An evaluation of water-yield relations in maize (Zea mays L.) in Turkey

The objective of this study was to compare the responses of maize (Zea mays L.) to deficit irrigation. A field experiment was conducted during the 1999 and 2000 growing seasons in western Turkey. Irrigation treatments were tested with 100, 70, 50, 30 and 0% replenishment of water depleted at 120 cm soil profile from 100% replenishment treatment at ten days intervals. The irrigation amount ranged between 0 and 323.20 mm in the first year and 0-466.61 mm in the second year of the experiment. Seasonal crop water use values were between 142.19 and 481.91 mm in 1999 and 136.25-599.45 mm in 2000. Average maximum and minimum yields were 10639-10383 kg ha(-1) for full irrigated treatment (I100) and 3750-2136 kg ha(-1) for non-irrigated treatment (I0) in 1999 and 2000, respectively. Water deficit significantly affected maize yield. In both years, yield increased linearly with irrigation applied but the relationship varied from one year to the other. Water Use Efficiency (WUE) ranged from 1.49 to 2.71 kg m(-3), while Irrigation Water Use Efficiency (IWUE) varied from 1.44 to 2.55 kg m(-3) in both years. The yield response factor (ky) relating relative yield decrease to relative evapotranspiration deficit was found to be 0.99 for the data of the two experiments combined. Also, dry matter yields (DM) and leaf area index (LAI) were markedly affected by the irrigation treatments. The finding of this work showed that well-irrigated treatment should be used for maize grown in semi arid regions under no water scarcity.     

Downy mildew resistance in maize (Zea mays L.) across Peronosclerospora species in lowland tropical Asia

Downy mildew (DM) is one of the most destructive diseases of maize in the humid sub-tropical and tropical regions of Asia. The most effective and efficient way of managing losses due to DM is to develop durable host-plant resistance in Asian maize across different DM pathogens. We assessed resistance in released DM (P. zeae) resistant CIMMYT maize lines (CMLs) against Peronosclerospora sorghi and Perenosclerospora heteropogoni to develop DM resistant (DMR) maize germplasm with a broad-spectrum of resistance, and identify and further improve new sources of DMR maize germplasm for use in regional breeding programs targeting DM-prone environments. Data indicated that out of 19 DM resistant CMLs, four (CML-433, 465, 466 and 472) were resistant and 15 susceptible to P. sorghi. Screening of new inbred lines from CIMMYT-Asia (CA) resulted in identification of a set of yellow maize lines with good level of DM resistance (disease score – 0.0–25%). However, the high quality protein maize (QPM) lines derived from CIMMYT Population 61 and bi-parental pedigree crosses between elite QPM lines showed very poor resistance to DM. Progenies of the bi-parental population developed by crossing DMR (P. sorghi) CA lines showed further enhanced levels of resistance to both P. sorghi and P. heteropogoni. The study resulted in identification of 10 new inbred lines, in addition to the 4 released CMLs, offering consistent high resistance to both the DM pathogens. Promising bi-parental populations (13) with combined DM resistance and other desirable agronomic traits were identified for the extraction of a new generation of DMR lines with broad-spectrum DM resistance and other commercial traits. Comparison of genotypic response under different screening methods/DM species clearly indicated that the glasshouse-based sandwich method of screening against P. sorghi was the best method for identifying promising genotypes with a high level of DM resistance that were also resistant to DM under field conditions for both the species. However, the highly controlled conditions used for sandwich screening, which is most favourable for disease development, resulted in high disease pressure potentially masking the identification of genotypes with a moderate level of DM resistance.     

Effect of nitrogen supply on leaf appearance,leaf growth,leaf nitrogen economy and photosynthetic capacity in maize (Zea mays L.)

