• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.2
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• pp.208-214
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• 1987

A genetic study on the panicle characters in Oryza sativa was carried out by means of a 5 x 5 diallel cross. The five parental varieties were Raekyung, Yeongnamjosaeng, Nongbaek, Yushin and Honenwase. All characters were correlated positively each other, except number of kernels per primary branch. The number of secondary branches per primary branch.was the most effective factor in determining the number of kernels per panicle, the next being the number of primary branches per panicle. Regression analyses of the data of Vr/Wr indicated the presence of non-allelic gene interactions for all characters. Overdominant characters were the number of kernels per panicle, the number of primary branches per panicle, the number of secondary branches per primary branch, the number of kernels per primary branch and sum of kernels on all the tertiary branches per panicle, suggesting that the characters were more influenced by dominant effect than additive effect. However, the number of kernels per secondary branch was partially dominant where the genetic variation was due more to additive effect than to dominance effect. But after omitting the parent which had non-allelic interaction gene, the characters; the number of kernels per panicle, the number of secondary branches per primary branch, and the number of kernels per secondary branch, were partially dominant. Narrow sense heritabilities(h$^2$ N) in number of kernels per panicle and number of secondary branches were high and moderate, respectively, but those of the rest were lower. Mean squares of GCA and SCA of all characters, except SCA of the number of kernels per secondary branch, were highly significant. Effects of GCA were larger than SCA effects in all characters. Raekyung, Yushin and Nongbaek had highly positive GCA, and the best positive SCA was observed in crosses of Nongbaek x Tongillines (Raekyung, Yushin, and Yeongnamjosaeng) in all characters.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.503-514
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• 1997

The morphogenesis of panicle and spikelet in paddy rice has been studied in high yielding Indica$\times$Japonica hybrid cultivar, Milyang 23 and a Japonica type cultivar, Koshihikari. Germinated seeds planted in $5000^{-1}$ a pots filled with submerged soil and cultured under natural conditions. The young panicle of main stem were continuously dissected and observered by Cryo-SEM from the panicle initiation stage until heading stage. Although the date of panicle differentiation and heading in Koshihikari earlier than those of Milyang 23. the sequence of panicle development in two cultivars begins when first bract primordium at opposite side of flag-leaf primordium differentiated, synchronously followed by growth of the primary branch primordia (PBPs) and secondary branch primordia (SBPs), spikelet primordia(SPs), glumes as lateral organs on rachilla and organs composing single floret, and successive sporogenesis in the young spikelets continue after the enclosure by lemma and palea. The PBPs are acropetally initiated from the base of the panicle primordium, and the SBPs alternately differentiate from the base of upper PBP which differentiate later than the lower PBP. Spikelet development starts at the top of upper side PBP of the young panicle and continue basipetally even though SBPs continue to develop at the lower primary branch. Each PBP, SBP and SP differentiate with differentiation bract or bract hair cell around the base of each their primordia. The observation could confirm that Milyang 23 has not only 2~3 more defferentiated PBPs, but also more SBPs and SPs especially from middle-lower primary branch, at end of their differentiation stages, as compared to those of Koshihikari.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.833-840
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• 1997

Differentiation and degeneration of spikelets in paddy rice has been studied in high yielding Indica$\times$Japonica hybrid cultivar, Milyang 23 and a Japonica type cultivar, Koshihikari. Germinated seeds planted in 5000$^{-1}$ a pots filled with submerged soil and cultured under natural conditions. The young panicles of main stem were continuously dissected and observered by Cryo-SEM from the panicle initiation stage, and investigated about formation position of the differentiation and degeneration spikelet within a panicle of 7 days after heading. The degeneration of spikelet appeared simultaneously throughout panicle just after closure of spikelet by the palea and lemma. Differentiated and degenerated spikelets per panicle were about 240, 80 for Milyang 23 and 87, 6 for Koshihikari, respectively. The spikelets degeneration in Milyang 23 was mainly on the secondary and tertiary branch which were developed from primary branch of middle-basal panicle node and hardly not the spikelets of primary branch, and degeneration rate of secondary and tertiary rachis branch and spikelets for Milyang 23 were 2.5 times greater than those of Koshihikari. The proper relation equation between total differentiation or normal spikelets number per panicle(Y) and each rachis branch number were different between cultivars, Le., Y=5.5X$_1$＋3.0X$_2$ for Koshihikari as previously proposed, but those of Milyang 23, Y=5.7X$_1$＋3.5X$_2$＋2.8X$_3$ for total differentiation spikelets and Y=5.6X$_1$＋3.2X$_2$＋2.4X$_3$ for normally developed spikelets, where X$_1$, X$_2$, X$_3$ are number of primary, secondary, tertiary rachis branch, respectively.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.414-421
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• 2008

