Overwintering capacity, closely related to winter hardiness, of Chinese milk vetch planted with different sowing times and sowing practices was investigated to improve the incorporation into cropping system in Korea. The tolerance to low temperature was evaluated with LT50 using leaf disc leaching method. Dry weight of CMV was reduced remarkably with delayed planting from Sep. 5 to Oct. 20. The differences in tolerance to freezing temperature were not conspicuous among CMV genotypes, however, the differences between genotype (collections at different regions) were due to the plant architecture, mainly to the leaf angle. The crouching genotype collected at central region of Korean peninsula, which showed excellent freezing tolerant, has planophile leaves. The feature of internal constituents of CMV genotypes did not show any noticeable differences with respect to the freezing tolerance which evaluated by leaf disc leaching experiment. To overcome the poor overwintering capacity, tolerant genotype should be developed by selection with considering the plant architecture. The reduction of CMV growth during overwintering period was ameliorated with furrow-sowing under late-sown condition, therefore, when the CMV is inevitably sown late after recommended time, the seeds should be sown on furrow to overcome the cold stress.
Demand for the domestic hairy vetch seed production will be increased with the increasing interest of environment-friendly agriculture in Korea. This study was conducted during from 2000 fall to 2003 spring at upland field of National Institute of Crop Science in Suwon, Korea to compare wheat and triticale (TC) as stake crop of hairy vetch (HV), and to know proper seeding rates and ratios between TC and HV for the maximum HV seed production. As supporting crop of HV, TC was superior to wheat at the points of higher HV seed yield, stronger TC stalk for supporting, consistence of ripening stage of two seeds. In seeding method, row seeding was superior to broadcast seeding at the points of less lodging and higher HV seed yield. HV seed yield decreased with the increase of TC seeding rate in mixture cropping (row seeding), particularly at TC seeding rates over 5kg/10a. HV seed yield increased with the increase of HV seeding rate at the condition of TC seeding rates under 5kg/10a in spite of higher lodging of mixed crops at higher HV seeding rate due to higher HV aboveground dry matter. Maximum HV seed yield was obtained at TC seeding rate of 1~~1.5kg/10a as indicating HV seed yield 176kg/l0a (CV. Madison) at seeding rate of TC 1kg/10a + HV 2 kg/10a in 2001, and HV seed yield 96kg/10a (CV. Common) at seeding rate of TC 1.5kg/10a + HV 4.5kg/10a in 2003. Use of all-purpose combine harvester for harvesting and appliance for separation of mixed seeds using centrifugal force, which are prerequisite for HV seed production, was excellent in the simultaneous seeds production system of HV and TC.
Rice and weed interference in the paddy field caused by resource competition and allelopathy. Evaluation method of active weed suppressive behavior of rice to weed was developed by eliminating light competition at soil condition. Twenty eight days old rice seedlings (6-7 leaf stage) which was grown at saturated, no drainage pot were clipped above 3~~4cm from the soil surface. Weeds seeded around clipped rice stem, named ratoon seeding screening method, showed varietal suppressive difference to Echinochloa crus-galli, Echinochloa crusgalli var. praticola and Monochoria vaginalis. Potential allelopathic rice varieties, Sathi, AC1423 and PI312777 showed better suppressive activity to weed seedling growth than Nonganbyeo and Keumobyeo. Weed suppression of one plant of rice cultivars could be evaluated by the cell size of 2.5~times2.5cm at rice clipping of seedling 29 days after rice seeding.
The effects of UV-B radiation on the seedling growth, carbohydrate metabolism and antioxidants activities of rice (Oryza sativa L.) were investigated under environmentally controlled chamber. Supplementary UVB radiation reduced dry matter as well as leaf area, therefore, relative growth rates (RGR) of seedlings were decreased by up to half compared to control. Photosynthetic products such as soluble sugars and starch were rapidly and significantly reduced by within 1 day of enhanced UV-B radiation due to the inhibition and degradation of photosynthetic processes and thylakoid membrane integrity. In our study, nonstructural carbohydrate levels were proved to be a main indicator on UV-Binduced stress. The behavior of SOD, CAT, APX and POD activities was monitored in the leaves of rice seedlings subjected to UV-B radiation. Under UV-B treatments, SOD activity was initially increased, whereas CAT and POD activities were slowly and slightly increased. However, APX activity showed no presumable results with an increase of UV-B dose. In leaves of rice seedlings, supplementary UV-B radiation caused an increase in free putrescine and spermidine, however spermine remained unaltered, although 24-hrs UV-B treatment slightly increased. This result presumes that an excess UV-B dose may induce ethylene biosynthesis (senescence) rather than polyamine biosynthesis (defense).
