Pedro Soares Vidigal Filho

Allelic relationships of anthracnose (Colletotrichum lindemuthianum) resistance in the common bean (Phaseolus vulgaris L.) cultivar Michelite and the proposal of a new anthracnose resistance gene, Co-11

The genetic resistance of Phaseolus vulgaris L. cultivar Michelite to races 8 and 64 of Colletotrichum lindemuthianum, causal agent of bean anthracnose, was characterized. Crosses were made between Michelite and Mexico 222 cultivars and the F2 population was inoculated with race 64 in order to study the inheritance of resistance to anthracnose in Michelite. The segregation of F2 population fitted in a ratio of 3R:1S, showing the presence of a dominant gene in Michelite gene conditioning resistance to race 64. Allelism tests were conducted with F2 populations derived from crosses between Michelite and AB 136, AND 277, BAT 93, Cornell 49-242, G 2333, Kaboon, Mexico 222, Michigan Dark Red Kidney (MRDK), Ouro Negro, Perry Marrow, PI 207262, TO, TU, and Widusa. All the cultivars (except Mexico 222) were resistant to race 64. While F2 derived from the Michelite x Mexico 222 was inoculated with race 8. Additionally, allelism tests indicated that the gene present in Michelite is independent from Co-1, Co-2, Co-3, Co-4, Co-5, Co-6, Co-7, Co-9 and Co-10 genes. The monogenic inheritance observed in Michelite and the independence of this gene from those previously characterized allow the authors to propose that the anthracnose resistant gene in Michelite should be named Co-11.

Isozyme diversity in cassava cultivars (Manihot esculenta Crantz).

Isoenzyme electrophoresis was used as a method to determine genetic diversity in various M. esculenta cultivars collected in the Southwestern (SW) and Northwestern (NW) regions of the State of Parana, in the South region of Brazil, and in cultivars produced at the Agronomic Institute of Campinas (IAC), S~ao Paulo State, Southeastern region of Brazil. The cultivars have been maintained by vegetative propagation for 5 years and are useful in production programs. A total of 28 loci in the acid phosphatase (ACP; EC 3.1.3.2), esterases (EST; EC 3.1.1.1), malate dehydrogenase (MDH; EC 1.1.1.37), and shikimate dehydrogenase (SKDH; EC 1.1.1.15) isozymes was analyzed. The proportion of polymorphic loci for NW, SW, and IAC cultivars was 57.14, 50.0, and 53.6%, respectively. Genetic diversity calculated by Neis genetic identity (I) showed high I values for the three M. esculenta subpopulations. The high degree of polymorphism expressed by cassava cultivars is highly relevant to stimulate breeding programs with M. esculenta species.

Diallel analysis of the combining ability of common bean (Phaseolus vulgaris L.) cultivars.

Six common bean cultivars (LPSPI 93-17, LPSPI 93-19, FT-Nobre, Apore, Ruda and Campeao-1) and their 15 diallel hybrids were evaluated for four agronomic characteristics using Griffings methodology (1956). The analysis indicated the predominance of non-additive gene effects for days to germination and plant height. The mean number of days to flowering and mean height of the first pod insertion were predominantly controlled by genes showing additive effects. The results showed that LPSI 93-19 and Apore were indicated for intra-population breeding, while the combinations LPSPI 93-17 x FT-Nobre, LPSPI 93-17 x Apore, LPSPI 93-17 x Ruda, LPSPI 93-19 x Campeao-1, FT-Nobre x Apore and Ruda x Campeao-1 were indicated for interpopulational breeding. Plants with reduced height, greater height of first pod insertion, fewer number of days to flowering and to emergence can be obtained from the segregant population of the crosses LPSPI 93-17 x FT-Nobre and LPSPI 93-19 x Ruda.

Genetic divergence in sweet cassava cultivars using morphological agronomic traits and RAPD molecular markers

In this work the genetic divergence among 14 sweet cassava cultivars was estimated by their morphological agronomic traits and RAPD molecular markers. The Tocher cluster analysis and the Nearest Neighbor Method were applied. The most dissimilar cultivars were Pao and Guaira, Fecula Branca and Pao, and Pao and Caipira, while the most similar cultivar were the Fecula Branca and Branca 1, Branca 3 and Branca 1, and Guaira and Branca 1. The Jaccards coefficient showed that the most similar cultivars were Guaira and Quarenta Quilos, while the most dissimilar were Branca 3 and Amarela da Rama Cinza. The divergence analysis indicated that promising crosses could be made between the Branca 3 cultivar and the Pao, Amarela 1, Fecula Branca and Amarela 2 cultivars for the high genetic divergence, favorable agronomic and culinary traits, and disease resistance on the part of at least one of the parents involved in the cross.