Leaf area growth and nitrogen concentration per unit leaf area, N_a (g m⁻² N) are two options plants can use to adapt to nitrogen limitation. Previous work indicated that potato (Solanum tuberosum L.) adapts the size of leaves to maintain N_a and photosynthetic capacity per unit leaf area. This paper reports on the effect of N limitation on leaf area production and photosynthetic capacity in maize, a C4 cereal. Maize was grown in two experiments in pots in glasshouses with three (0.84–6.0 g N pot⁻¹) and five rates (0.5–6.0 g pot⁻¹) of N. Leaf tip and ligule appearance were monitored and final individual leaf area was determined. Changes with leaf age in leaf area, leaf N content and light-saturated photosynthetic capacity, P_max, were measured on two leaves per plant in each experiment. The final area of the largest leaf and total plant leaf area differed by 16 and 29% from the lowest to highest N supply, but leaf appearance rate and the duration of leaf expansion were unaffected. The N concentration of expanding leaves (N_a or %N in dry matter) differed by at least a factor 2 from the lowest to highest N supply. A hyperbolic function described the relation between P_max and N_a. The results confirm the ‘maize strategy’: leaf N content, photosynthetic capacity, and ultimately radiation use efficiency is more sensitive to nitrogen limitation than are leaf area expansion and light interception. The generality of the findings is discussed and it is suggested that at canopy level species showing the ‘potato strategy’ can be recognized from little effect of nitrogen supply on radiation use efficiency, while the reverse is true for species showing the ‘maize strategy’ for adaptation to N limitation.     

ZmMS39 encodes a callose synthase essential for male fertility in maize(Zea mays L.)

Callose contributes to many biological processes of higher plants including pollen development, cell plate and vascular tissue formation, as well as regulating the transport function of plasmodesmata. The functions of callose synthase genes in maize have been little studied. We describe a maize male-sterile mutant 39(ms39) characterized by reduced plant height. In this study, we confirmed using CRISPR/Cas9 technology that a mutation in Zm00001d043909(ZmCals12), encoding a callose synthase, is re...     

Transition from vitreous to floury endosperm in maize (Zea mays L.) kernels is related to protein and starch gradients

Relationships between kernel vitreousness and proteins and starch partitioning to the floury and vitreous regions of the endosperm were monitored in a set of 13 maize inbred lines. Decrease of protein contents from the vitreous to the floury endosperms were mainly assigned to α-zeins. Using Raman microspectroscopy, we observed a protein gradient from the periphery to the center of endosperms that well fitted with the inverse relationships between vitreousness and protein content of the vitreous and floury regions. In addition, Raman microspectroscopy highlighted an increase of starch crystallinity from the periphery to the center of the maize endosperms. This agrees with the higher amylose and associated lipid contents within starches of vitreous than in those of floury endosperms. Finally, starch granules from vitreous regions displayed more channels than the floury ones. These channels contain proteins that might favor adhesion of proteins to starch granules or granule–granule contacts to form the close packing of the vitreous endosperm. Therefore transition from vitreous to floury endosperm is at least the result of both protein and starch gradients. These gradients are probably associated with metabolic gradients that have been observed during endosperm development.     

Use of strips of Zea mays L. to trap European corn borer (Ostrinia nubilalis Hbn.) oviposition in maize fields

The object of the investigation was to control egg laying by O. nubilalis in maize crops, by using trapping plant strips all around the field. Previously, strips planted with the same hybrid maize showed that they were of no effect and in fact were less infested. If the strips were planted with mixed hybrid maize such as in the field itself, there was the same concentration of infestation in them both. However, traps consisting of the susceptible maize hybrid (Zea mays L.) laid in strips showed a high concentration of egg masses. Comparison of the different strip sides showed that diversity of infestation depended on the insect day shelters outside the maize field. These shelters may vary with the plant species cultivated in the neighbourhood, their harvest dates and abiotic conditions (not studied here): it is therefore necessary to grow the trapping strips all around the maize field. This method of protection limits egg-mass density and can be integrated in a planned pest control to increase effectiveness with regard to environment protection.     

