Among the cereal crops maize is the third most important one in the world providing a major source of food in many countries. It is mainly grown as fodder and feed. In the industrialized countries, it is used as raw material for manufacturing pharmaceutical and other industrial products [1]. Rice is the major staple food in Bangladesh but globally the yield growth of rice has become either stagnated or slowed down [2]. At present, agricultural land is shrinking due to urbanization, industrialization and infrastructure development but the demand for food is increasing with growing population and rising income. Introduction of white maize in Bangladesh as human food can be a viable alternative for sustaining food security given the productivity of maize much higher than rice and wheat [3]. Maize is a comparatively new crop in Bangladesh. It is suitable for rice-maize cropping system and has been expanded rapidly in the northern districts of Bangladesh [4], mainly in response to increasing demand for poultry food [5]. Currently maize is planted to about 307,000 ha producing 2.12 million tons of grains annually [6]. In the Chittagong Hill Tracts (CHT) maize is grown since long as a secondary staple crop for the ethnic communities contributing to 2.1% of national production. With the advancement in breeding and biotechnology high yielding modern varieties and hybrids of maize are developed. In addition, improvement in agronomic management practices also contributes greatly to increasing grain yields [7]. However, the yield performance differs remarkably across hybrids depending on environmental conditions, agronomic management and choice of varieties. The growth and yield attributes of maize differ among and between local and hybrid maize varieties [8] [9]. Different agronomic management has different degrees of impact on growth and yield of maize. Among those agronomic management practices weeding is the most important one. Weed management practices significantly influenced the growth attributes at different growth stages [10]. White maize is most sensitive to weed competition during its early growth period. The growth of white maize plants in the first week is rather slow and weeds establish rapidly and become competitive during this period. Maximum weed competition in white maize occurs during 3-and 14 leaf stage of plant development which is 2 to 6 weeks after sowing. It is important to maintain the fields weed free during this critical period of weed competition. Worldwide maize production is decreased to about 40% due to competition from weeds, which are the most dominant pest groups [11]. Another report shows that yield losses in maize fields due to weeds infestation range from 50% - 90% in Central and West Africa [12]. Weed control in white maize has not received adequate attention on the part of farmers and season in which weeding operations are performed depends on the availability of time, labor and cash. An appropriate weeding frequency can help to alleviate yield losses due to weeds. There are different kinds of weed control methods viz., Chemical methods, biological methods, hand weeding method etc. Different levels of hand weeding were used to conduct this experiment. Therefore, the objective of this work was set: to compare the growth and yield of different white maize varieties, to evaluate the performance of different weed control treatments on the performance of white maize varieties, to evaluate the interactions of white maize varieties and weed control treatments.

The present experiment was conducted at Agronomy farm of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh. The location of the experimental site is 23˚74'N latitude and 90˚35'E longitude and at an elevation of 8.2 m from sea level. The experimental area was under the sub-tropical climate. The soil of the experimental area is medium high land having red brown terrace soil. Two factors were used in the present experiment to get 8 treatment combinations which were as Factor A: Variety (02) (V₁ = Yangnuo-3000, V₂ = PSC-121). Factor B: Weed control treatments (04) (T₀ = No Weeding, T₁ = One hand weeding at 60 DAS (days after sowing), T₂ = Two hand weeding at 40 DAS (days after sowing) and 60 DAS (days after sowing), T₃ = Weed free after 40 DAS (days after sowing)). Eight treatment combinations are as follows-V₁T₀, V₁T₁, V₁T₂, V₁T₃, V₂T₀, V₂T₁, V₂T₂ and V₂T₃. The experiment was laid out in factorial RCBD with three replications. The total number of unit plots was 24. The size of each unit plot was 2.40 m × 2.50 m. The distance maintained between the unit plots and blocks were 0.70 m and 1.0 m respectively. Healthy seeds of PSC-121 and Yangnuo-3000 were collected from the seed store of Krishi Gobesona Foundation. The experimental field was first opened on September, 2017 with the help of a power tiller and prepared by three successive plowing and cross-plowing followed by laddering. All kinds of weeds and residues of previous crop were removed from the field. Individual plots were cleaned and finally leveled with the help of wooden plank. Manures and fertilizers that were applied to the experimental plot presented in Table 1. Total amount of TSP, MoP (murate of potassium), Gypsum, Zinc sulphate, Boric acid and half of Urea were applied as basal dose at the time of land preparation. The rest amount of Urea was applied at 25 days after seed sowing and before flowering. Seeds were sown on the 23^rd November, 2017 in line sowing method. Seeds were sown by maintaining the spacing of 60 cm × 20 cm with two seeds per hill. The intercultural operations like thinning, irrigation were done for ensuring the normal growth of the experimental crop. Weeding was done as a part of the treatment factor B. The sampling was done consecutively at 40, 60, 80 DAS and finally at harvest. At each sampling, five plants were selected randomly from each plot. The crop was harvested at 10^th April, 2018 when the leaves, stems become yellowish and the base of the grain turns into black color. After collecting the necessary data like Weed species present in the field, Weed density (no. m⁻²), Weed biomass (g·m⁻²), Weed control efficiency (WCE %), Plant height (cm), Number of leaves pant⁻¹, Number of grains cob⁻¹, 100 grains weight (g), stover and grains (at final harvest) were oven dried at 60˚C for 72 hours to record constant dry weights to

Source: KGF, 2016.

collect the data like Grain yield (t ha⁻¹), Stover yield (t ha⁻¹) and Harvest index (%).Weed control efficiency was analyzed by following the formula, WCE% = {(W₀ - W_t)/W₀ × 100} (Where, WCE = Weed control efficiency, W₀ = No. weed present in per square meter of weedy check plot, W_t = No. of weed present in per square meter of treated plot). The yield per hectare was computed by converting the yield per plant to yield per hectare by using the following relation: Yield per hectare = [{(mean grain yield per plant × 83,000) ÷ 1000} ÷1000]; (83,000 plants stand when planting spacing is maintained to 60 cm × 20 cm) [13]. After that the stover yield of the mean dry weight value of the five plants was derived by using the following formula: Stover Yield = [{(mean dry weight of shoot excluding cob × 83,000) ÷ 1000} ÷ 1000]; (83,000 plants stand when planting spacing is maintained to 60 cm × 20 cm) [13]. The following formula was used to calculate. Harvest index (%) = {(Grain yield/Biological yield) × 100}. The analyses of variance were done following RCBD (factorial) with the help of a computer package program Statistix-10. The mean values were compared using LSD at 5% level of significance.

The results obtained from the study have been presented, discussed and the possible interpretation has also been given under the following headings.

From the above findings it can be concluded that PSC-121 is the best performer regarding growth and yield attributes of white maize. Weed free (T₃) is the most suitable one to control weeds in white maize fields but almost in all cases T₂ was statistically similar to T₃. Treatments V₂T₃ and V₁T₃ were the most effective combination offering the maximum growth and yield in white maize. On the other hand, in the consideration of weed tolerance capacity, the best interaction to be recommended is V₁T₂.

The authors acknowledge the financial contribution of the Krishi Gobeshona Foundation (KGF), Farmgate, Dhaka, Bangladesh to carry out this research work.

The authors declare no conflicts of interest regarding the publication of this paper.

Akter, S., Mannan, M.A., Ahmmed, T., Khan, S., Tasnim, M. and Ullah, J. (2021) Influence of Weeding on the Performance of White Maize Varieties. American Journal of Plant Sciences, 12, 1011-1022. https://doi.org/10.4236/ajps.2021.127069