improved the grain yield, economics, bioavailable Zn, and grain quality of desi chickpea. The maximum improvement in grain yield (43.7%) was recorded with Zn soil application followed by Zn seed coating (38.8%). The highest protein contents (22.8%), grain Zn concentration (45.8 μg g−1), bioavailable Zn contents (4.38 mg Zn day−1), and minimum phytate contents (12.0 mg g−1) were recorded by Zn soil application. The maximum mineral matter (3.89%) and fiber contents (4.81%) were recorded with Zn soil application + PGPB. The maximum agronomic efficiency (6409 kg kg−1), agro-physiological efficiency (160 kg kg−1), and apparent recovery efficiency (76.8%) were noted by Zn osmopriming + PGPB. However, the maximum physiological (289 kg kg−1) and utilization (10,559 kg kg−1) efficiencies were recorded with Zn osmopriming. Moreover, the highest economic returns ($1518.2 ha−1) and marginal net benefits ($571.5 ha−1) were recorded with Zn soil application + PGPB. To improve the productivity, profitability, and grain quality of desi chickpea, Zn application through soil or seed coating in combination with plant growth-promoting bacteria may be opted to maximize the productivity and profitability.

Analysis of QTL for Grain Size in a Rice Chromosome Segment Substitution Line Z1392 with Long Grains and Fine Mapping of qGL-6

BackgroundGrain size affects not only rice yield but is also an important element in quality of appearance. However, the mechanism for inheritance of grain size is unclear.ResultsA rice chromosome segment substitution line Z1392, which harbors three substitution segments and produces grains of increased length, was identified. The three chromosome segments were located on chromosomes 1, 5, and 6, and the average length of the substitution segment was 3.17 Mb. Cytological analysis indicates that the predominant cause of increased grain length in Z1392 could be cell expansion in the glumes. Seven quantitative trait loci (QTLs) for grain size related traits were identified using the secondary F2 population produced by Nipponbare/Z1392. The inheritance of grain length in Z1392 was mainly controlled by two major QTLs, qGL-5 and qGL-6. qGL-6 was localized on a 1.26 Mb region on chromosome 6, and OsARF19 may be its candidate gene. Based on QTL mapping, three single-segment substitution lines (S1, S2, and S3) and two double-segment substitution lines (D1 and D2) were selected, and the mapping accuracy for qGL-5 and qGL-6 was further verified using three single-segment substitution lines. Analysis of QTL additive and epistatic effects revealed that the additive effect of alleles qGL-5 and qGL-6 from ‘Xihui 18’ was estimated to increase grain length of Z1392 by 0.22 and 0.15 mm, respectively. In addition, a positive epistatic interaction between qGL-5 and qGL-6 was detected, which indicates that the pyramiding of qGL-5 and qGL-6 for grain length produces a novel genotype with longer grains.ConclusionsInheritance of grain length in the triple-segment substitution line Z1392 is mainly controlled by two major QTLs, qGL-5 and qGL-6. qGL-6 was found to be located in a 1.26 Mb region on chromosome 6, and OsARF19 may be its candidate gene. A positive epistatic interaction between qGL-5 and qGL-6 results in longer grains. The present results can be used to facilitate cloning of the qGL-5 and qGL-6 genes and contribute to improvement of grain yield in rice.

Role of the Fungicide Seed Dressing in Controlling Seed-Borne Fusarium spp. Infection and in Enhancing the Early Development and Grain Yield of Maize

