Resistance to Meloidogyne enterolobii in sweet potatoes

The present work was designed to select for sweet potatoes clones (Ipomoea batatas) resistant to Meloidogyne enterolobii (Syn. M. mayaguensis) as well as evaluate the efficiency of the selection methods used by estimating their genetic (VCg) and environmental (VCe) variation coefficients as well as broad sense heritability. A total of 142 sweet potato genotypes were tested, including four commercial varieties (Brazlândia Rosada, Brazlândia Roxa, Brazlândia Branca, and Palmas) as well as the Santa Clara tomato cultivar (utilized as a susceptibility standard). The experimental design was completely randomized blocks, in two repetitions of six plants each. Resistance levels were classified according to the numbers of eggs per gram of roots, the reproduction factor (RF), and the reproduction index (RI) relative to the Santa Clara tomato cultivar. The b= VCg/VCe ratio and broad sense heritability were high in terms of the numbers of eggs per gram of roots, as well as in terms of the reproduction factor and reproduction index, demonstrating the efficiency of the methodology used in the selection of resistant genotypes. Thirty-one sweet potato genotypes resistant to M. enterolobii were identified as having significant potential for continuing the breeding program.The present work was designed to select for sweet potatoes clones (Ipomoea batatas) resistant to Meloidogyne enterolobii (Syn. M. mayaguensis) as well as evaluate the efficiency of the selection methods used by estimating their genetic (VCg) and environmental (VCe) variation coefficients as well as broad sense heritability. A total of 142 sweet potato genotypes were tested, including four commercial varieties (Brazlândia Rosada, Brazlândia Roxa, Brazlândia Branca, and Palmas) as well as the Santa Clara tomato cultivar (utilized as a susceptibility standard). The experimental design was completely randomized blocks, in two repetitions of six plants each. Resistance levels were classified according to the numbers of eggs per gram of roots, the reproduction factor (RF), and the reproduction index (RI) relative to the Santa Clara tomato cultivar. The b= VCg/VCe ratio and broad sense heritability were high in terms of the numbers of eggs per gram of roots, as well as in terms of the reproduction factor and reproduction index, demonstrating the efficiency of the methodology used in the selection of resistant genotypes. Thirty-one sweet potato genotypes resistant to M. enterolobii were identified as having significant potential for continuing the breeding program

Seleção de clones de batata-doce resistentes a Meloidogyne incognita raça 1

The objective of this work was to select sweetpotato (Ipomoea batatas) resistant clones to Meloidogyne incognita race 1, and to assess the efficiency of the selection method deployed, through the estimation of genetic and environmental coefficients of variation, and broad-sense heritabilities. Genotypes assessed comprised 123 sweetpotato entries altogether, including four commercial cultivars - Brazlândia Rosada, Brazlândia Roxa, Brazlândia Branca, Palmas - and 119 clones previously selected by the Universidade Federal de Lavras sweetpotato breeding program. The experimental setup was a an augmented block design, using three common treatments: the sweetpotato cultivars Brazlândia branca and Palmas, and the nematode-susceptible tomato cultivar Santa Clara. Nematode resistance levels were defined both by the nematode reproduction factor and by the nematode reproduction index relative to tomato cv. Santa Clara. The ratio between genetic and environmental coefficients of variation and the broad-sense heritability estimates were high, for both nematodes reproduction factor and reproduction index, indicating that the selection method deployed was efficient for the selection of resistant genotypes. Fifty-seven sweetpotato clones were identified as resistant to M. incognita race 1, and selected to continue in the sweetpotato breeding program.O objetivo deste trabalho foi selecionar clones de batata-doce (Ipomoea batatas) resistentes à raça 1 de Meloidogyne incognita e avaliar a eficiência do método de seleção empregado, pela estimação dos coeficientes de variação genética e ambiental e das herdabilidades no sentido amplo. Foram utilizados 123 genótipos de batata-doce, entre os quais quatro cultivares comerciais - Brazlândia Rosada, Brazlândia Roxa, Brazlândia Branca e Palmas -, e 119 acessos previamente selecionados no programa de melhoramento vegetal da Universidade Federal de Lavras. O delineamento experimental utilizado foi o de blocos aumentados, com três tratamentos comuns: as cultivares de batata-doce Brazlândia Branca e Palmas, e a cultivar de tomate Santa Clara, suscetível ao nematoide. A classificação dos níveis de resistência foi realizada de acordo com o fator de reprodução do nematoide e o índice de reprodução relativo à cultivar Santa Clara, de tomateiro. A relação entre os coeficientes de variação genética e ambiental e as herdabilidades no sentido amplo foram altas, tanto para o fator de reprodução quanto para o índice de reprodução dos nematoides, o que demonstra a eficiência do método empregado para a seleção de genótipos resistentes. Foram identificados 57 genótipos promissores de batata-doce, resistentes à raça 1 de M. incognita, e selecionados para continuar no programa de melhoramento

Aptidões de genótipos de batata-doce para consumo humano, produção de etanol e alimentação animal

