Variability in European Maize (Zea mays L.) Landraces under High and Low Nitrogen Inputs

The present study investigated the effects of colchicine treatment on leaf length, leaf width, and leaf area index (LAI) in two species of Acha (fonio), namely Digitaria exilis and Digitaria iburua. Colchicine, a potent mitotic inhibitor, has been widely used to induce polyploidy and in studying the effects of genome duplication on various morphological traits. This study aimed to explore if colchicine treatment could alter the leaf morphology of the two Acha species. Seeds of the two species were treated with colchicine solution at various concentrations (0.05, 0.10, 0.15, and 0.20 g/dL), while a control group was maintained without any treatment. Leaf length and width were measured using a meter rule, and LAI was calculated by multiplying the leaf length and leaf width with the constant for both species. Statistical analysis was performed using the Analysis of Variance on SPSS to determine significant differences between treated and control groups. The results showed that colchicine treatment had a significant effect on leaf morphology in both Acha species. Leaf length and width increased significantly in response to colchicine treatment, with the degree of increase depending on the concentration. Moreover, the LAI also exhibited a significant increase in treated plants compared to the control group. Colchicine concentration level of 0.10 g/dL produced the best results that can be exploited to enhance the morphological characteristics of both Acha species. The findings suggest that colchicine-induced polyploidy can enhance leaf growth and overall leaf area in Acha plants, leading to potential implications for agricultural productivity and yield improvement. Further studies are needed to elucidate the underlying mechanisms and long-term effects of colchicine-induced polyploidy on other growth parameters, reproductive traits, and yield in Acha. Understanding the genetic and physiological changes associated with polyploidy in Acha species will contribute to the development of improved breeding strategies and cultivation practices for this important cereal crop.

Core Ideas Maize can adjust its morphology to adapt to the low light environment in close planted stands. Maize adapts to close planting by increasing leaf spacing below the ear and leaf orientation value above the ear, and by reducing leaf width and leaf angle. Morphological changes allow more light transmission into the mid‐ and lower canopy under high plant density. Increasing plant density is a common method for increasing maize (Zea mays L.) yield. However, the yield increases are limited by light competition and mutual shading that occur within close canopies. The objectives of this 2‐yr field experiments were to determine the effect of plant density on maize plant morphology, canopy structure, and canopy light distribution. The leaf length, leaf width, leaf area and leaf area index (LAI) increased from both the top and the bottom of the canopy. The leaf angle generally decreased from the bottom to top of the canopy; however, the leaf orientation value (LOV) displayed the opposite trend. The leaf length and width decreased as plant density increased. The decrease in width was greater than in length. Changes in leaf dimensions caused leaf area to decline. Increasing plant density resulted in a decrease in leaf angle; however, an increase in LOV. Changes in the leaf canopy were more affected above the ear compared to below the ear as plant density increased. This made the leaves above the ear more upright as plant density increased. The leaf spacing below the ear increased as the plant increased, causing the ear height, plant height coefficient to increase. Light intensity within maize canopy decreased with increasing density. The results indicate that maize adapts to increasing density by (i) increasing leaf spacing below the ear and LOV above the ear and by (ii) reducing leaf width and leaf angle. These changes allow more light transmission into the mid‐ and lower canopy.

