scholarly journals Path analysis for agronomic traits and yield of salt tolerant rice cultivars under moderate salinity condition in Central Vietnam

Author(s):  
H. L. Nguyen ◽  
P. D. Tran ◽  
D. H. Tran

This study was done with the aims to determine: (i) the correlation between agronomic traits and yield and (ii) the direct and indirect effects of agronomic traits on salt-tolerant rice yield. The field experiment was conducted directly on moderate salinity level of EC= 6.35 dS m-1 during the 2017 winter-spring cropping season in Central Vietnam. Ten salt-tolerant rice cultivars were studied. Results showed that yields of salt-tolerant rice cultivars had a positive correlation with traits of plant height, panicles per plant, panicle weight, and dry biomass, r = 0.3624*, 0.7019***, 0.4530** and 0.7837***, respectively. Total panicles per plant, panicle weight, and the number of grains per panicle directly affected rice yield with coefficients of dC = 0.5524, 0.8294 and 0.4355, respectively. Therefore, these traits should be used as good indicator traits for selecting salt-tolerant rice cultivars for the moderate salinity soil in Central Vietnam.

2017 ◽  
Vol 31 (5) ◽  
pp. 658-665
Author(s):  
Mason L. Young ◽  
Jason K. Norsworthy ◽  
Robert C. Scott ◽  
Lon T. Barber

Benzobicyclon is the first 4-hydroxyphenylpyruvate dioxygenase-inhibiting herbicide pursued for commercial registration in U.S. rice production. A study was conducted in 2015 and 2016 to evaluate the response of eight rice cultivars to post-flood application timings of benzobicyclon at 494 g ai ha-1(proposed 2X rate). ‘Caffey’, ‘CL151’, ‘CLXL745’, ‘Jupiter’, ‘LaKast’, ‘Mermentau’, ‘Roy J’, and ‘XL753’ were evaluated in response to applications of benzobicyclon. The highest level of visible injury was observed in LaKast at 7% in 2015. No visible injury was detected among other cultivars either year at 2 weeks after treatment. In 2015 and 2016, no more than a four-day delay to reach 50% heading occurred across all cultivars. Rough rice yield was not affected by any of the post-flood application timings of benzobicyclon. A second study was conducted in 2016 at three locations throughout Arkansas to investigate the tolerance of 19tropical japonica(inbred and hybrid) and twoindicainbred cultivars to a premix containing benzobicyclon at 494 g ai ha-1and halosulfuron at 72 g ai ha-1 applied 1 week after flooding. Thetropical japonicacultivars have excellent crop safety to benzobicyclon while application to theindicacultivars, Rondo and Purple Marker, expressed severe phytotoxicity. Benzobicyclon caused less than a 2 d delay in heading to thejaponicacultivars. Rough rice yield of thetropical japonicacultivars was not affected by benzobicyclon while yields of bothindicacultivars were negatively affected. Benzobicyclon can safely be applied to drill-seededtropical japonicainbred and hybrid cultivars in a post-flood application without concerns for crop injury. Benzobicyclon should not be used onindicacultivars as it will cause severe injury, delayed heading, and yield loss.


2017 ◽  
Vol 45 (1) ◽  
pp. 1-8
Author(s):  
Gerland Akhmadi ◽  
Bambang Sapta Purwoko ◽  
Iswari Saraswati Dewi ◽  
Dan Desta Wirnas

Anther culture technique is able to accelerate plant breeding activities. The objectives of this research was to determine the agronomic traits that could be used for selection of the dihaploid rice line population through the calculation of heritability, genotypic correlation, path analysis and selecting dihaploid rice lines. The plant material used was 65 dihaploid rice lines DH 1 of F1 anther culture plants and Ciherang and Inpari 13 as check varieties. Agronomic characters that could be used as selection character are generative plant height, number of filled grain per panicle, the total number of grains per panicle, weight of 1,000 grains, and grain per hill. Twenty three dihaploid lines were selected based good agronomic characters with criteria generative plant height between 80-120 cm, number of filled grains per panicle > 100, number of grains per panicle > 120, weight of 1,000 grains > 20 g, and grain per hill > 25 g.Keywords: anther culture, heritability, agronomic characters