Fusarium spp. are key pathogens in maize seeds and seedlings. The aim of this study has been to evaluate the effects of applying fungicides to maize seeds to increase the survival of seedlings and to enhance the early vigor and grain yield of the plants. The protective effects of 2-way (fludioxonil, metalaxil-M) and four-way (fludioxonil, metalaxil-M, azoxystrobin, thiabendazole) fungicide seed treatments were compared with an F. verticillioides seed infected control in 11 field trials carried out in North Italy. A second study focused on the impact F. verticillioides and F. graminearum seed-borne infection on plant growth and on the possible advantages of applying the previously reported seed dressing. The seed dressing increased the plant density, vigor during the whole vegetative growth cycle for all the production situations, and grain yield. F. verticillioides led to a higher seedling mortality than F. graminearum, while both species reduced plant growth and delayed the flowering date. Seed-borne infection has an important impact on both the population and vigor of maize plants. The four-way fungicide enhanced both the defense of the seedlings and the vigor of F. verticillioides infected plants, which in turn resulted in a significant improvement in grain yield, compared to a conventional two-way fungicide.

Study on variability, relationships and path analysis for agro-morphological traits in elite wheat (Triticum aestivum L.) germplasm lines under Northern Hill Zone conditions

Thirty elite wheat germplasm lines were evaluated at wheat research area of Rice and Wheat Research Station, Malan, for morphological traits to identify the most promising wheat lines. Analysis of variance indicated that mean squares due to genotypes were highly significant for all the characters under study. Moderate PCV, GCV, genetic advance and high heritability was observed for grain yield per plant, flag leaf area and peduncle length. Moderate PCV, GCV, heritability and genetic advance was observed for harvest index. Correlation studies indicated significant positive correlations of grain yield with harvest index, biological yield and 1000-grain weight. Further, harvest index and biological yield had positive high direct effects on grain yield. This indicated that selection of these traits under normal conditions will be effective of improvement of grain yield. Thus, based on present findings, 1000-grain weight, biological yield and harvest index can be utilized as suitable criteria to select high yielding genotypes. DOI.10.25174/2582-2675/2020/92518

Foliar Potassium-Induced Regulations in Glycine Betaine and Malondialdehyde Were Associated with Grain Yield of Heat-Stressed Bread Wheat (Triticum aestivum L.)

Heat stress at reproductive stages of wheat causes grain shriveling. The present study aimed at comparing thermo-sensitivity of terminal stages of wheat and optimization of foliar potassium to alleviate heat and to determine correlation of biochemical attributes with agronomic attributes. The experiment was laid out in a randomized complete block design under split treatment structure and replicated thrice. Main plot was comprised of heat stress (H), viz. H0 = no heat imposition; H1 = heat stress imposition from complete emergence of spike to grain filling initiation, and H2 = heat stress imposition from flowering initiation to grain filling initiation. Foliar potassium (K) sprays consisted of K0 = control (water spray); K15 = 15; K30 = 30; K45 = 45; and K60 = 60 g L−1. Under “H0” similar and more glycine betaine, water relations and lesser malondialdehyde were recorded with 45 and 60 g L−1 K, While 60 g L−1 K proved more beneficial under “H1” and “H2” for these attributes, “H1” proved more damaging compared with “H0” and “H2” for grain yield and yield components, while similar and more improvements in grain yield and yield components were recorded with 45 and 60 g L−1 K compared with other doses. Conclusively, more deleterious responses were observed under “H1” compared with other heat treatments. Application of 40 g L−1 K under “H0” and 60 g L−1 K under heat stress exhibited more remarkable responses. Moreover, a strong association of biochemical attributes with agronomic parameters was recorded.

