Population dynamics of Meloidogyne graminicola and Hirschmanniella oryzae in a double rice-cropping sequence in the lowlands of Myanmar

Nematology ◽  
2013 ◽  
Vol 15 (7) ◽  
pp. 795-807 ◽  
Author(s):  
Pa Pa Win ◽  
Pyone Pyone Kyi ◽  
Zin Thu Zar Maung ◽  
Dirk De Waele
Keyword(s):  
Population Density ◽  
Growing Season ◽  
Lowland Rice ◽  
Population Densities ◽  
Rice Varieties ◽  
Meloidogyne Graminicola ◽  
Rice Plants ◽  
Double Rice ◽  
Heading Stage ◽  
Rice Growing Season

The rice root-knot nematode, Meloidogyne graminicola, and the rice root nematode, Hirschmanniella oryzae, are considered potentially important nematode pathogens in lowland rice. A study was undertaken from December 2009 until December 2010 in the Ayeyarwady River Delta, the major lowland rice-producing area of Myanmar, to monitor the population dynamics of M. graminicola and H. oryzae in a naturally infested field. Root samples of the two rice varieties Yatanartoe and Taungpyan that are commonly cultivated in double rice-cropping sequences in Myanmar and represent irrigated and rainfed lowland rice varieties, respectively, were obtained for nematode analysis. During the summer-irrigated rice-growing season the root population density of second-stage juveniles (J2) of M. graminicola showed two distinct peaks – at the maximum tillering stage of the rice plants in January and at the heading stage of the rice plants in March 2010. With the onset of the monsoon rains, the J2 population densities in the roots of ratoon rice plants gradually decreased in May. During the rainfed monsoon rice-growing season, very low population densities of M. graminicola J2 were detected in the roots of rice plants, while the root population density of H. oryzae juveniles and adults showed two distinct peaks – at the maximum tillering stage of the rice plants in August and at the heading stage of the rice plants in October 2010. With the onset of the dry season, population density of H. oryzae in the roots reached the lowest density at harvest in November. Root galling caused by M. graminicola followed the same trend as the J2 population densities throughout the irrigated season. No root galls were observed during the monsoon season. Our results can be used for practical purposes aimed at a better management of both M. graminicola and H. oryzae.

scholarly journals Quantification of Cultivar Change in Double Rice Regions under a Warming Climate during 1981–2009 in China

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 794 ◽  
Author(s):  
Xiaolei Qiu ◽  
Liang Tang ◽  
Yan Zhu ◽  
Weixing Cao ◽  
Leilei Liu
Keyword(s):  
Global Warming ◽  
Management Practices ◽  
Growing Season ◽  
Rice Production ◽  
Future Climate Change ◽  
Rice Productivity ◽  
Double Rice ◽  
Late Rice ◽  
Early Rice ◽  
Rice Growing Season

Maintaining high double rice productivity in China is very important for ensuring the food security of China. However, the double rice production system is sensitive to changes in both climate and management practices. Previous studies showed that rice production has been negatively impacted by global warming without considering the changes of cultivars and management practices. However, cultivar improvements and the impact of cultivar change must not be ignored in any assessment. In the current study, we combined data analysis with crop modeling to investigate the impacts of changes in climate and cultivars on rice productivity at three different double rice sites (Nanchang, Hengyang, and Gaoyao) in China. The results showed a warming trend at the study sites during 1981–2009, and the temperature increase rates (maximum, average, and minimum temperatures) in the late rice growing season were larger than in the early rice growing season. Global warming has led to a reduction in the length of the rice growth period. Adopting new rice cultivars may partially mitigate the declining trend of the growing duration and grain yield, but it would not completely compensate for the negative impact observed in double rice regions. In general, the changes in cultivars prolonged the growing duration by increasing the basic vegetative phase and the photoperiod formation phase. The main reasons for yield improvement were the increase in the percentage of filled grains for early rice and the increase in grain number per spike for late rice. In the face of future warming, breeding efforts are necessary for producing new cultivars that are resilient to the negative impacts of future climate change on agriculture.

scholarly journals Responses of Local Wheat Varieties to Greenbug Schizaphus graminum and Bird-Cherry Oat Aphid Rhopalosiphum padi Infestation