Effects of crude oil spillage on growth and yield of maize (Zea mays L.) in soils of midwestern Nigeria

The effect of crude oil spillage on growth, productivity and nutrient uptake of maize (Zea mays L.) was assessed in a pot experiment using an Evwreni manifold sample of a petroleum development company, which had aspecific gravity of 0.8778. The Suwan 1 variety of maize was used in the experiment. In crude oil polluted soils, germination was delayed and the germination percentage was significantly affected by oil pollution. Growth was poor in polluted soils using parameters such as plant height, stem girth,ear height, leaf area at four weeks after planting, leaf area at maturity and average length of primary roots as growth indicators. Grain yield was significantly reduced at 95% level of probability with yield (when compared with the control) reduced by as much as 98.6%, 96.5% and 58.3% for preplant,five weeks after planting (5 WAP) and seven weeks after planting (7 WAP) treatments, respectively. Leaf analysis of the maize plants grown in soilscontaminated with crude oil a week before planting (preplant treatment) revealed mean levels of heavy metals (6.18 ppm Zn²⁺, 0.62 ppm Cu²⁺,26.24 ppm Fe²⁺, 10.84 ppm Mn²⁺, 2.96 ppm Pb²⁺ and 3.88 ppm Co²⁺) which are higher than the maximum permissible levels (MPL) for maize in tropical soils. Maize plants that were polluted at other time intervals showed no significant (p>0.05) variation in heavy metal concentrations when compared with the control, and were considered potentiallysafe for human consumption.     

玉米子粒性状种子和母体效应的遗传分析

采用二倍体种子遗传模型及其分析方法,以5个玉米自交系及其间配制的F₁,F₂,BC₁,BC₂世代为材料,研究了7个玉米子粒性状的直接效应、母体效应和细胞质效应。分析结果表明,除粒厚外,各性状的遗传均以母体加性效应为主,种子直接显性效应和母体显性效应较小,细胞质基因对各性状均无显著影响,而环境效应极显著。除粒长的直接显性效应与母体显性效应间的协方差外,直接效应与母体效应间的协方差均较小,且不显著。因此,通过母体植株的遗传表现可对这些性状进行有效的直接选择。S₂₂是改良粒重的优良亲本,而N_O1,N_O2,N_O3对改良粒重不利。各部位子粒百粒重的直接显性效应、母体加性效应、母体显性效应及机误均存在极显著正相关。在自交系选育过程中,直接选择粒较宽的分离类型,容易获得大粒的遗传材料,选择粒厚而宽的亲本组配杂交组合有利于提高F₁粒重。     

Irrigation frequencies and corn (Zea mays L.) yield relation in northern Turkey

A field experiment was conducted during summer season of 2005 at the Research Station (altitude 180 m above sea level, 41 degrees 21' N and 36 degrees 15'E) Faculty of Agriculture, Ondokuz Mayis University, Samsun, Turkey. Experiment consisted of three irrigation levels and a non-irrigation level. Drip irrigation treatments consisted of three soil water deficits in the 90 cm soil profile depth was replenished to field capacity. Irrigation treatments were A: no irrigation, B: irrigation at 50% of available soil water capacity, C: irrigation at 30% of available soil water capacity, D: irrigation at 15% of available soil water capacity. The average seasonal water use values ranged from 257.14 to 285.71 mm in corn treatments. Irrigation frequencies (intervals) significantly affected corn crop yields. The average corn grain yields varied from 7.98 to 29.16 t ha(-1). The treatment D was recorded significantly higher corn grain yield 29.16 t ha(-1) compared to B (21.59 t ha(-1)); C (19.15 t ha(-1)) and A (7.98 t ha(-1)), respectively. According to research results, the maximum corn grain yield was obtained when the corn plants were irrigated at 15% of available soil water capacity to field capacity.     

Stability of anthocyanins of blue maize (Zea mays L.) after nixtamalization of seperated pericarp-germ tip cap and endosperm fractions

Most naturally occurring foods that are sources of anthocyanins are often processed under severe temperature, pressure, and pH conditions that may extensively alter the naturally occurring pigments with loss of their potential antioxidant properties. It is desirable that anthocyanins present in pigmented maize not be completely destroyed when producing processed products. In the present study, the effect of different concentrations of calcium hydroxide used in the nixtamalization after fractionation process on the stability of the pigments found in blue maize was evaluated. The anthocyanin profile was analyzed using HPLC. The total anthocyanin content as well as that of acyl-type anthocyanins decreased during the cooking process and as the concentrations of calcium hydroxide used increased (P<0.001). More anthocyanin was retained in the nixtamalization after fractionation process with 0.5% calcium hydroxide than in the traditional nixtamalization process. In maize cooked and nixtamalized with up to 1.5% calcium hydroxide, only 16.1% of the acyl-type anthocyanin remained, compared to between 32 and 38% in the original uncooked maize. Conversely, the cyanidin and pelargonidin anthocyanin content increased.     

