Potato improvement for tropical conditions: II. Selection indices and efficiency of indirect selection

This study evaluated the efficiency of selection indices that can contribute to potato clone selection underfavorable and stressful conditions as well as the possibility of indirect selection for heat tolerance. Among the selectionindices, the arithmetic and geometric means and index 4 were the most appropriate. The susceptibility index and percentageof yield reduction indicate only specifically adapted clones. Indirect selection for heat tolerance is not suitable in view of thelow correlation coefficient among clone means in the environments. Selection based on the overall environment mean is morefit to select broadly adapted genotypes. In general, clones that performed best under stress conditions and presented heattolerance were specifically adapted, in spite of low performance means under favorable conditions. Well-adapted genotypes toboth stress and favorable conditions can however be selected

Performance of grain sorghum hybrids in soils with low and high aluminum saturation

The presence of aluminum (Al3+) in acidic soils is one of the main causes of low crop yield, since it inhibits the root growth, thus affecting the nutrients and water uptake by plants. An approach to grow crops in areas with high Al3+ saturation is the use of tolerant cultivars. This study aimed to evaluate commercial sorghum hybrids in soils with low and high aluminum saturation, in order to select cultivars with high grain yield, even when exposed to abiotic stress. Twenty hybrids were evaluated for characteristics such as plant flowering, plant height and grain yield. All three traits were significantly affected by Al3+, being grain yield the most affected one. Despite the significant genotypes x environments interaction for grain yield, it was possible to select hybrids with yield above the national average in both environments. The hybrids BRS373, 50A50, AS4639, DKB540, AS4625, A9721R, 1167092, DKB550, 1G282 and AG1040 showed a high yield under low and high Al-saturation conditions

Identificação de genótipos de tomateiro resistentes a tospovirus em progênies segregantes com marcador molecular

The SCAR (Sequence Characterized Amplified Region) 'Sw-421' molecular marker is located at 1.0 cM from the Sw-5 allele, originated from Lycopersicon peruvianum (L.), which confers resistance to the tomato spotted wilt virus (TSWV). However, it had not been tested yet in advanced tomato populations. The goal of this study was to distinguish resistant homozygotes (Sw-5/Sw-5) and heterozygotes (Sw-5/Sw-5+) from susceptible (Sw-5+/Sw-5+) plants in crossing populations with the Stevens cultivar and advanced backcrossing populations by using 'Sw421' SCAR marker. The amplification of 940 bp and 900 bp bands characterized the resistant homozygotes and susceptible controls, respectively. A two band pattern (900 bp and 940 bp) was observed in heterozygote genotypes (Sw-5/Sw-5+), which confirmed the co-dominant inheritance mechanism of the marker. Fifty seven plants from the isogenic progenies were characterized based on bands pattern: 18 plants (31.6%) were identified as resistant homozygotes, 8 plants (14.0%) as resistant heterozygotes and 31 plants (54.4%) were characterized as susceptible. The SCAR 'Sw-421' marker is an important tool for selection and pyramid resistance alleles, mainly when other resistance sources to the TSWV are available, such as the Rey de los Tempranos source.O marcador molecular SCAR 'Sw-421' é localizado a 1,0 cM do alelo Sw-5, proveniente de Lycopersicon peruvianum (L.), que confere resistência ao vira-çabeça em tomateiro. Contudo, o mesmo ainda não havia sido testado em populações avançadas de tomateiro. O objetivo do trabalho foi distinguir plantas resistentes homozigotas (Sw-5/Sw-5), resistentes heterozigotas (Sw-5/Sw-5+) e suscetíveis (Sw-5+/Sw-5+) pelo marcador SCAR 'Sw-421'. As amplificações de bandas de 940 pb e 900 pb caracterizaram os genótipos resistentes homozigotos e suscetíveis, respectivamente. Duas bandas (900 pb e 940 pb) foram observadas nos genótipos heterozigotos, confirmando a herança codominante do marcador. De 57 plantas das progênies isogênicas avaliadas 18 (31,6%) plantas foram caracterizadas como resistentes, 8 (14,0%) como heterozigotas e 31 (54,4%) plantas suscetíveis. O marcador molecular SCAR 'Sw-421' constitui importante ferramenta para seleção e piramidação de alelos de resistência, especialmente quando se utilizam outras fontes de resistência ao vira-cabeça, como por exemplo, a fonte Rey de los Tempranos

Retenção de compostos fenólicos e aceitabilidade de churros sem glúten feitos com farinha de sorgo com ou sem tanino