2011 ◽  
Vol 25 (2) ◽  
pp. 192-197 ◽  
Author(s):  
Jason A. Bond ◽  
Timothy W. Walker

Field studies were conducted to compare the response of one inbred (‘CL161’) and two hybrid (‘CLXL729’ and ‘CLXL745’) Clearfield (CL) rice cultivars to imazamox. Imazamox was applied at 44 and 88 g ai ha−1to rice in the panicle initiation (PI) and PI plus 14 d (PI + 14) growth stages and at 44 g ha−1to rice in the midboot growth stage. Maturity of hybrid CL cultivars was delayed following imazamox at 44 g ha−1applied at PI + 14 and midboot. Furthermore, imazamox at 44 g ha−1, applied at midboot, delayed maturity of CLXL745 more than CLXL729. Expressed as a percentage of the weed-free control plots, rough rice yields for CLXL729 were 91% following imazamox at 44 g ha−1applied at PI + 14, 78% following imazamox at 44 g ha−1applied at midboot, and 77% for imazamox at 88 g ha−1applied at PI + 14. Rough rice yield for CLXL745 was 77 to 92% of the control following all imazamox treatments. All imazamox treatments reduced CLXL745 rough rice yield compared with CL161. Rough rice yield, pooled across CL cultivar, varied with imazamox treatment between years, and these differences may have been a consequence of lower temperatures and solar radiation in the first year. Hybrid CL cultivars CLXL729 and CLXL745 were less tolerant than was CL161 when imazamox was applied at nonlabeled rates (88 g ha−1) and/or timings (PI + 14 or midboot). Because of variability in rice growth stages and irregularities in imazamox application in commercial fields, inbred CL cultivars should be planted where an imazamox application will likely be required.


2009 ◽  
Vol 23 (1) ◽  
pp. 167-170 ◽  
Author(s):  
Jason A. Bond ◽  
Timothy W. Walker ◽  
Clifford H. Koger

Field studies were conducted from 2005 through 2007 to determine the response of three rice cultivars (‘Cocodrie’, ‘Wells’, and ‘Lemont’) to three application timings and two formulations of pendimethalin in a stale seedbed rice production system. Pendimethalin formulated as an emulsifiable concentrate and capsule suspension was applied to rice 0, 3, and 7 d after planting. No visual injury was detected for any cultivar. Seedling density, days to 50% heading, and rice yield were not affected by pendimethalin formulation or application timing. The practice of planting cultivars with excellent seedling vigor into nondisturbed soils with greater available moisture could provide an opportunity to use pendimethalin as a preemergence herbicide for rice production.


2020 ◽  
Vol 113 (3) ◽  
pp. 1248-1253
Author(s):  
Blake E Wilson ◽  
Michael J Stout

Abstract The rice stink bug, Oebalus pugnax (F.), is the most important pest of headed rice, Oryza sativa L., in the United States. Numerous studies have attempted to quantify the impact of O. pugnax feeding on rice yield and grain quality, but these studies have often produced conflicting results. Across mid-south U.S. rice, thresholds based on sweep net sampling are used to determine the need for insecticide applications, but few studies have related sweep net captures to rice quality parameters. Field trials were conducted in Louisiana in 2015 and 2016 that used different rates of insecticides to establish rice plots with mean O. pugnax infestations ranging from 0.8 to 24.6 insects per 10 sweeps. Insecticide applications improved panicle weight and head yields as well as decreased percentage peck. A series of linear regressions examined relationships between O. pugnax captures and rice yield and quality parameters, including panicle weight, head yield (% whole kernels), and peck (discolored grains). Mean O. pugnax sweep net captures across all sampling dates in both years were significantly and negatively correlated to panicle weight and head yield and positively correlated to percentage peck. Peck was negatively correlated with head yield. Results from sampling at different maturity stages indicate sweep net captures at grain fill and soft dough stages had the greatest influence on rice yield and quality parameters, respectively. Further research into impacts of milling quality reductions on farm revenue and the influence of cumulative infestations over grain development is needed to improve economic thresholds for O. pugnax in rice.


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