Maize Plantation Research Articles

Use of serological techniques for determination of Spodoptera frugiperda(J E Smith) predators (Lepidoptera: Noctuidae)

Spodoptera frugiperda (J E Smith) is an important pest of several crops, but especially on maize in Brazil. The implementation of biological control measures hinges on the identification of its predators and other natural enemies. As a means of identifying predators, antibodies against S. frugiperda eggs were generated by inoculating rabbits with macerated S. frugiperda eggs, and the production of antibodies against S. frugiperda egg proteins was verifi ed by double immunodiffusion (DID). These antibodies were then utilized in another serological technique, counterimmunoeletrophoresis (CIE), to identify insects that could have ingested S. frugiperda eggs. Macerates of entire insects collected in maize plantations and of individual parts of their digestive tract, including the crop, were the source of antigens in the CIE, while predators fed S. frugiperda eggs in the laboratory served as the control. Antibodies produced by the inoculated rabbits were effective in detecting S. frugiperda egg proteins, especially if crop macerates were used as antigens. Among the species of insects collected from maize plantations, Lagria villosa Fabricius (Coleoptera: Lagriidae) and a species of Lygaeidae (Hemiptera) were identified as possible S. frugiperda predators.

Potential phytate-degrading enzyme producing bacteria isolated from Malaysian maize plantation

Phytases catalyze the hydrolysis of phosphomonoester bonds in phytate, thereby releasing lower forms of myo-inositol phosphates and inorganic phosphate. Phytase enzyme preparations have a wide range of applications in animal and human nutrition. The addition of phytate-degrading enzyme can improve the nutritional value of plant-based foods by enhancing protein digestibility and mineral availability through phytate hydrolysis during digestion in stomach or during food processing. 30 strains of potential phytate-degrading enzymes bacteria isolated from Malaysian maize plantation were cultivated in Luria Bertani (LB) and Luria Bertani + Rice Bran (LBRB) media for 5 days and were analyzed for phytase activity. The 6 strains with highest activity were chosen for species identification. Two set of broad-range 16S rRNA PCR primers were used for genotypic identification. ASUIA279 was the strain that had has the highest phytase activity in LBRB followed by ASUIA271, ASUIA138, ASUIA260, ASUIA243 and ASUIA30. The genotypic technique revealed Pantoea stewartii ASUIA271, Enterobacter sakazakiiASUIA279, Bacillus cereus ASUIA260, Bacillus subtilis ASUIA243, P. stewartiiASUIA138 and B. cereus ASUIA30. Key words: Bacterial phytase, rice bran, production, genotypic.

Cercospora zeina is the causal agent of grey leaf spot disease of maize in southern Africa

The aim of our study was to identify the causal agent of grey leaf spot disease of maize in southern Africa. Single-conidial cultures were recovered from maize leaves with typical disease symptoms sampled from several fields in South Africa, Zambia and Zimbabwe. Morphology, cultural characteristics, and a PCR-based test using Cercospora zeae-maydis and C. zeina-specific primer sets identified all single-conidial cultures as C. zeina. In addition, sequence alignment of DNA fragments of the internal transcribed spacer region (ITS1, ITS2, and the 5.8S gene) and elongation factor 1-α grouped all cultures in the same clade as the C. zeina ex-type culture CBS 118820. To by-pass cultivation of the slow-growing fungus, a rapid method to isolate DNA directly from lesions was successfully applied for PCR identification of C. zeina with species-specific ITS and histone primers. Koch’s postulates were fulfilled for C. zeina by artificially inoculating maize plants in a greenhouse, re-isolating conidia emerging from lesions and verifying pathogen identity with molecular techniques. These results provide evidence that confirms the presence of C. zeina and absence of C. zeae-maydis in commercial maize plantations in southern Africa.

