Crop rotation sequencing to minimize yield losses of summer-irrigated lowland rice in Myanmar caused by the rice root-knot nematode Meloidogyne graminicola

Abstract

The effect of different rice-based crop rotation sequences on the population densities of Meloidogyne graminicola and on the yield of rice was evaluated in a microplot experiment under lowland rice field conditions. Ten treatments of cropping sequences were grown in four successive growing seasons: continuous growing of the susceptible rice cultivar Thihtatyin (rice-rice-rice-rice), four treatments of 1- season crop rotation sequences (rice-rice-chickpea-rice, rice-rice-black gram-rice, rice-rice-soybean-rice, rice-rice-cowpea-rice), and five treatments of 2-season crop rotation sequences (groundnut-rice-chickpea-rice, green gram-rice-black gram-rice, cowpea-rice-soybean-rice, sesame-rice-cowpea-rice, sunflower-rice-sesame-rice). Population densities of M. graminicola recovered from the rice plants and the nematode multiplication factors (Mf) in the soil in the continuous rice cropping sequence (rice-rice-rice-rice) was the highest among the ten cropping sequences. Lowest nematode Mf in the soil was observed in the 2-season crop rotation sequence sunflower-rice-sesame-rice and the highest was observed in the 1-season crop rotation sequence rice-rice-cowpea-rice among the nine crop rotation sequences. Highest rice yield was obtained in the 2-season crop rotation sequences green gram-rice-black gram-rice, sesame-rice-cowpea-rice and sunflower-rice-sesame-rice, which were about 2 times higher compared with the 1-season crop rotation sequences and about 3 times higher compared with the continuous rice cropping sequence.     

Variance in leaf spot susceptibility in chestnut trees of different species and hybrids

Journal of Plant Diseases and Protection - Prior to the first occurrence of chestnut blight in 1976, leaf spot caused by Cylindrosporium castaneae was one of the most important diseases of European...     

Effect of dietary Schizochytrium microalga oil and fish oil on plasma cholesterol level in rats

The purpose of the study was to test the hypothesis that the dietary oils with different content of n‐3 polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) affect plasma lipid level in rats in a different degree. The diets with 6% of fish oil (FO) and Schizochytrium microalga oil (SchO; EPA+DHA content in the diets 9.5 + 12.3 and 2.6 + 29.5% of the sum of total fatty acids, respectively) were used; the diet with 6% of safflower oil (high content of n‐6 PUFA linoleic acid, 65.5%; EPA+DHA content 0.7 + 0.9%) was used as a control. The difference between FO and SchO was established only in the case of plasma triacylglycerol (TAG) level: plasma TAG of the FO‐fed rats did not differ from the control rats (p > 0.05), while SchO decreased (p < 0.05) plasma TAG to 46% of the control. On the other hand, FO and SchO decreased (p < 0.05) total plasma cholesterol (TC) in rats in the same extent, to 73% of the control. Regarding the underlying mechanisms for the TC decrease, both SchO and FO up‐regulated hepatic Insig‐1 gene (181 and 133% of the control; p < 0.05), which tended (p = 0.15 and p = 0.19 respectively) to decrease the amount of hepatic nSREBP‐2 protein (61 and 66% of the control). However, neither SchO nor FO influenced hepatic 3‐hydroxy‐3‐methyl‐glutaryl‐CoA reductase gene expression (p > 0.05); SchO (but not FO) increased (p < 0.05) low‐density lipoprotein receptor mRNA in the liver. It was concluded that the decrease of total plasma cholesterol might be caused by an increased cholesterol uptake from plasma into the cells (in the case of SchO), but also by other (in the present study not tested) mechanisms.     

Entomofauna jetele (Trifolium pratense L.) a jejívývoj. Entomofauna des Kleefeldes (Trifolium pratense L.) und ihre Entwicklung

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Stand structure of an uneven-aged fir–beech forest with an irregular diameter structure: modeling the development of the Belevine forest, Croatia

This study focuses on the problem of irregular diameter structure in a silver fir–beech selection (plenter) forest with a “surplus” of large diameter trees and a lack of natural regeneration and small diameter trees. We sampled 274 plots (900 m² each) in the Belevine research site (266.24 ha) in the mountain region Gorski Kotar (Croatia), where diameter (dbh) distribution, diameter increment, and natural regeneration were analyzed in detail. A low density of natural regeneration, weak annual recruitment of small (10 cm dbh) diameter trees (only five trees per hectare), delayed diameter growth of trees, and a low annual rate of trees reaching the next dbh class were attributed to the current irregular dbh structure. The stand development prediction for the next 50 years is based on a simulation model, which considers the current diameter structure, increment, recruitment, and future cutting regime. Intensive cutting in the first of five 10-year cutting cycles (intensity higher of 25%) is needed to initiate natural regeneration and to accelerate growth of young silver fir trees. In the next 50 years, the irregular diameter structure will be gradually improved.     

