Joênes Mucci Peluzio

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.

Comportamento de cultivares de soja, em diferentes épocas de semeaduras, visando a produção de biocombustivel

The sowing season is defined by a set of environmental factors that react with each other and interact with the plant, thus affecting variations in production and other agronomic traits. This work was carried out to evaluate the behavior of 21 cultivars of commercial soybean, during different times, looking forward to the production of biofuel. Were conducted five essays in the 2008/09 agricultural year, being two of them in Palmas-TO and three in Gurupi-TO. The sowing in Gurupi-TO was in 03/12/08, 18/12/2008 and 05/01/2009,and in Palmas in 30/11/2009 and 16/12/2009. The experimental design was a randomized blocks with 21 treatments and three repetitions. The treatments were constituted on the cultivars P98Y70, M-SOY 8766RR, M-SOY 9144RR, BR/Emgopa 314, P98R91, P98Y51, M-SOY 9988RR, P99R01, M-SOY 8867RR, M-SOY 9056RR, M-SOY 8527RR, M-SOY 8360RR, FT ESPERANCA, FTS 4188, CM 07, CM 017, CM 136, CM 149, CM 102, NIDERA A 7002 and M-SOY 9350. The following characteristics, were evoluated production of grains, oil content of the grain and oil yield. Significant differences were detected among cultivars, sowing season and cultivate x sowing season for all characteristics. The first planting time in Palmas (30/11) and Gurupi (03/12), were the most favorable to the development of cultivars. There was positive and significant association between oil yield and production of grains (R = 0.97). Higher temperatures and rainfall precipitation averages, during the phase of stuffing of grains, favored the oil accumulation in the grains. NIDERA A 7002, MSOY 9144RR, BR/Emgopa 314, P98Y51 and FTS 4188 were the best cultivars for oil content of the grain and oil yield.

Flutuação populacional de Pragas e seus inimigos naturais em Soja no projeto Rio Formoso - Formoso do Araguaia - TO, Brasil

This experiment was carried out at the Experimental Station of the Universidade do Tocantins in Formoso do Araguaia-TO, to study the population dinamics of soybean pests and their natural enemies. The weekly surveys were made using the plant-shaking method, in three cultivars of the medium cycle, during the period from July to October 1995, installed in a randomized block design, with four blocks. The majority of species collected ocurred in low numbers, and from the stink bug complex, only ocurred the species Piezodorus guildinii, (Heteroptera, Pentatomidae), with population peaks in the stage of grain filling. The defoliator catterpilars were found Anticarsia gemmatalis (Lepidoptera, Noctuidae), Hedylepta indicata (Lepidoptera, Pyralidae) and Chrysodeixis includens (Lepidoptera, Noctuidae), in decrease order of the abundance. Cerotoma sp., was the most abundant defoliator beetle found in the extension of the culture development cycle, with populations peaks closely the reprodutive stage. Among the natural enemies collected, Cicloneda sanguinea (Coleoptera, Coccinellidae); Geocoris sp. (Heteroptera, Lygaeidae) and Lebia sp. (Coleoptera, Carabidae) were the most abundants.

Nitrogênio em cobertura e estresse salino na qualidade fisiológica de sementes de meio-irmãos de milho, no Tocantins

Genotype and plant nutrition influence the production of physiological qualities in maize seeds, and the use of vigor tests under stress conditions allows for the identification of superior genotypes. The aim of this study was to verify the effect of covered nitrogen fertilization on the physiological quality of seeds from 12 half-sib maize families, with or without saline stress. Seeds were used from plants that were growing with two levels of top dressed nitrogen fertilization (0; 150 kg ha-1), in the 2012/13 growing season, at Gurupi, in the state of Tocantins. In the laboratory, two experiments were conducted: one without and another with saline stress (KCl – 16.73 g L-1). The experimental design was fully randomized, with a factorial arrangement (12x2x2) and four replications. The following tests were carried out: germination, length and dry weight of seedling. The effects of topdressed nitrogen were more visible in the conditions of saline stress on the seeds. In this situation, when seeds were produced without topdressed N the half-sib L8 showed higher: total length (15.3 cm), root length (9.54 cm) and aerial part length (5.75 cm), and dry weight of roots (26 mg seedling-1) and aerial part (28 mg seedling-1). The half-sib L9 had shown significant (positive) influence from the use of topdressed N when germination was carried out with saline stress. The concentration of KCl (16.73 g L-1) promoted significant decreases in the germination and vigor of the seeds, however, it allowed for the visualization of the effect of covered nitrogen fertilization. In conditions without topdressed N and saline stress at germination, the half-sibs P6 and L8 showed superiority.

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.