The simulation results of popcorn maize seeding in the laboratory at a theoretical spacing of 20.993 cm with vacuum plates with 18, 22, 27, 31, 33, 36, and 44 holes at working speeds of 4, 6, 8, and ...10 km/h are presented. At a working speed of 6 km/h, the vacuum plate n = 18 with a peripheral speed of 0.223 m/s achieved an average seeding spacing of 21.518 cm, with a reduction of 1 650/ha plants. At this peripheral speed, the plate achieved a QFI of 97.19 with Prec. index (CV.sub.m) of 13.108. The vacuum plate n = 44 at the lowest acceptable speed of the seeding machine with a peripheral speed of 0.091 m/s achieved an average spacing of 20.816 cm with a QFI index of 98.63 while Prec. index (CV.sub.m) was 8.397. By increasing the working speed of 10 km/h, the listed vacuum plate achieved an average spacing of 20.935 cm, and an increase in seeding was recorded for 187 plants/ha where the achieved value of QFI index was 97.31 while the value of Prec. index (CV.sub.m) was 14.041. The choice of vacuum plate, as well as the speed of work had a statistically significant effect on the set of plants and the seeding spacing. The obtained results of vacuum plates n = 22, 27, 31, 33 and n = 36 are within the limit values of vacuum plates n = 18 and n = 44.
Heterosis, also known as hybrid vigor, is the basis of modern maize production. The effect of heterosis on maize phenotypes has been studied for decades, but its effect on the maize-associated ...microbiome is much less characterized. To determine the effect of heterosis on the maize microbiome, we sequenced and compared the bacterial communities of inbred, open pollinated, and hybrid maize. Samples covered three tissue types (stalk, root, and rhizosphere) in two field experiments and one greenhouse experiment. Bacterial diversity was more affected by location and tissue type than genetic background for both within-sample (alpha) and between-sample (beta) diversity. PERMANOVA analysis similarly showed that tissue type and location had significant effects on the overall community structure, whereas the intraspecies genetic background and individual plant genotypes did not. Differential abundance analysis identified only 25 bacterial ASVs that significantly differed between inbred and hybrid maize. Predicted metagenome content was inferred with Picrust2, and it also showed a significantly larger effect of tissue and location than genetic background. Overall, these results indicate that the bacterial communities of inbred and hybrid maize are often more similar than they are different and that non-genetic effects are generally the largest influences on the maize microbiome.
Cultivated maize (Zea mays L.) is the oldest and one of the most important crop species in the world. Changing climatic conditions in recent years, warm weather, expansion of acreage and ...intensification of maize cultivation have resulted in an increase in the threat posed by diseases caused by, among others, Fusarium fungi. Breeding success in all plant species is determined by access to starting materials with possible high genetic diversity also in terms of disease resistance. Identification of parental combinations that produce offspring that are high-yielding and resistant to Fusarium, among other diseases, is one of the costliest steps in breeding programs. We used maize lines which, as a result of five-year field observations, were divided into resistant and susceptible to F. verticillioides. It is known that resistance to fusarium is a trait strongly dependent on environmental conditions. Due to the fact that the years of observation of the degree of infestation were hot and dry, the resistance of some lines could result from favorable environmental conditions. In view of the above, the aim of this study was to analyze the genetic basis of the resistance of these lines and to correlate molecular analyses with field observations. Comprehensive field and molecular analyses will allow the selection of reference lines that will be resistant to fusarium in the field and, at the same time, will have pyramidized resistance genes. Such lines can be used for crossbreeding to obtain fusarium-resistant varieties. In addition, an attempt was made to develop Multiplex PCR conditions for faster identification of the analyzed markers. As a result of the analyses, it was found that the resistance of the studied maize lines was correlated with the number of molecular markers identified in them. Both field and laboratory analyses have shown that the best line that can be used for crossbreeding as a source of fusarium resistance genes is the line number 25. It has a resistance level of 8-9 on the nine-point COBORU scale. In this line, as a result of molecular analyses, 10 out of 12 markers were identified (SSR 85, Bngl 1063, Bngl 1740, Umc 2082, Bngl 1621, Umc 2059, Umc 2013, SSR 93, SSR 105, STS 03) related to fusarium resistance genes, which may be the reason for such a high resistance to this pathogen. Similarly, 9 markers were identified for line number 35 (SSR 85, Bngl 1063, Bngl 1740, Umc 2082, Bngl 1621, Umc 2059, Umc 2013, SSR 93, STS 03). This line, however, was characterized by a slightly lower resistance at the level of 7-8. Line 254 turned out to be the least resistant, as the resistance was at the level of 4-5, and the number of identified molecular markers was 5. Lines numbered 25 and 35 can be successfully used as a source of fusarium resistance genes.
Originating in Mesoamerica 9,000 years ago, maize-or, as we know it, corn-now grows in 160 countries. In the New World, indigenous peoples referred to corn as "Our Mother," "Our Life," and "She Who ...Sustains Us." Today, the United States is the world's leading producer of corn, and you can find more than 3,500 items in grocery stores that contain corn in one way or another-from puddings to soups, margarine to mayonnaise. In Corn: A Global History, Michael Owen Jones explores the origins of this humble but irreplaceable crop. The book traces corn back to its Mesoamerican roots, following along as it was transported to the Old World by Christopher Columbus, and then subsequently distributed throughout Europe, Africa, and Asia. Jones takes readers into the deliciously disparate culinary uses of corn, including the Chilean savory pie pastel de choclo, Japanese corn soup, Mexican tamales, a Filipino shaved ice snack, and the South African cracked hominy dish umngqusho, favored by Nelson Mandela. Covering corn's controversies, celebrations, and iconic cultural status, Jones interweaves food, folklore, history, and popular culture to reveal the vibrant story of a world staple.
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