The critical period for weed control in three corn (Zea mays L.) types

Knowledge of the crop-weed competition period is vital for designing effective weed management strategies in crop production systems. Field studies were conducted at the Agricultural Research Institute, Kahramanmaras, Turkey in 2013 and 2014 to determine the critical period for weed control (CPWC) in three corn (Zea mays L.) types (field corn, popcorn, and sweet corn). A four parameter log-logistic model described the relationship between relative crop yield to both increasing duration of weed interference and length of weed-free periods. The relative yield of corn was influenced by duration of weed-infested or weed-free period, regardless of corn types. Increasing periods of weed interference significantly reduced corn yields in both years. In field corn, the CPWC ranged from 175 to 788 growing degree days (GDD) in 2013 which corresponded to V2–V12 growth stages, and 165–655 GDD (V1–V10 growth stages) in 2014 based on the 5% acceptable yield loss (AYL) level. In popcorn, the CPWC ranged from 92 to 615 GDD (VE–V10 growth stages) in 2013 and 110–678 GDD (V1–V10 growth stages) in 2014. In sweet corn, the CPWC ranged from 203 to 611 GDD in 2013 (V2–V10 growth stages) and 182–632 GDD (V2–V10 growth stages) in 2014. The practical implication of this study is that weed management should be initiated around V1 stage and maintained weed-free up to V12 stage in all corn types to prevent yield losses greater than 5%. These findings could help corn producers improve the cost effectiveness and efficacy of their weed management programs.     

Alternate Furrow Irrigation with Different Irrigation Intervals for Maize (Zea mays L.)

Abstract

This research was conducted to determine the yield and water-use efficiency of maize under fixed and variable alternate furrow irrigation (fixed AFI, variable AFI) and every furrow irrigation (EFI) at different irrigation intervals in areas with shallow and deep groundwater. In variable AFI, water was applied to the furrow, which was dry in the previous irrigation cycle. The results indicated that even at 4-day irrigation intervals the water needs of maize on a fine textured soil in both areas (with deep and shallow water table) are not met by AFI. The decrease in grain yield due to water stress was mainly due to the decrease in the number of grains per cob and to a lesser extent to the decrease in 1000-grain weight. At the Kooshkak site with shallow groundwater (between 1.31 and 1.67 m), grain yields in AFI at 4- and 7-day intervals were comparable to those obtained in EFI at 7- and 10-day intervals, respectively. This might be due to the contribution of groundwater to the water use of the plant (about 5-10%). In the Badjgah area, with deep water depth, grain yield in AFI at 7-day intervals was statistically lower than that obtained in EFI at 10-day interval. In AFI, a shorter irrigation interval (4-day) may alleviate the water stress and result in no yield reduction compared with that in EFI at 7-day intervals even though water application was reduced. Furthermore, in the area with a shallow water table, AFI at 7-day intervals may be superior to EFI at 10-day irrigation intervals. When seasonal irrigation water is less than 700 mm, it may be preferable to use AFI at 10-day intervals to increase water-use efficiency, especially in areas with shallow groundwater. In general, when water was insufficient for full irrigation, the relative grain yield (yield per unit water applied) of maize under AFI was higher than those under EFI.     