The present investigation was carried out in forty genotypes of ber at the Department of Fruit Science, College of Horticulture, Chandra Shekhar Azad University of Agriculture and Technology, Kanpur (UP) from 2021–22 to 2022–23. Phenotypic correlations were worked out among eighteen characters of Ber to know the nature of the association existing among the characters. The correlation among the quantitative characters was worked out. The length of the fruit was found to be significantly and positively correlated with fruit weight (0.617**), and the width of the fruit exhibited a significant positive correlation with fruit weight (0.853**). Leaf length showed significant positive correlations with length of fruit (0.443*) and a non-significant but positive correlation with weight of fruit and width of fruit. Leaf width showed significant positive correlations with fruit weight (0.794**), length of fruit (0.563**), and leaf length (0.487*). Stone weight has shown significant positive correlations with fruit weight (0.626**) and width of fruit (0.874**), and stone length has shown significant positive correlations with fruit weight (0.440*), leaf width (0.409*), and stone weight (0.584**). Stone width has shown significant positive correlations with leaf length (0.417*), leaf width (0.701**), and stone weight (0.487*). The height of the tree has shown significant positive correlations with length of fruit (0.576**), width of fruit (0.977**), stone length (0.803**), and stone width (0.628**). The stem girth also exhibited a significant positive correlation with fruit weight (0.966**), width of fruit (0.496*), leaf length (0.650**), stone weight (0.397*), and height of the tree (0.406*). Specific gravity has shown significant positive correlations with fruit weight (0.817**). leaf length (0.641**) leaf width (0.424*), stone weight (0.455*), stone length (0.417*), and stone width (0.734**).
 TSS content was also found to be significantly and positively correlated with fruit weight (0.774**), leaf length (0.645**), leaf width (0.970**), stone weight (0.539**), stone length (0.425*), stone width (0.765**), stem girth (0.855**), and specific gravity (0.547**). Total acidity content in fruit was found to be significantly and positively correlated with fruit weight (0.725**), length of fruit (0.882**), width of fruit (0.948**), leaf length (0.809**), leaf width (0.989**), stone weight (0.772**), stone length (0.605**), stone width (0.892**), height of the tree (0.792**), and specific gravity (0.702**). TSS: acid ratio has shown significant positive correlations with fruit weight (0.981**), length of fruit (0.455*), width of fruit (0.963**), leaf length (0.929**), leaf width (0.854**), stone length (0.813**), stone width (0.727**), height of the tree (0.832**), stem girth (0.453*), and specific gravity (0.728** ).Reducing sugar has shown significant positive correlations with fruit weight (0.680**), leaf width (0.821**), stone length (0.835**), stone width (0.503*), height of tree (0.747**), stem girth (0.812**), and TSS acidity ratio (0.410*). Non-reducing sugar has shown significant positive correlations with fruit weight (0.782**), length of fruit (0.999**), width of fruit (0.499*), leaf width (0.482*), stone weight (0.662**), stone length (0.399*), stone width (0.453*), specific gravity (0.488*), and TSS (0.787**). Total sugars have shown significant positive correlations with fruit weight (0.960**). length of fruit (0.412*) leaf length (0.539**), leaf width (0.710**), stone length (0.745**), stone width (0.897**), height of the tree (0.658**), stem girth (0.841**), and acidity (0.584**). Ascorbic acid has shown significant positive correlations between length of fruit (0.938**), leaf width (0.642**), stone length (0.664**), stone width (0.685**), height of tree (0.400**), and specific gravity (0.942**).

The present study was undertaken to study the gene action, narrow sense heritability, interrelationships among traits and path coefficient analysis for grain yield and its components, silking date, plant and ear height, leaf area index (LAI), specific leaf weight (SLW) and specific leaf area (SLA). Fifteen hybrids produced using a half diallel fashion in 2008 season were evaluated for grain yield and its components and morpho- physiological traits during 2009 season. The obtained results indicate that all estimates of VA and VD were significant for all traits except VA for specific leaf weight and ear length. In addition, VD for grain yield per plot, leaf area index, specific leaf weight, plant height, ear length, ear diameter, number of rows per ear and number of kernel per row. However, the magnitude of VA was consistently larger than that of VD for all traits. High narrow sense heritability estimates were detected for leaf area index (93%), leaf angel (90%), plant height (90%), ear height (89%), ear length (89%), number of rows per ear (89%) and number of kernel per row (83%). However, moderate narrow sense heritability estimates were obtained for grain yield per plot (77%), one hundred kernel weight (77%), silking date (74%), ear diameter (74%), specific leaf area (64%) and specific leaf weight (55%). While it was very low for stay green (5%). These results indicate the importance of choosing the suitable segregating generations for exhibiting the best expression of gene of different studied traits. Correlation coefficients among traits indicated that grain yield was positively and significantly associated with ear diameter (0.788**), one hundred kernel weight (0.747**), ear length (0.600**), specific leaf weight (0.518**), leaf area index (0.466**), number of rows per ear (0.458**), plant height (0.408**), number of kernels per row (0.361*) and silking date (0.351*). The path coefficient analysis was calculated to detect the relative importance of characters contributing to grain yield per plot. Data show that each of ear diameter, one hundred kernel weight and ear length had high positive direct effects on grain yield per plot.