Comparison of methods for phenotypic stability analysis of cassava (Manihot esculenta Crantz) genotypes for yield and storage root dry matter content

O objetivo deste trabalho foi comparar diferentes metodologias de analise de estabilidade fenotipica considerando producao e teor de materia seca nas raizes tuberosas de oito genotipos de mandioca, avaliados em oito ambientes na regiao Noroeste do Parana. Todas as metodologias aplicadas se mostraram aptas no estudo da estabilidade dos genotipos avaliados, cada uma delas com suas particularidades. As metodologias de Eskridge, Annicchiarico e Lin e Binns se mostraram mais adequadas para situacoes de menor efeito da interacao G x A. A analise AMMI e a metodologia de Toler e Burrows propiciaram um melhor detalhamento das adaptacoes especificas dos genotipos a ambientes favoraveis e desaforaveis. E sugerido o uso simultâneo da analise AMMI e da metodologia de Toler e Burrows. O clone IAC 190-89 mostrou-se mais promissor.

Effect of harvest period on the quality of storage roots and protein content of the leaves in five cassava cultivars (Manihot esculenta, Crantz)

The effect of harvest period on the quality of storage roots and leaves of cassava cultivars was determined in an experiment carried out in a randomized complete block design with four replications in a split plot scheme, with five cultivars in the plots and ten harvest times in the subplots. The IAC 13 cultivar had the highest rate of dry matter accumulation in the storage roots and the Mico cultivar the lowest. The period of least dry matter content in the storage roots occurred later for the Fecula Branca, Mico and IAC 14 cultivars, and the minimum starch content in the storage roots occurred later for the Fecula Branca and Mico cultivars. In general, the IAC 13, IAC 14 and Fecula Branca cultivars had higher dry matter content in the storage roots, while higher starch content in the dry and fresh matter were obtained in the Fecula Branca cultivar. The crude protein content in the leaves decreased as the plant aged.

Dry matter production and distribution in three cassava (Manihot esculenta Crantz) cultivars during the second vegetative plant cycle

A study was carried out in Araruna County, State of Parana, to understand the relationship between the total dry matter yield and its proportion allocated to the storage roots of cassava (Manihot esculenta Crantz) plants in the second vegetative cycle. The experimental design was a randomized complete block in split-plot scheme with four replications. The plots consisted of the Mico, IAC 13 and IAC 14 cultivars and the monthly harvesting dates were assessed in the sub-plots. The results showed that the Mico and IAC 13 cultivars were more efficient in allocating dry matter to the storage roots. The IAC 14 cultivar allocated a higher proportion of assimilates to stems compared with the other two cultivars. With regard to the influence of harvesting time, the lowest harvest indexes were observed in the periods of more intense vegetative growth. However, the highest carbohydrate proportions were allocated to the storage roots during periods of low vegetative growth.

Componentes do rendimento, teores de isoflavonas, proteínas, óleo e qualidade de sementes de soja

Soybean seeds have been used not only for animal, but also for human nutrition because of the presence of proteins; lipids; some vitamins and polyphenolic compounds, such as isoflavones, in their chemical composition. The antioxidant activity of isoflavones may be considered a safe mechanism of seed quality. This is due to the deterioration theory which leads to a cellular detriment because of the action of free radicals on cell membranes. Experiments were carried out during the 2004/05 agricultural year in two different sowing locations (Maringa and Umuarama). The objective of this study was to evaluate the yield, physiological quality of seeds produced in two sowing locations; to determine oil, protein and isoflavone contents; as well as to correlate isoflavone contents to the yield, physiological quality and oil-protein contents of soybean seeds. The seed quality was evaluated by the germination test (first count and final count); the tetrazolium test (vigor and viability) and the concentration of oil, protein and isoflavone tests. Analysis of the isoflavone contents showed that the BRS 133 and EMBRAPA 48 cultivars presented the highest isoflavone contents whereas the BR 36 cultivar showed the lowest isoflavone contents in both places. Germination was above 80% in all cultivars tested in Maringa. The correlation between isoflavones and the weight of one thousand seeds was negative for both locations.

Effect of harvest period on foliage production and dry matter distribution in five cassava cultivars during the second plant cycle

The objective of this work was to study the leaf production pattern and dry matter distribution in cassava during the second plant cycle. The completely randomized experimental design with four replications was used, with five cultivars in the main plots and ten harvest times in the sub-plots. Foliage production was affected by plant age, being higher in hot periods. Leaf blades and petioles dry matter content presented a linear increase due to a progressive decrease in the amount of young leaves and ontogenetic factors. The stems provided, temporarily, carbohydrates to the plant re-growth, delaying the availability and use of storage roots dry matter. The dry matter content in the storage roots was lower during the vegetative and higher during rest period. The storage roots diameter increased considerably when the amount of leaves was higher, indicating the importance of leaf area in the cassava plant production.

Esterase polymorphism marking cultivars of Manihot esculenta, Crantz

Esterase isozymes were used to detected substrate-preference polymorphism in twenty cultivars of Manihot esculenta, and to show cultivar-specific variation of this species. A relatively complex extraction solution of proteins from leaves was needed to show a larger number of esterase isozymes. Similarity between cultivars from six groups ranged from 51 to 96%. The cultivars identified by the same name seemed to be biochemically different regarding esterase isozymes. Esterase isozyme electrophoretic patterns could, therefore, be used to discriminate the cultivars identified by the same name, and to monitor the vegetative propagation of cultivars maintained in the germplasm collection. In breeding strategies, isoesterase analysis could be used to avoid intercrossing between the similar genotypes.