Proper choice of source populations contributes to the ultimate success of selection for genetic improvement. The source population should possess the most desirable alleles at as many loci as possible for intra population improvement. Such desirable alleles can be intensified by introgression of exotic germ plasm into locally adapted ones through hybridization followed by selection. The objectives of this study were to determine the mean performance, genetic variability (~sigma2G) and heritability of fresh ear yield and other important traits within two sweet corn source populations, BC1-10~timesSyn-II and BC2-10. One hundred selfed progenies from each of the two source populations were evaluated in a 10~times10 lattice design, at the Institute of Bioscience (IBS) Farm, University of Putra Malaysia (UPM) following the recommended cultural practices. Significant differences among selfed progenies within BC1-10~timesSyn-II were observed for all traits, while differences among selfed progenies within BC2-10 were noted for fresh ear yield, ear length, ear diameter, number of kernels per row, ear height, days to tasseling and days to silking. Progenies developed from BC1-10~timesSyn-II population had higher estimates of ~sigma2G than did progenies from BC2-10 population for number of kernel rows per ear, total soluble solids, plant height, days to tasseling and days to silking, showing that selection to improve these traits would be more effective in selfed progenies of BC1-10~timesSyn-II than that in BC2-10. On the other hand, progenies developed from BC2-10 population had higher estimates of ~sigma2G for ear length, ear diameter and ear height, indicating that progenies from this population would have better genetic gain than BC1-10~timesSyn-II . Comparable estimates of genetic variance were found for fresh ear yield, and number of kernels per row, indicating that genetic improvement of the two source populations is expected to produce similar genetic gains for these two traits. Therefore, selfed progenies developed from both source populations could be used to improve the two populations for various traits and thereby develop superior genotypes for immediate use in the production system.
Mass selection (MS) is an efficient selection method to directly improve highly heritable traits. In the present study, two cycles of MS for ear length were conducted on two sweet corn populations, BC2-l0 and BC1-10~timesSyn-II after introgression of exotic germplasm. The improved populations generated from these selections were evaluated in comparison with the base populations at two locations, to determine the genetic gains and performance of the improved populations. The two base populations showed varied average realized responses to MS. In BC2-l0 derived population, the realized responses were 9.1~% in BC2-l0 C1 and 1.2~% in BC2-l0 C2, whereas inBC1-10~timesSyn-II derived population, the realized responses were 5.6~% in BC1-10~timesSyn-II C1 and 2.9~% in BC1-10~timesSyn-II C2. All the improved populations showed longer ears than their respective base populations and the check varieties. Ear length, which was used as the selection criterion in this study, showed high broad-sense heritability in the BC2-l0 and BC1-10~timesSyn-II derived populations, while fresh ear yield revealed low heritability, indicating that selection for ear length in these populations would be more effective than direct selection for yield. Results of this study indicate that MS conducted on BC210 and BC1-10~timesSyn-II had significantly increased ear length and fresh ear yield in both populations. The improved populations obtained would serve as better germplasm sources and further selection in these populations could offer better responses.
A field study was conducted to investigate and ascertain the effects of boron and molybdenum with recommended N P K S Zn fertilizers (RFD) for sustained sugarcane yield in the sandy acidic soil in Old Himalayan Piedmont Plain of Bangladesh. Results revealed that the treatment T7 having recommended fertilizers of N 120, P 35, K 100, S 25 and Zn 2kg ha-1 + B 2kg ha-1 + Mo 2 kg ha-1 produced significantly higher number of millable cane (126.96~times103~;ha-1) except in T9 with RFD + B 2 kg ha-1 + Mo 4kg ha-1 , and higher cane yield (92.83 Mg ha-1 ) among all except in T3 with RFD + B2 kg ha-1 , T5 with RFD + Mo 2kg ha-1 and T9 where the effects were statistically identical. The increase in cane yield by T7 was 164.6~% over control. The treatment T7 having RFD + B 2kg ha-1 + Mo 2kg ha-1 further gave the highest additional net economic benefit of Taka 16, 500.00 for added Band Mo at 2kg ha-1 among all the treatments in the study.
A field study was conducted to develop an economically suitable combination of organic and inorganic fertilizers for sugarcane cultivation in sandy acidic soil of a commercial sugarcane farm under Old Himalayan Piedmont Plain of Bangladesh. Results revealed that the treatment T4 which received 75~% of Recommended fertilizers (N 120, P 35, K 100, S 25, Zn 2 kg ha-1 ) + 10 Mg ha-1 Rice mill ash + Mg ha-1 press mud significantly produced higher sugarcane yield (72.34 Mg ha-1 ) among all the treatments except T5 having 100~% of Recommended fertilizers + 10 Mg ha-1 Rice mill ash + 10 Mg ha-1 press mud, which was identical. T4 also gave the highest net economic benefit at Bangladesh Taka 15,920.47 per hectare from the added nutrient management. Thus, the integrated use with organic and inorganic fertilizer is highly essential for sustainable production of sugarcane in commercial farm of the region in Bangladesh, where it has been grown year after year.