2021 ◽  
Vol 34 (1) ◽  
pp. 124-138
Author(s):  
Haider D. Al-Hussine ◽  
Aqeel A. Alyousuf
Keyword(s):  
Population Density ◽  
Rhopalosiphum Padi ◽  
Dry Weight ◽  
Growing Season ◽  
Abu Ghraib ◽  
Laboratory Studies ◽  
Population Densities ◽  
Wheat Varieties ◽  
Effective Role ◽  
Density Rate

Field and laboratory studies were conducted to assess the sensitivity of 12 varieties of local wheat varieties (IPA-95, IPA-99, Abu-Ghreib, Babel-113, Bhooth-10, Bhooth-22, and Bhooth-158, Baraka, Tammuz, Fatih, Latifia and Rasheed) against infestation by Greenbug Shizaphis graminum and Bird-Cherry Oat Aphid Rhopalosihum padi in the province of Basrah. The field trial was carried out in Al-Nashwa district, county of Shatt Al-Arab, during the growing season 2019/2020. The first infestation of R. padi appeared on 9/1/2020, and reached the peak of population density on 30/1/2020, while the first appearance of S. graminum was on 17/1/2020; it reached its peak on 13/2/2020. The results of responses of local wheat varieties to the infestation of Greenbug showed that the highest average population density of greenbug was on Bhooth-158, Abu-Ghraib, Bhooth-22, and Babel-113 reaching 51.59, 17.84, 16.41, and 16.63 aphids/plant, respectively. Whereas the lowest population densities were at Fatih, Tammuz, Bhooth-10, Rasheed, and IPA-99, with averages of 8.28, 8.09, 8.87, 7.19, and 7.62 aphids.plant-1, respectively. The highest density rate of R. padi was recorded on the cultivars IPA-95 and Abu-Ghraib, with an average of 139.83 and 169.31 aphids.plant-1 respectively, while the verities Bhooth-22, Bhooth-158, and IPA-99 recorded the lowest population density rate (89.03, 99.41, and 100.25 aphids.plant-1) compared to the other varieties. The results of the chemical analysis determined the proportions of some metabolites of the local wheat varieties and their relationship to the infestation of Greenbug and showed that phenols have an effective role by reducing the population density of aphids. The verities Rasheed and IPA-99 which recorded low population rates of the aphids have the highest rates of phenols at a rate of 7 and 6.78 mg.100g-1 dry weight Also, varieties Abu-Ghraib, IPA-99, and Rasheed cultivars recorded the highest productivity rates (weight of thousand grains), with an average of 33.47, 43, and 67.42 g, respectively.

EFFECTS OF ROW SPACING AND POPULATION DENSITY ON GRAIN SORGHUM PRODUCTION IN SOUTHERN ALBERTA

1976 ◽  
Vol 56 (1) ◽  
pp. 31-37 ◽  
Author(s):  
B. R. HEGDE ◽  
D. J. MAJOR ◽  
D. B. WILSON ◽  
K. K. KROGMAN
Keyword(s):  
Population Density ◽  
Grain Yield ◽  
Yield Components ◽  
Growing Season ◽  
Grain Sorghum ◽  
Row Spacing ◽  
Population Densities ◽  
Southern Alberta ◽  
Sorghum Production ◽  
Narrow Row

Row spacings of 18–72 cm and population densities of 75,000 to 346,000 plants/ha had no consistent effect on grain yield of two sorghum hybrids (Pride X4004 and Pride X4053) because of compensating variations within yield components. Grain yield per panicle increased as row spacing increased but this was offset by a decrease in panicles per plant and panicles per square meter. Grain yield per panicle, panicles per plant, and panicles per square meter decreased as population density increased. The choice of row spacing and population density in field production will, therefore, depend on convenience factors related to crop management. Evapotranspiration for the growing season was 179 mm in 1973 and 204 mm in 1974. Highest water use efficiencies occurred at the low population densities and narrow row spacings. There were differences between the two hybrids. Grain yield of Pride X4004 was greater than that of Pride X4053 because the former produced a greater number of seed-bearing tillers. Grain yield differences in Pride X4004 among the three experiments were due to differences in grain yield per panicle.

scholarly journals Cowpea and beet intercropping agro-economic dynamics under spatial arrangement and cowpea population density