Parasitoids of several lepidopterous pests in maize plantations in the Southeast Anatolian Region of Turkey

The parasitoid complex of several lepidopteran pests were studied in maize plantations in the Southeast Anatolian Region of Turkey during 2003-2004. Apenteles sp., Bracon hebetor (Say.), Chelonus oculator Panzer, Meteorus rubens Nees (Hym.: Braconidae), Conomorium patulum Walk. (Hym.: Pteromalidae), Diadegma crassicornis (Gray.) subsp. africator Aubert (Hym.: Ichneumonidae), Euplectrus sp. (Hym.: Eulophidae), Exorista larvarum (Linnaeus), E. xanthaspis (Wiedemann) Gonia bimaculata Wiedemann, Drino imberbis (Wiedemann), Pseudogonia rufifrons (Wiedemann), and Linnaemya neavei Curran (Dip.: Tachinidae) were reared from field-collected larvae. Mythimna loreyi (Duponchel) (Lep.: Noctuidae) was for the first time found to serve as a host for Diadegma crassicornis (Gray.) subsp. africator (Hym.: Ichneumonidae).

Effects of some herbicides on the microbiological characteristics of soil nitrogen cycle under maize plantation

Nitrogen is a key element for the living organisms and influence not only for the quantity but for the quality of the yield, considerable. Availability of nitrogen from the soil is influenced by several microbiological processes of the Nitrogen-cycle. Among the intensive agricultural production the herbicide application cannot be omitted more information needs therefore about the inhibitor effect of herbicides on the different microorganisms.An experiment was set up on calcareous chernozem soil under maize culture. Effect of four different herbicides (Acenit, Frontier, Merlin, and Wing) was investigated. The effect of herbicides was measured to four microbiological parameters of the Nitrogencycle (abundance of nitrifying bacteria, nitrate solubilisation, biomass nitrogen and urease enzyme activity). There were singledouble- and five times of recommended doses of herbicides applied for two onsecutive vegetation periods.From the results of the different doses of herbicides, the following can be stated:– The Acenit has a stimulating effect on nitrifying bacteria in general. The Frontier and Merlin also influenced the quantity of nitrifyers, however in certain cases decreased in another cases increased the number of bacteria.– The double doses and five times doses of herbicides was found to be increasing the nitrate content of soil, -especially in 2006.– The quantity of microbial biomass nitrogen increased in the 60% of treatments and decreased in the 40% of the treatments.– Except of the result of Wing in 2006 and Merlin in 2005, the effect of simple dose herbicides was the smallest on the urease enzyme activity. According to the results the effect of Merlin was positive; the effect of Wing was negative on the soil enzyme’s activity.Regarding the application of four different herbicides in three different doses on the microbiological parameters of soil (at two consecutive years-) in 39% of the treatments has resulted a significant inhibitory effect, 28% of the treatments, however have significant stimulating effect on the parameters measured. More than 50% of the inhibitory effect was measured in case of the Wing, at more than 50% of the Frontier the microbiological parameters have not changed.

Análise do tempo de consolidação do sistema de plantio direto

O sistema de plantio direto já está consagrado como sistema conservacionista de cultivo agrícola, o que motivou este trabalho, através do qual se visa analisar o tempo de consolidação deste sistema, considerando-se cultivos de milho com plantio direto implantado entre 2 e 14 anos. Esta análise foi feita por meio da medição da área das estruturas presentes no perfil cultural do solo com um SIG e, posteriormente avaliada pelo método estatístico de componentes principais. Constatou-se que as estruturas onde o plantio direto foi implantado há menos de 8 anos assemelharam-se às estruturas do sistema de plantio convencional, e quando implantado há mais de 9 anos, assemelharam-se às estruturas do perfil de floresta, concluindo-se que o período de consolidação do sistema de plantio direto situa-se entre o 9º e o 10º ano após a sua implantação, para as condições da área estudada. O excesso de detalhamento na nomenclatura das unidades morfologicamente homogêneas dificultou a análise dos dados.

Phytate-degrading enzyme production by bacteria isolated from Malaysian soil.

Over two hundred bacteria were isolated from the halosphere, rhizosphere and endophyte of Malaysian maize plantation and screened for phytases activity. Thirty isolates with high detectable phytase activity were chosen for media optimization study and species identification. Ten types of bacterial phytase producers have been discovered in this study, which provides opportunity for characterization of new phytase(s) and various commercial and environmental applications. The majority of the bacterial isolates with high detectable phytase activity were of endophyte origin and 1.6% of the total isolates showed phytase activity of more than 1U/ml. Most of the strains produced extra-cellular phytase and Staphylococcus lentus ASUIA 279 showed the highest phytase activity of 1.913U/ml. All 30 species used in media optimization study exhibit favorable enzyme production when 1% rice bran was included in the growth media.

