Winter Maize Research Articles

Tillage and leaf colour chart-guided nitrogen management: Key to growth and yield improvement of winter maize in Chitwan, Nepal

Maize requires efficient nitrogen management to maximize productivity and sustainability. This research aimed to establish a critical Leaf Colour Chart (LCC) values for maize under zero tillage and conventional tillage. This research also focuses on evaluating LCC-based nitrogen management versus recommended practices. The experiment was conducted during the winter season of 2016-17 at the National Maize Research Program, Rampur, Chitwan, Nepal. The experiment was performed using a strip plot design with three replications. The main plot factor included two tillage methods (conventional and zero tillage) while the sub-plot factor comprised six nutrient management practices, namely nitrogen omission, recommended dose of nitrogen, nitrogen application at leaf color chart (LCC) values 3 (45 kg N/ha), LCC value 4 (88.33 kg N/ha), LCC value 5 (119.7 kg N/ha), and LCC value 6 (140 kg N/ha). Standard split nitrogen application and LCC-based nitrogen management at LCC 4, 5, and 6 critical values resulted in statistically similar LAI during all dates of observations; however, it was high at 90 days after sowing (DAS). Total dry matter accumulation was significantly higher under LCC-5 at 90 DAS. Grain yield was strongly influenced by nitrogen management, with LCC-5 achieving the highest yield (4814.26 kg ha-1), followed by LCC-6 (4511 kg ha-1). Conventional tillage slightly outperformed zero tillage in grain yield. According to the study, LCC threshold 5 is useful for real-time nitrogen application in maize. Therefore, maize farmers are encouraged to embrace LCC-based split nitrogen application rather than following standard nitrogen fixed schedules for sustainable and profitable production.

Impact of freezing temperatures on winter maize production in the Yaqui Valley, Sonora, Mexico

Impact of freezing temperatures on winter maize production in the Yaqui Valley, Sonora, Mexico

Stability analysis of promising winter maize (Zea mays L.) hybrids tested across Bihar using GGE biplot and AMMI model approach

Multilocation evaluation facilitates the quantification of genotype-environment interaction (GEI) and the identification of high-yielding, stable hybrids along with partitioning the evaluating location into mega environments. Testing of 24 single cross hybrids and four checks across three environments revealed the significant GEI for all the studied traits. The environment contributed 12.90, 57.10, and 17.59% of the total variation for grain yield, anthesis silking interval, and days to maturity. The study indicated a negative genotypic correlation among grain yield and anthesis silking interval (-0.2244); days to maturity and anthesis silking interval (-0.019), whereas the positive correlation between grain yield and days to maturity (0.067). Location Sabour was found as the most representative environment for testing commonly adapted hybrids. Location Begusarai and Dholi are discriminatory and non-representative environments suitable for selecting location-specific genotypes. Both GGE biplot and AMMI analysis revealed that three hybrids, viz., IMHSB1, IMHSB20, and IMHSB13 were high-yielding with average stability. The identification of superior and stable maize hybrids may contribute to farmers’ income in Bihar.

Night Warming Has Mixed Effects on the Development of the Fall Armyworm, Spodoptera frugiperda (Lepidoptera, Noctuidae), in Southern China.

The Fall Armyworm, Spodoptera frugiperda (Lepidoptera, Noctuidae), is a serious migratory pest. After invading China in 2019, the species was established as a year-round breeding population in most of the southern provinces. The area of winter maize in this region has been increasing due to the huge demand of fresh maize consumption, which is potentially at risk from this invasive pest, although the growth and development of S. frugiperda in the region's changing climate is unclear, particularly with rising temperatures at night. Here, we used the highest daytime temperatures of 27 °C, 24 °C, 20 °C and decreased these by 2, 4 and 6 °C to reflect the range of nighttime temperatures indicative of winter conditions in a warming climate to evaluate the effect of increasing night temperatures on the growth and development of S. frugiperda. Results show that the survival of larvae and pupae significantly declined with daytime temperatures declining and the nighttime temperature range increasing. Significant developmental effects were observed across all daytime-nighttime temperature treatments, except for adults. Additionally, there were significant interaction effects for all stages, except the egg stage, and generation time. The development rate increased with the increasing daytime temperatures and nighttime temperatures, except for the intermediate treatments (Group II). The uniformity of pupation and emergence times were higher under high daytime temperatures and nighttime temperature treatments. Predictions of FAW development and warnings to local farmers need to be adjusted to take into account the more rapid development when nighttime temperatures increase in the warming climate. These results will support decision makers in developing long-term management strategies for FAW in southern China.

