Combining ability of S3 maize inbred lines and related contributing traits for high yield under high population density

The productivity of maize may be increased by using maize hybrid ideotype (erect leaves and small leaf angles) which is adaptive under high plant population density. The hybrids maize was desirable in increasing the plant density due to better light interception and space so that it can increase the yield per unit area. The aim of the research was to assess S3 lines that had good combining ability and to determine the traits associated with high yields under high plant population density (83.333 plants/ha). A total of 242 hybrids (F1) were examined from a crossed combination of 121 lines x 2 tester were evaluated with three commercial hybrid varieties such as Bisi 18, P 27, and P 36. The evaluation was carried under high plant population density (83,333 plants/ha) in the rainy season (November 2020 – February 2021). The research used an alpha lattice design with three replications. The results showed that the inbred lines had a greater effect on the yield character and yield components, while the leaf angle and leaf orientation effected by the tester. The lines that had good general combining ability for high yielding were M3B11P27T3-11-3-1, P27M3B11T3-1-4-2, P27M3B11T3-1-2-1, M3B11P27T3-8-4-1, P27M3B11T1-7-1-1, M3B11P27T1-1-1-3. The yield range of the hybrids were 8.43-9.90 t/ha, significantly higher than Bisi 18, P 27, P 36 varieties were 7.13 t/ha. Traits such as small leaf angle, erect leaf, root and stem lodging resistance, stem diameter, leaf length, ear diameter, and kernel row number were significantly correlated with high yield under high plant population density.

Plant population is the function of grain yield of maize

A field experiment on hybrid maize with different plant population density was conducted at the Agronomy field of BARI, Joydebpur, Gazipur during the consecutive rabi season of 2019-2020 and 2020-2021. Five plant population density viz; T1= 66666 plants/ha (75cm × 20cm spacing: 6.67 plants/m2), T2= 83333 plants/ha (60cm × 20cm spacing:8.33 plants/m2), T3=100000 plants/ha (50cm × 20cm spacing:10 plants/m2), T4=125000 plants/ha (40cm × 20cm spacing:12.5 plants/m2) and T5=166666 plants/ha (30cm × 20cm spacing:16.67 plants/m2) were used in the experiment. LAI (leaf area index) and TDM (total dry matter) increased with the increase of plant population, those influenced grain yield of maize. The highest grain yield (10.12-10.78 t/ha) was recorded in T3 (100000 plants/ha) and the lowest (5.02-5.33t/ha) in T5 (166666 plants/ha) treatment. Functional relationship between plant population and grain yield of maize was established as Y = 2.0795x-0.1067x2; (R² = 0.92). The effect of plant population on the grain yield of maize could be explained 92% by the functional model. The co- efficient indicated that increase of one plant/m2 would increase grain yield at the rate of 2.0795 t/ha up to a certain limit. The estimated optimum plant population was 9.74 plants/m2 (974000 plants/ha) through functional model. Then the predicted maximum grain yield would be 10.13 t/ha at that optimum plant population of 9.74 plants/m2 (974000 plants/ha). There existed a good consistency between observed and predicted grain yield of maize (r=0.96 at p<0.01 and R2=0.97; using the developed functional model).

Grain Yield Gains and Associated Traits in Tropical X Temperate Maize Germplasm Under High and Low Plant Density

Development of ideal breeding and crop management strategies that can improve maize grain yield under tropical environments is crucial. In the temperate regions, such yield improvements were achieved through use of genotypes that adapt high plant population density stress. However, tropical germplasm has poor tolerance to high plant population density stress, and thus it should be improved by temperate maize. The aim of this study was to estimate the genetic gains and identify traits associated with such gains in stable and high yielding temperate x tropical hybrids under low and high plant population densities. A total of 200 hybrids derived from a line x tester mating design of tropical x temperate germplasm were developed. These hybrids were evaluated for grain yield and allied traits under varied plant population densities. High yielding and stable hybrids, such as 15XH214, 15XH215 and 15XH121 were resistant to lodging and had higher number of leaves above the cob. The high genetic gains of 26% and desirable stress tolerance indices of these hybrids made them better performers over check hybrids under high plant population density. At high plant population density yield was correlated to stem lodging and number of leaves above the cob. Future gains in grain yield of these hybrids derived from temperate x tropical maize germplasm can be achieved by exploiting indirect selection for resistance to stem lodging and increased number of leaves above the cob under high plant density conditions.

