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Santa Bárbara d'Oeste, Brazil

The aim of this work was evaluate the physiological indicators of association between water deficiency and soil acidity, by determining the nitrate reductase activity, the levels of free proline and initial growth of the root system of seedlings of sugarcane cv. IAC91-5155. After 30 days, the seedlings were transferred to plastic pots with 12 dm3 of dystrophic alic Red Latosol (Oxisol) and submitted to association of three treatments of water availability: no stress (70%), moderate stress (55%) and severe stress (40%), in according with field capacity and three acidity treatments: no stress (55%), moderate stress (33%) and severe stress (23%), considering the base saturation. The experimental design was that of random blocks under factorial scheme of 3×3, with four replicates. After 60 days under the stress association, the levels of free proline, the nitrate reductase activity and the growth of the sugarcane roots system were evaluated in seedlings of sugarcane. The nitrate reductase enzyme activity can be considered a physiological indicator of the effect of the association of acid and water stress in moderate conditions in soil, while the free proline can be considered physiological indicator to both stress in severe conditions. Water deficiency increasing reduced growth of sugarcane roots. Source


Queiroz R.J.B.,Sao Paulo State University | dos Santos D.M.M.,Sao Paulo State University | Ferraudo A.S.,Sao Paulo State University | Carlin S.D.,APTA Polo Centro Oeste | Silva M.A.,Sao Paulo State University
Scientia Agricola | Year: 2011

For sugarcane (Saccharum spp.) crops, the effects of an environmental stress, especially water deficiency, may cause severe productivity reduction, inferring negatively in the sugarcane industry. The tolerance of two sugarcane cultivars to a lack of water was made by analyzing the levels of the osmoprotectors, trehalose and free proline, and the biometrical variables of their initial growth. Biochemical and physiological responses of the cultivars, when subjected to water stress, were assayed to determine how these plants tolerate drought. The study was conducted in an acclimatized greenhouse (29.7 ± 4.3°C and 75.0 ± 10.1% relative humidity) during 100 days and was divided into random blocks using a factorial 2 × 3 × 2 design (sugarcane cultivars × water availability × time periods) with four replicates. Forty days after germination, sugarcane was planted in pots (12 dm 3) containing topsoil material taken from a medium textured Rhodic Ferralsol, submitted to three levels of water availability (WAS): 55% (control), 40% (moderate stress) and 25% (severe stress), for 60 days. The effect of the WAS on the accumulation of trehalose and free proline was detected in both cultivars, although it was found to be more distinctive for the cv. IAC91-5155. Trehalose and free proline are biochemical and physiological indicators of water deficiency. The cv. IAC91-5155 had altered growth and allocation of biomass when subjected to severe water stress conditions. The univariate and the multivariate analysis of the biochemical and physiological responses, presented by the IAC91-5155 cultivar, indicate relative tolerance to drought conditions. Source


Wilcken S.R.S.,Sao Paulo State University | Rosa J.M.O.,Sao Paulo State University | Higuti A.R.O.,Sao Paulo State University | de Garcia M.J.M.,APTA Polo Centro Oeste | Cardoso A.I.I.,Sao Paulo State University
Horticultura Brasileira | Year: 2010

Grafting is an alternative technique often recommended for the cucumber crop in root-knot nematodes infested areas. This study aimed to determine the reproduction factor of Meloidogyne javanica and M. incognita race 2 on six rootstocks for cucumber (squash 'Menina Brasileira, pumpkim 'Exposição', 'Shelper', 'Tetsukabuto', 'B8-A Tetsukabuto' and 'Excite Ikki') and four cucumber (Cucumis sativus) Japanese type hybrids of ('Yoshinari', 'Kouki', 'Taisho' and 'Tsuyataro'). Two experiments were carried out in greenhouse, each one with a nematode specie. Each plot consisted of one plant per pot containing 2 liters of autoclaved soil. Nine days after the seedlings transplantation, each plant was inoculated with 5,000 eggs and second-stage juveniles (initial population - Pi) of M. javanica or M. incognita race 2. 'Rutgers' tomatoes were used as a standard for inoculum viability in both experiments. The experimental design was completely randomized with five replicates per treatment. Sixty days after inoculated, each plant was evaluated, when root fresh weight, total number of nematodes in the soil and in the roots (final population - Pf), nematodes number per gram of root and the reproduction factor of both Meloidogyne species (FR=Pf/Pi) were determined. All rootstocks and cucumber hybrids allowed the M. javanica and M. incognita race 2 multiplication, but, generally, reproduction factor values were greater in cucumbers than in rootstocks. Source


Wilcken S.R.S.,Sao Paulo State University | Rosa J.M.O.,Sao Paulo State University | Westerich J.N.,Sao Paulo State University | Garcia M.J.M.,APTA Polo Centro Oeste | Cardoso A.I.I.,Sao Paulo State University
Horticultura Brasileira | Year: 2013

This study aimed to determine the resistance of six rootstocks for cucumber (squash 'Menina Brasileira', pumpkin 'Exposição', 'Shelper', 'Tetsukabuto Takaiama', 'B8-A Tetsukabuto' and 'Excite Ikki') and four Japanese cucumber hybrids ('Yoshinari', 'Kouki', 'Taisho' and 'Tsuyataro') to Meloidogyne enterolobii. The experiment was conducted in greenhouse; each plot consisted of one plant per pot containing 2 liters of autoclaved soil. The experimental design was completely randomized, with five replicates per treatment. Two days after transplanting the seedlings, each plant was inoculated with 5,000 eggs and second-stage juveniles (initial population = Pi) of M. enterolobii. Tomato 'Rutgers' was used as indicative of inoculum viability. Sixty days after inoculated, each plant was evaluated for total number of nematodes in the roots (final population = Pf) and reproduction factor (FR=Pf/Pi). All rootstocks and cucumber hybrids allowed M. enterolobii multiplication, but FR values were lower in 'Shelper', 'Excite Ikki KY' and 'Menina Brasileira' rootstocks. In a second experiment, the low FR in these three rootstocks was confirmed, but with higher values in 'Menina Brasileira'. So, these rootstocks can be recommended to M. enterolobii infested areas, but with low populations, because they don't permit great multiplication of the patogen. It is concluded that 'Shelper' and 'Excite Ikki KY' rootstocks had the lowest FR and can be classified as moderate resistant to this nematode. Source


Gava G.J.C.,APTA Polo Centro Oeste | Silva M.A.,APTA Polo Centro Oeste | da Silva R.C.,University of Sao Paulo | Jeronimo E.M.,APTA Polo Centro Oeste | And 2 more authors.
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2011

This study aimed to evaluate the effect of drip irrigation technology in different sugarcane varieties in two crop cycles (plant cane and ratoon). The experimental design was in completly randomized blocks, in split-plot with four replications, constituted by three sugarcane genotypes: RB867515; RB855536 and SP80-3280 and two crop management: drip irrigation system and rainfed system, totalizing six treatments. The first cycle lasted for 336 days, with rainfall of 1,480 mm. The volume of water provided by the system of drip irrigation was 400 mm, totaling 1,880 mm. The second cycle lasted for 365 days, the volume of water through rainfall was 1,394 mm, added to 320 mm provided by the system of irrigation, totaled 1,714 mm. Interaction between management and cultivars was found significant for the variables: productivity of stalks (TCH) and sugar yield (TPH), in which the largest difference was observed for cultivar SP80-3280. There was significant response to drip irrigation, on average the increase of production of stalks and sugar was 24 and 23%, respectively. Source

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