We conducted a QTL analysis of agronomic traits using 117 $BC_3F_5$ and $BC_3F_6$ lines developed from a cross between Ilpumbyeo and Moroberekan. Genotypes of 117 $BC_3F_5$ lines were determined using 134 simple sequence repeat (SSR) markers. A total of 832 Moroberekan chromosome segments with 410 homozygous and 422 heterozygous, respectively, were detected, and the genetic distance of introgression segments ranged from 0.5 cm to 112.1 cm. A linkage map constructed using 134 SSR markers was employed to characterize quantitative trait loci (QTL). The 117 $BC_3F_5$ and $BC_3F_6$ lines were evaluated for seven agronomic traits at two locations in 2006 and 2007 and at one location in 2007. A total of 26 QTLs were identified for seven traits including days to heading, and the phenotypic variance explained by each QTL ranged from 9.2% to 24.2%. Moroberekan alleles contributed positive effects in the Ilpumbyeo background at eleven QTL loci including panicle length and spikelets per panicle. Five QTLs, two for days to heading and one each for culm length, panicle length and spikelets per panicle were consistently detected in every occasions indicating that these QTLs are stable. Among them, two QTLs, spp6 for spikelets per panicle and pl6 for paniclel length were localized in the similar region. Increase in spikelets per panicle at this locus might be due to the increase in panicle length, because both traits were associated with increase in spikelets per panicle and panicle length due to the presence of the Moroberekan allele. These Moroberekan QTLs might be useful in breeding programs to develop high-yielding cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.1
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• pp.5-11
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• 1988

Varietal differences of grain filling duration and rate are generally recognized in rice (Oryza sativa L.). But the differences of grain filling characteristics between the parts within a panicle might be present since it takes 6-8 days to finish anthesis in a panicle. To elucidate this, 6 Japonica and 6 Japonica/Indica varieties were grown under three nitrogen levels at the Experimental Farm of Chungbuk National University in 1986, and grain filling characteristics of top, middle and bottom parts of a panicle were analyzed. Rice grain filling duration could be divided into 3 phases, i.e., Lag phase(LP) of 5 days after heading. Linear increasing period (LIP) of 5-20 days after heading and Late filling period (LFP) thereafter. Grain weight difference between the panicle parts was greater during LIP in all the varieties and was decreased during LFP. The difference was greater in Japonica/Indica varieties. Samgangbyeo and Seomjinbyeo had the shortest and the longest grain filling durations with 22.6 and 37.1 days, respectively. In average, grain filling duration of the bottom part of a panicle was 1-2 days shorter than that of top or middle part. The differences were negligible in Daecheongbyeo, Taebaegbyeo and Milyang 23, while it was greater in Tongil with 4.9 days. Grain filling rates were ranged from 0.612 to 1.097 mgㆍgrain$^{-1}$ㆍday$^{-1}$ㆍMilyang 23 showed the lowest rate with 0.612-0.682 mgㆍgrain$^{-1}$ㆍday$^{-1}$, while the rates of Baegyangbyeo, Yongmoonbyeo, Samgangbyeo, Nongbaeg and Daeseongbyeo were about 1 mgㆍgrain$^{-1}$ㆍday$^{-1}$ㆍGrain filling rate of bottom part of a panicle was lower than that of top or middle part. The difference was samll in Nongbaeg and Daeseongbyeo, while it was the greatest in Tongil with 0.222 mgㆍgrain$^{-1}$ㆍday$^{-1}$. Grain filling duration and rate were not afftected by nitrogen level, but varietal and spatial differences of grain filling characteristics were highly significant. However, the spatial difference of grain filling rates within a variety was not significant. Grain filling characteristics of each part of a panicle were significantly correlated (r=0.7207-0.9879) with those of a whole panicle.