Note: Tachinid parasitoids (Diptera: Tachinidae) ofMythimna (Acantholeucania) loreyi in the southeast Anatolian region of Turkey

The loreyi leaf worm,Mythimna (Acantholeucania) loreyi (Duponchel) (Lepidoptera: Noctuidae), is a serious pest of gramineous crops and reduces yields in maize plantations. This study was undertaken to determine the tachinid parasitoid complex ofM. loreyi in the southeast Anatolian region of Turkey. Four tachinid species were found:Pseudogonia rufifrons (Wiedemann),Exorista larvarum (Linnaeus),Drino imberbis (Wiedemann) andLinnaemya neavei Curran were reared from field-collectedM. loreyi larvae. Of the four tachinid speciesM. loreyi is a new host record forE. larvarum andD. imberbis. L. neavei was recorded for the first time in Turkey and was the most frequently encountered parasitoid in this study. Total parasitism level was 7.1% in 2003 and 15.5% in 2004.

Spontaneous Hybridization between Maize and Teosinte

The closest wild relatives of maize, Zea mays ssp. mays are various Zea taxa known as "teosinte." Hybrids between maize and the teosinte taxon, Zea mays ssp. mexicana, often occur when the 2 are sympatric in Mexico. Measuring the spontaneous hybridization rate of the 2 taxa would shed light on the mechanisms contributing to the evolution and persistence of these hybrid swarms. We conducted a series of field experiments in Riverside, CA, to measure the natural hybridization rates between maize and 2 teosinte taxa, Z. m. ssp. mexicana and Zea mays ssp. parviglumis. We planted teosinte within and near maize plantations. Hybrids were identified by progeny testing for a maize-specific herbicide resistance allele and a teosinte-specific allozyme allele. Hybridity was confirmed by growing putative hybrid progeny to maturity to evaluate whether they had the characteristic morphology of maize x teosinte hybrids. We found that maize and Z. m. ssp. mexicana naturally hybridize at a low rate (<1%), whereas Z. m. ssp. parviglumis hybridizes with the crop at a high rate (>>50%).

UJI KETAHANAN TERHADAP ALUMINIUM DAN pH RENDAH PADA JAGUNG (Zea mays L) VARIETAS PIONEER DAN SRIKANDI SECARA IN VITRO

One effort to increase maize productivity is by using marginal land for maize plantation. The marginal land that can be used is acid soil, but the problem are Al toxicity and low pH. To cope with these problems, cultivars having tolerance to Al toxicity and low pH are needed. Plant material used in this research were two maize varieties (Pioneer and Srikandi). Media selection is used there are 4 doses treatment aluminium (0, 250, 500 and 750 ppm AlCl3). All variables were observed except at the variable width of the leaf in this results showed that the treatment of aluminium (AlCl3) would not influence. Treatment combination Variety Srikandi and 250 ppm AlCl3 produces plant height, leaf length and leaf width is the shortest compared to other treatments. Variety Pioneer and Srikandi are suspected of varieties resistant aluminum and low pH values based on relative root length.

Archæological Exploration in Guatemala

THE first part of the fourth, volume of the Memoirs of the Peabody Museum, Harvard University, is devoted to an account of exploration by. Mr. Teobert Maler in the valley of the Upper Usumatsintla, or the Usumacinta, as it appears in some modern maps, a river rising in Guatemala, falling into the Gulf of Mexico, and forming for part of its course the boundary between the Peten province of Guatemala and the Chiampas of Mexico. The exploration has thrown much new light on the geography of a region which has up to the present been very imperfectly explored. It is a wild country largely covered with tropical jungle, the main industry, that of lumber, attracting a particularly disreputable class of workmen, while agriculture is confined to a few scattered maize plantations. The author gives a very gloomy account of the population. “The dubious elements,” he says, “sunk in sloth, filth, and every possible vice, whose miserable habitations are met with here and there, are constantly shifting since they acquire no fixed property rights.” Whoever commits murder across the Mexican border takes refuge in Guatemala, and vice versa. Attempts are, of course, made to secure the extradition of offenders, but these are generally unsuccessful. In fact, the negro is gradually taking the place of the Spanish-Indian population, which, having become enervated and degraded, is rapidly dying out.