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

Abstract

RESUMOCom o objetivo de determinar o efeito da época de colheita no crescimento vegetativo, na produtividade e na qualidade de raízes tuberosas de três cultivares de mandioca (Manihot esculenta Crantz), desenvolveu-se em Araruna, Noroeste do Estado do Paraná, um experimento em área de Latossolo Vermelho Distrófico, no período de outubro de 1997 a maio de 1999. O delineamento experimental utilizado foi o de blocos completos casualizados, em esquema de parcelas subdivididas, com quatro repetições, sendo os tratamentos principais as cultivares Mico, IAC 13 e IAC 14 e os tratamentos secundários, dez épocas de colheita, realizadas mensalmente a partir do início do segundo ciclo de crescimento das plantas. A produção da parte aérea apresentou, no segundo ciclo, aumentos de 50,0% em relação a um único ciclo vegetativo. O bom desenvolvimento da estrutura vegetativa das plantas levou ao acúmulo de material de reserva nas raízes tuberosas, aumentando a sua produtividade. Os maiores índices de colheita ocorreram dos 19 aos 21 meses de idade, com valores, em média, superiores a 54,0%. As cultivares não diferiram entre si quanto à produção de raízes tuberosas, de massa seca e de amido. Para todas as cultivares, a segunda fase de repouso fisiológico das plantas mostrou-se mais propícia à colheita, em face da maior produção de raízes tuberosas (92,5%), de massa seca (125,0%) e de amido (144,0%). Palavras-chave: parte aérea, índice de colheita, produção de raízes, produção de amido, idade das plantas. ABSTRACT EFFECT OF THE HARVESTING TIME IN THE VEGETATIVE GROWTH, YIELD AND QUALITY OF THE STORAGE ROOTS OF THREE CASSAVA CULTIVARSWith 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 Paraná 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%).

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

“…2, 3 and 4 contrast the productive performance of the storage root dry matter for Mico, IAC 13 and IAC 14 cultivars, respectively. Leaf dry matter yield indicated that the initial reduction in the storage root yield coincided exactly with the restructuring period of the plant photosynthesis apparatus and that the later increase and stabilization was probably related to the intensification on assimilate production by the photosynthesis apparatus (Sagrilo et al, 2002). Generally, for the cultivars under study, the performance of the storage root dry matter yield followed the same yield pattern as the stem dry matter, and the values of the first were always superior to those of the latter.…”

“…Rimoldi et al (2006) found that the traditional cultivars Caipira, Branca 1, Amarela 1, Amarela 2 and Fécula Branca showed high roots yields and starch contents, a good and regular cooking time, low HCN content, and also tolerance to the bacterial blight. Furthermore, Sagrilo et al (2002) assessed the performance of cassava cultivars in the Northwest Paraná at different harvest times and concluded that, for those conditions, the physiological rest period at the end of the second crop cycle was more indicated for harvest, due to the higher production of the storage root fresh and dry matter and starch. Sagrilo et al (2003) observed that the cultivars IAC 13, IAC 14 and Fécula Branca had high dry matter content in the storage roots.…”

Physicochemical properties of three sugary cassava landraces

“…However, this content is signifi cantly lower than that of conventional cassava (25-30g 100g -1 of root) (VIEIRA et al, 2008). Based on the estimated root productivity of the Manicueira 62 landrace (57.30ton ha -1 ), the yield in starch would be 2.19ton ha -1 while that a conventional 12-month-old cassava plant would be more than double (4.5ton ha -1 ) (SAGRILO et al, 2002).…”

Selectivity of clomazone and S-metolachlor applied after cassava pruning

“…According to Andrade et al (2011), cassava plants prunig during the dormant period increases the production of roots, which tend to present more dry mass and lower flour production at the end of the cycle. Likewise, Sagrilo et al (2002) observed that the second stage of the physiological rest of the varieties Mico, IAC 13 and IAC 14 was more beneficial to harvest than a single growing cycle due to the increased production of tuberous roots (92.5%), dry mass (125.0%), and starch (144.0%). These are important characteristics for the starch industry.…”

“…Cassava (Manihot esculenta), having originated from Brazil and being cultivated in over 90 countries, is a plant very tolerant to drought and low soil fertility, commonly grown and consumed by small farmers in areas of poor soils and where the weather conditions are often unfavorable to other cultures (Doretto, 1993;Sagrilo et al, 2002). However, it is one of the main economic sources of carbohydrates in the tropical regions, playing a key role in human and animal nutrition and in the industrial processing of flour and starch (Albuquerque et al, 2008).…”