Performance Evaluation of 4-Wheel Tractor Drawn 3-Rows Precision Maize Planter for Mechanization of Maize Farming in Nepal

Hybrid winter maize is gaining popularity in the Terai region, as traditional maize growing practices are resource-consuming and labor-intensive. High inputs and labor costs have been a burden for hybrid maize growers. This study aimed to evaluate a Chinese-made 2BMZJ-3 model tractor-drawn 3-rows precision maize planter in actual field conditions and on-farm, comparing it with farmers' practices. The planter was hitched with 3-point linkages at the rear of a 35 hp tractor and could be operated in both tilled and no-tilled conditions. The seed rate was about 20 kg/ha, with a germination of 98% and an average of 4-5 plants/m² of length of row. The actual field capacity was 0.38 ha/hr in clay loam soil with an initial moisture of 26.11% and a bulk density of 1.18 g/cm³. The total cost of sowing was NRs 4050/ha, while the planting cost for farmers' practices was around NRs 7500/ha. The planter reduced the planting cost by 46% and increased the grain yield per unit area compared to farmers' practices. It is concluded that the maize planter not only reduces the planting cost but also increases grain yield per unit area.

Assessing the Variations in Canopy Temperature, Relative Humidity and Soil Temperature within the Canopy of Winter Maize in Bihar

Variations in canopy temperature, relative humidity and soil temperature within crop micro-environment exert full control over plant’s physiological processes and thereby over growth, development and yield of crop. These micro-meteorological parameters tend to significantly control the exchange of energy between the crop environment and the atmosphere. Keeping all this in view, a field experiment with winter maize ( var. Rajendra hybrid 4) was conducted with five dates of sowing viz., 1 November (D1), 10 November (D2), 20 November (D3), 30 November (D4) and 10 December (D5) and three spacings viz., 60 X 20 cm (S1), 75 cm X 20 cm (S2) and 45 cm X 20 cm (S3) at the University farm of Dr Rajendra Prasad Central Agricultural University, Pusa, Samastipur, Bihar during rabi season of 2021-22 to assess the variations in canopy temperature, relative humidity and soil temperature, as influenced by micro-environments and planting density. The experiment was laid out in split plot design with sowing dates as main-plots and spacings as split plots. Results revealed that canopy temperature was found to be the highest for the crop planted on D4 (30 November) with S2 (75cm X 20 cm) spacing, while the lowest was associated with the crop sown on D1 (1 November) with S3 (45 cm X 20 cm) spacing. Mean canopy temperature decreased from sowing to knee high stage, thereafter it increased with every phenological stage up to physiological maturity. Crop sown on D3 (20 November) having S3 (45 cm X 20 cm) spacing recorded maximum relative humidity. Highest soil temperature at 15 cm depth was recorded for D5 (10 December) sown and S2 (75cm X 20cm) spaced crop and the lowest for D2 (10 November) having S3 (45cm X 20cm) spacing. Information generated on the variation in canopy temperature, relative humidity and soil temperature at different phenophases of winter maize would be useful in managing abiotic stresses on crop production.

