• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.3
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• pp.175-178
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• 2005

The research was conducted to evaluate a different seedling establishment of rice germplasms which were obtained from the IRRI (International Rice Research Institute) under the direct seeded condition. There was highly significant difference in terms of statistical analysis among cultivars. The seedling establishment of cultivars tested was the highest with ASD1 > IR50 > IR72 > Taothabi > Uplri5 > CO25 > Dula > Moroberakan. The difference of seedling establishment among cultivars particular in dry condition was high between ASD1 and Moroberakan and other cultivars.

• Proceedings of the Korean Society of Crop Science Conference
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• 1993.10a
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• pp.14-15
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• 1993

• Proceedings of the Korean Society of Crop Science Conference
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• 1996.05a
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• pp.108-109
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• 1996

• KOREAN JOURNAL OF CROP SCIENCE
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• v.8 no.1
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• pp.37-45
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• 1970

• Proceedings of the Korean Society of Crop Science Conference
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• 1996.10a
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• pp.96-97
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• 1996

• KOREAN JOURNAL OF CROP SCIENCE
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• v.4 no.1
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• pp.73-79
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• 1968

In order to investigate varietal competition effects on yield of rice, two experiments were conducted under paddy field condition. In experiment I, two leading varieties were grown in pure and mixed stands and examined the influence of spacings and nitrogen levels on the varietal competition effects and competitive ability of two varieties. In experiment II, three leading varieties were grown in pure and mixed stands with different combinations and examined the competition effects on yield in different combinations. The results are summarized as follows: 1. No significant differences were found in grain yield between varietal mixture and pure stands, though the level of nitrogen and spacings affected plot yield. 2. In the mixture of Suwon ＃82 and Shin ＃2, Suwon ＃82 appeared to be a better competitor to the Shin #2 in terms of grain yield. 3. The performance of mixtures were determined by the balance of the increment of better competitor and the decrement of poorer competitor. Here, the increment of Suwon ＃82 due to competition did not much exceeded the decrement of Shin ＃2. 4. Spacings and Nitrogen levels, tested here, did not affect significantly to the varietal competition effects. 5. Jaekun, Paltal and Norin ＃6 showed no varietal difference in competing ability.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.6
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• pp.513-523
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• 1993

Varietal difference in structural and physical characteristics of rice starch and interrelationships between these starch properties and the physicochemical components of rice grains were investigated for twenty four rice varieties, which were considerably different in amylose content, gelatinization temperature and gel consistency, to obtain the basic informations for diversifying the utility of rice grains and for developing various rice cultivars adaptable to rice food processing. Wave length of maximum absorbance for blue color reaction of starch-I$_2$ complex was 520nm for glutinous rice and 560～600nm for nonglutinous rice. The higher amylose rice showed the longer wave length but there was considerable difference of the wave length among rice materials with similar amylose content. Varietal difference in frequency distribution of debranched starch molecules by isoamylase hydrolysis was largest in amylose fraction, the longest fraction(Fr. I), and was next bigger in intermediate fraction(Int.Fr.) and the ratio between short and long glucose chain of amylopectin fraction(Fr. III /Fr. II). The Fr. III / Fr II ratio was higher in glutinous rice than in nonglutinous one but it was considerably different among nonglutinous rice varieties without any connection with amylose content. The lower alkali digestible rice showed the longer half-hydrolysis time in acid solution. Both soft and hard gel rice varieties in gel consistency test revealed significant varietal difference of 50% acid hydrolysis time. The harder rice in gel consistency exhibited the less frequency of short branch fraction of amylopectin (Fr. III) and the higher amylose content. Twenty four rice varieties were cleary classified by upper two principal components contracted from structural or physical traits of rice starch and some physicochemical properties of rice grain by principal component analysis. The 1st and 2nd principal components can be characterized to components related with amylose and amylopectin structure respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.20
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• pp.95-99
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• 1975

Flowering of the sunflower varieties tested was accelerated by growing in the green-house as well as by short-day treatments at 8 or 12 hours. It may be concluded that the sun-flower plant is sensitive to short-day condition. Significant difference was observed between the , early and late maturing varieties in the flowering response to temperature treatment. Varietal difference, however, was not recognizable in the flowering response to the short-day treatment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.1
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• pp.1-6
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• 1977

The varietal differences of protein content in barley grain and its variation under different cultural conditions were studied. The varietal variation of protein content was significant with the range of 8～18%. The protein content of barley grain were increased by heavier nitrogen application and decreased by shading treatment and drill seeding. There was negative correlation between protein content and grain weight in hulled barley, while positive correlation between nitrogen content of plant and leaf at heading stage and protein content of barley grain was significant in Haganemugi and Buheung.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.4 no.1
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• pp.25-29
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• 1968

The effect of differences in grain size on the initial growth of seedlings was studied in rice with two leading varieties of Jaekun and Nongkwang. The grains were classified into three classes of large, medium and small size by their specific gravity. The results observed at seedling stage are summarized as follows. 1. Higher percentage of seeds with larger size was observed to be normally developed into sound seedlings comparing with those with small seeds. This suggests the more effective maintainance of seedings. 2. Seedlings from larger seeds also showed higher values in the number of roots, leaves and tillerings where no varietal difference was observed. 3. Varietal speciality led to the lorger coleoptile of Nongkwang variety, with rather longer plant, than that of Jaekun, while higher value in coleoptile length was observed at the seedlings from larger seeds. 4. Thus larger seeds and the Aariety Nongkwang yielded heavier dry matter of upper part. These trends appeared more clearly at the late seedling stage. 5. There was constant decrease in the dry matter weight per unit coleoptile length until the seedling-selfsupportingstage while after this stage abrupt increase was observed. Seedlings from larger seeds showed higher value in the dry matter weight per unit coleoptile until this stage, thought the differences became insignificant after this stage. And no varietal difference was found.