• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.6
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• pp.568-575
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• 1991

The morpho-anatomical characteristics of panicle in rice plant is generally correlated with the number of spikelets and grain weight per panicle. For the increase of grain yield potential in rice, a low -tillering plant type with large panicles has been suggested as an ideotype. This study was conducted to investigate the panicle morphology and peduncle anatomy of different tillers within a plant in low -and high-tillering cultivars and their relationships on the number of spikelets and grain weight per panicle. A low-tillering, large panicled IR25588 was compared with a high-tillering. small panicled IR58. IR25588 had more inner(IVB) and outer vascular bundles (OVB). bigger peduncle diameter and peduncle thickness just below the panicle neck node than IR58. The top six tillers(M. P1, P2, P3. P4 and S1P2) within a plant had more IVB and OVB. larger peduncle diameter and thickness than the rest of the tillers in both cultivars. Tillers that emerged earlier had more IVB and OVB than tillers that emerged Jater. The total number of primary and secondary rachis-branches of IR25588 was much higher than that of IR58. IR25588 had more number of spikelets per panicle than IR58. and the top six panicles showed more spikelets per panicle than the rest of the panicles in both cultivars. The peduncle diameter was more important than peduncle thickness on the spikelet differentiation and panicle weight. especially in low-tillering cultivars. The number of IVB and OVB were highly correlated with the number of rachis-branches. spikelets and grain weight per panicle. The number of spikelets per IVB and spikelets per primary branch were higher in IR25588 than IR58 indicating the higher sink strength in low -tillering with large panicled cultivars than in high-tillering with small panicled cultivars. Based on the morpho-anatomical characteristics of a low-tillering cultivar and the top six tillers within a plant. the present results could be support that 'a low-tillering sturdy culms with large panicles' is an ideo-type of rice plant for increasing grain yield potential.potential.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.143-148
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• 1999

Soil moisture condition is an important limiting factor in growth and yield in rice culture. The purpose of this study was to compare the influence on the growth, yield and Quality of rice subjected to soil moisture stress (SMS) at different growth stages. Ajaponica rice cultivar, Dongjinbyeo, was cultured under flooded conditions in a plastic container filled with silty loam soil. The container was subjected to SMS until the initial wilting point (IWP) coincided with about 10% in soil moisture content and about-200 kPa in soil matric potential, and was then irrigated again, at 6 and 5 of main growth stage in 1996 and 1997, respectively. At maturity, the plant height, tiller number, leaf area and top dry weight were decreased more in SMS treatments at the early stage than the late stage. The averaged yield index of SMS to control in both years was lowest at meiosis (62.5%), which primarily resulted from lower percent ripened grain and 1,000 grain weight, and second＇ reduced the spikelet number per panicle and panicle number per hill, and followed at tillering stage (68.5%) which resulted from the lower production in tiller number and top dry matter during and after SMS treatment. The percent-age of read rice in SMS plants varied with the treatment stage as order of lower at meiosis (44.0%), heading (53.9%), panicle initiation (70.1%), tillering (72.1%), ripening (75.8%) and 5 days after transplanting (DAT) (79.0%). Protein content in brown rice was slightly larger in SMS at late growth stage than the control, while the contents of fat and ash differed very little between SMS and control. Contents of Mg and K and Mg/K in brown rice with SMS were lower at some treatment stages such as at ripening or panicle initiation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.3
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• pp.239-245
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• 1989

This experiment was conducted to study the physiological and ecological responses of agronomic characters related to source and sink relation in rice. Standard deviation and coefficient of variability of agronomic characters by individual tiller were greatly influenced by the lower internodes in the length of internode, flag leaf in the leaf blade, lower leaf blade in the leaf width, and the number and spikelets of secondary rachis branch in panicle. In relation to the parts of source and sink of rice plant and the number of spikelet in panicle, the number of spikelet was significantly correlated with the length and leaf area of second leaf blade, the length of second internode, and culm diameter of third internode. The correlation of the length of panicle with the length of internode and leaf blade was greatly influenced by the length of second leaf blade and second internode. The number of spikelet was increased with increasing the second rachis branch rather than first rachis branch. The content of total inorganic nutrients was greatest at leaf blade followed by leaf sheath and internode, and panicle.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.356-363
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• 2017