Impact of different quantity and quality of irrigation water on crop yield and biomass of winter maize using FAO-Aqua crop model

Irrigation has a major role to play in the productivity of winter maize. Precise information about the quantity and quality of irrigation water is the key for higher productivity of winter maize. In the present study attempt has been made to asses the impact of different depth of irrigation water on crop yield and biomass of winter maize using FAO-Aquacrop Model. In the first case crop yield and biomass was simulated for irrigation water depth varied from 20 mm to 80 mm, keeping the irrigation water quality constant. Similarly, in another case the optimum irrigation depth was kept constant and irrigation water quality varied from 1 to 10 ds/m. The simulated crop yield and biomass increases up to 40 cm depth of irrigation water application for all three seasons. When a similar comparison was made for 30 cm depth of irrigation water application the simulated yield reduction was only 0.79%, 2.2% and 2.4 % for the year 2016-17, 2017-18 and 2018-19 respectively. The analysis suggested that this yield reduction can easily be compromised for saving 10 cm of irrigation water. This study indicated that 30 cm depth of irrigation water is optimum for Winter maize in BurhiGandak river basin of North Bihar In case of deficit irrigation of 20 cm depth of irrigation water application the simulated yield reduced by 14.4 %, 25.4 % and 11.4 % for the year 2016-17, 2017-18 and 2018-19 respectively. Assessment of response of different quality irrigation water on simulated crop yield and biomass of winter maize using FAO-Aquacrop model suggests that simulated yield was found maximum with 1 ds/m. The reduction in simulated yield with 10 ds/m water quality was observed maximum with a value of 41.3 %, 44.4 % and 38.4 % respectively for the year 2016-17, 2017-18 and 2018-19. FAO-Aquacrop model can be used as an important tool for efficient planning of irrigation water under diminishing water supply and deteriorating water quality.

Productivity and profitability of zero till winter maize as influenced by integrated weed management practices

Productivity and profitability of zero till winter maize as influenced by integrated weed management practices

Synergism of Organic Manure and Mycorrhizae Along with Inorganic Fertilizers on Crop Growth and Yield of Maize

Field experiment was conducted during Rabi 2021-22 to evaluate the synergistic effect of organic manure and mycorrhizae on soil health and crop performance in winter maize (Zea mays L.) at Agronomy Research Farm of Acharya Narendra Deva University of Agriculture & Technology, Kumarganj, Ayodhya- 224229. The experiment was laid out in randomized block design and replicated thrice. The experiment consists of 8 treatments i.e. T1 (Control),T2 (100% RDF), T3 (80% RDF + 20% VC+ Mycorrhizae), T4 (80% RDF + 20% PM+ Mycorrhizae), T5 (60% RDF + 40% VC+ Mycorrhizae), T6 (60% RDF+ 40% PM+ Mycorrhizae), T7 (60% RDF+ 20% PM + 20 % VC+ Mycorrhizae), T8 (50% VC+ 50% PM+ Mycorrhizae). Results showed that growth and yields were substantially improved under Treatment T6 (60% RDF+ 40% N- PM+ Mycorrhizae) viz. plant height (cm), leaf area index (LAI), dry matter accumulation (kg ha-1), cob length (cm), number of grain rows cob -1, number of grains cob-1, test weight (g), weight of cob (g), grain yield (q ha-1), stover yield (q ha-1) and biological yield (q ha-1). Conclusively, synergistic incorporation of inorganic fertilizers with organic manure and mycorrhizae can be used with optimum rates to improve crop growth and productivity on sustainable basis.

Productivity, nutrient use efficiency, energetic, and economics of winter maize in south India.

