• Korean Journal of Breeding Science
• /
• v.42 no.5
• /
• pp.470-480
• /
• 2010

The objectives of this study were to identify QTLs for agronomic traits using introgression lines from a cross between a japonica weedy rice and a Tongil-type rice. A total of 75 introgression lines developed in the Tongil-type rice were characterized. A total of 368 introgressed segments including 285 homozygous and 83 heterozygous loci were detected on 12 chromosomes based on the genotypes of 136 SSR markers. Each of 75 introgression lines contained 0-9 homozygous and 0-8 heterozygous introgressed segments with an average of 5.8 segments per line. A total of 31 quantitative and 2 qualitative loci were identified for 14 agronomic traits and each QTL explained 4.1% to 76.6% of the phenotypic variance. Some QTLs were clustered in a few chromosomal regions. A first cluster was located near RM315 and RM472 on chromosome 1 with QTLs for 1,000 grain weight, culm length, grain width and thickness. Another cluster was detected with four QTLs for 1,000 grain weight, grain length, grain width and grain length/width ratio near the SSR marker RM249 on chromosome 5. Among the 31 QTLs, 9 (28.1%) Hapcheonaengmi3 alleles were beneficial in the Milyang23 background. ILs would be useful to confirm QTLs putatively detected in a primary mapping population for complex traits and serve as a starting point for map-based cloning of the QTLs. Additional backcrosses are being made to purify nearly isogenic lines (NILs) harboring a few favorable Hapcheonaengmi3 alleles in Milyang23 background.

• Korean Journal of Breeding Science
• /
• v.43 no.5
• /
• pp.383-390
• /
• 2011

Near-isogenic lines (NILs) carrying bacterial blight resistance genes (Xa4, xa5 and Xa21) were developed in japonica rice using Suweon345 as genetic background. NILs were selected by gene specific DNA markers and inoculation of K1 or K3a race. NILs conferring Xa4 were resistant to K1, K2, K3, and moderately resistant to K3a. NILs conferring xa5 were resistant to K1, K2, K3, and K3a. NILs having Xa21 were susceptible to K1, while resistant to K2, K3 and K3a. Target genes of NILs with the genetic background of Suweon345 were also confirmed by using eleven Philippines races and International Rice Bacterial Blight (IRBB) NILs carrying Xa4, xa5 and Xa21. All NILs had no significant difference from their recurrent parents in the major agronomic traits except for panicle length and brown rice 1,000 grain weight. Heading date of NILs ranged from Aug. 10 to Aug. 11, which was similar to that of recurrent parent, Suweon345. Culm length, number of grains per panicle and ratio of ripened grain of NILs were similar to those of Suweon345. Milled rice of NILs was ranged from 4.82 to 4.93MT/ha. These NILs will be useful for improving resistance to K3a race of bacterial blight pathogens in Korean japonica cultivars.

• Korean Journal of Breeding Science
• /
• v.41 no.2
• /
• pp.92-100
• /
• 2009

To investigate the mutagenecity of sodium azide (SA) and to select mutants having various agronomic characteristics in rice (Oryza sativa L. ssp. japonica), dry seeds of rice variety 'Suweon 472' were treated with 0, 0.5, 1.0, 2.0, and 4.0 mM SA solutions prepared in 0.1 M phosphate buffer (pH 3.0). Germination rate, seedling height and sterility were investigated in $M_1$ generation and chlorophyll mutations were observed in $M_3$ generation. Germination rate and seedling height decreased as the increase of SA concentration in $M_1$ generation, the maximum seed sterility (40.8%) was found at 4.0 mM SA concentration. Chlorophyll mutants were occurred in $M_3$ generation and the frequency calculated on a line basis was 13.5% at the same treatment. Many kinds of mutations for morphological and agronomic characters were observed and mutations with short culm and glabrous leaf were frequently found in $M_3$ generation. Interestingly, five mutant lines resistant to blast or bacterial blight (BB) were selected and evaluated with several isolates in $M_3$ generation although Suweon 472 has been known to be susceptible to blast and BB. These mutants showed all resistance to seven isolates of blast and a total of 76 lines among 2,567 lines evaluated showed resistant to race K1 of bacterial blight. Two mutant lines (440172 and 41272) showed different reaction to BB isolates from the other resistant mutants. A few kinds of endosperm mutants were also identified and most of them were waxy mutants.