Twenty four inbred lines developed by the Ethiopian National Maize Breeding Program were evaluated at Jimma Agricultural Research Center during the main season of the year 2016 in an 8 X 3 Alpha Lattice (0, 1) design with three replications. The objective was to determine the phenotypic and genotypic association among traits in Ethiopian maize inbred lines and to compare the direct and indirect effects of traits on grain yield. Analysis of variance showed statistically significant (p<0.01) differences among the tested maize inbred lines for most of the traits indicating the existence of sufficient genetic variability which can be exploited in future breeding programs. Grain yield per hectare, thousand kernels weight, ear height, ear diameter, anthesis-silking interval, and plant aspect had higher phenotypic and genotypic coefficients of variation. Grain yield showed positive and highly significant (p<0.01) genotypic association with ear diameter, number of kernels per row, days to 50% silking, number of kernel rows per ear, 1000-kernels weight and leaf width. Grain yield also had positive and highly significant (p<0.01) phenotypic correlation with number of kernels per row and ear diameter. Path coefficient analysis revealed that number of kernels per row, number of kernel rows per ear, plant height, days to maturity, 1000-kernels weight, leaf width and plant aspect had a positive direct genotypic effect on grain yield. Number of kernels per row, number of kernel rows per ear, plant height and 1000-kernels weight exerted high direct effects and also indicated positive and strong association with grain yield indicating that they can be used for indirect selection of inbred lines having higher yield potential per se.   Key words: Character association, inbred lines, morphological traits, path coefficient analysis.

The nature and extent of correlation and path coefficients of aqua edible aroid taro (Colocasia esculenta L., Panikachu) accessions were studied for plant height, petiole length, petiole breadth, leaf number, leaf length, leaf breadth, leaf area index, inflorescence length, peduncle length, spath length, spath breadth and yield per plant. The yield per plant showed significant and positive phenotypic correlation with petiole length (0.481), leaf length (0.576), leaf breadth (0.918), leaf number (0.620), inflorescence length (0.662), spath length (0.890) and spath breadth (0.992). The residual effect was 0.2205 which indicated that characters studied contributed 78% of yield per plant. At genotypic level, yield per plant expressed positive and significant correlation with plant height (0.560) and leaf number (0.600). The residual effect (0.424) indicated that about 58% yield was contributed by these characters.Keywords: Genotypic correlation; Phenotypic correlation; Path coefficient; Aqua aroid; Panikachu (Colocasia esculenta L Schott.stoloniferous).© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi:10.3329/jsr.v3i1.6078 J. Sci. Res. 3 (1), 169-176 (2011)

