Leaf area estimation of cassava from linear dimensions

ABSTRACT The objective of this study was to determine predictor models of leaf area of ​​cassava from linear leaf measurements. The experiment was carried out in greenhouse in the municipality of Botucatu, São Paulo state, Brazil. The stem cuttings with 5-7 nodes of the cultivar IAC 576-70 were planted in boxes filled with about 320 liters of soil, keeping soil moisture at field capacity, monitored by puncturing tensiometers. At 80 days after planting, 140 leaves were randomly collected from the top, middle third and base of cassava plants. We evaluated the length and width of the central lobe of leaves, number of lobes and leaf area. The measurements of leaf areas were correlated with the length and width of the central lobe and the number of lobes of the leaves, and adjusted to polynomial and multiple regression models. The linear function that used the length of the central lobe LA = -69.91114 + 15.06462L and linear multiple functions LA = -69.9188 + 15.5102L + 0.0197726K - 0.0768998J or LA = -69.9346 + 15.0106L + 0.188931K - 0.0264323H are suitable models to estimate leaf area of ​​cassava cultivar IAC 576-70.

Wild Manihot species: botanical aspects, geographic distribution and economic value

A total of 98 Manihot species have been recognized in the genus. All of them are native to the tropics of the New World, particularly Brazil and Mexico. The cultigen, Manihot esculenta Crantz (cassava), grows throughout the lowland tropics. Wild species vary in growth habit from acaulescent or short shrubs to tree-like. Because of their adaptations to different conditions, they are gene reservoirs for tackling many abiotic and biotic stresses such as improving root quality and resistance to diseases. They have been used successfully by the first author for improving protein content, seed-fertility, apomixis, resistance to mealy bug, and tolerance to drought. A table of the most important species from an economic viewpoint is presented.

Ocorrência de isômeros do beta-caroteno em raízes de cinco cultivares de mandioca (Manihot esculenta Crants) do Estado de São Paulo / Beta-carotene isomers in roots of five manioc (Manihot esculenta Crantz) cultivars of São Paulo State

Raízes de cinco cultivares de mandioca (Manihot esculenta Crantz), provenientes do Instituto Agronômico de Campinas, a saber: Branca de Santa Catarina (SRT-59), Pioneira (SRT-13l0), Ouro do Vale (SRT-797), IAC-576-70 e IAC 289-70. As análises visaram a identificação dos principais carotenóides presentes nas raízes dos cultivares de mandioca produzidos no Estado de são Paulo, bem como a determinação da atividade pró-vitamínica A dos mesmos. Pelo cozimento das raízes ou a transformação em farinha, foi possível avaliar as perdas do teor vitamínico A de correntes do processamento. As análises foram realizadas no período de julho/86 a janeiro/87, sendo, desta maneira, possível avaliar as prováveis perdas decorrentes do armazenamento. Os resultados das análises permitiram concluir que os principais carotenóides presentes nas raízes dos cultivares de mandioca estudados foram o neo-ß-caroteno B, o ß-caroteno todo¬-trans e o neo-ß-caroteno U. |Os teores de vitamina A nas mandiocas estudadas, expressos em equivalentes de retinol/l00g, variaram de 2,8 a 13,9 para as amostras cruas e de 0,4 a 10,7 para as amostras processadas, sendo que o cozimento promoveu uma diminuição da atividade pró-vitamínica A, que variou de 20 a 55%. Dos cultivares estudados o IAC 289-70 foi o que apresentou menor porcentagem de perda de atividade pró-vitamínica A com o cozimento. Quanto ao armazenamento, foi possível observar que a mandioca crua com casca armazenada por 6 meses em freezer a –20°C não apresentou perdas na sua atividade pró-vitamínica A enquanto que o armazenamento das farinhas à temperatura ambiente, ao abrigo da luz, pelo mesmo período de tempo, apresentou total degradação de seus carotenóides

Roots of five following cultivars of cassava (Manihot esculenta Crantz) from "Instituto Agronômico de Campinas" were analyzed: "Branca de Santa Catarina" (SRT-59), "Pioneira" (SRT-1310), "Ouro do Vale" (SRT-797), "IAC 576-70" and "IAC 289-70". The analyses were made for the identification of the main carotenoids present in roots of the cassava cultivars produced in São Paulo State, as well as for determination of their pro-vitamin A activity. The cooking of the roots or their transformation as flour made possible to evaluate the loss of the pro-vitamin A value which occurs with processing. The analyses were made from July/1986 to January/1987. This permitted to evaluate the possibility of losses during storage. The results of the analyses allowed to conclude that the main carotenoids present in roots of the studied cassava cultivars were neo-ß-carotene B, all-trans-ß-carotene and neo-ß-carotene U. The vitarnin A values in these cassava expressed as retinol equivalents/lOOg varied from 2,8 to 13,9 for the raw samples; and with cooking, a diminution of the pro-vitarnin A activity occurred, which varied from 20 to 55%.Of all the studied cultivars, the "IAC 289-70" was the one that showed the greatest percentages of loss of pro-vitamin A activity with the cooking. The raw cassavas stored at –20°C for 6 months didn't show losses of their pro-vitamin A value, while the storage of the flour, at room temperature with no light, for the same period of time, showed total degradation of their carotenoids

Anatomical alterations due to polyploidy in cassava, Manihot esculenta Crantz

Information on anatomical structure is needed by breeders working on improvement for drought tolerance. For studying the effect of polyploidy on cassava anatomy and its significance to tolerance to drought, we induced a polyploidy type of a selected clone (UnB 530) by applying an aqueous solution of 0.2% colchicine on lateral buds for a period of 12 h. The stem identified as tetraploid was propagated to produce the whole plant. Free-hand cross-sections of the median portion between stem internodes were made. They were clarified using 50% sodium hypochlorite solution, stained with 1% safranin-alcian blue, passed through an ethanol series and butyl acetate and mounted in synthetic resin. The tetraploid type showed more prismatic and druse crystals in the cortical parenchyma, and its pericycle fibers had thicker walls. The secondary xylem of tetraploid types was wider than diploid ones, having thinner walls and less starch.

Relación entre caracterizaciones molecular y morfológica en una colección de yuca / Relationship between molecular markers and morphological traits in a cassva collection

Con el objeto de estudiar la relación entre las caracterizaciones molecular y morfológica del Banco de Germoplasma de Manihot esculenta Crantz del CENIAPINIA, Maracay; Venezuela se evaluaron 19 descriptores morfológicos y fueron comparados con la estructura no-jerárquica generada por los iniciadores aleatorios (RAPD) OPA-04 y 07, OPB-07, OPK-03, 05 y 15 OPM-04, 14, 18 y 20, para 65 entradas de colección. Las relaciones entre las caracterizaciones fueron estudiadas a través del análisis lineal discriminante, análisis de correspondencia simple y el índice de diversidad de Shannon. Los resultados muestran cuatro grupos bien definidos para la caracterización molecular y morfológica, respectivamente, y le confieren a la función linear discriminante un 60,12 por ciento de certeza en la clasificación de las entradas utilizando los descriptores morfológicos a partir del uso de la función discriminante generada por la caracterización molecular: La mayor diversidad genética fue detectada a través de la caracterización molecular. El estudio de las relaciones entre las caracterizaciones muestra que ofrecen información que puede ser considerada complementaria ya que no se origina un patrón único de asociación entre las entradas e indican que la similitud fenotípica necesariamente no es producto de la similitud genotípica, sino a que diferentes pool de genes pueden generar fenotipos similares