• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.54 no.4
• /
• pp.433-440
• /
• 2009

Korean sweetpotato, Ipomoea batatas, varieties were examined for their flowering response as a fundamental research to improve breeding efficiency by hybridization of this crop. Under 10.0~10.5 hours short day condition, self-rooted plants of three varieties such as Shinmi, Hongmi and Hwangmi flowered sparsely or moderately, and those of fourteen varieties including Eunmi flowered very sparsely. Under 10.6~12.0 hours day length condition, self-rooted plants of three varieties such as Shinmi, Hongmi and Hwangmi flowered very sparsely. Under the day length longer than 12 hours, none of the tested plants flowered. In all the sweetpotato plants grafted on morning glory, flowering occurred with varying degrees by varieties and day lengths. Under 10.0~10.5 hours day length, thirty two varieties including Hongmi flowered moderately or profusely, and one variety such as Mokgye 1 flowered sparsely. Under 10.6~12 hours day length, twenty three varieties including Sinchunmi flowered moderately or profusely, nine varieties including Jeungmi flowered sparsely, and Mokgye 1 didn't flower at all.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.65 no.3
• /
• pp.172-181
• /
• 2020

Koshihikari has been one of the most popular rice cultivars with good eating quality since the 1960s despite its susceptibility to blast disease and lodging. To map the genes controlling blast resistance and to develop promising blast-resistant breeding lines inheriting Koshihikari's high eating quality, a recombinant inbred line (RIL) population was developed from a cross between Koshihikari and a blast resistance donor with early maturity, Baegilmi. A total of 394 Koshihikari × Baegilmi RILs (KBRIL), and the two parents, were evaluated for blast resistance and major agronomic traits including heading date, culm length, panicle length, and tiller number. A linkage map encompassing 1,272.7 cM was constructed from a subset of the KBRIL (n = 142) using 130 single nucleotide polymorphisms. Two quantitative trait loci (QTL) for blast resistance, qBL1.1 harboring Pish/Pi35 and qBL2.1 harboring Pib, were mapped onto chromosomes 1 and 2, respectively. qBL1.1 was detected in both of the experimental sites, Namwon and Jeonju, while qBL2.1 was only detected in Namwon. qBL1.1 and qBL2.1 did not affect agronomic traits, including heading date, culm length, panicle length, and tiller number. From the 394 KBRILs, lines that were phenotypically similar to Koshihikari were selected according to heading date and culm length and were further divided into the following two groups based on blast resistance: Koshishikari-type blast resistant lines (KR, n = 15) and Koshishikari-type blast susceptible lines (KS, n = 15). Although no significant differences were observed in the major agronomic traits between the two groups, the KR group produced a greater mean head rice ratio than the KS group. The present study provides useful materials for developing blast-resistant cultivars that inherit both Koshihikari's high eating quality and Baegilmi's blast resistance.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.53 no.3
• /
• pp.261-272
• /
• 2008

This study was conducted to provide the fundamental data based on the agronomic characteristics of domestic aroma rice, widely cultivated domestic rice and foreign aroma rice for breeding of functional aromatic rice. Among the 104 varieties, all of domestic aroma rice and widely cultivated rice varieties were headed, 24 of 84 varieties of foreign aroma rice were not headed. The average heading date of domestic aroma rice Japonica types of domestic rice was later as 136 day, and Tongil types of domestic aroma rice were faster as 122 day. The average culm length of Indica types of foreign aroma rice was longer as 130 cm, and Tongil types of were shorter as 74 cm. The average panicle length of domestic aroma rice and traditional rice were about 21 cm, and Indica types of foreign aroma rice were longer as 29.5 cm. The average 1,000 grain weight of Tongil types of domestic aroma rice and was not a difference with the domestic aroma rice and was more 2.5 g than the Indica types of foreign aroma rice. The average ratio of grain width and length of Indica types of foreign aroma rice were highest as 3.29 (W/L), and the domestic traditional rice was lowest as 1.7 (W/L). The average fertility rate of the domestic aroma rice, the widely cultivated domestic rice, and the Japonica types of foreign aroma rice were above 89.7%, but the Indica types of foreign and the Tongil types of domestic aroma rice were below 65.4%. The average germination rate of foreign aroma rice were above 83.7%, and domestic aroma rice were above 90.4%. The non-glutinous rice were 64 varieties (84.2%) of total 104 accessions of material rice and the waxy rice were 7 varieties (1%). In the domestic aroma rice, Hyangmi2ho and Aranghyangchalbyeo has a mild aroma grade. In the foreign aroma rice, 22 of 40 varieties of Indica types and 9 of 16 varieties of Japonica types has a lightly aroma grade. And 13 varieties of widely cultivated domestic rice has a non-aroma grade.