Core Ideas The optimum leaf area index (LAI) at beginning bloom to reach the yield potential is between 3.6 (indeterminate stem termination) and 4.5 (determinate stem termination).The optimum LAI maximum to reach the yield potential is between 6.0 and 6.5 for indeterminate and determined cultivars.The optimum LAI for high yield potential should be adjusted according to the maturity group, stem termination and sowing date.The increase in yield was observed with the increase of LAI for experiments and farms with a high technological level (soybean yield more than 4.5 Mg ha−1). The interactive influence of climate and management factors on leaf area index (LAI) of soybean yield potential has not been investigated in subtropical environments. Such information can help in optimizing current soybean management practices to increase seed yield and efficiency of resource use. The objective of this study was to identify the optimum leaf area index for attaining yield potential in modern soybean cultivars grown in a subtropical environment. A large soybean yield, LAI, and phenology database collected from a combination of on‐farm and research‐station experiments conducted during four soybean growing seasons (2011–2015) in southern Brazil was used. The database represented a wide range of weather conditions, soil types, sowing dates, and cultivar maturity groups (MGs). A boundary function was derived for the relationship between soybean yield and LAI at R1 and R5 developmental stages for cultivars of determinate and indeterminate growth habit, and for both types combined. An increase in yield was in line with the increase of LAI for experiments with a small yield gap (soybean yield more than 4.5 Mg ha−1). In this case, optimum LAI at R1 growth stage (LAIR1, opt) to reach the soybean yield potential was between 3.4 (indeterminate) and 4.5 (determinate) whereas the optimal maximum LAI (LAImax,opt) is between 6.0 and 6.5 for indeterminate and determinate cultivars, respectively. These results suggested that management practices for soybean crops that involve the LAI and high yield potential must be adjusted according to the maturity group, growth habit and sowing date in a subtropical environment.

Increasing seeding rates in wide row spacing soybean [Glycine max (L.) Merr.] may improve vegetation growth. This study evaluated vegetation indices of five maturity groups (MGs) at six seeding rates (68,000; 136,000; 204,000; 272,000; 340,000; and 408,000 seeds ha−1) under dryland conditions for soybean production system on the southeastern coastal plain in 2007–2009. In this region, MG IV is part of early soybean production system (April planted), MG V and VI are full‐season soybean (May planted), and MG VII and VIII for double‐cropping system (June planted). Leaf area index (LAI) varied with seeding rate by linear functions at 60 and 90 days after planting (DAP) for MG IV in 2008/2009, V in 2007/2008, and VIII in 2008; by quadratic functions at 60 and 90 DAP for MG V and VI in 2009, 60 DAP for MG VII in 2007, and 90 DAP for MG IV in 2007 and VII in 2008. Normalized difference vegetation index (NDVI) increased with seeding rate linearly at 60 DAP for MG IV, V, VI, and VIII in 2008, IV and V in 2009; at 90 DAP for MG IV in 2008, VI and VII in 2009. Quadratic responses of NDVI to seeding rate were found at 60 DAP for MG VI in 2009 and VII in 2008; 90 DAP for MG IV and V in 2009, VII and VIII in 2008. Results suggest that increasing seeding rate may improve soybean growth at early development stages; however, increase of seeding rate above 272,000 seeds ha−1 may not achieve significant improvement of vegetation growth.