2020 ◽  
Vol 38 (2) ◽  
pp. 192-203 ◽  
Author(s):  
Aridênia P Chaves ◽  
Francisco Bezerra Neto ◽  
Jailma SS Lima ◽  
Josimar N Silva ◽  
Renato LC Nunes ◽  
...  
Keyword(s):  
Experimental Design ◽  
Population Density ◽  
Economic Efficiency ◽  
Maximum Yield ◽  
Growing Season ◽  
Spatial Arrangement ◽  
Productivity Index ◽  
Population Densities ◽  
System Productivity ◽  
Growing Seasons

ABSTRACT The objective of this work was to evaluate the effect of planting spatial arrangements between the cowpea and beet crops in intercropping and of cowpea population densities on the crop’s productivity and in the agro-economic efficiency of the association at two growing seasons. The experimental design was of randomised blocks with the treatments arranged in a 4 x 3 factorial scheme, in four replications. The first factor was constituted by three spatial arrangements between the component cultures (2:2, 3:3 and 4:4), formed by beet rows alternated with cowpea rows, while the second factor was constituted by the population densities of cowpea: 40, 60, 80 and 100% of the recommended population in single crop (RDSC). The production and its components were evaluated in the beet and cowpea. Apart from these characteristics, the following agro-economic indicators were also determined for each treatment: system productivity index (SPI), the land equivalent coefficient (LEC), and the monetary equivalent ratio (MER). The maximum production of commercial beet roots was obtained with 15.60 t ha-1 productivity at density of 61.82% of RDSC within the 4:4 arrangement, while the maximum yield of cowpea green grains of 2.23 t ha-1 was reached at density of 79.57% of RDSC within 2:2 spatial arrangement. The productivities of beet roots of extra A, extra AA and great types decreased with increasing cowpea population density, without any influence of the tested spatial arrangements. The maximum mean productivity of cowpea green pods of 1.74 t ha-1 was obtained at density of 87.47% of RDSC, reached within 2:2 spatial arrangement. The maximum economic efficiency of the cowpea-beet intercropping was obtained with MER of 1.11 at cowpea density of 100% of RDSC, irrespective of the spatial arrangement and growing season.

scholarly journals Understanding Farmer and Government Measure in Rat Pests Control in Rice Fields

2021 ◽  
Vol 2 (2) ◽  
pp. 24-30
Author(s):  
Thuy Xuan ◽  
Tiuen Yen ◽  
Tuyet Caugh
Keyword(s):  
Population Density ◽  
Rice Field ◽  
Growing Season ◽  
Rice Paddy ◽  
The Other ◽  
Cropping Pattern ◽  
Population Peak ◽  
Government Measure ◽  
Intensive Control ◽  
Rice Growing Season

This paper discusses the control of rat pets through highlighting its population growth, ecosystem, types and possible mechanism to use. During extended periods of fallow, rice field rats tend to congregate in escape places (refuge regions) such as bushes, yards, or rice warehouses. Rice plants suffered damage equivalent to five times their feeding requirements when rats were present. Rats damage plants from the tiller stage to the maximal tiller stages by devouring the growth point and the soft base of the stem while leaving the other portions of the plant unharmed. Without intensive control efforts (since the start of MT1), the rat population density on MT2 is confirmed to be higher and poses a serious threat to the success of MT2 harvesting. In one rice growing season, there is one population peak so in the rice-paddy-fallow cropping pattern there are two (2) population peaks.

The effect of varying plant population density on the seed yield of Navy beans (Phaseolus vulgaris)in south-east Enland

1977 ◽  
Vol 88 (3) ◽  
pp. 567-576 ◽  
Author(s):  
D. H. Scarisbrick ◽  
J. M. Wilkes ◽  
R. Kempson
Keyword(s):  
Phaseolus Vulgaris ◽  
Population Density ◽  
Seed Yield ◽  
Plant Density ◽  
Growing Season ◽  
Plant Population ◽  
Population Densities ◽  
Growing Seasons ◽  
Navy Beans ◽  
Plant Population Density