The winter maize area is rapidly spreading in south India in response to rising demand from the poultry and fish feed industries due to the absence of major environmental constraints. Further farmers' are using the winter environment to expand maize area and production. Hence there is immense potential to increase the area under winter maize cultivation. There were no planned field experiments to explore and optimize the right time of sowing and quantity of fertilizer to be added previously due to the presence of negligible winter maize area. Farmers used to cultivate maize as per their choice of sowing time with the application of a quantity of fertilizer recommended for rainy season maize. There were no efforts made towards working on economic analysis including energy budgeting. And hence the investigation was conducted with the objective to explore the optimal planting period and fertilizer levels for winter maize through economic and energy budgeting. Planting windows (1st week of October, 2nd week of October, 3rd week of October, 4th week of October, and 5th week of October) and fertility levels (100 percent recommended dose of fertilizer (RDF), 150 percent RDF, and 200 percent RDF) were used as factors in Factorial Randomized Complete Block Design (RCBD) with three replications. The present investigation revealed that significantly higher winter maize productivity was achieved from the first and second week of October planting along with the application of 200% RDF (recommended dose of fertilizer) followed by 150% RDF. Planting of winter maize during the first week of October recorded significantly higher grain yield (8786kg ha-1) and stover yield (1220 kg ha-1) and was found on par with sowing during the second week of October. Among fertility levels, significantly higher grain yield (8320 kg ha -1) and stover yield (1195 kg ha-1) was recorded with the application of 200% RDF and were found on par with the application of 150% RDF. Further interaction effect showed that higher dry matter production, more days for physiological maturity, higher accumulation of growing degree days, photothermal units, and heliothermal units were recorded from crops planted during the first and second week of October along with the application of either 200% or 150% RDF. However, higher nutrient use efficiency was recorded from the first and second week of October planted crop supplied with lower fertility level (100% RDF). Similarly, significantly higher net returns and gross returns, output energy, net energy, and specific energy were higher from crops planted during the first week of planting along with the application of 200% RDF. Whereas, energy use efficiency and energy productivity were higher with the first week of October planted crop applied with 100% RDF. From the overall interaction, it is recommended to plant winter maize during the first fortnight of October with the application of 150 percent RDF for sustaining higher maize productivity, energy output, and economics in the maize growing area of south India.

Adapted Conservation Agriculture Practices Can Increase Energy Productivity and Lower Yield-Scaled Greenhouse Gas Emissions in Coastal Bangladesh

While numerous studies have documented the benefits of conservation agriculture (CA) in South Asia, most focus on favorable environments where farmers have reliable access to energy supporting irrigation and inputs. The performance of CA in South Asia’s under-developed coastal environments is comparatively understudied. In these environments, farmers are increasingly interested in growing a second crop to meet food security and income generation objectives in rotation following the predominant monsoon season rice crop, though labor, energy costs, and investment constraints limit their ability to do so. We hypothesized that rotating rice (Oryza sativa) with maize (Zea mays) using conservation agriculture, or CA (i.e., strip-tilled maize followed by unpuddled transplanted rice), or seasonally alternating tillage (SAT, i.e., strip-tilled maize followed by fully-tilled, puddled rice with residues retained across rotations) would reduce costs and energy use, increase energy-use efficiency, and reduce yield-scaled CO2-eq emissions (YSE) and total global warming potential (GWP), compared to farmers’ own practices (FP) and conventional full-tillage (CT) under the same rotation in Bangladesh’s coastal region. Starting with winter maize followed by summer rice, we evaluated four tillage and crop establishment treatments in farmer-managed experiments in partially irrigated and rainfed environments over three years in 35 farmer’s fields across Bangladesh’s coastal districts. Treatments included FP, CT, complete CA, and SAT under a rice-maize rotation. Across years, the full suite of CA practices and SAT were significantly more energy-efficient and energy-productive than FP or CT. The order of YSE in rice was CA< CT or FP < SAT while in maize, it was CA or SAT < FP < CT. Across environments, CA and SAT resulted in 15-18% higher yield at the cropping systems level (maize and rice yields combined) and 26-40% less manual labor than CT or FP. CA and SAT also reduced by 1-12% and 33-35% total production costs respective to CT and FP. This was associated with 13-17% greater grain energy output in CA and SAT, and 2-18% lower YSE, compared to CT or FP. While our data suggest that both CA and SAT can result in a range of positive agronomic, economic, and environmental outcomes compared to FP or CT, post-trial surveys and discussions with farmers revealed a strong practical aversion to use of the full suite of CA practices and preference for adapted practices due to logistical constraints in negotiating the hire of laborers for unpuddled manual transplanting.