LATEX paint as an antifeedant againstHylobius abietis (L.) (Col., Curculionidae) on conifer seedlings

LATEX paint in water solution applied to newly planted conifer seedlings was found to prevent damage byHylobius abietis adult weevils for the whole season. Treatment of the basal third of the trunk was sufficient. Also, utilisation of the results as a model for deerantifeedant treatments and protection againsts the weevils is recommended.With 1 figure     

Buchbesprechungen

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Experimentelle Infizierung einiger anБereuropäischerPinus-Arten durch die KiefernnadelgallmückeThecodiplosis brachyntera (Schwägr.)(Diptera,Cecidomyiidae)

Zusammenfassung Die KiefernnadelgallmückeThecodiplosis brachyntera (Schwägr.), die in Europa anPinus sylvestris L.,P. mugo Turra undP. nigra Arnold lebt, wurde im Arboretum Bolevec in Westböhmen auch an der nordamerikanischen KiefernartPinus resinosa Aiton und den ostasiatischen KiefernartenPinus tabuliformis Carriere undP. yunnanensis Franchet festgestellt.Experimentell gelang es durch die Kiefernnadelgallmücke vonPinus mugo subsp.mughus (Scop.) Domin, auch die obengenannten außereuropäischen Kiefernarten und als Kontrolle die europäischen ArtenPinus sylvestris L. undPinus mugo subsp.uncinata (Ant.) Domin zu infizieren. Experimentelle Infizierung war erfolglos an den Kiefernarten:Pinus cembra subsp.alpina (Rikli),P. strobus L.,P. rigida Miller,P. radiata D. Don.,P. echinata Miller,P. contorta Douglas undP. thunbergii Parlatore.Die Ursache der Nichtinfizierung der untersuchten Kiefernarten kann folgenden Ursprung haben: Unterschiede in dem Chemismus, besonders in der Qualität und Quantität der Terpene im Innern der Nadeln, oder: Unterschiede in der Gestalt der Nadeln, besonders die Nichtanwesenheit der Nadelscheide, die den Basalteil der Nadeln umhüllt und deshalb die Entwicklung der Eier und Larven nicht ermöglicht, oder aber: es waren morphologisch die Nadeln in der Zeit der Infizierung für die Eiablage nicht geeignet — entweder noch mit Schutzschuppen bedeckt, oder schon zu groß entwickelt.Die befallenen Nadeln der außereuropäischen Arten waren verkürzt, in dem Basalteile grö ßtenteils einige mm zusammengewachsen. Die Lavalkammer befand sich in der Mehrzahl der Fälle in der Nadelbasis.Nach den gewonnenen Ergebnissen erscheint es notwendig, eine taxonomische Revision der 5 von 11 nordamerikanischen Kiefernarten beschriebenen Gallmückenarten durchzuführen.

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Summary The Needle shortening gall midgeThecodiplosis brachyntera (Schwägr.) occurring in Europe on the pinesPinus sylvestris L.,P. mugo Turra andP. nigra Arnold was found in an Arboretum in Bolevec in Western Bohemia on the North American speciesP. resinosa Aiton and on the East Asian speciesP. tabuliformis Carriere andP. yunnanensis Franchet.The following non-European species:Pinus resinosa Aiton,P. tabuliformis Carriere andP. yunnanensis Franchet and European species:P. sylvestris L. andP. mugo subsp.uncinata (Ant.) Domin were experimentally infested withThecodiplosis brachyntera (Schwägr.) fromPinus mugo subsp.mughus (Scop.) Domin. The experimental infestation was not successful in the case ofPinus cembra subsp.alpina (Rikli),P. strobus L.,P. rigida Miller,P. radiata D. Don.,P. echinata Miller,P. contorta Douglas andP. thunbergii Parlatore.The failure to infest some pine species might have three causes: the chemical compositions of the pine needles differed; the sheath shielding the basal part of brachyblast was missing; the needles of some pine species were not in the right state for oviposition and development of larvae at the time of infestation — they were either too mature or completely covered with scales.Infested needles of the non-European species were considerably shortened compared with non-infested ones. Their basal part usually coalesced for several mm and in most cases the larval chamber was situated right in the base of the needle.Results mentioned above showed the necessity of revision of the taxonomic position of 5 gall midge species developing in the bases of 11 North-American pine species.

     

Metody Chovu Hmyzu

Ohne Zusammenfassung