Modelling leaf production and crop development in maize (Zea mays L.) after tassel initiation under diverse conditions of temperature and photoperiod

Prediction of the initiation, appearance and emergence of leaves is critically important to the success of simulation models of crop canopy development and some aspects of crop ontogeny. Data on leaf number and crop ontogeny were collected on five cultivars of maize differing widely in maturity and genetic background grown under natural and extended photoperiods, and planted on seven sowing dates from October 1993 to March 1994 at Gatton, South-east Queensland. The same temperature coefficients were established for crop ontogeny before silking, and the rates of leaf initiation, leaf tip appearance and full leaf expansion, the base, optimum and maximum temperatures for each being 8°C, 34°C and 40°C. After silking, the base temperature for ontogeny was 0°C, but the optimum and maximum temperatures remained unchanged. The rates of leaf initiation, appearance of leaf tips and full leaf expansion varied in a relatively narrow range across sowing times and photoperiod treatments, with average values of 0.040 leaves (°Cd)⁻¹, 0.021 leaves (°Cd)⁻¹, and 0.019 leaves (°Cd)⁻¹, respectively. The relationships developed in this study provided satisfactory predictions of leaf number and crop ontogeny (tassel initiation to silking, emergence to silking and silking to physiological maturity) when assessed using independent data from Gatton (South eastern Queensland), Katherine and Douglas Daly (Northern Territory), Walkamin (North Queensland) and Kununurra (Western Australia).     

A thermal time analysis of ageing of maize (Zea mays L.) seed can account for reduced germination in hot moist soil

After sowing into moist soil, maize seed imbibe although the soil moisture content may be too low to permit seedling emergence. The hypothesis tested here is that in such circumstances, and especially at high temperature, the seed age in the soil with the result that when the moisture restriction is subsequently removed, germination and seedling emergence are reduced.First, maize seed were artificially deteriorated in the laboratory at four elevated moisture and five constant temperature regimes for four different periods in order to determine the effect of ageing on radicle and coleoptile emergence. Next, the responses when seed were deteriorated at alternating temperatures were shown to be the same when the temperature exposure was expressed as thermal time. A base temperature for thermal ageing time was estimated as about 30°C. Finally, when four Sri Lankan maize cultivars were sown in soil, the seed imbibed and experienced temperatures above 30°C with the result that final seedling emergence was reduced. The effect of ageing in the soil appeared greater than that in the laboratory because the moisture content of seed in the soil was not constant but increasing.     

Meta-QTL analysis for mining of candidate genes and constitutive gene network development for fungal disease resistance in maize(Zea mays L.)

The development of resistant maize cultivars is the most effective and sustainable approach to combat fungal diseases. Over the last three decades, many quantitative trait loci(QTL) mapping studies reported numerous QTL for fungal disease resistance(FDR) in maize. However, different genetic backgrounds of germplasm and differing QTL analysis algorithms limit the use of identified QTL for comparative studies.The meta-QTL(MQTL) analysis is the meta-analysis of multiple QTL experiments, which entai...     

玉米杂交种及自交系抗盐性的鉴定

1992～1995年对105份玉米杂交种及自交系进行了抗盐性鉴定．结果表明，玉米杂交种及自交系受盐害后，植株干物质积累速度变慢；黄叶指数增多，干物重下降；根变粗，变短；侧根和根毛减少；节根条数增多；冠/根比值增大；叶细胞透性增大．在105份材料中，抗盐性强的玉米材料有15份，中抗的78份，不抗的12份．     

Weed emergence as affected by maize (Zea mays L.)-cover crop rotations in contrasting arable soils of Zimbabwe under conservation agriculture

