Physiological Evaluations of Maize Hybrids under Low Nitrogen

Hindawi Advances in Agriculture Volume 2019, Article ID 2624707, 6 pages https://doi.org/10.1155/2019/2624707 Research Article Physiological Evaluations of Maize Hybrids under Low Nitrogen A. W. Abubakar,1 A. A. Manga ,2 A. Y. Kamara,3 and A. I. Tofa3 1 Department of Biological Sciences, Federal University Dutse, Jigawa, Nigeria Department of Agronomy, Bayero University Kano, Nigeria 3 International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria 2 Correspondence should be addressed to A. A. Manga; Received 30 May 2018; Revised 22 October 2018; Accepted 8 January 2019; Published 1 April 2019 Academic Editor: Gábor Kocsy Copyright © 2019 A. W. Abubakar et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A field experiment was conducted during 2014 and 2016 rainy season at Tudun Wada, Kano and Shika, Zaria in the Northern Guinea Savanna of Nigeria in order to study the physiological responses of maize hybrids under low nitrogen. The experiment consisted of two nitrogen levels 0 and 120 N kg ha−1 as main plot and 8 drought-tolerant maize hybrids and 2 controls as subplot laid out in a randomized split plot design and replicated three times. Physiological parameters of hybrids were significantly affected by low nitrogen at both locations. Interaction between hybrids and nitrogen was significantly affected at both locations. Based on these results, application of nitrogen significantly increased the physiological growth indices of maize hybrids. The extent of increment in physiological reactions was additionally higher in Zaria in view of higher soil natural carbon and nitrogen and higher precipitation was better dispersed at this area. However recent hybrids were more tolerant to nitrogen stress and out-yielded the older hybrids. Therefore the recently released hybrids were more adapted to abiotic stresses. 1. Introduction Maize is a major important cereal crop being cultivated in the savanna zones of Nigeria. It has been in the diet of Nigerians for centuries. It started as a subsistence crop and has gradually become more important crop. Maize thrives best in a warm climate and is now grown in most of the countries that have suitable climatic conditions [1]. Maize is an important crop for security, serving as cash and food crop and recently replacing some crops, such as sorghum in Nigeria, as the most consumed cereal. It is consumed as a vegetable although it is a grain crop [2]. Maize is the most widely grown staple crop in Africa; more than 300 million Africans depend on it as their main food source. Improving maize grain yield is a substantial challenge given the reliance on maize for food, feed, fiber, and fuel [3]. The moist savannas of West Africa have great potential for maize production. Higher radiation levels, lower night temperatures, and reduced incidence of diseases and insect pests increase yield potential in comparison with the traditional area (forest zone) for maize cultivation [4]. Recently, researchers have linked maize grain yield to both high nitrogen uptake and high ability to utilize nitrogen accumulated in the plant in grain production. Nitrogen is the most important element required for plant growth and development. It is a key component in the manufacture of tissues and plays a major role in photosynthetic activity and crop yield [5]. Nitrogen being the most yield constraining supplement, its pressure diminishes grain yield by deferring plant development and improvement. Normally for ideal yield generation nitrogen fertilization has by and large been resolved from field experimentation keeping distinctive rates of nitrogen compost application [3]. Henceforth, use of nitrogen has been outstanding among other methods for supplying nitrogen to convene this high demand. At low nitrogen supply, crop growth rate slows down causing reproductive structures to decline, as a result lower physiological components and maize grain yield and its components are achieved. Similarly the deficiency of nitrogen is evident in the reduction of light interception by decreasing leaf area index, which results in lower grain yield [6]. A deeper understanding of the physiological determinants of maize endurance to the applied 2 nitrogen may play a pivotal role to accomplish greater yield plateau by revealing ways to achieve a better resource use and capture in the next decades. The study was therefore conducted to determine the physiological responses of maizehybrids under low nitrogen. 2. Materials and Methods The experiment was conducted in two locations at Tudun Wada, Kano (11∘ 11󸀠 N, 8∘ 24󸀠 E) and Shika, Zaria (11∘ 11󸀠 N and 7∘ 38󸀠 E) in the Northern Guinea Savanna of Nigeria. Ten recently developed maize hybrids were evaluated at two nitrogen levels 0 and 120 kg N ha−1 . Eight hybrids were (M0826-7, M0926-8, M1026-10, M1026-13, M1124-4, M112410, M1227-12, and M1227-14) and two widely cultivated maize hybrids (Oba-98 and Oba super-1). In both years, the trials were laid out in a split plot design with three replications. Two nitrogen levels 0 and 120 kg N ha−1 were main plots, whereas the ten hybrids were the subplots within each main plot. Field data were collected from the two middle rows of each plot leaving the outside rows and a distance of 25 cm at the ends of each middle row to serve as borders. Each plot size measured 3 m × 5 m (15 m2 ) consisting of 4 rows of 0.75 m apart and 5 m in length, while the net plot size measured 1.5 m × 4.5 m (6.75 m2 ). Alley way of 0.75 m between plots and 2 m between replications giving a total area of 1848.75 m2 per replication and 5981.25 m2 for the gross experimental area. The land was ploughed and ridged with work bulls mounted with plough. The ridges were made 0.75 m apart and the plots were then laid out as per the number of treatment. Two seeds were planted per holes at a spacing of 25 cm intraraw and thinned to 1 plant per stand. At one week after planting (WAP), Phosphorus and potassium were applied to low nitrogen treatment plots using triple super phosphate (TSP) and muriate of potash (MOP) fertilizers at the rate of 60 kg ha−1 , respectively. NPK 15:15:15 was used to supply 60 kg ha−1 of N, P, and K at one week after planting for the optimal nitrogen application plots and was top dressed with urea at the rate of 60 kg N ha−1 at 5 WAP. After planting, the area was sprayed with preemergence herbicide Gramoxone (1:1-dimethyl-4, 4bipyridinium dichloride, manufactured by Syngenta Crop protection AG, Switzerland) at the rate of 276 g a.i/liter and 2 liters/ha. Weeding was done at 3 WAP, using a hoe. At 6 WAP, weeding was done by hand pulling method. Pests and diseases attacks were treated using appropriate agrochemicals at the recommended rates. Harvesting was carried out when the cob reached maturity, from the net plot i.e., the two i (...truncated)