Abstract
Many studies on grain quality as affected by rice cultivation density have been conducted on one or two rice varieties, but there are few studies on varieties of hybrid midseason-rice. The hybrid midseason-rice grown in southern and eastern Sichuan Province has very low grain quality, especially the percentage of head milled rice, because of high temperatures and summer droughts. This paper explores the effects of low density cultivation on the percentage of head milled rice and source to sink ratios of varieties of hybrid midseason-rice, and it provides a theoretical and practical basis for improved cultivation. The experiment was conducted with eighteen mid-season rice hybrids grown at two densities, a low density cultivation and a traditional cultivation system, in a randomized block design with 4 replications using two hybrids (a big-panicle type hybrid `Gangyou 22' and a small-panicle type hybrid `II you 7') with 3 different treatments of grain or leaf cut. By using variance, correlation and regression analysis, the results indicated that the percentage of head milled rice increased in hybrids with small-medium panicles under low density cultivation but not for the hybrids with big-panicles. This was because of the significant decrease in the leaf to grain ratio and grain filling rate of hybrids for small-middle panicle under low density cultivation, as compared to the traditional cultivation system, resulting in an increase in the grain unit weight and percentage of head milled rice. The leaf to grain ratio and the grain filling rate of big panicle hybrids were low in traditional cultivation, and decreased significantly under low density cultivation, causing a decrease in the grain unit weight and percentage of head milled rice. These results were produced because of an imbalance in the leaf to grain ratios. Hybrids with less than 177 spikelets per panicle under cultivation using traditional densities can adapt to the low density cultivation in the eastern and southern regions of Sichuan Province.
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Claims 8
Claim · model-written summary
Low density cultivation increased head milled rice percentage in small-medium panicle hybrids.
- Taxon
- rice
Oryza sativae0 - Material
- hybrids with small-medium paniclese0
- Treatment
- low density cultivatione0
- Outcome
- percentage of head milled ricee0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“percentage of head milled rice increased in hybrids with small-medium panicles under low density cultivation but not for the hybrids with big-panicles”
Claim · model-written summary
Low density cultivation did not increase head milled rice percentage in big-panicle hybrids.
- Taxon
- riceOryza sativae0
- Material
- hybrids with big-paniclese0
- Treatment
- low density cultivatione0
- Outcome
- percentage of head milled ricee0
- Direction
- note0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“percentage of head milled rice increased in hybrids with small-medium panicles under low density cultivation but not for the hybrids with big-panicles”
Claim · model-written summary
Leaf-to-grain ratio and grain filling rate significantly decreased in small-medium panicle hybrids under low density.
- Taxon
- riceOryza sativat0
- Treatment
- low density cultivatione0
- Outcome
- leaf to grain ratio and grain filling ratee0
- Direction
- decreasee0
- Comparator
- traditional cultivation systeme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significant decrease in the leaf to grain ratio and grain filling rate of hybrids for small-middle panicle under low density cultivation, as compared to the traditional cultivation system”
t0“HYBRID RICE”
Claim · model-written summary
Grain unit weight and head milled rice percentage increased in small-medium panicle hybrids.
- Taxon
- riceOryza sativat0
- Outcome
- grain unit weight and percentage of head milled ricee0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“resulting in an increase in the grain unit weight and percentage of head milled rice”
t0“HYBRID RICE”
Claim · model-written summary
Big-panicle hybrids had low leaf-to-grain ratio and grain filling rate under traditional cultivation.
- Taxon
- riceOryza sativat0
- Material
- big panicle hybridse0
- Outcome
- leaf to grain ratio and the grain filling ratee0
- Setting
- traditional cultivatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“leaf to grain ratio and the grain filling rate of big panicle hybrids were low in traditional cultivation”
t0“HYBRID RICE”
Claim · model-written summary
Low density significantly decreased leaf-to-grain ratio and grain filling rate in big-panicle hybrids.
- Taxon
- riceOryza sativat0
- Treatment
- low density cultivatione0
- Outcome
- leaf to grain ratio and the grain filling ratet1
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“decreased significantly under low density cultivation, causing a decrease in the grain unit weight and percentage of head milled rice”
t0“HYBRID RICE”
t1“leaf to grain ratio and the grain filling rate of big panicle hybrids were low in traditional cultivation”
Claim · model-written summary
Low density decreased grain unit weight and head milled rice percentage in big-panicle hybrids.
- Taxon
- riceOryza sativat0
- Treatment
- low density cultivatione1
- Outcome
- grain unit weight and percentage of head milled ricee0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“causing a decrease in the grain unit weight and percentage of head milled rice”
t0“HYBRID RICE”
e1“decreased significantly under low density cultivation”
Claim · model-written summary
The authors conclude that hybrids with fewer than 177 spikelets per panicle can adapt to low density cultivation in eastern and southern Sichuan.
- Taxon
- RICEOryza sativat0
- Outcome
- can adapt to the low density cultivatione0
- Qualifier
- less than 177 spikelets per paniclee0
- Setting
- eastern and southern regions of Sichuan Provincee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Hybrids with less than 177 spikelets per panicle under cultivation using traditional densities can adapt to the low density cultivation in the eastern and southern regions of Sichuan Province”
t0“HYBRID RICE”