ARice is an important staple food in the world and rice yield is one of the main traits for rice breeding. Several genes involved in increasing the yield have been identified through map-based gene cloning within natural variations in rice. These identified genes are good targets for introducing a genetic trait in molecular breeding. Here, we chose five genes reported to be involved in increasing grain number per panicle in rice; Gn1a, dep1, Apo1, Ghd7, and Nal1. We developed In/Del markers for Gn1a, and dep1, Apo1, and applied the reported SNP markers for Ghd7 and Nal1. We were easily able to examine the genotype of each gene on agarose gel. We tested the genotypes on 479 rice resources that we held with evaluated molecular markers. According to the genotype of each gene, rice resources were divided into 13 haplotypes, and most of the Indica and Japonica varieties were included in haplotypes 1 and 13, respectively. When we examined the effect of each gene on grain number per panicle and panicle number per plant, panicle number per plant in the yield negative allele group for each gene was reduced by approximately 0.3 to 0.8 compared to that in the yield positive allele group. However, the number of yield positive alleles for each gene was higher by about 21 to 27 grains per panicle than that of yield negative alleles. Although most of the varieties were grouped in haplotypes 1 and 13, we believe that this genotype information with evaluated molecular markers will be useful in rice breeding for increasing the yield with grain number per panicle.

• Current Research on Agriculture and Life Sciences
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• v.1
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• pp.27-34
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• 1983

This study was conducted to obtain the basic informations on the selection for the early and high-yielding lines in $F_2$ populations of wheat. Two combinations such as Olmil-Saemil cross and Naphal-Cheonggemil cross and their eight populations were used and genetic parameters of genetic variances and path-coefficients for agronomic traits mainly in $F_2$ populations were analyzed. Genetic coefficient of variability in Olmil-Saemil cross was higher in harvest index, grain number, grain yield and plant height in decreasing order, but in Naphal-Cheonggemil cross harvest index, plant height, and 1,000-grain weight were higher in order. Heading and maturing dates, plant height, and harvest index showed high hertability (0.525-0.808) in both crosses, but very low heritabilities were observed in grain numbers per panicle and yield. In both crosses, genetic advances(%) was higher in heading and maturing stage, but lowest in yield. High genetic advance was obtained in 1,000-grain weight of Naphal-Cheonggemil cross. The highly significant correlations between yield and panicle number, yield and grain number per panicle were obtained, and the highest direct effect on yield was obtained in panicle number followed by grain number per panicle number.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.4
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• pp.356-361
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• 1984

The experiment was carried out in order to investigate the development of vascular bundles and air spaces of rice internode, and its relationships to the panicle characteristics of rice varieties. The results obtained were as follows; The number of total vascular bundles in upper 1st internode was significantly different among varieties, but there was no remarkable differences among varieties and nodal positions below the 2nd internode. In the 5th internode 21-31 air spaces according to varieties was developed, however, no air space was found in upper 1st and 2nd internodes at maturing stage. Significant varietal difference of air space was observed in upper 4th internode. The number of vascular bundles, internodal thickness were positively correlated with panicle length, the number of rachis branches, and the spikelets in rice varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.3
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• pp.233-238
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• 1981

