Eliane Aparecida Rotili

Divergência genética em genótipos de milho, no estado do Tocantins

Este trabalho objetivou avaliar a divergencia genetica em genotipos de milho no sul do estado do Tocantins. O experimento foi realizado no municipio de Gurupi - TO. As populacoes foram obtidas de 70 hibridos top cross pelo cruzamento de linhagens S6 com um testador, utilizando-se 11 cultivares como testemunha, totalizando 81 genotipos. O delineamento experimental utilizado foi blocos casualizados com duas repeticoes. As caracteristicas avaliadas foram: altura da planta, altura da espiga, prolificidade, comprimento de espiga, diâmetro de espiga, peso de 100 graos, peso hectolitrico e produtividade de graos. A divergencia genetica foi avaliada por procedimentos multivariados como a distância generalizada de Mahalanobis e pelos metodos de agrupamento de otimizacao de Tocher e vizinho mais proximo. Encontrou-se divergencia genetica entre as populacoes estudadas promovendo a formacao de grupos diferentes entre o metodo de Tocher e do vizinho mais proximo. As caracteristicas produtividade e comprimento de espiga foram as que mais e menos, respectivamente, contribuiram na diversidade genetica dos genotipos.This study aimed to evaluate the genetic diversity in maize genotypes in the southern of Tocantins. The experiment was conducted at Gurupi - TO, Brazil. The populations were obtained from 70 top cross, with crossing the lineages S 6 with a tester, and using 11 cultivars as a witness, totaling 81 genotypes. The experimental design was randomized blocks with two replications. The characteristics assessed were: plant height, ear height, prolificacy, ear length, ear diameter, weight of 100 grains, hectoliter weight and grain yield. Genetic divergence was assessed by multivariate procedures: Mahalanobis distance, clustering methods of Tocher and nearest neighbor. It was found genetic divergence among populations and the formation of non congruent groups between the method of Tocher and nearest neighbor. The yield grain was the major contributor to the genetic diversity and the ear length was the least.

Eficiência do uso e resposta à aplicação de fósforo de cultivares de arroz em solos de terras altas

This researchs objective was to study the efficiency in the usage of phosphorus by rice cultivars in highland soils in the South of Tocantins State. The experiments evaluated six commercial cultivars of rice (BRS-Bonanca BRS-Caiapo, BRS-Sertaneja, BRSMG-Curinga, BRSMG-Conai and BRS-Primavera), grown in areas with high and low phosphorus application: 20 and 120 kg ha-1 of P2O5. The experiments were carried out in a completely randomized blocks design, with four replicates. Based on grain yield, cultivars were classified in respect to the efficiency and response to phosphorus fertilization. The cultivar BRS-Bonanca presented the highest phosphorus use efficiency and was the most responsive.

Eficiência no uso de fósforo de variedades de arroz cultivadas em solos de várzea irrigada

Efficiency in the use of phosphorus by rice varieties grown in lowland soils Rice stands out as one of the most important crops in the world, because of its easy adaptability to distinct edaphoclimatic conditions. Rice is cultivated and consumed worldwide and stands out by the large production and cultivation area, playing strategic economic and social roles. In Brasil, the largest rice productions are obtained in lowland ecosystems. This work aimed to study the efficiency in phosphorus use by rice varieties in lowland areas in the southwest of Tocantins State. The treatments involved eight rice commercial varieties (BRS-Jacana, Best2000, BRS-Guara, BRS-Alvorada, BRA-01381, AN-Cambara, BRS 7-TAIM and EPAGRI-109), which were farmed in two distinct environments. In order to simulate environments with low and high phosphorus levels, P 2 O 5 was used at the levels of 20 and 120 kg ha -1 respectively. The experiments were carried out in a randomized complete blocks design, with four replications. Grain yield was used to classify the varieties regarding the efficiency in use and response to phosphorus application. Was shown that only the variety BRS-Alvorada was efficient in using phosphorus and responsive to its application.

Nitrogênio em cobertura no estudo de dois grupos de genótipos de milho em Gurupi-TO

The nitrogen is the most absorbed nutrient by maize, and its supply after seeding is common. However, its available for the plants is associate with soil and weather conditions and with kind of genetic material that is used, due the yield potential and the genetic base. This paper had the aim to evaluate two maize genotype groups at levels of nitrogen in covered, in Gurupi, Tocantins State, Brazil, season 2012/13. The experiments with 30 genotypes had two levels of covered nitrogen (0 and 150 kg ha -1 ) and they were seeding in two dates. The experiments with 12 genotypes had three levels of covered nitrogen (20; 80; 140 kg ha -1 ) and they were seeding in four dates. The experimental design was randomized blocks with three replications. For the analysis of variance, the experiments were clustering in accordance with the seeding date for the evaluation the effects of genotypes and covered nitrogen. In the two genotypes groups were not observed the significant interaction between the sources of variation. The leaf chlorophyll, between stages VT-R1, was the most sensible with the change of covered nitrogen level.