scholarly journals Karyotypic diversity among eight Zea mays L. varieties

2020 ◽  
Vol 49 (4) ◽  
pp. 1157-1161
Author(s):  
Chandan Kumar Dash ◽  
Kazi Nahida Begum ◽  
Syeda Sharmeen Sultana

Staining property of interphase nuclei and prophase chromosomes, diploid chromosome number, total chromosome length (TCL), symmetric and asymmetric indices of karyotype were studied in eight maize varieties released by BARI. 2n = 20 chromosomes were found in Barnali, Mohor, Khoi Vhutta, BS-1, B-5 and BM-7 whereas 2n = 22 chromosomes in China and 2n = 24 chromosomes in B-73 were observed. TCL was highest in Mohor (190.49 ± 5.61 μm) and lowest in B-73 (69.30 ± 2.51 μm). These varieties showed significant variation in cytogenetical parameters. Results obtained are expected to supplement genetic identification of maize varieties in variety conservation efforts.

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 182
Author(s):  
Jan Bocianowski ◽  
Kamila Nowosad ◽  
Barbara Wróbel ◽  
Piotr Szulc

Microsatellite or simple sequence repeat (SSR) markers have wide applicability for genetic analysis in crop plant improvement strategies. Marker-assisted selection is an important tool for plant breeders to increase the efficiency of a breeding process, especially for multigenic traits, highly influenced by the environment. In this paper, the relationships between SSR markers and 26 quantitative traits of hybrid maize varieties (Zea mays L.) were analyzed. Association analyses were performed based on 30 SSR primers in a set of thirteen hybrid maize varieties. A total of 112 SSR markers were detected in these genotypes. The number of alleles per locus ranged from 1 to 17, with the average number of alleles per locus equal to 3.7. The number of molecular markers associated with observed traits ranged from 1 (for the number of kernels in row, ears weight and fresh weight of one plant) to 14 (for damage of maize caused by P. nubilalis) in 2016 as well as from 1 (for soil plant analysis development—SPAD, the number of grains in ear and fresh weight of one plant) to 12 (for carotenoids content) in 2017. The sum of statistically significant associations between SSR markers and at least one trait was equal to one hundred sixty in 2016 as well as one hundred twenty-five in 2017. Marker trait associations (MTAs) were found on the basis of regression analysis. The proportion of the total phenotypic variances of individual traits explained by the marker ranged from 24.4% to 77.7% in the first year of study and from 24.3% to 77.9% in 2017. Twenty-two SSR markers performed a significant effect on at least one tested trait in both years of experiment. The three markers (phi021/4, phi036/3, and phi061/2) can be a good tool in marker-assisted selection because they allow simultaneous selection for multiple traits in both years of study, such as the number of kernels in row and the number of grains in ear (phi021/4), the number of plant after germination, the number of plants before harvest, and the number of ears (phi036/3), as well as moisture of grain and length of ears (phi061/2).


2019 ◽  
Author(s):  
Timothy Omara

The moisture content and total aflatoxin (AF) content of 27 samples of freshly harvested white maize (Zea mays L.) from Mubende (n = 3), Ibanda (n = 3), Jinja (n = 3), Mayuge (n = 3) , Buikwe (n = 3), Hoima (n = 3), Mpigi (n = 3), Masindi (n = 3) and Bugiri (n = 3) districts of Uganda representing the agroecological zones: Lake Victoria crescent, Western Highlands, South East and Lake Albert Crescent were determined in the second season harvest of January 2019 to March 2019. Moisture content ranged from 12.9 to 18.8% (mean moisture content varied from 13.9±0.35-17.2±1.55%) with the highest moisture recorded in maize from Ibanda. The highest mean AF contamination of 11.0±3.01 μg/kg was recorded in maize from Hoima while the lowest AF content of 3.8±1.30 μg/kg was recorded in maize from Mpigi. Despite the fact that all the samples had detectable aflatoxins, none of the maize samples had aflatoxin greater than WHO regulatory limit of 20 μg/kg. White maize in Uganda are precontaminated by aflatoxins prior to harvest. Whereas the spectre of aflatoxigenic contamination of foods remains a ticklish challenge to address, strategic adaptation and deployment of appropriate interventions can help secure a safe harvest. Farmers should plant maize varieties with established maturity periods to ensure timely harvesting. Further research should assess the presence of other mycotoxins as zearalenone, sterigmatocystin, ochratoxin A, citrinin, vomitoxin and diacetoxyscirpenol that may co-occur with aflatoxins in freshly harvested maize.