This trial was conducted to find out some tendencies in variations of grain chalkiness according to their position on a panicle. To know the varietal character in variations of chalkiness and their relations with grain weight, distribution of chalkiness in bulk seed was observed for four varieties. Milyang 23, relatively clear variety and SR601-25-1, much chalky variety were checked for the grain chalkiness in their positions on the panicle. The results obtained are summerized as follows: Rice chalkinss were varied in degree from 0 (clear) to 9 (chalky) within a variety. Large number of grains were distributed to clear for clear variety and to chalky for chalky variety, but almost equal number of grains were distributed to all degree of chalkiness for intermediate chalky variety. For the relationship between degree of chalkiness and grain weight, chalky grains founded in clear variety and clear grains founded in chalky variety decreased in weight, while in intermediate chalky varieties both grains of clear and chalky decreased. There were great varietions in grain chalkiness on a panicle for both clear and chalky varieties. There was no definite trend in distribution of chalkiness except that the first primary branch and terminal grains in every primary branch showed clear in Milyang 23. Mean degree of grain chalkiness was relatively high in grains of middle part of panicle only from Milyang 23.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.4
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• pp.359-367
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• 1985

This experiment was conducted to study effect of cold water damage on some growth characters related to source and sink at reproductive growth stage in Jinan (sea level 303m). The cold water irrigation duration had irrigated 4, 8 and 12 days at panicle formation stage and reproduction division stage compared to perennial water irrigation. Cold water irrigation shortened culm length and panicle length and degree of panicle exsertion. The shortening effect appeared great at lower internodes when treated at panicle formation stage but at higher internodes when treated at reduction division stage. Cold water irrigation decreased the number of secondary branches and spikelets per panicle, and increased the number of degenerated spikelets being high degeneration when treated at panicle formation stage. Spikelet sterility and impediment of grain filling were affected by duration of cold water irrigation being great when treated at spikelet primodium differentiation stage and reduction division stage in particular. Grain weight was also reduced. Significant relationship existed between spikelets sterility, grain filling and yield. The degeneration of secondary branches and spikelets correlated with leaf area but spikelet sterility and yield with culm length, panicle length and panicle exsertion.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.20-27
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• 1982

Two rice varieties were planted and four degrees of defoliated tiller num ber ratio and another four levels of defoliation-panicle removal tiller number ratio were made at heading stage of know the possibility of translocation of photosynthetic products between tillers during grain filling stage of rice plant. The more tillers defoliated in a hill, the less matured grain ratio and the less grain weight per panicle of normal tillers were found. But the matured grain ratio and the grain weight per panicle of tillers defoliated partly in a hill showed higher than those of tillers of completely defoliated plant. No differences of the matured grain ratio and the grain weight per panicle were found between different levels of defoliation-panicle removal tiller number ratio in a hill. But the matured grain ratio and the grain weight per panicle of tillers of completely defoliated plant were significantly lower than those of tillers of partly defoliation-panicle removal treatments. These results indicated that the translocation of photosynthetic products between tillers was possible during grain filling period in rice plant. Source-sink relationship can be applied to interpret the result obtained in this study.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.69 no.1
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• pp.15-24
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• 2024

Environmental factors play an important role in crop growth and development. In recent years, climate change has become a challenge that limits environmental factors. Light is an important environmental factor for photosynthesis in rice. In addition, temperature is one of the most important factors for rice production; thus, a 1℃ increase in temperature because of climate change can affect rice growth and development. Therefore, we investigated the effect of shading on the growth characteristics of rice under different temperature conditions from the vegetative stage to the flowering stage. Plants were grown at three different temperatures: 26℃/16℃ for 21℃, 29℃/19℃ for 24℃, and 22℃/32℃ for 27℃ in a phytotron. A 55% shade treatment was applied after 10 days of transplanting until the flowering stage. Plant height was not affected by the shading treatment. In the maximum tiller number response to shading, a lower tiller number and growth speed of tiller was found in the 27℃ condition. Among leaf characteristics, shading increased the flag leaf area, length, width, and effective leaf area; however, it decreased the leaf number on the main stem, especially at 27℃. In terms of stem characteristics, shading affected culm wall thickness in both varieties. Finally, regarding the panicle characteristics, lower panicle numbers, spikelet numbers per panicle, primary numbers, and secondary numbers per panicle were found under the shading treatment. Most of the desirable characteristics were affected by the shading treatment at 27℃. Overall, these results indicated that shading had a greater effect on rice plant growth at high temperature.