Quantification of yield losses with relation to sheath blight development at different growth stages in mega rice varieties of South Asia

2021 ◽  
Author(s):  
Jagjeet S. Lore ◽  
Jyoti Jain ◽  
Mandeep S. Hunjan ◽  
Pritpal Singh ◽  
Sanjay Kumar ◽  
...  
2012 ◽  
Vol 5 (1) ◽  
pp. 45-55 ◽  
Author(s):  
P. Gautam ◽  
R. Dill-Macky

Fusarium graminearum Schwabe [teleomorph Gibberella zeae (Schwein) Petch] is the predominant causal agent of Fusarium head blight (FHB), an economically important disease of wheat, in North America. Warm and humid environments at and shortly after anthesis favour FHB. FHB results in yield losses and quality losses in infected grain due to the accumulation of mycotoxins produced by the invading fungus. The objective of this study was to characterise the influence of different F. graminearum isolates and host resistance on FHB development and mycotoxin accumulation. A series of two greenhouse experiments were established where five single isolates of F. graminearum were tested. Three wheat cultivars were examined: Alsen (moderately resistant), 2375 (moderately susceptible) and Wheaton (susceptible). In the point-inoculation experiments, ca. 1000 conidia were placed into a central spikelet of spikes at anthesis. Point-inoculated spikelets were sampled at different growth stages up to soft dough stage. Samples from both experiment series were analysed for mycotoxins. The susceptible cultivar Wheaton had both the highest FHB severity and mycotoxin accumulation. The spread of symptoms both below and above the inoculated central spikelet was significantly higher in 2375 and Wheaton than Alsen. Though deoxynivalenol (DON) did not peak and decline in all experiments, when a peak in the DON content was present it was earlier in 2375 (early milk) than in either Alsen (early dough) or Wheaton (late milk). Though the isolates did not rank similarly in all experiments and in all cultivars, generally isolates Butte86Ada-11 and B63A were more aggressive and isolates 49-3 and B45A were less aggressive in terms of disease severity and mycotoxin accumulation.


2009 ◽  
Vol 60 (4) ◽  
pp. 328 ◽  
Author(s):  
C. Ye ◽  
S. Fukai ◽  
I. Godwin ◽  
R. Reinke ◽  
P. Snell ◽  
...  

Low temperature is a common production constraint in rice cultivation in temperate zones and high-elevation environments, with the potential to affect growth and development from germination to grain filling. There is a wide range of genotype-based differences in cold tolerance among rice varieties, these differences often reflecting growth conditions in the place of origin, as well as breeding history. However, improving low temperature tolerance of varieties has been difficult, due to a lack of clarity of the genetic basis to low temperature tolerance for different growth stages of the rice plant. Seeds or plants of 17 rice varieties of different origins were exposed to low temperature during germination (15°C), seedling, booting, and flowering stages (18.5°C), to assess their cold tolerance at different growth stages. Low temperature at the germination stage reduced both the percentage and speed of germination. Varieties from China (B55, Banjiemang, and Lijianghegu) and Hungary (HSC55) were more tolerant of low temperature than other varieties. Most of the varieties showed moderate levels of low temperature tolerance during the seedling stage, the exceptions being some varieties from Australia (Pelde, YRL39, and YRM64) and Africa (WAB160 and WAB38), which were susceptible to low temperature at the seedling stage. Low temperature at booting and flowering stages reduced plant growth and caused a significant decline in spikelet fertility. Some varieties from China (B55, Bangjiemang, Lijiangheigu), Japan (Jyoudeki), the USA (M103, M104), and Australia (Quest) were tolerant or moderately tolerant, while the remaining varieties were susceptible or moderately susceptible to low temperature at booting and flowering stages. Three varieties from China (B55, Lijianghegu, Banjiemang) and one from Hungary (HSC55) showed consistent tolerance to low temperature at all growth stages. These varieties are potentially important gene donors for breeding and genetic studies. The cold tolerance of the 17 rice varieties assessed at different growth stages was correlated. Screening for cold tolerance during early growth stages can therefore potentially be an effective way for assessing cold tolerance in breeding programs.


1968 ◽  
Vol 8 (34) ◽  
pp. 587
Author(s):  
PC Owen

A series of differing leaf area index regimes during the growth of two tropical rice varieties was produced by partial defoliation at different growth stages. In addition, part of the crop was completely defoliated after panicle emergence. Comparison of the effects of the range of leaf area durations (D) thus produced showed that these rice varieties differed from temperate climate cereals. Grain yields were least associated with D after panicle emergence, but were most influenced by D before emergence. This effect is mainly via an influence upon the number of spikelets formed per panicle. Grain : leaf ratio, a measure of photosynthetic efficiency, was considerably lower than values reported for wheat.


2017 ◽  
Vol 28 (1) ◽  
pp. 42-54
Author(s):  
R Sen ◽  
NN Karim ◽  
MT Islam ◽  
AKM Adham

A study was carried out to analyze the rainfall and evapotranspiration for successful planning of two aman rice varieties i.e., BRRI dhan33 and BRRI dhan34 in Bogra and Dinajpur districts of Bangladesh. Reference crop evapotranspiration (ET0) was determined by employing the FAO Penman-Monteith method. By multiplying ET0by crop coefficient (Kc) actual evapotranspiration of the two rice varieties at different growth stages was determined. Probability analysis was done by Weibull’s method and the expected rainfall and actual evapotranspiration at 75% probability level were estimated for different growth stages of BRRI dhan33 and BRRI dhan34 for 14 years. The results revealed that the ETc varied over the total growing season. After probability analysis, the supplemental irrigation was calculated for BRRI dhan33 during mid and late stages; but for BRRI dhan34, it was calculated during development, mid and late stages in Bogra and Dinajpur districts. The study was found quite effective to assess the water availability period for aman cultivation and to indicate when supplemental irrigation is necessary. These results may enable to optimize utilization of valuable water resources and will help to create an irrigation schedule for BRRI dhan33 and BRRI dhan34 for their successful cultivation.Progressive Agriculture 28 (1): 42-54, 2017


Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 239 ◽  
Author(s):  
Chengxin Zheng ◽  
Zhanyu Zhang ◽  
Shurong Hao ◽  
Wenmeng Chen ◽  
Yongchun Pan ◽  
...  