1978 ◽  
Vol 20 (1) ◽  
pp. 97-100 ◽  
Author(s):  
David F. Weber

When a monosomic plant of a diploid species undergoes meiosis, two haploid and two nullisomic cells are produced. Zea mays L. microspore quartet cells nullisomic for chromosome number 1, 2, 4, 6, 7, 8, 9, or 10 produced by monosomics were analyzed. Cells nullisomic for chromosome 6, as expected, do not contain a nucleolus because chromosome 6 bears the nucleolar organizing region. Cells nullisomic for chromosome 2 contain nucleoli; therefore, the 5S rRNA template on chromosome 2 is not necessary for nucleolar formation. Cells nullisomic for chromosomes 1, 4, 7, 8, 9, or 10 also contain nucleoli; thus, no factors located on these chromosomes are necessary for nulceolar formation at the quartet stage.


2020 ◽  
Author(s):  
Marlina

The study, entitled the effect of the administration of Palm Oil Long Palm (AJKS) to the growth and production of two corn varieties inpeatlands, was carried out from October 2017 to March 2018 in trench 3 in Tembilahan Hulu Village, Tembilahan Hulu District, Indragiri Hilir Regency,soil analysis and AJKS conducted at the Bogor Institute of Agriculture Laboratory. The purpose of this study was to determine the effect of AJKSadministration on the growth and production of two maize varieties (Zea mays L) on peatlands, and to determine whether there was an interactionbetween the dosage of AJKS and corn varieties on peat soil ameliorating AJKS. The design used was factorial Randomized Block Design (RBD) using 2factors with three replications. The first factor is the dose of AJKS administration consisting of 4 levels, namely: A0: 0 kg / ha, A1: 500 kg / ha, A2: 1000kg / ha, A3: 1500 kg / ha. The second factor is corn varieties with 2 levels, namely: V1: Pioneer Varieties and V2: Varieties N35. Of the two factors aboveobtained 8 treatment combinations. Based on the results of research that has been done, that there is no real interaction and influence between thetreatment of giving AJKS with varieties to all observed parameters. Giving AJKS 1500 kg / ha gives the highest yields on all parameters observed exceptfor the number of cobs, Pioneer variety is the variety that responds most to AJKS administration.


Caryologia ◽  
2021 ◽  
Vol 74 (1) ◽  
pp. 53-61
Author(s):  
Maryam Hasaninejad ◽  
Ziba Jamzad ◽  
Saeid Afsharzadeh ◽  
HojJatollah Saeidi

In this survey, the chromosome counts of eight Nepeta L. species were investigated and the karyotypic diversity among these species was studied. The examined species belong to N. cephalotes Boiss. species group, namely N. eremokosmos Rech.f., N. gloeocephala Rech. f., cephalotes Boiss., N. pungens (Bunge) Benth., N. ispahanica Boiss., N. mahanensis Jamzad & Simonds, N. hormozganica Jamzad and N. denudata Benth. collected from different habitats in Iran. The ploidy levels, karyotype formula, chromosome length range, total karyotype length, several karyotype asymmetries values and Stebbins classification were determined in this study. Results showed the same chromosome number, 2n = 2x= 18 for all studied species. The basic chromosome number for the above mentioned species are x = 9. Also, the smallest chromosome length is 1.02 μm in N. mahanensis. The largest chromosome length is 2.3 μm in N. ispahanica. The chromosomes of species were metacentric or submetacentric. According to the Stebbins classification, these species were located into three classes 1A, 2A and 3A. The chromosome numbers for six of studied species are reported here for the first time.