Effect of fire retardants on germination of agricultural seeds

The occurrence of fires in agricultural areas grown with winter maize has become recurrent in the Central-West region of Brazil, since the harvest occurs in the dry season in the region. Fire retardants can be used as an indirect control of fire; they consisted of chemical products that can remain in the straws or on the soil after the fire extinction. The objective of this work was to evaluate the effect of two short-term fire retardants (Phos-Chek WD881® and Hold Fire®) and a hydrogel (alternative fire retardant) on germination of rice (Oryza sativa), common bean (Phaseolus vulgaris), millet (Pennisetum glaucum), maize (Zea mays), and soybean (Glycine max) seeds. The control treatment consisted of only distilled water. The seed germination percentage and speed index, mean time for germination, and seedling growth (shoot and root length and dry weight) were evaluated. A completely randomized experimental design was used, with 4 replications per treatment; each experimental unit consisted of 100 seeds maintained in germination chambers (30 °C and photoperiod of 12 hours). The effects of the fire retardants and hygroscopic polymer on the seed germination and seedling initial growth were specific, and no significant effect caused by the variations in the concentrations of the fire retardants was found.

Nitrogen Reduction Combined with Organic Materials Can Stabilize Crop Yield and Soil Nutrients in Winter Rapeseed and Maize Rotation in Yellow Soil

Objective: To investigate the effect of nitrogen reduction combined with organic materials on crop growth of winter rapeseed and maize rotation in yellow soil. Methods: A 2-year, four-season winter rapeseed and maize rotation experiment using three organic materials (biochar (B), commercial organic fertilizer (O) and straw (S), 3000 kg·hm−2) and three nitrogen application rates (100%, 85% and 70%) was carried out from 2018 to 2020 in Guizhou Province, China. By comprehensively analyzing the crop yield, biomass and nutrient absorption, soil nutrients indicators, and the efficiency of nitrogen fertilizer was calculated. Results: All organic materials could increase the yield of both crops, and 100% N + O treatment was the best, and the 2-year winter rapeseed and maize yields reached 3069 kg·hm−2, 3215 kg·hm−2 and 11,802 kg·hm−2, 11,912 kg·hm−2, respectively. When nitrogen application was reduced by 15%, the addition of the three organic materials could stabilize or increase the yield and biomass, and nitrogen, phosphorus and potassium absorption in both crops showed an increasing trend, which could improve or maintain soil nutrients. When nitrogen application was reduced by 30%, the yields of two crops with organic materials addition were lower than those of 100% N treatment. Through the interaction, it was found that nitrogen and organic material were the main reasons for the increase in yield, respectively. Conclusions: The addition of three organic materials can replace 15% of nitrogen fertilizer. It is recommended to apply 153.0 kg·hm−2 and 127.5 kg·hm−2 of nitrogen fertilizer in winter rapeseed and maize seasons, respectively, in the rotation area of Guizhou yellow soil, with the addition of 3000 kg·hm−2 organic materials, most appropriately commercial organic fertilizer.

Effect of Organic Manures and Chemical Fertilizers on Maize Productivity and Soil Properties in the Winter Season