This paper aimed to explore the correlation between Morus alba L. leaf node and its size or mass change and provide a theoretical basis for the development of scientific Morus alba L. cultivation technology. During 2016-2017, the correlation between Morus alba L. leaf node and its size or mass change was investigated and researched. Results showed that through the correlation coefficient analysis, there was a weakly positive correlation between the leaf node and some indicators such as leaf length÷leaf width and petiole length, there was a weakly negative correlation between the leaf node and some indicators such as leaf width,( leaf length+ leaf width), ( leaf length×leaf) width and leaf mass, and there was a weakly negative correlation between the leaf node and the other indicators; there was a highly positive correlation between the leaf mass and some indicators such as Morus alba L. leaf length, leaf width, (leaf length+ leaf width) and (leaf length×leaf width), there was a significantly positive correlation between the leaf mass and some indicators such as petiole transverse diameter in width and petiole mass, and there was a weakly positive correlation between the leaf mass and some indicators such as petiole transverse diameter in thickness. In terms of significant level of difference, it was found that there was not significant difference in the correlation coefficients between the leaf nodes on the Morus alba L. shoots and some indicators such as leaf length, leaf width, (leaf length+ leaf width), (leaf length×leaf width) and leaf mass; there was an extremely significant difference in the correlation coefficients between the leaf mass and some indicators such as Morus alba L. leaf length, leaf width,( leaf length+ leaf width),( leaf length×leaf width), petiole transverse diameter in width and petiole mass; there was not significant difference in the correlation coefficients between the leaf mass and the other indicators. The regression analysis was performed on the leaf node and leaf length, leaf width, (leaf length＋leaf width), (leaf length×leaf width),( leaf length÷leaf width), petiole length , petiole diameter in width, petiole diameter in thickness, petiole mass and leaf mass. Significance F values were 0.4864, 0.1995, 0.2888, 0.3004, 0.2350, 0.2407, 0.8925, 0.5227, 0.7022 and 0.2000, respectively, that is, there was an extremely significant difference between Morus alba L. leaf node and petiole diameter in width, there was a significant difference between Morus alba L. leaf node and petiole mass, and there was not significant difference between Morus alba L. leaf node and the other indicators. The comparative analysis of quadratic curve regression equation and linear regression equation was performed on some indicators such as leaf length, and it was found that the R value between the leaf node and petiole diameter in width was in line with the logarithmic curve regression equation, and the other R values of quadratic curve regression equation was larger than the other R values of linear regression equation, indicating that different Morus alba L. leaf nodes, leaf length, leaf mass and other indicators were in line with the quadratic curve regression equation. It was concluded that by investigating the leaf node on the Morus alba L. shoots and regression equation, we could predict the leaf size, leaf mass and other indicators, and we could take the leaf node on the Morus alba L. shoots as one of the main factors affecting the Morus alba L. leaf size and mass.

Yield performance of the European Union Maize Landrace Core Collection under multiple corn borer infestations

BackgroundThe technology of cotton defoliation is essential for mechanical cotton harvesting. Agricultural unmanned aerial vehicle (UAV) spraying has the advantages of low cost, high efficiency and no mechanical damage to cotton and has been favored and widely used by cotton planters in China. However, there are also some problems of low cotton defoliation rates and high impurity rates caused by unclear spraying amounts of cotton defoliants. The chemical rate recommendation and application should be based upon crop canopy volume rather than on land area. Plant height and leaf area index (LAI) is directly connected to plant canopy structure. Accurate dynamic monitoring of plant height and LAI provides important information for evaluating cotton growth and production. The traditional method to obtain plant height and LAI was s a time-consuming and labor-intensive task. It is very difficult and unrealistic to use the traditional measurement method to make the temporal and spatial variation map of plant height and LAI of large cotton fields. With the application of UAV in agriculture, remote sensing by UAV is currently regarded as an effective technology for monitoring and estimating plant height and LAI.ResultsIn this paper, we used UAV RGB photos to build dense point clouds to estimate cotton plant height and LAI following cotton defoliant spraying. The results indicate that the proposed method was able to dynamically monitor the changes in the LAI of cotton at different times. At 3 days after defoliant spraying, the correlation between the plant height estimated based on the constructed dense point cloud and the measured plant height was strong, with R^2 and RMSE values of 0.962 and 0.913, respectively. At 10 days after defoliant spraying, the correlation became weaker over time, with R^2 and RMSE values of 0.018 and 0.027, respectively. Comparing the actual manually measured LAI with the estimated LAI based on the dense point cloud, the R^2 and RMSE were 0.872 and 0.814 and 0.132 and 0.173 at 3 and 10 days after defoliant spraying, respectively.ConclusionsDense point cloud construction based on UAV remote sensing is a potential alternative to plant height and LAI estimation. The accuracy of LAI estimation can be improved by considering both plant height and planting density.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13007-022-00966-z.