• Plant Resources
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• v.5 no.2
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• pp.104-108
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• 2002

In order to obtain basic information for selecting early maturing rice varieties which is suitable for early cropping before Alisma plantago in the southern part of Korea. Six rice varieties were grown from May to August in 2002 at Youngjeon Experiment Field, Sunchon and yield components and yield of plants were investingated. Early maturing rice cv. Grubyeo showed higher rough rice yield than any other varieties used in the experiment. It showed high yield components, such as culm length, panicle length, number of panicles per plant, number of spikelets per panicle and ratio of ripened grains. Therefore, it was concluded that Grubyeo was the most suitable variety with high yield for the cultivation before growing of Alisma plantago at the southern part of Korea. The heritability of culm length number of spikelets per panicle and rough rice yield were high and that of panicle length number of panicle per plant, ratio of ripened grain and 1,000 grain wt. of milled rice were low. According to the result of path coefficient analysis, characters highly correlated with rough rice yield showed large direct effects on rough rice yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.117-121
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• 1999

Spikelet and vascular bundle development in rice panicles is considered to be the important elements in determining the genotype's yield capacity and translocation ability of assimilates into grains, respectively. This study was conducted to clarify the varietal differences of the spikelet and vascular bundle formations among three rice cultivars; Iksan 435 (japonica), Dongjinbyeo (japonica) and Namcheonbyeo (Tongl-type). Iksan 435 had more primary rachis branches (PRBs), secondary rachis branches (SRBs) and spikelets per panicle than Dongjinbyeo, but less than Namcheonbyeo. Among three cultivars, Namcheonbyeo showed the highest spikelet number per panicle which were differentiated SRBs mainly on PRBs of lower rachis nodes. And Namchenbyeo showed the highest number of large vascular bundle (LVB) as well as small vascular bundle (SVB) and it displayed the largest diameter of LVB. Between the two japonica cultivars, the numbers of LVBs end SVBs were significantly higher in Iksan 435 than those in Dongjinbyeo. The PRBs to LVBs ratio of Namcheonbyeo was twice as large as those of Dongjinbyeo and Iksan 435. These results indicate that the newly bred cultivar, Iksan 435, has improved yield capacity by increasing the number of especially rachis branches and spikelets formation as well as 1,000 grain weight, compared to other former japonicas.

• The Korean Journal of Mycology
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• v.12 no.4
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• pp.171-174
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• 1984

To investigate the relationship between symptom development of Bakanae disease and yield component (the length of panicle, weight of panicle, number of healthy grain per panicle and number of panicle per hill), rice seedlings infected with F. moniliforme were transplanted. The number of panicles per hill and healthy grain per panicle were greatly decreased by the development of Bakanae symptom. Yield components was not correlated with the time of the Bakanae symptom development. Rice plants with Bakanae symptom had lower yield as 210g per 10 hills than healthy plants as 469g per 10 hills.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.2
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• pp.121-124
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• 1981

The panicle enclosing Gamadi rice cultivar from western Tarai of Nepal was treated with different daylengths; 8 hours, natural daylength i.e. 14 hours 30 minutes to 12 hours 30 minutes, and 24 hours throughout its life cycle. The extremely long daylength of 24 hours induced the panicle exsertion, and elongated the first internode from the top, but did not affect the second internode significantly, suggesting that the panicle exsertion was strongly correlated with the first internode elongation in the Gamadi rice cultivar.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.1
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• pp.32-37
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• 2000

The in vitro culture of rice panicles is a culturing technique only panicle without other organs in culture solution containing organic substance, so that would be useful to study how assimilate supply affects grain development and maturation. To find the optimum stage for in vitro culture, rice panicles grown in greenhouse were sampled periodically after anthesis and cultured in nutrient medium. The panicles older than 1 weeks after anthesis had produced normal grains. Grain-filling was apparently dependent upon sucrose concentration (8-12 %) in medium, but not affected by nitrogen concentration supplied with glutamine. As far as rice panicle was supplied with sucrose and N in nutrient medium, grains continued accumulation of dry matter and maturation regardless to light condition. Considerably, grain-filling was improved when panicles were positioned horizontally inside flask, so that each grain was partially submerged to nutrient medium.