Maria Celeste Gonçalves Vidigal

Variabilidade genética em germoplasma tradicional de feijão-preto em Santa Catarina

O objetivo deste trabalho foi avaliar a diversidade genetica entre 45 cultivares de feijoes tradicionais do grupo comercial preto, por meio de tecnicas multivariadas baseadas em 11 caracteres morfoagronomicos e nutricionais. A distância generalizada de Mahalanobis fundamentou as tecnicas de agrupamentos Tocher e UPGMA. Pelo metodo Tocher foram constituidos nove grupos. Foi detectada divergencia genetica entre as cultivares tradicionais e as testemunhas comerciais de feijao. A maior divergencia foi observada entre as cultivares do grupo 7, em especial a cultivar CFE 22, que se apresentou mais divergente em relacao as demais. Para compor programas de hibridacao com os genotipos avaliados, sugerem-se cruzamentos entre as cultivares do grupo 2, em especial CFE 25, CFE 100 e FT Nobre, e as do grupo 7, em especial o acesso CFE 22. Essas cultivares se destacam por serem as mais divergentes entre si e por possuirem as melhores produtividades.

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.

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.

Genetic control of soybean (Glycine max) yield in the absence and presence of the Asian rust fungus (Phakopsora pachyrhizi)

Soybean is one of the most important crops in Brazil and continuously generates demands for production technologies, such as cultivars resistant to diseases. In recent years, the Asian rust fungus (Phakopsora pachyrhizi Syd. & P. Syd 1914) has caused severe yield losses and the development of resistant cultivars is the best means of control. Understanding the genetic control and estimating parameters associated with soybean (Glycine max) resistance to P. pachyrhizi will provide essential information for cultivar selection. We investigated quantitative genetic control of P. pachyrhizi and estimated parameters associated to soybean yield in the absence and presence of this phytopathogen. Six cultivars and their 15 diallel derived F2 and F3 generations were assessed in experiments carried out in the absence and presence of P. pachyrhizi. The results indicated that soybean yield in the presence and absence of P. pachyrhizi is controlled by polygenes expressing predominantly additive effects that can be selected to develop new cultivars resistant or tolerant to P. pachyrhizi. These cultivars may prove to be a useful and more durable alternative than cultivars carrying major resistance genes.

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 .

Genetic and phytochemical analysis to evaluate the diversity and relationships of mate (Ilex paraguariensis A. St.-Hil.) elite genetic resources in a germplasm collection.

The aim of this study was to evaluate the phytochemical and genetic diversity, relationships and identification of mate (Ilex paraguariensis A.St.‐Hil.) elite genetic resources belonging to the Brazilian germplasm collection and mate breeding program. Mate has been studied due to the presence of phytochemical compounds, especially methylxanthines and phenolic compounds. The samples were collected from the leaves of 76 mate elite genetic resources (16 progenies × 5 localities). Total DNA was extracted from mate leaves and 20 random primers were used for DNA amplification. Methylxanthines (caffeine and theobromine) and phenolic compounds (chlorogenic, neochlorogenic, and criptochlorogenic acids) were quantified by HPLC. The genetic divergence estimated was higher within (92%) than among (8%) the different populations. Analysis of genetic distance between origins provided the formation of two groups by UPGMA cluster analysis, with higher polymorphism (94.9%). The average content of caffeine ranged from 0.01 to 1.38% and theobromine of 0.10 – 0.85% (w/w). The caffeoylquinic acids concentrations (1.43 – 5.38%) showed a gradient 3‐CQA > 5‐CQA > 4‐CQA. The coefficient of genetic variation (CVg) was of low magnitude for all mono‐caffeoylquinics acids. Significant correlations (positive and negative) were observed between the phytochemical compounds. Genetic diversity analysis performed by RAPD markers showed a greater intra‐populational diversity; genetic resources with low caffeine and higher theobromine content were identified and can be used in breeding programs; the correlation between methylxanthines and phenolic compounds can be used as a good predictor in future studies.