The objective of this work was to evaluate the acceptability of gluten-free churros made either with tannin or tannin-free sorghum flour, as well as the retention of their phenolic compounds and antioxidant capacity retention after cooking and frying. The churros were developed by replacing wheat flour with sorghum flour from the sorghum cultivars BRS 305 with tannin (T-churro) or BRS 501 tannin free (TF-churro). The content of phenolic compounds and antioxidant activity were evaluated before and after the thermal processing. Both products had a high acceptability (84.5‒95.5%) for all evaluated sensory attributes, and no difference was observed for color, aroma, and flavor. However, the T-churro showed a higher acceptance for texture, overall acceptability, and purchase intention. The churros had a similar proximate composition for fiber content. The phenol content was about three times and antioxidant activity about 20 times higher for T-churro than for TF-churro. Although subjected to two types of processing (cooking and frying), the fried and ready-to-eat T-churro retained more than 50% of anthocyanins, phenols, and antioxidant activity. The TF-churro product showed a retention of these compounds above 70, 40, and 65%, respectively. The tannin content of 'BRS 305' sorghum increases its functional potential and does not negatively affect the acceptability of the churros. Sorghum either with or without tannins has the potential to be used for the production of gluten-free churros.O objetivo deste trabalho foi avaliar a aceitabilidade de churros sem glúten, feitos com farinha de sorgo com ou sem tanino, assim como a retenção de seus compostos fenólicos e da sua capacidade antioxidante após processamento por cozimento e fritura. Os churros foram desenvolvidos pela substituição da farinha de trigo por farinhas de sorgo das cultivares BRS 305 com tanino (T-churro) ou BR 501 sem tanino (TF-churro). O teor de compostos fenólicos e a atividade antioxidante foram avaliados antes e depois do processamento térmico. Ambos os produtos apresentaram alta aceitabilidade (84,5‒95,5%) para todos os atributos sensoriais avaliados, e nenhuma diferença foi observada quanto à cor, ao aroma e ao sabor. Entretanto, o T-churro teve maior aceitação quanto à textura, à aceitabilidade geral e à intenção de compra. Os churros apresentaram composição centesimal semelhante quanto ao conteúdo de fibra. O teor de fenol foi cerca de três vezes e a atividade antioxidante cerca de 20 vezes maior no T-churro do que no TF‑churro. Apesar de ter sido submetido a dois tipos de processamento (cozimento e fritura), o T-churro frito pronto para consumo apresentou mais de 50% de retenção de antocianinas, fenóis e atividade antioxidante, após a fritura. O produto TF-churro apresentou retenção desses compostos acima de 70, 40 e 65%, respectivamente. O teor de tanino do sorgo 'BRS 305' aumenta seu potencial funcional e não afeta negativamente a aceitabilidade dos churros. Sorgos com ou sem taninos têm potencial para a produção de churros sem glúten

PERFORMACE AGRONÔMICA DE HÍBRIDOS DE SORGO GRANÍFERO ESTIMADA PELO MÉTODO GGE BIPLOT

A great advantage of sorghum its xerophytic characteristics, which gives the potential, as a succession to summer crops in grain production. Therefore, it is fundamental to choose cultivars adapted and productive to different growing conditions. The objective of this study was to provide information about adaptive capacity of sorghum hybrids by the GGE biblot method. The trials were conducted, in 2017 as a second crop, no-tillage system, in four environments, Rio Verde, Sete Lagoas, Teresina and Sinop. All trials were conducted in a randomized complete block design with three replicates and 36 treatments. The characteristics of flowering, plant height and grain yield were evaluated, being the data applied to the individual and joint analyses of variance, being applied the test of Scott-Knott measures and estimated the parameters of adaptability and stability. Promising hybrids for the characteristics evaluated were 1610001, 1610006, 1610051 and 1G100.Uma grande vantagem do sorgo são suas características xerófitas, o que lhe atribui um potencial, como sucessão às culturas de verão, na produção de grãos, sendo fundamental a utilização de híbridos adaptados aos diferentes ambientes de cultivo. Assim, o objetivo deste trabalho foi gerar parâmetros a respeito da capacidade adaptativa de híbridos de sorgo granífero pelo método GGE biplot. Os ensaios foram conduzidos, na safrinha de 2017, em sistema de plantio direto, em quatro ambientes, Rio Verde, Sete Lagoas, Teresina e Sinop. Todos os ensaios foram conduzidos, no delineamento em blocos casualizados, com três repetições e 36 tratamentos. Foram avaliadas as características florescimento, altura de plantas e produtividade de grãos, sendo os dados submetidos às análises de variância individuais e conjunta, sendo aplicado o teste de comparação de médias de Scott-Knott e estimados os parâmetros de adaptabilidade e estabilidade. Os híbridos promissores quanto às características avaliadas foram 1610001, 1610006, 1610051 e  1G100