Field experiments were conducted at the National Maize Research Program Rampur, Chitwan, Nepal, during the two consecutive winter seasons of 2018/19 and 2019/20. The objective was to identify the impacts of different sources of nutrients on the growth and yield parameters of winter maize and soil properties. The experiment was laid out in a randomized complete block design with three replications and twelve treatments. Combinations of different organic and inorganic sources, including the recommended dose of chemical fertilizer, use of farmyard manure, poultry manure, vermicompost, mustard oil cake, green manure, and bone meal, were made. Different nutrient levels significantly influenced the maize grain yield. The maximum grain yields of 7102 kg/ha (2018/19) and 6985 kg/ha (2019/20) were obtained with the combined application of 50% recommended dose (RD) of chemical fertilizer along with mustard oilcake at the rate of 5 t/ha, which was at par (6970 kg/ha and 6535 kg/ha) with the sole application of mustard oilcake at 5 t/ha. It can be concluded that maize performed best when 50% of the recommended dose of N, P2O5, and K2O fertilizers were combined with a 5 t mustard oilcake/ha application, followed by a sole application of 5 t mustard oilcake/ha. Soil properties, namely soil organic matter, were found to be significantly improved due to the application of a combined application of organic and inorganic fertilizer. Thus, in subtropical conditions, integrated organic manures and chemical fertilizers can enhance soil properties and increase maize productivity during the winter season.

Evaluation of pro-vitamin A enriched maize hybrids for fighting hidden hunger in Nepal

Prevailing vitamin A deficiency is a malnutrition repercussing retarded growth, weak immune system and night-blindness in human beings. Pro-vitamin A enriched maize hybrids could be a strategy for combating vitamin A deficiency, mostly prevailing in children and women of Nepal. With the objective to investigate superior pro-vitamin A enriched ‘bio-fortified’ maize cultivars, twice replicated experiments were laid out in α-lattice design over two consecutive growing seasons of 2019 and 2019/20 at the National Maize Research Program (NMRP), Rampur, Chitwan, Nepal. The results revealed that the difference among tested hybrids was glaring for all agro-morphological, yield, and yield components traits. Among the evaluated traits, days to 50% anthesis and silking, plant and ear height, numbers of kernel rows per cob, grains per row, and grain yield varied significantly among the tested maize hybrids. Effect of planting season was significant for grain yield where winter maize produced 32% higher grain yield than spring maize. HPO16-2, HPO49-3, HPO49-5, and HPO49-2 were the 38-61% high yielding ‘bio-fortified’ maize genotypes than normal hybrid check. Therefore, these hybrids might be the potential higher-yielding future pro-vitamin A enriched maize hybrids to resolve food insecurity, malnutrition, trade deficit on maize grains and specially to combat vitamin A deficiency in Nepal.

Diversification Options in Sugarcane-Based Cropping Systems for Doubling Farmers' Income in Subtropical India.

Crop diversification provides an opportunity for farmers to maximize their profits, fulfilling multiple needs, avoid monsoon threats, and make the crop production system sustainable. Inclusion of various pulse/oilseed/vegetables/cereals/medicinal/aromatic crops with sugarcane brings forth cultivation of these crops in irrigated agro-system and improves the yields of component crops. Besides, the component crops improve soil fertility and create a favorable environment for the further growth of sugarcane crops. Sprouting in winter-initiated sugarcane ratoon could be enhanced by adopting fodder legumes such as Indian clover and Egyptian clover. Intercropping vegetables provides an ample opportunity for mid-season income generation and improves profitability. Besides, high-value medicinal and aromatic crops such as tulsi (holy basil), mentha could also be included in the sugarcane-based system. Crop residue management has been recognized as a critical issue in managing the crops in the various cropping systems. Including multiple bio-agents for fast decomposition of crop residues provides scope for managing soil organic carbon through crop residue recycling in the system. Resource use efficiencies, nutrient use, water use, and weed control could be increased by adopting suitable crops in intercropping systems. An integrated farming system involving crop, livestock, and fisheries options could improve farmers’ profit besides employment generation in rural India. Recycling of bye products and co-products of other enterprises influences the viability and farmer’s profitability of the system. Trash, press mud cake, vinasse, composted bagasse, rhizodeposition of stubble play a significant role in sustaining soil fertility and increasing crop productivity. New emerging crop diversification options, viz., intercropping of rajmash, winter maize, and garlic in autumn cane generate mid-season income and enhance the system's profitability for small and marginal cane growers. Dual-purpose legumes, viz., cowpea, and green gram as intercrops with spring-planted cane increase the pool of soil microbial biomass nitrogen capitalize allelopathic effects and sustain soil health. In the present paper, these issues have been discussed. Due to the adoption of location-specific and farmers-centric systems, farmers’ profitability could be increased, providing sustainability to the sugarcane-based systems.