BREEDING FOR DROUGHT TOLERANCE IN MAIZE

This study carried-out in four successive summer seasons (2015 to 2018) at the experimental farm of the faculty of agriculture, Menoufia University, in Shebin El-Kom, Egypt. In 2015 season, S1 recurrent selection procedure was provied (Tep#5 and Gemmeiza yellow), where 200 S0 plants from each population were selfed to produce S1 progenies. In 2016 season, kernels of 100 S1 lines that selected from each two populations were separately sown for evaluation under two water regimes, i.e normal irrigation (NI) and drought stress conditions (DS). In 2017 season, the highest 10% of S1 progenies (10 S1 progenies of first Population (Tep#5) and 10 % S1 progenies of second Population (GMY) were planted for randomly mated by bulking pollen from the S1 plants. kernels harvested, four blends of seeds were obtained (Tep#5-NI, Tep#5-DS, GMY-NI and GMY-DS). In 2018 summer season, for each population the original cycle (C0) and the improved cycle (C1) were evaluated under normal irrigation (NI) and drought stress (DS). The results could be summarized as follows: Evaluate of 100 S1 progenies (Tep#5 and Gemmeiza yellow) for drought tolerance. Analysis of variance showed significant differences among the genotypes (S1 progenies) for all studied traits under both normal and drought stress conditions for two populations. A significant average reduction of 59.88% and 61.93% in grain yield/plot of the 100 S1’s for Tep#5 and Gemmeiza yellow respectively, due to drought stress. The superiority of the selected 10 S1’s over the 100 S1’s in grain yield was higher under drought stress than under normal conditions. Evaluation of the effectiveness of S1 recurrent selection of the two cycles for Tep#5 and Gemmeiza yellow populations under normal and drought conditions. One cycle of S1 recurrent selection using water-stress as a selection environment caused a significant actual improvement of grain yield of the newely developed populations (Tep#5-DS and GMY-DS) over its original populations (Tep#5 and GMY) of 15.47 and 12.78% under water stress condition. The improved populations Tep#5-NI and GMY-NI developed by using normal irrigation as a selection environment showed significant actual improvements in grain yield under normal irrigation (12.46 and 9.06%) environment. Both water stressed and non-stressed selection environments were efficient in improving grain yield under target environments. The two improved populations showed significant superiority in grain yield/fed over origin population under normal and drought stress conditions.

Improving Strategic Growth Stage-based Drought Tolerance in Quinoa by Rhizobacterial Inoculation

ABSTRACTClimate change is imposing high temperature resulting in prolonged drought episodes and shrinking of fresh water resources across the globe. In this scenario, even drought tolerant crops like quinoa are also losing significant yield. However, this study was planned to investigate the impact of drought on quinoa at critical growth stages and bacterial inoculation to improve drought tolerance. Drought was imposed by maintaining 25% pot water holding capacity (PWC) at multiple leaf, flowering, and seed filling stage (DSFS), while 80% PWC was considered as control. Three strains of plant growth promoting rhizobacteria (PGPR) named as: Bacillus licheniformis, Pseudomonas fluorescens, and Azospirillum brasilense were inoculated with quinoa seeds before sowing with respect to drought treatments. PGPR inoculation mitigated the drastic effects of drought by improving crop growth, net assimilation rate, water use efficiency, leaf chlorophyll, and phenolic contents, all of these ultimately contributed to improvement in grain yield and its contributing attributes. Moreover, PGPR markedly improves the grain quality attributes including protein, phosphorus, and potassium contents. Principal component analysis linked the different scales of study and demonstrated the potential of physio-biochemical traits to explain the quinoa yield variations under drought condition with response to PGPR inoculation. Among different PGPR, A. brasilense was found most effective both under normal and drought conditions. Overall, DSFS has more detrimental effects among critical growth stages of quinoa and A. brasilense can be used as a shotgun tactic to ameliorate drought stress in quinoa.

Correlation and path coefficient analysis for grain yield and yield components in rice (Oryza sativa L.) under aerobic condition

An experiment was conducted during kharif season of year 2018 to study correlation and path coefficient analysis in 50 diverse rice genotypes under aerobic condition at Regional Research Station, Anand Agricultural University, Anand. Analysis of variance showed significant differences among genotypes for all the 12 characters studied. Correlation studies revealed that grain yield per plant had positive and significant association with spikelet fertility percent, 1000 grain weight, plant height and straw yield per plant at both genotypic and phenotypic levels. Hence, these characters should be given due consideration while applying selection for increasing yield. Results of path analysis indicated that the maximum direct effects as well as appreciable indirect effects were exerted by straw yield per plant, harvest index followed by spikelet fertility percent towards grain yield per plant. These characters also exhibited significant positive correlation with grain yield per plant. Therefore, selection pressure imposed on these characters would bring improvement in grain yield of rice.