Many water-saving techniques have been developed for rice production in response to irrigation water scarcity. The selection of the water-saving methods and the optimum thresholds for obtaining maximum benefits of these regimes are largely site-specific depending mainly on soil type, soil texture, and the environment. A two-year (2017 and 2018) experiment was conducted to evaluate the response of the agronomic growth performance, yield, and water use of super rice varieties under different irrigation regimes in Jiangsu Province, China. The irrigation regimes were comprised of different water-controlled thresholds, in different growth stages. Treatments included traditional flooding irrigation (FI, as the control) and the following four water-saving irrigation (WSI) regimes: shallow adjusting irrigation (WSI1), rainwater-catching and controlled irrigation (WSI2), controlled irrigation (WSI3), and drought planting with straw mulching (WSI4). The results showed that WSI treatments significantly increased the irrigation water use efficiency by 20.60% to 56.92% as compared with FI. The WSI treatments significantly decreased the crop evapotranspiration during the rice growth period. The grain yields of WSI1, WSI2, and WSI3 were significantly increased (6.62%~7.20% for WSI1, 8.21%~12.39% for WSI2, and 8.30%~12.91% for WSI3) as compared with that of the control, whereas WSI4 decreased the rice yield by 11.69%~18.10%. This research implies that WSI2 and WSI3 have the greatest potential for promotion in the lower reaches of the Yangtze River. An optimization of the irrigation threshold of WSI1 and WSI4 should be considered to guarantee the overall benefit.


1988 ◽  
Vol 28 (3) ◽  
pp. 343 ◽  
Author(s):  
DP Heenan ◽  
LG Lewin ◽  
DW McCaffery

The salt tolerance of several Australian and overseas rice varieties was studied at germination, early vegetative growth, and reproductive development in a temperature controlled glasshouse to determine the reliability of screening at any particular stage. At all 3 stages, varieties differed in their degree of tolerance, but the order of tolerance varied considerably between stages. Of the varieties used, the Australian long grain variety Pelde was tolerant for germination but most intolerant during early vegetative growth and reproductive development. The Japanese variety Somewake was intolerant during germination and vegetative growth but most tolerant during reproductive development. Linear regressions showed inverse relationships (r2 = 0.97-0.73) between sodium concentration in the shoots during early growth and shoot dry weight for most varieties. For Pelde, dry matter production was most closely related to potassium concentration in the shoots (r2 = 0.92).


2010 ◽  
Vol 2 (2) ◽  
pp. 230-233 ◽  
Author(s):  
Ramji Singh ◽  
Laxmi Shankar Singh ◽  
Durga Prasad ◽  
R.S. Kureel ◽  
Rakesh Sengar ◽  
...  

The present paper deals with most susceptible growth stage of rice with different farms and quantitiy of inoculum for development of sheath blight of rice by Rhizoctonia solani.Among seven different growth stages of rice crop i.e. seedling, initial tillering, maximum tillering, boot leaf, panicle emergence, flowering and dough stage, the flowering stage was found to be most susceptible and highly prone for sheath blight development, while seedling stage was found to be least susceptible and with low proneness for disease development. Disease severity, number and length of lesions get increased with the increasing crop growth stages up to flowering stage and thereafter disease severity decreases with the increases in further growth stages of rice plant. Among four different growth stages of the pathogen (inoculum capacity) i.e. five days old mycelium, seven days old mycelium, milky sclerotial stage and mature sclerotial stage which were inoculated at maximum tillering stage of rice plants, five days old mycelial inoculum was found to be most virulent. Disease severity decreased and incubation period increased with further ageing of inoculum. Among five different amount of inoculum (inoculum density) i.e. 0.20 mg, 5.50 mg, 6.00 mg, 7.00 mg and 8.00 mg of sclerotial inoculum, which were inoculated at maximum tillering stage of rice plants, highest disease severity and minimum incubation period was observed with 8.00 mg amount of sclerotial inoculum. Whereas, least disease severity and longest incubation period was observed when inoculation was done with 0.2 mg of sclerotial inoculum.


2021 ◽  
Vol 9 (4) ◽  
pp. 1-7
Author(s):  
Urooj Fatima Chaudhry ◽  

From many years, global cotton production suffers from waterlogging stress. Climatic variation and heavy rainfall conditions with poor internal soil drainage mechanism limits the growth and development of cotton crop due to waterlogging. It reduced the soil oxygen which causes the severe yield losses and sometimes even failure of a crop. Indeterminate growth habit of cotton plant makes it able to adapt this stress by activation of the escape, self compensation and quiescence mechanism. The reduction of biomass, development of adventitious roots and accelerated growth mechanism, all are associated with adaption and tolerance mechanisms. Waterlogging significantly affect the cellulose and sucrose content of fiber in cotton. Sodic soils also exacerbate the waterlogging stress because these soils already suffer by aeration stress. Different growth stages are effect differently but flowering and boll setting stage is more sensitive to waterlogging conditions.


Author(s):  
Jagjeet Singh Lore ◽  
Mandeep Singh Hunjan ◽  
Jyoti Jain ◽  
Sanjay Kumar ◽  
Pritpal Singh ◽  
...  

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