Abstract
In the eastern and southern districts of Sichuan Province, grain yields of hybrid midseason-rice varieties have been increased, but its grain quality remains very poor. In particular, the head rice percentage is low and chalkiness is high due to high air temperatures that occur 0 to 20 days after full heading. Although many studies have examined the effects of cultivation factors on grain quality, few improvements in grain quality have been made in these special districts. This paper explores the effect of super sparse cultivation on head rice recovery and chalkiness in hybrid rice varieties and provides a theoretical and practical basis for the cultivation of high quality rice. The experimental design consisted of three hybrid rice varieties (‘II you 7’,‘Shanyou 63’ and ‘Xiangyou 2’) planted at six different densities, where the hill was removed at full heading and N applied on different days after full heading in a randomized block design with 3～4 replications. Using analysis of variance and correlation analysis, the results indicated that there were highly significant negative correlations between planting density and the percentage of head milled rice and highly significantly positive correlations between plant seedling density and the chalky percent. When super sparse cultivation was at 7.51×10 4 hill·hm -2 with 150-210 kg N·hm -2 , the grain yield was equal to CK (21.64×10 4 hill per hm 2 with 150 kg N·hm -2 ), but the percentage of head milled rice increased by 15.69% to 22.92%, and the chalky percent decreased by 16.34% to 21.22%. The increase in grain quality in super sparse cultivation was due to an increase in the number of spikelets per panicle, a decrease in the weight of leaf per grain at full heading, and reduced grain filling rate; hence, the percentage of head milled rice and chalkiness were improved. Additionally, the seed setting rate and the percentage of head milled rice in super sparse cultivation were increased by applying N 20 days after full heading.
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Claims 7
Claim · model-written summary
Planting density was highly significantly negatively correlated with the percentage of head milled rice in hybrid rice.
- Taxon
- hybrid rice
Oryza sativae0 - Treatment
- planting densitye1
- Outcome
- percentage of head milled ricee1
- Direction
- negative correlationse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three hybrid rice varieties”
e1“there were highly significant negative correlations between planting density and the percentage of head milled rice”
Claim · model-written summary
Planting seedling density was highly significantly positively correlated with the chalky percent in hybrid rice.
- Taxon
- hybrid riceOryza sativae0
- Treatment
- plant seedling densitye1
- Outcome
- chalky percente1
- Direction
- positive correlationse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three hybrid rice varieties”
e1“highly significantly positive correlations between plant seedling density and the chalky percent”
Claim · model-written summary
Super sparse cultivation with 150-210 kg N per hm2 gave grain yield equal to the CK.
- Taxon
- hybrid riceOryza sativae0
- Treatment
- super sparse cultivatione1
- Outcome
- grain yielde1
- Direction
- equal toe1
- Qualifier
- 7.51×10 4 hill·hm -2 with 150-210 kg N·hm -2e1
- Comparator
- CKe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three hybrid rice varieties”
e1“When super sparse cultivation was at 7.51×10 4 hill·hm -2 with 150-210 kg N·hm -2 , the grain yield was equal to CK (21.64×10 4 hill per hm 2 with 150 kg N·hm -2 )”
Claim · model-written summary
Super sparse cultivation increased the percentage of head milled rice by 15.69% to 22.92% relative to CK.
- Taxon
- hybrid riceOryza sativae0
- Treatment
- super sparse cultivatione1
- Outcome
- percentage of head milled ricee3
- Direction
- increasede3
- Value
- 15.69% to 22.92%e3
- Comparator
- CKe2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three hybrid rice varieties”
e1“super sparse cultivation was at 7.51×10 4 hill·hm -2 with 150-210 kg N·hm -2”
e2“the grain yield was equal to CK”
e3“the percentage of head milled rice increased by 15.69% to 22.92%”
Claim · model-written summary
Super sparse cultivation decreased the chalky percent by 16.34% to 21.22% relative to CK.
- Taxon
- hybrid riceOryza sativae0
- Treatment
- super sparse cultivatione1
- Outcome
- chalky percente3
- Direction
- decreasede3
- Value
- 16.34% to 21.22%e3
- Comparator
- CKe2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three hybrid rice varieties”
e1“super sparse cultivation was at 7.51×10 4 hill·hm -2 with 150-210 kg N·hm -2”
e2“the grain yield was equal to CK”
e3“the chalky percent decreased by 16.34% to 21.22%”
Claim · model-written summary
The authors attribute the improved grain quality under super sparse cultivation to more spikelets per panicle, lower leaf weight per grain at full heading and a reduced grain filling rate.
- Taxon
- hybrid riceOryza sativae0
- Treatment
- super sparse cultivatione1
- Outcome
- grain qualitye1
- Qualifier
- an increase in the number of spikelets per panicle, a decrease in the weight of leaf per grain at full heading, and reduced grain filling ratee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three hybrid rice varieties”
e1“The increase in grain quality in super sparse cultivation was due to an increase in the number of spikelets per panicle, a decrease in the weight of leaf per grain at full heading, and reduced grain filling rate”
Claim · model-written summary
In super sparse cultivation, applying N 20 days after full heading increased the seed setting rate and the percentage of head milled rice.
- Taxon
- hybrid riceOryza sativae0
- Treatment
- applying N 20 days after full headinge1
- Outcome
- seed setting rate and the percentage of head milled ricee1
- Direction
- increasede1
- Qualifier
- in super sparse cultivatione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three hybrid rice varieties”
e1“the seed setting rate and the percentage of head milled rice in super sparse cultivation were increased by applying N 20 days after full heading”