Latest Research on Maize cultivar : Apr 2022

Soil Type and Maize Cultivar Affect the Genetic Diversity of Maize Root–Associated Burkholderia cepacia Populations

Burkholderia cepacia populations associated with the Zea mays root system were investigated to assess the influence of soil type, maize cultivar, and root localization on the degree of their genetic diversity. A total of 180 B. cepacia isolates were identified by restriction analysis of the amplified 16S rDNA (ARDRA technique). The genetic diversity among B. cepacia isolates was analyzed by the random amplified polymorphic DNA (RAPD) technique, using the 10-mer primer AP5. The analysis of molecular variance (AMOVA) method was applied to estimate the variance components for the RAPD patterns. The results indicated that, among the factors studied, the soil was clearly the dominant one in affecting the genetic diversity of maize root–associated B. cepacia populations. In fact, the percentage of variation among populations was significantly higher between B. cepacia populations recovered from maize planted in different soils than between B. cepacia populations isolated from different maize cultivars and from distinct root compartments such as rhizoplane and rhizosphere. The analysis of the genetic relationships among B. cepacia isolates resulted in dendrograms showing bacterial populations with frequent recombinations and a nonclonal genetic structure. The dendrograms were also in agreement with the AMOVA results. We were able to group strains obtained from distinct soils on the basis of their origin, confirming that soil type had the major effect on the degree of genetic diversity of the maize root–associated B. cepacia populations analyzed. On the other hand, strains isolated from distinct root compartments exhibited a random distribution which confirmed that the rhizosphere and rhizoplane populations analyzed did not significantly differ in their genetic structure.[1]


Additive Main Effects and Multiplicative Interaction Analysis of Two International Maize Cultivar Trials

The methodology used by the International Maize and Wheat Improvement Center (CIMMYT) to develop and improve its maize (Zea mays L.) germplasm involves evaluation of families or experimental varieties in extensive international testing trials. The genotype-environmental interaction is produced by differential genotypic responses to varied environmental conditions. Its effect is to limit the accuracy of yield estimates and complicate the identification of specific genotypes for specific environments. The objective of this study was to use the Additive Main effects and Multiplicative Interaction (AMMI) method, with additive effects for genotypes and environments and multiplicative terms for genotype-environment interaction, for analyzing data from two international maize cultivar trials. Results from the first trial were: (i) predictive assessment selected AMMI with one principal component axis, (ii) AMMI increased the precision of yield estimates equivalent to increasing the number of replications by a factor of 4.30, (iii) AMMI provided much insight into genotype-environment interactions, and (iv) AMMI selected a different highest-yielding genotype than did treatment means in 72% of the environments. Results for the second trial were that predictive assessment selects the AMMI with none of the principal component axes, which increased precision equivalent to increase the number of replications by a factor of 2.59.[2]


Influence of plant development, cultivar and soil type on microbial colonization of maize roots

An understanding of the environmental factors affecting size and composition of rhizosphere microbial populations is important when introducing exogenous microorganisms in the rhizosphere of crop plants for plant growth promotion. The influence of plant development, cultivar and soil characteristics on the total rhizosphere microbial population and community structure of maize plants was investigated using the concept of r/K strategy. During maize growth microbial population density did not vary significantly, whereas the microbial community structure changed markedly in the early stages of plant growth but afterwards remained stable. Comparisons of the rhizosphere microflora of several maize cultivars, showing differential susceptibility to Fusarium, revealed that different cultivars support similar numbers of indigenous bacteria. Moreover the bacterial community structures of different maize cultivars did not show any significant difference. On the contrary, soil type had a marked influence on the microbial population of maize rhizosphere. Indeed the rhizosphere microbial density and community structure varied significantly among the different sampling sites. In conclusion, plant development and soil type have a marked influence on the rhizosphere microflora of maize, whereas cultivar type does not have a role.[3]

Effect of Variety and Spacing on Growth and Yield of Maize (Zea mays L.) in Bauchi State, Nigeria

A field experiment was conducted at the Abubakar Tafawa Balewa University teaching and research farm Bauchi state of Nigeria, during the 2013 rainy season, to investigate the effect of variety and intra-row spacing on growth and yield of maize (Zea mays L.) in Bauchi state. The Treatments consist of three varieties of corn (DMR, TZEE and QPM) and three intra-rows spacing (20, 25 and 30 cm). The experiment was laid-out in a randomized complete block design, replicated three times. Data was collected on plant height, number of leaves, leaf area, leaf area index, number of cobs per plot, cob length, 100 seeds weight and grain yield. The results obtained showed that varieties differ significantly, in which, DMR significantly produced the highest yield, and followed by QPM and TZEE which are similar in yield performance. Intra-row spacing of 25 cm was observed to be significantly (p=0.05) higher than 20 cm and 30 cm spacing in all the characters studied. Based on the results of the study, it may be concluded that DMR variety and 25 cm intra-row spacing proved more promising in the study area. [4]


Response of Maize Varieties (Zea mays) to Biochar Amended Soil in Lafia, Nigeria

The experiments were conducted during 2010 and 2011 at the research and teaching farm of the college of agriculture, Lafia, Nasarawa state, Nigeria. To determine the effect of biochar-amended soil on the performance of maize varieties (Zea mays). The study was carried out in screen house and field. The first phase of the experiment: treatment consist of three rates of biochar: 0, 100, 200g/pot and maize varieties (Oba 98 and Sammaize 18). The second phase of the experiment was carried out in the field; the treatment consisted of three levels of biochar: 0, 5, 10t/ha and two varieties of maize (oba 98 and sammaize 18) factorialy combined to form six treatments. The experimental design used was Randomized Complete Block Design (RCBD). The result showed that 10t/ha Biochar had a significant (P=0.05) effect on the percentage germination, seedling height, seedling stem girth, number of roots, length of roots and seedling vigour index. Application of 10t/ha of biochar produced the highest grain weight of 5.05 t/ha and 5.54 t/ha in both years; which is at par with application of 5t/ha of biochar, but higher than control (3.5t/ha and 3.32t/ha) in both years. However, maize varieties did not showed any significant effect in both cropping season, but oba 98 proofs to be superior to the other variety in most of the character assessed. Interaction between biochar and maize varieties did not produced any significant effect [5]




Reference

[1] Dalmastri, C., Chiarini, L., Cantale, C., Bevivino, A. and Tabacchioni, S., 1999. Soil type and maize cultivar affect the genetic diversity of maize root–associated Burkholderia cepacia populations. Microbial Ecology, 38(3), pp.273-284.

[2] Crossa, J., Gauch Jr, H.G. and Zobel, R.W., 1990. Additive main effects and multiplicative interaction analysis of two international maize cultivar trials. Crop science, 30(3), pp.493-500.

[3] Chiarini, L., Bevivino, A., Dalmastri, C., Nacamulli, C. and Tabacchioni, S., 1998. Influence of plant development, cultivar and soil type on microbial colonization of maize roots. Applied Soil Ecology, 8(1-3), pp.11-18.

[4] Sabo, M.U., Wailare, M.A., Aliyu, M. and Sanusi, J., 2016. Effect of variety and spacing on growth and yield of maize (Zea mays L.) in Bauchi State, Nigeria. International Journal of Plant & Soil Science, pp.1-6.

[5] Ndor, E., Dauda, S.N. and Azagaku, E.D., 2015. Response of maize varieties (Zea mays) to biochar amended soil in Lafia, Nigeria. Journal of Experimental Agriculture International, pp.525-531.

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