Marcus Vinícius Kvitschal

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.

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.

Efeito da época de colheita no crescimento vegetativo, na produtividade e na qualidade de raízes de três cultivares de mandioca

With the objective of determining the effect of harvesting time in the vegetative growth, yield and quality of storage roots of three cassava cultivars (Manihot esculenta Crantz), an experiment was carried out in an area of red distrophic Red Latosol in Araruna, Northwest of Parana state, from October, 1997 to May, 1999. The experimental design was a randomized complete blocks with four replications and treatments arranged in split plots. The main treatments were the cassava cultivars Mico, IAC 13 and IAC 14 and the secondary treatments were ten monthly harvests starting from the second plant growing season. The canopy yield observed in the second season, presented an increase of 50.0%. The good development of the vegetative structure of the plants resulted in a greater accumulation of reserve material in the storage roots, increasing its yield. The highest harvest indices were observed from 19 to 21 months, with mean values superior to 54.0%. The cultivars were not significantly different in production of tuberous roots, dry matter and starch. The second phase of physiologic rest of the plants showed to be more favourable for harvesting, expressed in terms of production of storage roots (92.5%), of dry matter (125.0%) and starch (144.0%).

Genetic diversity and population structure of sweet cassava using simple sequence repeat (SSR) molecular markers

The objective of this study was to evaluate the population structure and genetic diversity among 66 sweet cassava (Manihot esculenta Crantz) traditional accessions collected in Maringa, Parana, Brazil, using microsatellite molecular markers. Population structure was analyzed by means of genetic distances and probabilistic models; allelic frequencies were used in order to assess the genetic diversity indexes (Ht, Ho, PIC, % polymorphism and number of alleles) for each locus studied. All evaluated loci were polymorphic and the average was highly heterozygote. The number of alleles per locus was low, suggesting that restrict genetic base is a consequence of accession exchange and a reduced number of ancestors in the population. The polymorphic information content (PIC) values showed considerable genetic diversity with a mean value of 0.5076 and peak of 0.5707 for locus GA140. The microsatellites markers revealed a wide genetic variability among the traditional accessions evaluated. Moreover, the sweet cassava populations were separated in two groups using two analytical methods (probabilistic and genetic distances). The most divergent accessions were BGM 17, BGM 20, BGM 51 and BGM 95. On the other hand, the most similar accessions were BGM 25, BGM 33, BGM 37, BGM 59 and BGM 214. Hybrid combinations formed by the most divergent combinations, especially between BGM 51 × BGM 296, BGM 95 × BGM 222 and BGM 20 × BGM 12, are the most promising ones for future sweet cassava breeding programs. Keywords : Genetic diversity, Manihot esculenta Crantz, microsatellite markers African Journal of Biotechnology Vol. 12(10), pp. 1040-1048, 6 March, 2013

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.

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.

Characterization of Colletotrichum lindemuthianum isolates using differential cultivars of common bean in Santa Catarina State, Brazil

ABSTRACT In 2003 and 2004, 32 isolates of Colletotrichum lindemuthianum obtained from the infected plants of field-grown common bean (Phaseolus vulgaris L.) in Santa Catarina state, Brazil were analyzed based on the virulence to 12 differential cultivars of Phaseolus vulgaris L.. Thirteen distinct races were identified, six of which had not been reported previously in Santa Catarina. This is the first report of the occurrence of 67, 83,101,103,105, and 581 races of C. lindemuthianum. Race 65 was most common (34%). All the isolates were compatible to the cultivars Michelite and Mexico 222. Some isolates infected not only differential cultivar of Mesoamerican origin, but also the ones of Andean origin. Key words: Anthracnose, common bean, new races, Phaseolus vulgaris L . * Author for correspondence INTRODUCTION Common bean (Phaseolus vulgaris L.) is an important source of food for the people in Brazil and it is a proven source of the protein and is also a good source of the carbohydrates and iron (Goncalves-Vidigal et al., 2007b). One of the most widespread and important diseases of this crop is anthracnose, caused by the fungus Colletotrichum lindemuthianum (Sacc. et Magn.), which causes complete yield loss when susceptible genotypes are used in favorable conditions to the pathogen (Pastor-Corrales and Tu, 1989; Poletine et al. 2000). The first studies in Brazil to identify C. lindemuthianum races were done in Sao Paulo state (Kimati, 1966). The author identified the alpha, delta and Mexican II group races. In 1973, the isolates collected in Rio Grande do Sul and Santa Catarina states were characterized as belonging to alpha, beta, Mexican I and Brazilian I races, while the gamma race was only identified in Santa Catarina (Oliveira et al., 1973). The occurrence of alpha group I in Parana state was first reported by Araujo (1973). In Minas Gerais, races from the alpha, Mexican II and Brazilian I and II groups were also characterized (Oliari et al., 1973). In 1988, 25 isolates from Santa Catarina state were characterized by Menezes and Dianese (1988). The authors identified 16 isolates belonging to Alpha race, three to Delta race, three to Epsilon, one to Kappa and two to Mu race. In Santa Catarina, Balardin et al. (1990), working on

Plant arrangement and grain yield of two simple maize hybrids

The objective of this work was to evaluate the effect of plant arrangement on grain yield and mass of a thousand kernels of two simple corn hybrids, in the North region of Parana State. The combination among two plant row spacing (0.45 and 0.90 m), four plant population densities (45,000, 60,000, 75,000 and 90,000 plants ha -1 ), two corn hybrids (DKB 234 and DKB 214) and two growing seasons (2005/06 and 2006/07) constituted the treatments. Experiments were designed in randomized complete blocks, in 2 x 2 x 4 x 2 factorial scheme, with four replications. The hybrid DKB 234 presented the highest grain yield, while hybrid DKB 214 presented the highest mass of a thousand kernels. In general, the plant row spacing did not affect too much the grain yield, being a viable option to crop the corn hybrids DKB 214 and DKB 234 for grain yield. The fine plant population density for grain yield of hybrid DKB 234 ranged from 65,000 to 75,000 plants ha -1 , while this fine plant population density for grain yield of hybrid DKB 214 was about 70,000 to 80,000 plants ha -1 . The fine plant population density for mass of a thousand kernels was 55,000 plants ha -1 .