Abstract-

The objective of this work is to study the agronomic performance and genetic divergence in corn in the Cerrado-Amazon ecotone. The trials were conducted in the 2017/18 harvest at a property in the state of Pará. The experimental design was a randomized block with nine treatments and three replications, where the treatments are represented by nine cultivars of corn. The characteristics to evaluate agronomic performance and genetic divergence were: ear height (cm), plant height (cm), ear length (cm), ear diameter (mm), number of rows, number of grains per row and grain yield (kg ha−1). The cultivars were separated into a multivariate model in five groups using the Tocher optimization method. The cultivar AG 1051 showed the best agronomic performance. The results of genetic divergence were according to the generalized distance of Mahalanobis (D2), with the commences AG 8088 x CATIVERDE and AG 1051 x AL BANDEIRANTE, the most promising for future crosses.

Lithium is a chemical element, symbol Li, this element can be new strand of world agriculture. The agronomic Biofortification of soybeans can be beneficial to the entire production chain that involves, because this practice can lead to an increase in the average productivity of culture in soils naturally poor, reversing the current picture of stagnation in productivity the last 10 years. Additionally, the producer of grains will benefit from adding value to the final product and the consumer will benefit by purchasing a product with higher Li content. Treatments were arranged in a completely randomized design (DIC), with three repetitions. The twelve treatments were arranged in a factorial scheme 2 x 6. The first factor is regarding the two lithium sources (Li2SO4 e LiOH) and the second factor refers to five doses of lithium in their fonts used (0; 20; 40; 60; 80 and 100 mg dm −3 ). Soybeans have had a positive effect on germination with the use of doses and sources of lithium compared with the witness, but the germination percentage was less than 65% well below the expected, which shows that the lithium in large doses can be harmful for the germination of seeds.

The genetic variability allows selection of superior genotypes and makes it possible to increase the frequency of favorable genes through appropriate selection methods that provide genetic mater ial's retrieval adapted to environmental conditions prevalent in the different producing regions. Thus, this work was performed with the goal of studying the genetic divergence of populations of open pollination of corn in the South of Pará State. To this end, two tests were made of corn genotypes competition, being the first to top P (100 kg ha-1 of P) and the second for low P (50 kg ha-1 of P). The study of genetic divergence was performed using together with the data from the two trials. The experimental design used in each trial was randomized with ten treatments (open-pollinated maize genotypes) and three repetitions. The characteristics studied were: plant Height, Ear height, the diameter of the Spike, Spike length, grain in the row numbers and productivity. In the study of genetic divergence was employed the Tocher optimization method. The importance of characters, was the Foundation of Singh. Three medium-sized groups were formed, which were in the same genotypes 08 groups, and two other genotypes (AG 1051 and AL BANDEIRANTE.), were in different groups. The characters presented more collaboration for the genetic divergence were productivity, plant height and ear height.

Aims: The research was carried out to evaluate the agronomic performance of corn cultivars in contrasting phosphorus environments in the state of Pará, Brazil. Study Design: The experimental design was randomized blocks with ten treatments and three replications. The treatments were composed of ten cultivars: AG 1051, AG 8088PRO2, BR 206, BRS 3046, PR 27D28, 2B655PW, AL BANDEIRANTE, ANHEMBI, CATIVERDE 02 and ORION Place and Duration of Study: In the 2017/18 crop, two competition trials of corn cultivars were carried out at Sítio Vitória, municipality of Santa Maria das Barreiras, state Pará, Brazil. Methodology: Two competition trials of corn (Zea mays L.) cultivars were carried out under contracting conditions of phosphorus: high P (100 kg ha-1 of P2O5) and low P (50 kg ha-1 of P2O5), using simple superphosphate (18% P2O5) as the source. The agronomic efficiency of phosphorus use was obtained by the difference between grain yield in both levels, divided by the difference between doses. The variables evaluated were: ear height, plant height, ear diameter, number of rows per year, number of grains per rows and grain yield. Results: The mean grain yield of the cultivars ranged from 5,446 kg ha-1 (low P) to 11,486 kg ha-1 (high P), and the means of all cultivars were higher in high P. The means agronomic efficiency ranged from 25.1 kg kg-1 (AL BANDEIRANTE) to 96.6 kg kg-1 (AG 1051). Conclusion: The highest phosphorus dose (100 kg ha-1 of P2O5) resulted in higher values in the variables studied. The cultivars that stood out the most, under high and low phosphorus, were AG 8088PRO2, AG 1051 and BRS 3046, the last two being agronomically efficient.