SUMMARYNavy beans were precision drilled in 1973–5 at a range of plant population densities. Within each growing season the density treatments did not influence seed yield, but mean yields differed significantly between years. The results suggest that cultivars similar to Purley King can only be regarded as a reliable break crop in a season such as 1973 which was slightly warmer and drier in mid-summer than average. Although the rate of drying increased with increasing plant density in two of the growing seasons, no practical advantages are proposed.

scholarly journals Response of rain-fed lowland rice varieties to different sources of N fertilizer in Fogera Plain, Northwest Ethiopia

2019 ◽  
Vol 5 (1) ◽  
pp. 1707020
Author(s):  
Amare Aleminew ◽  
Getachew Alemayehu ◽  
Enyew Adgo ◽  
Tilahun Tadesse ◽  
Manuel Tejada Moral
Keyword(s):  
Northwest Ethiopia ◽  
N Fertilizer ◽  
Lowland Rice ◽  
Rice Varieties ◽  
Different Sources

scholarly journals Effect of Heat Resource Effectiveness Change on Rice Potential Yield in Southern China

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 896
Author(s):  
Qing Ye ◽  
Xiaoguang Yang ◽  
Wenjuan Xie ◽  
Junmeng Yao ◽  
Zhe Cai
Keyword(s):  
Southern China ◽  
Cropping Systems ◽  
Reduction Rate ◽  
Growing Season ◽  
Scientific Basis ◽  
Yield Reduction ◽  
Percentage Increase ◽  
Potential Yield ◽  
Effective Heat ◽  
Rice Growing Season

During the rice growing season, farmers’ decisions about cropping systems and seed varieties directly affect the utilization of heat resource, and eventually affect the potential yield. In this study, we used the hourly accumulated temperature model to calculate the available heat resource as well as the effective heat resource in southern China. We conducted a spatiotemporal analysis of the heat resource effectiveness during rice growing season and an impact assessment of heat resource effectiveness on rice potential yield and cereal yield reduction. The results showed that, during the period of 1951–2015, heat resource effectiveness generally declined in the rice cropping area of southern China. And this decrease worsened during the most recent three decades compared with the period of 1951–1980. A strong correlation was detected between heat resource effectiveness and rice potential yield in the study area. When the effective heat resource during the growing season increased by 1 °C·d, rice potential yield would increase by 14 kg ha−1. For each percentage increase in heat resource effectiveness, the rice potential yield reduction rate would go down by 0.65%. This agro-climatological study aims to offer a scientific basis for rice production decisions in southern China, such as when to plant, which varieties to choose and so on.

Effects of crop sequence and rainfall on population dynamics of Fusarium solani f.sp. phaseoli in soil

1992 ◽  
Vol 70 (10) ◽  
pp. 2005-2008 ◽  
Author(s):  
Robert Hall ◽  
Lana Gay Phillips
Keyword(s):  
Population Dynamics ◽  
Phaseolus Vulgaris ◽  
Population Density ◽  
Fusarium Solani ◽  
Population Densities ◽  
Total Rainfall ◽  
Colony Forming Units ◽  
Bean Crop ◽  
Previous Summer ◽  
Crop Sequence

Evidence is presented that population dynamics of Fusarium solani f.sp. phaseoli in soil depend on the effects of crop sequence and rainfall on parasitic activities of the pathogen. In a rotation trial started in 1978 and conducted over 14 years, population densities (colony-forming units/g) of the fungus in soil remained below 50 in treatments (fallow, repeated corn, repeated soybean) where the preferred host plant (common bean, Phaseolus vulgaris) was not grown. Where bean was grown every 3rd year or every year, population densities reached 475 and 660, respectively, by 1984. Thereafter, population densities of the fungus fluctuated widely from year to year in both rotation and repeated bean treatments. In the rotation treatment, peaks in population density of the pathogen coincided with the years of bean production. In repeated bean plots between 1985 and 1991, population density of the fungus in June was significantly correlated (r = 0.77, p = 0.04) with total rainfall received during the previous summer (June–August). It is postulated that higher rainfall during the growing season of the bean crop stimulated root growth and root infection, leading to the accumulation of higher levels of potential inoculum in infected tissue and the release of higher levels of inoculum into the soil by the following June. Key words: Fusarium solani f.sp. phaseoli, bean, Phaseolus vulgaris, rainfall, crop rotation.

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