• Korean Journal of Breeding Science
• /
• v.43 no.3
• /
• pp.196-200
• /
• 2011

'Superjami', a new blackish purple pigmented rice cultivar was derived from a cross between 'CG2-3-5-1-6-1' (developed from a cross between 'Heugjinjubyeo' and 'Suweon 425') as high amount of C3G (Cyanidin 3-glucoside) and 'Daeribbyeo 1' with large seed size in 2003, and selected by pedigree breeding method until $F_7$ generation. As a result, a promising line, 'SR28721-7-9-3-1-2-1', was developed and designated as the name of 'KNOU 5' in 2008. This variety has about 125 days to heading after sowing and has 74.9 cm culm height. The ratio of fertility of 'Superjami' was about 89.6% and 1,000-grain weight was about 26.2 g. It was 1.5 times heavier than 'Heugjinjubyeo'. 'Superjami' has 10 times higher C3G content compared with 'Heugjinjubyeo'. The yield potential of 'Superjami' in brown rice was about 6.3 MT/ha at ordinary fertilizer level in local adaptability test.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.67 no.3
• /
• pp.155-163
• /
• 2022

The tillering potential of panicle number type (PNT) rice greatly varies with planting density. Moreover, grain filling and ripening differ depending on the panicle position, which may further affect rice grain quality. The present study evaluated the grain quality of PNT rice sparsely planted to reduce production costs. The physicochemical characteristics of starch from the grains of PNT type rice 'Ilpum' planted at different densities (37, 50, 60, and 80 plants/3.3 m²) and at different positions of panicles (upper or lower on the culm) were determined. Overall, as the planting density decreased, the number of panicles increased but the starch content decreased, which further reduced the 1,000-grain weight. In particular, at the lowest density (37 plants/3.3 m²), protein content increased but particle size, enthalpy, and relative crystallinity decreased. The effects were more pronounced at lower than at upper panicle positions. These findings indicate that tillering potential differs with planting density, ultimately affecting the palatability of rice grains. Based on these findings, we propose restricting rice transplantation to a planting density of ≤37 plants/3.3 m² to achieve the best quality of grains at lower costs and with less labor.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.25 no.2
• /
• pp.31-37
• /
• 1980

To study the photoperiodic affect on agronomic traits of wheat and barley this experiment was conducted under green house with 25 winter wheat. 25 barley. and 21 naked barley varieties. The data suggested that (1) short-culm varieties such as Ephrat, Combine, and Roussalka in wheat and Haganemugi, Musasinomugi and Yongweolyugag in barley, and Wasehadaka, Ichiwase and Cho-chinryac in naked barley (2) early-matured varieties such as Chukoku #81, Suweon #185 and Sekidori #66 in wheat, CI 07296, Olbori and Haganemugi in barley and Wasehadaka, Nagasaki and Kochiwase-hadaka in naked barley and (3) high-yielding potential varieties such as Shinkwang, Backa and Yukseung #3 in wheat, Jecheon #5, CI 07296 and Siyogimugi in barley and Wasehadaka. CI 09867 and Tawungmia 02 in naked barley could be used for breeding materials because of their super-characters and insensitivities to daylength.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.68 no.1
• /
• pp.1-7
• /
• 2023

We studied the changes in growth characteristics of major cultivated rice in low- density transplanting. The culm and spikelet length did not change in low density transplanting conditions. As the distance between hills increased by 10 cm, the number of tillers per hill increased by an average of 4.4 and the number of grains per spikelet increased by 7.5. The cultivar that had more tillers and higher grain number in 80 hills per 3.3 m² tended to have more tillers and grain in low-density transplanting conditions. However, the increase rate of tillers and grain in low-density transplanting was not significanty different from the tiller and grain number in 80 hills per 3.3 m². The total branch number and branch length in spikelets increased in low-density transplanting conditions. The grain number per spikelet was also increased by the in low-density transplanting method.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.42 no.6
• /
• pp.687-692
• /
• 1997

The barley grown in pot-soil was treated with the NaCl solution of -20 bar in osmotic potential for 10 days, varying the time of treatment: from 20th day before heading; from 10th day before heading and the time of heading. The greatest injury was observed in the case of salt stress at heading or at 10th day before heading: Culm length decreased by 87% : the number of spikes per plant by 82% ; the number of grain per spike by 92% : 1, 000-grain weight by 94% ; yield per pot by 75%. The results also greatly varied depending upon the cultivars and the time of salt stress. Salt stress at the time of heading or at 10th day before heading remarkably decreased yield and yield components. And in terms of grain yield the salt resistance was high in the order of Baegdong, Albori, Hyangmaeg, Olbori and Durubori.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.42 no.6
• /
• pp.722-728
• /
• 1997

This experiment was conducted to establish the cultural practice for reduction of lodging by the effective water management under direct seeding on flooded paddy surface as treated by the drainage times using Dongjinbyeo at National Honam Agricultural Experiment Station during 1994-1995. As the increased midsummer drainage times, the field lodging were reduced by reduction of culm length and large amounts of root with favorable distribution in deep soil, indicating low canopy architecture could promote the light transmission in the plants and favorable root growth. The yield performance was high by increased drainage times which contributed to mainly percentage of ripened grain and 1, 000-grain weight. As a result, two to three times midsummer drainage as effective water management during plant growth was desirable.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.22 no.1
• /
• pp.61-69
• /
• 1977

The affect of perennial weeds to rice yield and rice growing was evaluated. Rice heading date was shortened 1-4days and rice culm length was shortened 5-10cm in heavy weed growing condition. The ratio of yield reduction were about 50% in Cyperus serotinus, about 57 in Potamogeton distinctus in both rice varieties and about 60% of Eleocharis kuroguwal in heavy perennial growing condition.