Weed control in smallholder farming systems of sub-Saharan Africa is labour intensive or costly. Many researchers have therefore advocated for the use of cover crops in weed management as an affordable alternative for smallholders. Cover crops may be grown in rotations to suppress weeds and reduce the reliance on herbicides. The use of cover crops creates microenvironments that are either conducive or inhibitive to the emergence of certain weed species. A study, initiated in 2008 in contrasting soils at four different locations of Zimbabwe, investigated the effect of maize (Zea mays L.)-cover crop rotations on the emergence of weeds that showed dominance in those soils. Weed assessments were however, carried out from 2011 to 2014. The weed species Galinsoga parviflora Cav., Commelina benghalensis L., and Richardia scabra L. showed dominance in all four locations with weed densities as high as 500 plants m⁻² being recorded for R. scabra L. in a sandy soil. Maize-cover crop rotations resulted in higher densities of Bidens pilosa compared with maize monocropping (control treatment) due to its high nitrogen (N) requirement to produce more seeds. On the other hand, the integration of cover crops such as pigeon pea [Cajanus cajan (L.) Millsp.] that had poor shading qualities, due to large gaps or spaces and slower initial growth, had limited effects on competitive weeds such as Cyperus esculentus L. which tend to dominate exhausted soils. The density of C. esculentus was 38% greater in maize–pigeon pea rotations compared with the control treatment. Variability between seasons and sites affected emergence of all weeds in the present study, which masked long-term trends. The results suggest that there is need to identify the germination and emergence requirements of specific weeds and select cover crops best suitable for their control. The study provides useful information for farmers and advisors on the best cover crops for control of certain problematic weeds in different soil types of Zimbabwe.     

The impact of tillage system and herbicides on weed density,diversity and yield of cotton (Gossipium hirsutum L.) and maize (Zea mays L.) under the smallholder sector

The study was carried out to evaluate the impact of tillage system in combination with different herbicides on weed density, diversity, crop growth and yields on 18 farms in Kadoma, Zimbabwe. Experiments were set up as a split plot design with three replications on each farm. Tillage was the main plot (Conservation Tillage (CT), Conventional Tillage (CONV)) and weeding option (hand weeding, cyanazine, atrazine, glyphosate only and mixture of cyanazine + alachlor and atrazine + alachlor) as the sub-plots. Due to the heterogeneous nature of farmers' resource base, the farms were grouped into three farm types: high (Type 1), medium (Type 2) and poorly resourced farmers (Type 3). The hand hoe weeded treatments had 49 percent higher total weed densities in CT relative to CONV, and was statistically similar to the glyphosate treatment. The mixed pre-emergence herbicides reduced the diversity indices by 69 and 70 percent when compared to the hand hoe weeded treatment under CT in cotton and maize, respectively. The effectiveness of all pre-emergence herbicides were not influenced by tillage but were affected by farmers resource endowments with pronounced effect in Farm Type 1. Maximum plant heights of 85 and 238 cm were recorded for mixed pre-emergence herbicides under CT for cotton and maize, respectively. Minimum plant heights of 75 and 217 cm were recorded for the respective hand hoe weeded treatments. The hand hoe weeded treatments resulted in average cotton lint yield of 1497 and 2018 kg ha⁻¹ for maize. The mixed pre-emergence herbicides treatments gave yields of 2138 and 2356 kg ha⁻¹ of cotton and maize, respectively. The higher weed densities in CT under hand weeded treatments underscored the need for other weeding options. Similarly, a mixture of cyanazine + alachlor in cotton and atrazine + alachlor in maize is recommended for suppressing broad and grass weed populations and enhancing yields in CT systems.     

Efficacy of four post-emergence herbicides applied at reduced doses on weeds in summer maize (Zea mays L.) fields in North China Plain

Field experiments were conducted in 2010 and 2011 in a typical location of North China Plain to evaluate weed control efficacy of four post-emergence herbicides nicosulfuron, mesotrione, topramezone and the combination of mesotrione/nicosulfuron when they were applied at reduced doses at different weed growth stages. Experimental results showed that nicosulfuron, topramezone and the combination of mesotrione/nicosulfuron provided better weed control efficacy than mesotrione when they were applied at their label recommended doses at the 2- to 3-leaf and 4- to 5-leaf stages of weeds; nicosulfuron and mesotrione/nicosulfuron could at least be reduced by 33% and topramezone reduced by 67% without sacrificing total weed control efficacy and maize grain yield. Nicosulfuron and its combination with mesotrione could effectively control broadleaved and grass weeds when their doses were reduced by 67% and by 33%, respectively. Topramezone could effectively control broadleaved and grass weeds when its dose was reduced by 67%. The efficacy of mesotrione in controlling grass weeds was bad even at the label recommended dose. All four herbicides tested did not affect the maize grain yield.