Crop Diversification for Sustainable Agriculture

In India, over the years, the new cropping systems have become predominant in view of their higher productivity as well as income for farmers. Examples are rice-wheat cropping system in the north, groundnut in Gujarat, sugarcane in the north, chickpea in southern states, arhar in the north-western states, soybean in Madhya Pradesh and adjoining states, and winter maize in Bihar. Unfortunately, most of these systems require diversification for greater sustainability and conservation of natural resources. Time is ripe now to bring in needed reforms in the existing cropping systems that are more scientifically based and more suited to varying agro-climatic conditions. The possibilities of future crop diversification that can increase farmers’ production as well as income and also ensure conservation agriculture through sustainable intensification are described in this commentary. There is a need for long term planning and development of various strategies for crop diversification in the best national interest.

Effect of elevated temperature and carbon dioxide on grain quality of Rabi maize or winter maize cv. Raashi 4212

Effect of elevated temperature and carbon dioxide on grain quality of Rabi maize or winter maize cv. Raashi 4212

Effects of Crop Geometry and Nutrient Management On Nutrient Uptake and Quality Parameters of Potato Under Winter Maize + Potato Intercropping System

Effects of crop geometry and nutrient management on nutrient uptake and quality parameters of potato under winter maize + potato intercropping system were studied during two consecutive years (2015-2016 and 2016-17) at BHU, Varanasi, India. Results revealed that under different crop geometry the nutrient uptake (NPK kg/ha) were obtained significantly higher with 1 : 2 row ratio in additive series as compared to other row ratio due to maximum plant population. The minimum nutrient uptake (NPK kg/ha) were obtained with 1:1 row ratio in replacement series. However, quality parameters (protein and starch) did not vary significantly by different crop geometry during both the years of investigation. Amongst nutrient management, the highest nutrient uptake (NPK kg/ha) and quality parameters (protein and starch) were obtained significantly with the application of 100% RDF + 25% N through poultry manure followed by the application of 100% RDF + 25% N through vermicompost. Thus, the results suggest that 1:2 row ratio (crop geometry) in additive series with 100% RDF + 25% N through poultry manure (nutrient management) followed by 100% RDF + 25 % N through vermicompost were feasible and practicable during both the years of investigations. Bangladesh J. Bot. 50(4): 1011-1019, 2021 (December)

Unveiling combining ability and heterotic grouping of newly developed winter maize (Zea mays) inbreds

Pooled analysis of the test-crosses evaluation of 61 newly developed maize (Zea mays L.) inbred lines usingtwo inbred testers namely BML-6 and BML-7 during rabi 2016-17 and 2017-18 at ICAR-IIMR Regional Centre,Begusarai revealed significant variation among genotypes, general combining ability (GCA) and specific combiningability (SCA) effects for all the traits. Out of 61 inbred lines, 29 exhibited significant positive GCA effect for grainyield with maximum GCA effect value of 25.64. Inbred lines, viz. IMLSB-1299-5, IMLSB-406-2, IMLSB-334B-2,IMLSB-814-2 and IMLSB-285-1 were identified as the best general combiners on the basis of GCA effects whichcan be utilized to a greater extent in hybrid breeding programme. Out of 29 inbred lines with significant positive GCAeffects, 12 and 17 lines also showed significant positive SCA effects with tester, BML-7 and BML-6 respectively, thuswere classified into two heterotic groups ‘A’ and ‘B’, respectively. Out of 122 test-crosses, 14 exhibited significantand positive heterosis for yield over three national checks. The information generated on the heterotic grouping willhelp in further streamlining the available germplasm into heterotic pools and thereby augmenting the national hybridbreeding programme.