Effect of Plant Population Density and Methods of Weed Control on The Yield of Pepper (Capsicum annum L.) in Northeastern Nigeria

Field experiments were conducted at Yola and Garkida in Adamawa State, North-Eastern Nigeria during the 2017 rainy season. In the Yola location the experiment was conducted at the Teaching and Research Farm of the Department of Crop Production and Horticulture, Modibbo Adama University of Technology, Yola, and in Garkida it was conducted at Garkida village in Gombi Local Government Area of Adamawa State. The experiment was designed to study the effect of plant population density and methods of weed control on the yield of pepper (Capsicum annum L.). The treatments consist of three spacings, 25 x 30cm, 35 x 40cm and 45 x 50cm with four (4) different herbicides rates (No herbicide, pyrithiobac sodium 65.5kg a.i/ha, pendimethalin 1kg a.i/ha + pyrithiobac sodium 65.5kg a.i/ha and Haloxyfop 108g a.i/ha + hand hoe weeding. The experimental design was a split-plot design replicated three times. Spacing was assigned to the main plot while methods of weed control as subplots. Parameters measured were weed density, number of pepper fruits per plot, and fruit yield per hectare. All data were subjected to analysis of variance (ANOVA) appropriate to the split-plot design. The results of the experiment showed that herbicide pyrthiobac sodium 65.5kg a.i/ha recorded the highest number of fruit per plot of 72.4 while herbicide haloxyfop 108g a.i/ha followed by hand weeding recorded the least number of fruits of 50.1. The result of the experiment shows that there was a significant effect on spacing in both locations. Concerning yield per hectare spacing 25x30cm obtained the highest yield per hectare of 945kg in Garkida, while the least was from the Yola location which recorded 537kg. It was concluded that pepper yield depends on the proper spacing and proper use of herbicide which will suppress weed and increase yield significantly. Keyword: Weed Density, Weed Control, Yield, Pepper

Growth and yield of Sesame (Sesamum indicum) as influenced by plant population density and organo-mineral fertilizer rates

Sesame (Sesamum indicum L.) is an important oil-seed crop cultivated for its high nutrition and edible seeds. However, its cultivation is affected by low soil fertility, wrong choice of plant population density and time of sowing. The experiment was carried out during the 2016 and 2017 cropping seasons at the Research Site of Agronomy Section, Kabba College of Agriculture, Kabba, Kogi State, Nigeria. The experiment evaluated the influence of plant population density and organo-mineral fertilizer rates on the performance of Sesame in Kabba, Kogi State, Nigeria. The experiment was a split plot design replicated thrice. The main plot treatment was three plant population density (P1 = 111,111; P2 = 83,333 and P3 = 66,667 plants ha–1) and the sub-plot treatment was four organo-mineral fertilizer rates (F0 = 0, F1 = 500, F2 = 1000, F3 = 1500 kg ha-1). Data were collected on growth, morphological characters (plant height, number of leaves, number of branches) and yield components (number of capsules plant–1, 1000 seed weight and yield ha–1). The result showed that the plant at P1 produced the tallest plants throughout the period of sampling, which was closely followed by P2 while P3 produced the shortest plants. Numbers of capsules plant–1 was highest in plots with P1 which was statistically the same with the number of capsules plant–1 in P2. Number of capsules plant–1 in P1 and P2 were statistically better than the plots with P3. Plots treated with rate F2 gave the highest number of capsules and also recorded the highest yield in 2016 and 2017 growth seasons. The results indicated that Sesame with closest spacing was better in terms of seed yield land–1 area while widest spacing gave the highest individual yield attributes. For economic use of land, it is concluded that plant population density at 111,111 be adopted in the production of Sesame. Best growth and yield performance of Sesame was achieved with 1500 kg ha-1 of organo-mineral fertilizer and is recommended for optimum production of Sesame in the study area.

Leaf Nitrogen Traits in Response to Plant Density and Nitrogen Supply in Oilseed Rape

Understanding the response of plant nitrogen (N) and carbon (C) economies in oilseed rape, as well as their role in defining phenotypic plasticity, is necessary for designing new strategies to optimize plant and canopy C assimilation to improve potential yield. This paper aims to elucidate the extent to which the interaction between N supply and plant population density alters N distribution in oilseed rape plant (Brassica napus L.) and whether this interaction changes plant investment in leaf area or leaf mass per area. Spring oilseed rape was grown at two rates of N supply (50 and 150 kg N·ha−1) and two plant population densities (50 and 150 plants·m−2). Photosynthesis, leaf area, leaf biomass, and N content of selected leaves were measured at 20% of flowers on main raceme open. The interaction between N supply and plant population density altered leaf N content per area, which is the main determinant of photosynthesis. This interaction also affected leaf mass per area, while N supply determined N content per unit leaf mass. These results suggest that the interaction between N supply and population density affects both nitrogen distribution and leaf mass per area, which could have important implications for light distribution and, therefore, for C assimilation at the plant level.