Adriano dos Santos

Adaptabilidade e estabilidade de genótipos de feijão caupi ereto via REML/BLUP e GGE Biplot

The objective of this study was to investigate the association between the GGE Biplot and REML/BLUP methods and select cowpea genotypes that meet simultaneously high grain yield, adaptability and stability in the Mato Grosso do Sul environments. The experiments were carried out from February to July 2010, 2011 and 2012 in the municipalities of Dourados, Aquidauana and Chapadao do Sul. The experiments in Chapadao do Sul were conducted only in the years of 2010 and 2011, totaling eight environments. After detecting significant genotypes × environments (GE) interaction, the adaptability and the phenotypic stability of cowpea genotypes were analyzed by GGE Biplot and REML/BLUP methods. These methods were concordant in the identification of the best cowpea genotypes for the State of Mato Grosso do Sul. The BRS- Tumucumaque and BRS-Guariba cultivars are the closest to the ideal in terms of high grain yield and phenotypic stability, being suitable for cultivation in the State.

Reaction of popcorn germplasm to polysora rust under field conditions and natural inoculation

Polysora rust, caused by Puccinia polysora, is one of the most economically important foliar diseases of maize, and the use of resistant genotypes is the most efficient and economically appropriate measure to control this disease. In popcorn, damage caused by this disease is equivalent to that found in common maize. However, studies on the identification of sources of resistance in popcorn are much more scarce. This study aimed to evaluate the reaction of popcorn genotypes regarding polysora rust resistance. For this purpose, 37 temperate and tropical popcorn genotypes were evaluated in randomized block experiments with four replicates in two crop seasons, in Campos dos Goytacazes, RJ, Brazil. Disease intensity was estimated by quantifying incidence and severity using a diagrammatic scale, based on the plant and the leaf immediately below the first ear. We found that incidence can efficiently replace severity at low epidemic levels, facilitating field diagnostics. Also, we observed genetic variability for traits related to polysora rust resistance. The landraces PARA 172, ARZM 05083 and the line L80 are recommended to integrate breeding populations for Puccinia polysora resistance as they may carry favorable alleles for disease control.

Comparison of testers in the selection of S3 families obtained from the UENF-14 variety of popcorn

O uso de topcross vem se mostrando uma opcao interessante para a cultura do milho; entretanto, para o milho-pipoca, ha pouca informacao sobre a escolha do testador adequado. Nesse contexto, este estudo teve como objetivo analisar quatro testadores, sendo duas variedades de polinizacao aberta (BRS Angela e UENF-14), um hibrido topcross (IAC 125) e uma linhagem (P2), visando avaliar a capacidade combinatoria de 50 familias S3 de milho-pipoca, obtidas a partir da variedade UENF-14. Avaliou-se o rendimento de graos (RG) e capacidade de expansao (CE). Obtiveram-se as estimativas das capacidades geral e especifica de combinacao, bem como efetuou-se a discriminacao de cada testador por meio de indice de diferenciacao. Os testadores BRS Angela (para RG) e IAC 125 (para CE) foram os que se destacaram, quando combinados com as melhores familias S3derivadas da variedade UENF-14, para producao de hibridos de milho-pipoca para as Regioes Norte e Noroeste Fluminense.

Adaptability and phenotypic stability of sugarcane clones

The objective of this work was to select superior sugarcane (Saccharum officinarum) clones with good stability and adaptability, considering the genotype x environment interaction in two productive cycles. Twenty-five early clones plus five control clones were evaluated during two cuts (ratoon cane and plant cane) in 24 environments. A randomized complete block design was used, with three replicates. Tons of stems per hectare and tons of pol per hectare were evaluated. To verify adaptability and stability, the bisegmented regression and the multivariate (AMMI and GGE biplot) methods were used. According to the three methods, which are complementary regarding the desired information, the most promising clones in terms of stability and general adaptability are G5, G12, and G13; the last two are closest to the ideal genotype. The G13 clone is highly productive in favorable and unfavorable environments, presenting the highest averages for ton of stems and pol per hectare. The G3, G4, G10, G15, G17, G18, G22, G23, G25, G26, and G30 clones are not recommended for the 24 evaluated environments.

TOLERÂNCIA AO DÉFICIT HÍDRICO EM POPULAÇÕES F2 DE FEIJÃO-CAUPI

Water deficit affects plant development and the overcoming of its effects depends on the genotype, duration of stress, severity of damage and development stage of the plant at water stress. Cowpea is considered tolerant to water deficit, however, studies have shown that its yield can be reduced under this condition. Thus, the objective of this work was to evaluate the effect of water deficit on F2 populations of cowpea and select tolerant genotypes. Thirty F2 populations of cowpea and their parents (BRS-Paraguaçu, Pingo-de-Ouro-1-2, BRS-Xiquexique, CNCx-698-128G, Santo-Inácio and MNC99-510F-16-1) were evaluated in two experiments, one under induced water deficit and other under full irrigation, in the experimental field of the Embrapa Mid-North, in Teresina, State of Piauí, Brazil. A triple lattice incomplete block experiment design was used, with three replications. The experimental plots consisted of six 2-m rows, with spacing of 1.0 m between rows and 0.50 m between plants. The grain production was evaluated and its decrease related to the relative production and tolerance to stress was calculated. The grain production of the genotypes had an average decrease of 29.83% under water deficit. The genotypes from the crosses BRS-Paraguaçu x CNCx-698128G, BRS-Xiquexique x Pingo-de-Ouro-1-2, CNCx-698-128G x BRS-Xiquexique, CNCx-698-128G x MNC99-510F-16-1, Santo-Inácio x BRS-Xiquexique and MNC99-510F-16-1 x BRS-Paraguaçu had high production and high tolerance to water deficit.

Contribuição dos caracteres de qualidade da forragem ao teor de proteína bruta em Urochloa brizantha

The objective of this work was to identify which qualitative characters can be used in the direct and indirect selections for high-protein content of Urochloa brizantha genotypes. Nine genotypes were evaluated in a randomized complete block design, with two replicates. The following qualitative traits were studied: volume of packed gas in fast and slow fractions, crude protein, acid and neutral detergent fibers, cellulose, lignin, silica, and in vitro digestibility of organic matter. The in vitro digestibility of organic matter is indicated for both direct and indirect selections of U. brizantha genotypes with higher crude protein content.