Improving grain yield and protein concentration of maize (Zea mays L.) simultaneously by appropriate hybrid selection and nitrogen management

The simultaneous improvement of grain yield and protein concentration in crop production is an important global challenge. In maize, genotype selection and nitrogen (N) management are potential methods to improve grain yield and protein concentration. A field experiment was conducted in 2015–2016 in the North China Plain to evaluate the response of grain yield and protein concentration of different modern hybrids (XY1266, ZD958 and DH618) under different N rates (0–259 kg ha−1). The highest grain dry matter and protein concentration were observed in DH618. The averaged maximal grain dry matter over the 2 years was 10.3 Mg ha−1 for DH618, 6.1 % higher than for ZD958 (9.7 Mg ha−1) and 9.9 % higher than for XY1266 (9.4 Mg ha−1), and the maximal grain protein concentration in DH618 was 8.6 %, 11.1 % higher than for XY1266 (7.8 %) and 10.1 % higher than for ZD958 (7.9 %). DH618 had higher post-silking biomass accumulation, a stable high harvest index (HI), and higher post-silking N uptake as well as N harvest index (NHI) compared to the other two hybrids, meanwhile without reducing N remobilization efficiency (NRE). In DH618, high leaf N concentration after silking facilitated a higher rate of photosynthesis, further leading to greater post-silking biomass and N accumulation, and quickly remobilization of leaf N at late grain-filling stage improved the NRE and NHI. Together with choosing the right hybrid, optimisation of N management with split N application as well as appropriate N rate taking into account the residual soil mineral N could ensure both high grain dry matter and increased protein concentration in maize.

Improving soil quality for higher grain yields in Chinese wheat and maize production

AbstractImproved soil quality is required to sustainably achieve food security. Although the recycling of organic materials to fields is considered a key practice for improving soil quality, the effects of this procedure on productivity shows inconsistent results from strongly positive to negative. A long‐term field experiment was conducted over six crop seasons to test the hypothesis that large improvements in grain yield and soil quality of organic recycling could be achieved under high‐yielding management practices. The performance parameters of crop and soil were examined after applying two different organic amendment treatments: the continual application of manure in each season (chemical fertilizer [CF] + manure), and one application of a large volume of peat and vermiculite (PV; CF + PV); controls received CF only. All three treatments were applied at an optimal N rate with high‐yield management procedures. Treatments with organic soil amendments increased grain yields by 2.5–2.9 Mg ha−1 yr−1 compared with CF alone. These high‐yield plots had higher levels of soil organic carbon (65.3–111.0% higher), less bulk density (7.2–13.8% lower), and a larger proportion of macroaggregates in the topsoil. Compared with CF + manure treatment, the CF + PV produced similarly improved yields and soil properties, but the soil microbial biomass carbon and microbial community structure (including richness and diversity) differed between treatments. The recycling of organic materials was found to reduce farm profitability due to increases in material costs and labour. Our study provides an opportunity to increase both productivity and soil quality under integrated management, and the data will help adequately inform policies and strategic plans for food security and land use.

Foliar applied fullerol differentially improves salt tolerance in wheat through ion compartmentalization, osmotic adjustments and regulation of enzymatic antioxidants.