• Asian-Australasian Journal of Animal Sciences
• /
• v.13 no.6
• /
• pp.837-841
• /
• 2000

The study was conducted at semi urban area in Bangladesh. It was based on a field survey by a prepared questionnaire. Various milking and reproduction performance were analyzed. The effects of grazing hour were found significant on age at weaning (AW) (p<0.001), age at first heat (AFH) (p<0.001), age at first conception (AF conception) (p<0.001), age at first calving (AF calving) (p<0.001), post partum heat period (PPHP) (p<0.001), calving interval (CI) (p<0.001), lactation length (LL) (p<0.001) and total lactational production (TLP) (p<0.001). The effects of concentrate feed were significant on AW (p<0.01), AFH (p<0.01), AF conception (p<0.001), AF calving (p<0.001), PPHP (p<0.001) CI (p<0.001), LL (p<0.001) and TLP (p<0.001). The effects of management level were significant on AW (p<0.001), PPHP (p<0.01), CI (p<0.001), daily milk yield (DMY) (p<0.05) and TLP (p<0.001). The overall mean values were $251.88{\pm}2.97$ days for AW, $37.29{\pm}0.33$ months for AFH, $38.43{\pm}0.34$ months for AF conception, $47.62{\pm}0.34$ months for AF calving, $1.30{\pm}0.02$ number of services per conception (NSPC), $191.57{\pm}3.92$ days for PPHP, $17.02{\pm}0.15$ months for CI, $2.49{\pm}0.06kg$ for DMY, $247.23{\pm}3.51$ days for LL and $590.40{\pm}15.00kg$ for TLP.

• Korean Journal of Agricultural Science
• /
• v.41 no.4
• /
• pp.299-302
• /
• 2014

A freesia (Freesia hybrida Hort.) 'Shiny Bell' was developed for the cut flower in the National Institute of Horticultural Herbal Science in 2012. This hybrid was selected from a crossing between cn. 'Teresa' and 'Rossini', which is white semi-double flowering and red double flowering, respectively. in 2004. Morphological characteristics of the selected hybrid were investigated for 3 years from 2009 to 2011, and then it was named 'Shiny Bell'. 'Shiny Bell' had red color of RHS W155C, and double flower. The growth of the plant was vigorous and the average height was 109.3 cm. The average flower width was 5.8 mm, number of floret per stalk was 11.3, and stalk length was 8.5 cm. The average yield, 7.3 Branches per plant, was 3 stems per plant more than the control cultivar. The average days to first flowering of 'Shiny Bell', was 143.3 days, and it was approximately 7 days later than the control cultivar. The average yield of 'Shiny Bell' was 4.0 cormlets per plant.

• Journal of Plant Biotechnology
• /
• v.35 no.4
• /
• pp.257-263
• /
• 2008

Improvement of the macro- and micro-elements density of rice (Oryza sativa L.) is gradually becoming a new breeding objective. In this study, the genomic regions associated with potassium, calcium, magnesium and iron content in rice grain were identified and characterized by using a doubled haploid (DH) population. Fifty-six simple sequence repeat (SSR) and one hundred and twelve sequence tagged site (STS) markers were selected to construct the genetic linkage map of the DH population with a full length of 1808.3cM scanning 12 rice chromosomes. Quantitative trait loci (QTLs) were detected, and QTL effects and QTL interactions were calculated for five traits related to macro- and micro-elements in the DH population from a cross between 'Samgang' (Tongil) and 'Nagdong' (Japonica). Twelve QTLs were located on five chromosomes, consisting of two QTLs for potassium, three QTLs for calcium, two QTLs for magnesium, one QTL for iron content and four QTLs for the ratio of magnesium to potassium (Mg/K). Among them, qca1.1 was detected on chromosome 1 with an LOD value of 8.58 for calcium content. It explained 27% of phenotype variations with increasing effects from 'Samgang' allele. Furthermore, fifteen epistatic combinations with significant interactions were observed on ten chromosomes for five traits, which totally accounted for 4.19% to 12.72% of phenotype variations. The screening of relatively accurate QTLs will contribute to increase the efficiency of marker-assisted selection (MAS), and to accelerate the establishment of near-isogenic lines (NILs) and QTL pyramiding.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.40 no.2
• /
• pp.203-211
• /
• 1995