2013 ◽  
Vol 1 ◽  
pp. 23-27
Author(s):  
MN Paudel

Improved open pollinated maize (Zea mays L.) varieties exhibit different emergence reaction as a result of either inferior seed quality or affected by agronomic practices of maize planting. To address problem of low emergence percentage of maize varieties, an experiment was laid out in factorial design under two types of soil (red clay and sandy loam), three level of depth of sowing (7, 14 and 21 cm) for Rampur Composite, Manakamana-1 and Arun-2 maize varieties in Rampur, Chitwan for representing main season (May-August). The result of the experiment revealed that emergence count was highly significant for soil types and depth of sowing among the maize varieties tested. Manakamana-1 expressed lowest percentage (20 and 29%) followed by Arun-2 (22 and 33%) and Rampur Composite (24 and 39%) of emergence under red clay and sandy loam soils, respectively. Likewise, emergence count at 10 days after sowing was recorded highly significant for depth of showing indicating that irrespective of varieties higher the planting depth lower the emergence count.. There was a positive relation between depth of planting and length of mesocotyle resulting loss of seed vigor which furnished low emergence of the maize varieties. It is suggested that depth of sowing affect emergence percentage which consequently have effects on plant population maintenance. Hence, it was concluded that sowing below 7cm deep is not feasible for the tested varieties under red clay and sandy loam soils. DOI: http://dx.doi.org/10.3126/ajn.v1i0.7539 Agronomy Journal of Nepal (Agron JN) Vol. 1: 2010 pp.23-27


2021 ◽  
Vol 11 (20) ◽  
pp. 9513
Author(s):  
Waldemar Zielewicz ◽  
Barbara Wróbel ◽  
Piotr Szulc ◽  
Henryk Bujak ◽  
Barbara Stachowiak

Predicting yield at an early growth stage allows one to optimize the amount and timing of nitrogen fertilization to maximize crop yield. The aim of the study was to determine how different nitrogen doses would affect the nutrition of two maize varieties (Zea mays L.) with this element and their yields, and to demonstrate the potential of using the SPAD index as an early-stage predictor of dry matter yield (DMY) of maize biomass. The field experiment, with different pre- and post-sown N fertilizer doses, was conducted for two years in Poland. The two-factor experiment was set up in a randomized block design with three field replicates. There were four mineral fertilization variants: (I) 120 kg N·ha−1 without P and K fertilization, (II) 120 kg N·ha−1 + PK, (III) 160 kg N·ha−1 + PK, and (IV) 200 kg N·ha−1 + PK. The second-order factor was two stay-green maize varieties: Delitop (FAO 240) and Magitop (FAO 270). The mean values of the SPAD index of maize depended on the nitrogen dose. When the dose was increased from 120 kg·ha−1 to 200 kg·ha−1 with constant P and K fertilization, the value of the leaf greenness index increased significantly. The plants of both maize varieties fertilized with nitrogen at a dose of 120 kg N·ha−1 without P and K were characterized by the lowest values of the SPAD index, regardless of the year of the experiment. When the nitrogen dose was supplemented with P and K, the plants’ nutrition with nitrogen improved significantly. The values of the SPAD index in the maize plants of the variety Magitop were significantly greater than in the plants of the variety Delitop. The coefficients of correlation calculated for both maize varieties were highly significant at all measurement dates. Therefore, it is possible to conclude that the SPAD leaf greenness index can be used as an important, reliable, and non-invasive indicator for maize yield prediction. Nutrition of maize plants with nitrogen proved to be the main determinant of variability of the biomass yield. For this reason, it was the basis for the verification of individual mineral fertilization variants. The lack of phosphorus and potassium in the dose of mineral fertilizer limited the yield regardless of the variety, as compared to the variant that was optimally balanced with the nitrogen dose.


Author(s):  
Yao Kouakou Francois Konan ◽  
Ayolié Koutoua ◽  
Soro Dogniméton ◽  
Koné Sié Kissomanbien ◽  
Kouadio Akéssé Blaise ◽  
...  

Climate variability has been and continues to be the main source of food fluctuations. This variability threatens the production of cash crops such as maize (Zea mays L). Maize is a cereal and has become one of the main agricultural crops in Côte d’Ivoire. The objective of this study is to determine the agro-morphological characteristics of three (03) varieties of maize (EV 8728, GMRP / 18 and MDJ) which have undergone irradiation with gamma radiation (0, 100, 200 and 300 grays) to induce mutations. The agro-morphological evaluation was carried out in a completely randomized block device. morphological characters selected from the descriptors of maize were used in this study. The descriptive analysis revealed a significant diversity between the treatments. The comparison between all the agro-morphological characters and the different treatments showed that the treatments EV8728_0 and EV8728_100 Gy had the best characteristics of ears and grains and the treatment MDJ_200 had the best vegetative characteristics.


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