Earlier we reported that seed pre-treatment with PHF promoted early seedling growth and salinity tolerance in wheat. As a way forward, experiments were conducted to investigate whether and to what extent foliar spray of fullerol could influence growth and physio-biochemical responses in salt stressed wheat. Ina control experiment, seeds were sown in sand filled pots (500g) under control and 150mM NaCl stress. After 15days, foliar spray of fullerol at 0, 10, 40, 80 and 120nM concentrationwas applied and the data for various morpho-biochemical attributes recorded after 2weeks. Fullerol caused improvements in shoot growth attributes while had least effect on root growth traits. Increase in total chlorophyll while reduction in Car/Chl ratio was evident under salinity in response to fullerol spray. Only 40 and 80nM spray treatments improved antioxidant activities and reduced H2O2 contents while MDA contents which increased due to salt stress, remained unaffected by foliar spray. Fullerol spray also improved sugars, proline and free amino acids under salinity. During second experimentunder natural conditions, 60day old plants grown in sand filled pots (10kg) under 0 and 150mM NaCl were foliar sprayed with selected concentrations (0, 40 and 80nM) offullerol. Salinity inhibited gas exchange and grain yield attributes while fullerol-sprayed plants exhibited recovery. Fullerol spray resulted in high root and shoot K+ and shoot Ca2+ contents. Also, increase in shoot and root P, while lesser shoot Na+ was recorded due to 80nM spray under salt stress. Overall, 40 and 80nM fullerol spray improved photosynthetic activity, osmolytes accumulation and altered tissue ion compartmentalization which contributed to improvement in grain yield attributes under salinity.

Improving yield-related physiological characteristics of spring rapeseed by integrated fertilizer management under water deficit conditions.

Two separate field experiments were conducted in 2018 and 2019 as split-plot based on randomized complete block design with three replications to evaluate physiological responses of rapeseed to fertilization treatments (control, chemical fertilizer, inoculation of seeds with PGPR, vermicompost and combined fertilizers) under different irrigation levels (irrigation after 70,100, 130, and 160 mm evaporation). Water stress increased the activities of catalase, polyphenol oxidase, peroxidase and superoxide dismutase and the contents of proline, soluble sugars and malondialdehyde and also leaf temperature, but decreased membrane stability index, chlorophyll content, leaf water content, stomatal conductance and grain yield. Application of fertilizers particularly combined fertilizers decreased proline content and leaf temperature, but increased the antioxidant enzymes activities, soluble sugars, chlorophyll content, leaf water content, membrane stability index, and stomatal conductance under different irrigation intervals. These superiorities of fertilization treatments were led to considerable improvement in grain yield. The results revealed that the combined fertilizer application improved most of the physiological parameters. It was deducted that the application of combined fertilizers reduced chemical fertilizer by about 67% and alleviated the deleterious effects of water limitation on field performance of rapeseed.

Flooding Irrigation Weakens the Molecular Ecological Network Complexity of Soil Microbes During the Process of Dryland-to-Paddy Conversion.

Irrigation has been applied on a large scale for the improvement of grain yield per hectare and production stability. However, the dryland-to-paddy conversion affects the ecological environment of areas of long-term dry farming, especially soil microorganisms. Little attention has been paid to the changes in microbial communities and the interactions between their populations in this process. Therefore, in this paper, the compositions and diversity of soil bacterial and fungal communities were explored through a combination of high-throughput sequencing technology and molecular ecological network methods using bacterial 16S rRNA and fungal ITS. The results showed that: (1) both the abundance and diversity of soil bacteria and fungi decreased in a short time, and the abundance of Actinobacteria, Firmicutes and Olpidiomycota varied greatly. (2) Compared to dry land, the modular structure of interaction networks and interspecific relationships of bacterial and fungal communities in paddy soil were simpler, and the network became more unstable. A cooperative relationship dominated in the molecular ecological network of bacteria, while a competitive relationship was dominant in the network of fungi. Actinobacteria and Firmicutes were the dominant bacterial species in dry land and paddy field, respectively. Ascomycota was dominant in the fungal communities of both dry land and paddy field. (3) The change in soil environmental factors, such as pH, electrical conductivity (EC), organic matter (OM) and available potassium (AK), directly affected the soil microbial community structure, showing a significant correlation (p < 0.05). These environmental factors also influenced the dominant microbial species. Microorganisms are the most important link in the carbon and nitrogen cycles of soil, and a large-scale dryland-to-paddy conversion may reduce the ecological stability of regional soil.