The objective of this work was to identify agronomic aptitudes of sweet potato (Ipomoea batatas) genotypes for fresh consumption, ethanol production, and animal feed, using aptitude indices. The aptitude indices were established as the weighted means of standardized variables for 16 traits of interest, using different weights for each trait according to the evaluated aptitude. The experimental design was a completely randomized block, with two replicates and 39 sweet potato genotypes: 36 accessions of the germplasm collection of Universidade Federal de Lavras (Brazil) and three commercial cultivars (Palmas, Brazlândia-Branca e Brazlândia-Rosada). Eight genotypes were considered apt to ethanol production, 11 to animal feed, and 11 to human consumption, including the cultivars Palmas and Brazlândia-Branca. The accessions UFLA07-12, UFLA07-31, UFLA07-43, UFLA07-49, and UFLA07-53 showed aptitude for ethanol production, animal feed and human consumption. The selection index is efficient in establishing aptitudes for sweet potato genotypes.O objetivo deste trabalho foi identificar a aptidão de genótipos de batata-doce (Ipomoea batatas) para consumo humano, produção de etanol e alimentação animal, por meio de índices de aptidão. Os índices de aptidão corresponderam às médias dos valores das variáveis padronizadas para 16 características de interesse, ponderadas por pesos atribuídos a cada característica, conforme a aptidão avaliada. Utilizou-se o delineamento experimental de blocos ao acaso, com duas repetições e 39 genótipos: 36 acessos da coleção de germoplasma da Universidade Federal de Lavras e três cultivares comerciais (Palmas, Brazlândia-Branca e Brazlândia-Rosada). Oito genótipos foram considerados aptos à produção de etanol, 11 à alimentação animal e 11 ao consumo humano, incluindo as cultivares Palmas e Brazlândia-Branca. Os acessos UFLA07-12, UFLA07-31, UFLA07-43, UFLA07-49 e UFLA07-53 apresentaram aptidão para produção de etanol, alimentação animal e consumo humano. O índice de seleção é eficiente para estabelecer aptidões para genótipos de batata-doce

Triagem de genótipos de hortaliças para resistência a Meloidogyne enterolobii

The objective of this work was to identify genotypes of lettuce, sweet potato, bean, tomato, and Capsicum resistant to the nematode Meloidogyne enterolobii (Syn. M. mayaguensis), and to classify them according to their resistance degree. The following were evaluated: 10 genotypes of lettuce, 8 of sweet potato, 10 of bean and snap bean, 25 of Capsicum, and 6 of tomato genotypes. Reproduction factor and reproduction index were determined, and genotypes were classified according to their resistance degree to the nematode. Moderate levels of resistance were observed in the bean cultivar Aporé and in the accessions of pepper BGH-433 and BGH-4285, and of sweet pepper, PIM-031, PIX-022I-31-07-02, and PIX-022I-31-13-01. All tomato genotypes are susceptible to M. enterolobii. Lettuce cultivars Julia, Hortência, Verônica, Grand Rapids and Babá de Verão, and sweetpotato clones UFLA07-49 and UFLA07-53 are very resistant to the nematode. Apparently, the resistance to M. enterolobii is controlled by different genes from the ones which confer resistance to other species and races of Meloidogyne.O objetivo deste trabalho foi identificar genótipos de alface, batata-doce, feijão, tomate e Capsicum resistentes ao nematoide Meloidogyne enterolobii (Syn. M. mayaguensis) e classificá-los quanto ao grau de resistência. Foram avaliados: 10 genótipos de alface, 8 de batata-doce, 10 de feijão e feijão-vagem, 25 de Capsicum e 6 de tomate. Foram calculados o fator de reprodução e o índice de reprodução, e os genótipos foram classificados quanto ao grau de resistência ao nematoide. Foram observados níveis moderados de resistência na  cultivar de feijão Aporé  e nos  acessos de pimenta, BGH-433  e BGH-4285,  e de pimentão, PIM-031, PIX-022I-31-07-02  e PIX-022I-31-13-01. Todos os genótipos de tomate são suscetíveis  a M. enterolobii. As cultivares de alface Julia, Hortência, Verônica, Grand Rapids e Babá de Verão, e os clones de batata-doce UFLA07-49 e UFLA07-53 são muito resistentes ao nematoide. A resistência a M. enterolobii aparentemente é mediada por genes diferentes dos que conferem resistência a outras espécies e raças de Meloidogyne

Caracterização das resistências a múltiplos patógenos em híbridos experimentais de pimentão

The aim of this study was to assess resistance to some of the major sweet pepper pathogens [Phytophthora capsici, Pepper yellow mosaic virus (PepYMV) and Meloidogyne incognita] in a group of experimental hybrids and their respective parental lines, and to identify hybrids possibly resistant to all three pathogens. Ten parental breeding lines, thirty experimental hybrids and seven commercial controls (Konan-R, Magali-R, Martha-R, Stephany, Mallorca, Magnata Super and Criollo de Morelos-334) were used. Each experiment was set up in a randomized complete block design with three replications and plots consisting of 16 plants. For assessment of resistance to P. capsici and PepYMV, the percent of asymptomatic plants was considered. In evaluating reactions to M. incognita, both the nematode reproduction index and the nematode reproduction factor were calculated. Five hybrids were found with resistance to all three pathogens. For all three pathogens, there was evidence that hybrids with two resistant parental lines showed slightly higher levels of pathogen resistance than those with only one resistant parental line. © 2017, Sociedade de Olericultura do Brasil. All rights reserved

Strategies for recommendation of common bean lines tested for value of cultivation and use in different environments

The purpose of this study was to develop strategies for the recommendation of common bean cultivars testedin VCU trials with regard to the performance of lines with different growth habits, at different fertilizer rates and sowingdensities. It was found that the grain yield of lines is more affected by variations in fertilizer rates than of the sowing density;the response of the lines to higher planting density and fertilizer rate varies with the environment of evaluation and does notdepend on the growth habit, the interactions between fertilizer rates and sowing densities were significant, demonstrating theimportance of VCU trials with different fertilizer rates and sowing densities