Mutantes rin, norA, ogc e hp em diferentes backgrounds genotípicos de tomateiro

The objective of this work was to assess the viability of single and simultaneous use of rin, norA, ogc and hp as heterozygotes in tomato genotypes in order to improve post-harvest fruit quality. Eighteen genotypes differing in combinations among these loci in two backgrounds (Floradade and experimental background) were evaluated. Contrasts were used to quantify the effects of single and simultaneous application of mutant loci, in two different backgrounds, on the total and early fruit yield, fruit mean mass, fruit firmness, development of external fruit color, lycopene and beta-carotene fruit contents. The norA and the rin alleles, used as heterozygotes in the FloraDade background, delayed the fruit softening and reduced lycopene and beta-carotene contents of mature fruit. All heterozygous combinations between rin and the mutants norA, ogc and hp increased fruit firmness. The effect of the rin+/rin nor+/norA genotypes on fruit firmness was roughly the sum of the individual effects of each locus. The rin allele was more efficient than norA to keep fruit firmness. The ogc+/ogc and hp+/hp genotypes, singly or in combination, improved colour of rin fruits. The combination rin+/rin and nor+/norA can be used in breeding for long shelf life tomatoes; however, genotypic backgrounds where fruit colour is less adversely affected should be sought or, alternatively, the colour mutant heterozygotes ogc+/ogc and hp+/hp should be used.O objetivo deste trabalho foi avaliar a viabilidade do emprego isolado e simultâneo dos mutantes rin, norA, ogc e hp em heterozigose, em genótipos de tomateiro, visando à melhoria da qualidade pós-colheita dos frutos. Foram avaliados 18 genótipos que diferem quanto às combinações entre estes locos em dois diferentes backgrounds (FloraDade e background experimental). Contrastes não ortogonais foram estabelecidos para quantificar os efeitos dos alelos mutantes, isoladamente ou combinados em um mesmo genótipo, em dois backgrounds, sobre a produção total e produção precoce de frutos, massa média, firmeza, coloração externa, teores de licopeno e betacaroteno dos frutos. Os alelos norA e rin em heterozigose, no background FloraDade, desaceleraram a taxa de perda de firmeza e reduziram os teores de licopeno e betacaroteno nos frutos maduros. As combinações heterozigotas entre o mutante rin e os mutantes norA, ogc e hp aumentaram a firmeza dos frutos. O efeito do genótipo rin+/rin nor+/norA sobre a firmeza dos frutos foi o somatório dos efeitos individuais dos locos. O alelo rin mostrou-se, individualmente, mais eficiente do que norA, em prolongar a firmeza dos frutos. Os genótipos ogc+/ogc e hp+/hp, juntos ou isolados, aumentaram a coloração dos frutos rin+/rin. Recomenda-se a utilização dos genótipos rin+/rin nor+/norA no desenvolvimento de híbridos longa vida, buscando-se, contudo, backgrounds que sofram prejuízo menor sobre a coloração dos frutos e adicionando-se mutantes ogc+/ogc e hp+/hp

Potato improvement for tropical conditions: I. Analysis of stability

The development of cultivars adapted to high tropical temperatures is the chief objective of potato improvementin the tropics. To achieve this goal, it is necessary to select for more stable genotypes adapted to many environments. Theobjective of this research was to analyze 51 potato clones for stability regarding tuber yield, percentage of large tubers andtuber specific gravity at different sites, years and planting seasons in southern Minas Gerais state, Brazil. Clones with soundstability for all traits were selected. Greater efforts should be invested specifically into simultaneous selection for severaltraits under environmental stress, targeting above all the absence of physiological defects in tubers, apart from theabovementioned traits

Combining yield, earliness and plant height in a single genotype: a proposal for breeding in grain sorghum (Sorghum bicolor L.)

Grain sorghum production has expanded during the off-season when rainfall oscillates and becomes insufficient. Aiming to obtain better adapted cultivars, breeding programs have sought new combinations of hybrids with earliness, high grain yield, and ideal plant height for harvesting. This study aimed to estimate de combining ability of grain sorghum lines, proposing a breeding strategy, to identify hybrids gathering high yield, earliness, and desired plant height. Thirty-six hybrids from crosses of 12 lines were evaluated at two sites in the Brazilian region known as Cerrado biome. The evaluated traits were: days to flowering, plant height, and grain yield. For the diallel analysis, Method 4 of Griffing adapted to partial diallel was adopted. By combining ability analysis, we identified promising lines to be used as parents to obtain more yielding, early, and ideal height hybrids. The findings allowed us to propose a breeding strategy, in which complex crosses should be performed to gather favorable alleles in new restorer and male-sterile lines. The hybrids 7, 9, 19, and 22 are the most suitable for growing in the evaluated sites

Performance of grain sorghum hybrids in soils with low and high aluminum saturation

<div><p>ABSTRACT The presence of aluminum (Al3+) in acidic soils is one of the main causes of low crop yield, since it inhibits the root growth, thus affecting the nutrients and water uptake by plants. An approach to grow crops in areas with high Al3+ saturation is the use of tolerant cultivars. This study aimed to evaluate commercial sorghum hybrids in soils with low and high aluminum saturation, in order to select cultivars with high grain yield, even when exposed to abiotic stress. Twenty hybrids were evaluated for characteristics such as plant flowering, plant height and grain yield. All three traits were significantly affected by Al3+, being grain yield the most affected one. Despite the significant genotypes x environments interaction for grain yield, it was possible to select hybrids with yield above the national average in both environments. The hybrids BRS373, 50A50, AS4639, DKB540, AS4625, A9721R, 1167092, DKB550, 1G282 and AG1040 showed a high yield under low and high Al-saturation conditions.</p></div