Basal Application of Zinc to Improve Mung Bean Yield and Zinc-GrainsBiofortfication

Worldwide, the dietary deficiency of zinc (Zn) is prevailing in almost all arid and semi-arid regions. Zinc deficiency is not only the major constraint of lower yield, but also dietary Zn deficiency in cereals grains may cause increasing malnutrition and chronic health problems in human. Exogenous application of Zn through basal soil nutrition might be a useful option to recover Zn deficiency in mung bean. Therefore, field study was conducted to optimize the optimum level and method of Zn nutrition to enhance crop yield and Zn biofortification of mung bean through basal application. Zinc was applied at 0, 5, 10 and 15 kg/ha as basal application and side dressing, and in combination (50% basal application + 50% side dressing). The results highlighted that Zn nutrition prominently improved the mung bean yield as compared with control (no Zn applied). The maximum grains yield and Zn concentration in grains were obtained where Zn was applied at 15 kg/ha as basal application as compared with all other combinations. Better improvement in grain yield was due to significant increase in more number of pods and grain size owing to welldeveloped root system, improved leaf area index and high chlorophyll contents in mung beans leaves. Amongst all applied Zn nutrition’s the basal application of Zn (15 kg/ha) was a viable option to get higher yield and Zn biofortification of mung bean.

Genetic variability and interrelationship analysis of quantitative traits in Rice (Oryza sativa L.) germplasm

The present investigation was carried out to assess the genetic variability parameters, correlation and path analysis in 95 elite rice germplasm collections for 12 yield and its contributing traits during kharif, 2018 in a randomized block design, replicated twice. The analysis of variance for mean sum of squares due to genotypes showed significant differences for all the quantitative characters studied at 1 and 5% level of significance. PCV and GCV were high for traits like days to 50% flowering, tillers plant1, productive tillers plant−1, length/breadth ratio and grain yield plant−1. High heritability (> 60%) coupled with high genetic advance as percentage of mean (> 30%) was recorded for days to 50% flowering, leaf length, tillers plant−1, productive tillers plant−1, L/B ratio, grain width, 100 grain weight and grain yield plant−1 indicating the preponderance of additive gene action. The grain yield plant−1 had highly significant and positive correlation both at genotypic and phenotypic levels with tillers hill−1, productive tillers plant−1, panicle length and days to 50% flowering. High direct effects of these characters appeared to be the main reason for their strong association with grain yield except for number of productive tillers plant−1 which had strong association with yield through indirect effect (i.e. through tillers plant−1. Hence, direct selection for these characters would be very effective for further improvement of grain yield in rice and for the selection of elite genotypes.

Screening of Beneficial Microorganisms to Improve Soybean Growth and Yield

The objective of this research was to identify the best microorganisms, alone or in mixture for total biomass gain (root + shoot), positive change in gas exchange, nutrient uptake (root, shoot and grain) and yield and yield components in the soybean crop. Trial under greenhouse conditions had the experimental design in a completely randomized scheme with 26 treatments and four replicates. The treatments consisted of the rhizobacteria BRM 32109, BRM 32110 and 1301 (Bacillus sp.), BRM 32111 and BRM 32112 (Pseudomonas sp.), BRM 32113 (Burkholderia sp.), BRM 32114 (Serratia sp.), Ab-V5 (Azospirillum brasilense) and 1381 (Azospirillum sp.), and the fungus Trichoderma asperellum (a mix of the isolates UFRA.T06, UFRA.T09, UFRA.T12 and UFRA.T52). Besides, the same isolates were combined in pairs, completing 16 combinations. Control treatments received no microorganism. Microorganisms applied isolated or in combination, provided biomass gain, positive gas exchange, increases in nutrients uptake at the shoot and grain, and improved grain yield and its components than control plants. Stood out the combination Ab-V5 + T. asperellum pool, which provided a 25% improvement in grain yield.