This study was conducted to know how low temperature response of rice varieties is available for breeding lines adapted to cold weather. Some agronomic characters related to cold tolerance were evaluated for 188 varieties including three varietal types of Japonica, Tongil, and Indica. Cold tolerance of Japonica and Indica type varieties varied in leaf discoloration, heading delay, reduction of culm length, panicle number, spikelet number, panicle exsertion, spikelet fertility, and phenotypic acceptability at maturity, while Tongil type varieties were susceptible in most agronomic characters. In leaf discoloration, most Japonica type varieties were highly tolerant, while Indica type varieties showed various responses from tolerant to susceptibility. Not significant difference among three varietal types was observed on reduction of panicle number and spikelet number due to low temperature.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.37 no.1
• /
• pp.9-15
• /
• 1992

To establish the method of direct seeding cultivation in rice (Oryza sativa L.), direct surface seeding with treatments of N application rate, application of growth regulator(PP333), and seeding rate were conducted from May to Oct., 1989 at the experimental field of Sunchon National University. There were no significant differences among treatment means of N application rates, and seeding rates, which seemed to be due to severe occurrence of field lodging. Application of PP333 reduced culm length by 3-4m, but it did not affect the occurrence of lodging. The optimal seeding rate to maximize the number of spikelets per unit area was estimated to be 6kg seed /10a. To obtain stable yield in cultivation of direct surface seeded rice in submerged paddy field, it was necessary to reduce occurrence of field lodging through breeding of lodging resistance genotypes rather than cultural practices.

• Korean Journal of Plant Resources
• /
• v.20 no.1
• /
• pp.63-68
• /
• 2007

The purpose of this study was to applicate fundamental data for breeding new cultivar through selection of superior individuals and to investigate its nut characteristics in walnut hybrids. Selection of superior individuals with good nut qualities including high nut weight (NWT, >13g) and percentage of weight relative to total weight of nut (PWR, >50%) was carried out and then 4 promising individuals ($Sansung 4{\times}Concord-8,\;Concord{\times}Sansungl,\;Concord{\times}Sansung4\;and\;McKinster{\times}Punghan1$) were selected by quantitative characters. Especially width of pad of suture was main factor in selection of nut with high PWR (percentage of weight relative to total weight of nut) In addition, kernel length showed high correlation with kernel and nut weight. Thickness of septem (TOP) also had an effect on ease of kernel removal (EKR). In qualitative characters, there is a great difference among the individuals and cross combinations as well as showed simultaneously various characteristics in the same individual.

• Development and Reproduction
• /
• v.7 no.1
• /
• pp.35-40
• /
• 2003

Gonadotropin releasing hormone(GnRH), which is secreted from the hypothalamus, has a pivotal role in the reproduction of mammals. Golden hamsters are seasonal breeding mammal and their sexual activity is determined by photoperiod(length of light per day). Long photoperiod(LP, $\leq$ 12.5 hours of light) maintains the reproductive activity and short photoperiod(SP, $\leq$ 12 hours of light) suppresses it. In order to investigate in detail, the sexual activity was individually examined in SP-housed male golden hamsters received a vector at three different concentrations which contains rat GnRH cDNA. The gonadal regression was significantly(P<0.05) accelerated by the highest concentrations of the vector at 8 and 10 weeks after the treatment in comparison to the other groups. In the light of pulsatile release of GnRH in maintaining reproductive activity, the vector containing GnRH cDNA might secrete the GnRH in a constant high level. These results suggest that the GnRH-containing vector might desensitize the anterior pituitary, leading to acceleration or testicular regression.