Analysis of the relationship between the spectral characteristics of maize canopy and leaf area index under drought stress

Discovering the relationships among plant morphological and quantitative features is very important in maize breeding and production, particularly if they can be altered by selection or agro-technical methods. We examined tassel characteristics (tassel weight, tassel stalk diameter, number of primary branches, total length of branches, tassel length from lower and upper branches, Tassel Area Index) and several quantitative features (plant height, ear height, LAI, number of leaf, yield, 1000-kernel weight, test weight) of 12 hybrids in randomized block design during two subsequent years on two locations. Our aim was to find correlation between traits. Tassel weight was positively correlated with total number of branches (0.59**), number of primary branches (0.53**) and tassel area index (0.63**), and negatively correlated with plant height (−0.45**) and yield (−0.39**). Tassel area index was negatively correlated with plant height (−0.63**) and yield (−0.55**), as were number of branches and Leaf Area Index (0.39**). Number of primary branches showed medium correlation with plant height (−0.43**). Test weight correlated negatively with plant height, ear height, yield, leaf area index (LAI) and 1000-kernel weight. Because a number of these traits are highly heritable, these correlations could be used as a basis for indirect selection of special features in maize breeding programs.

Two field experiments were conducted on the Farm of Agric. Res. and Exp. Center of Fac. of Agric. Moshtohor, Benha University, Toukh Directorate, Qalyubia Governorate, Egypt, during the two successive summer growing seasons of 2016 and 2017 to study the effect of three plant population densities i.e. 20000, 24000 and 28000 plants/feddan (fed) and three nitrogen fertilizer rates, i.e. 90, 120 and 150 kg N/fed on the growth traits, yield components, yield and some kernels chemical properties of three white single cross hybrids of maize (S.C. 7071, S.C. 30K8 and S.C. 2031). The obvious results of this investigation can be summarized as follows: Increasing plant population density from 20000 to 28000 plants/fed significantly increased mean values of No. of days from planting to 50 % tasseling and silking, leaf area index, plant height (cm), ear height (cm) No. of barren plants/fed, No. of ears/fed, stover yield/fed (kg) and biological yield/fed (kg) in both seasons. On the other hand, mean values of No. of green leaves/plant, leaf area/plant (cm2), No. of plants carried two ears/fed, No. of kernels/ear, ear weight (g), shelling (%), 100-kernel weight (g), ear yield/fed (kg), grain yield/fed (kg), harvest index, nitrogen uptake/fed (kg) and protein yield/fed (kg) were significantly decreased in the two seasons. Allmost traits of maize under study were significantly increased by increasing nitrogen fertilizer rates from 90 and 120 to 150 kg N/fed except, No. of days to 50 % tasseling and silking as well as No. of barren plants/fed were significantly decreased with increasing nitrogen rates in the both seasons, nitrogen fertilizer rate of 150 gave the best mean values for all maize traits under study. White single cross hybrids of maize were significantly differed in all maize traits under study in the both seasons. Maize hybrid of S.C. 30K8 was significantly surpassed S.C. 7071 and S.C. 2031 in mean values of No. of plants carried two ears/fed, No. of ears/fed, No. of kernels/ear, grain yield/fed and harvest index as well as gave the lowest mean values of No. of barren plants/fed and the shortest period from planting to 50 % tasseling or silking in the both seasons. Moreover, S.C. 2031 surpassed the other two maize hybrids in mean values of leaf area/plant, leaf area index, ear weight, 100-kernel weight, ear yield/fed, biological yield/fed, nitrogen uptake/fed and protein yield/fed in the two seasons. Meanwhile, S.C. 7071 recorded the highest mean values of No. of green leaves/plant, plant height, ear height, shelling % and stover yield/fed in the two seasons. The first order interactions between (20000 plants/fed X 150 kg N/fed), (24000 plants/fed X S.C. 30K8), (20000 plants/fed X S.C. 2031) and (150 kg N/fed X S.C. 30K8) as well as the second order interactions between (24000 plants/fed X 150 kg N/fed X S.C. 30K8) and (20000 plants/fed X 150 kg N/fed X S.C. 2031) were significantly recorded the greatest grain yield/fed as compared with the others interactions in the both seasons.

Plant size traits are key contributors in the spatial variation of net primary productivity across terrestrial biomes in China