The effects of Rhizobium inoculant, nitrogen, phosphorus, and molybdenum on nodulation, dry matter production, yield attributes, pod and seed yields, protein and phosphorus contents in seed of pea (pisum sativum) var. IPSA Motorshuti-3 were assessed by a field experiment. Among the treatments Rhizobium inoculant in combination with 25kg P and 1.5kg Mo/ha performed best in recording number of nodules/plant, total dry matter yield, number of pods/plant, number of seeds/pod, 1000-seed weight, green pod yield, green and mature seed yields of pea. The highest green pod yield of 15.37 t/ha (97.05~% increase over control) and green seed yield of 9.6t/ha (69.31~% increase over control) were obtained by inoculating pea with Rhizobium inoculant in association with 25kg P and 1.5 Mo/ha. The effects of 60 or 120kg N/ha were comparable to Rhizobium inoculant in most cases. There were positive correlations among yield attributes, yield, protein and phosphorus contents in seeds of pea. From the viewpoint of yield attributes, yield, and seed quality, application of Rhizobium inoculant along with 25kg P and 1.5kg Mo/ha was considered to be the balanced combination of nutrients for achieving the maximum output from cultivation of pea in Shallow-Red Brown Terrace Soil of Bangladesh.
Expanded rice husk (ERR) is different from commercial rice seedling media in chemical and physical properties such as pH, permeability, and water content. This study was conducted to test a possibility of improving rice seedling growth by improving the texture of ERR as a rice seedling medium. The seedling media used were a commercial seedling medium (CSM), rice husk, and ERR 1, 2, 3, and 4 with different expansion degrees. The pH of the ERHs ranged from 6.3 to 6.8. As the expansion rate increased, ERR particle sizes decreased, and water permeability and absorption rates improved. No significant differences in shoot dry weight and rate of maturity were found among the seedlings cultivated in the different ERH media. However, the mat formation of seedling roots became loose as the expansion rates were decreased. Further studies are necessary to determine the cause of poor root growth in ERH media.
In the absence of exogeneous nitrogen supply, evaluation of a symbiosis effectiveness of Bradyrhizobium japonicum USDA 110 in a supernodulating soybean mutant, SS2-2, its wild type, Sinpaldalkong 2, and control genotype, Jangyeobkong, was conducted in this study. Nodules in SS2-2 were initially white and similar to its wild type, Sinpaldalkong 2. At the late stage, the wild type nodules became dark pinkish by maturation, by contrast, mature nodules in SS2-2 remained light green to pinkish, indicating a lack of leghemoglobin. Tap root length was short in nodulated symbiotic SS2-2 than that of its wild type and the control genotype. Nodulated root length and nodule density on root length were significantly increased by B. japonicum inoculation, but no significant increase was observed on root length and percentage of nodulation to total root length. Regardless of Bradyrhizobium inoculation, SS2-2 showed higher nodule dry weight and higher acetylene reduction activity (ARA) when compared with its wild type and the control genotype. Inoculation of B. japonicum leaded the increase of ARA in 47 days after planting (DAP), in part because of nodule development. Supernodulating mutant, SS2-2, less responded to B. japonicum induction in terms of nitrogen fixation and nodulation characteristics than its wild type. Thus, interaction of supernodulating soybean mutant with Bradyrhizobium had less symbiotically associated response than normal nodulating soybean.
Molecular-based genetic diversity for a set of 141 accessions of Korean barley cultivars and 24 accessions of foreign exotic cultivars were analyzed using random amplified polymorphic DNAs (RAPDs). Different level of genetic variability was observed with 30 random decamer primers in the Korean barley varieties and breeding lines which were preliminarily classified by morphological (hulled & hulless barley) and end-use (malting barley) and/or by the released periods. A total of 74 RAPD bands were scored, and the number of bands per primer varied from 1 to 7 with an average of 2.74. The hulled barley pool had one more marker genotype per primer than the hulless barley pool. The polymorphic information content (PIC) values based on the band pattern frequencies among genotypes varied depending on genetic pools where mean PICs of hulled, hulless and malting barleys were 0.62, 0.57, and 0.43, respectively. Certain genomic loci amplified by opR04, opF01, opB05, and opC13 were highly polymorphic with PIC>0.8. Patterns and temporal trends of genetic diversity assessed over the period from 1970s to 1990s had a tendency to increase, and in particular, this upward slant was quite clear and significant for the hulless barley pool. In the cluster analysis using genetic similarity matrix calculated from RAPD profiles, two major groups and several small subgroups were classified. Major grouping of materials was not affected by the presence of the husk but by their genetic background and the spike-row type. The validity of information on the genetic diversity and relationships between genotypes will have been reviewed to predict their yield potential.
Thirty-two germplasms of Korean adlay landraces were examined to analyse the genetic relationship through the amplified fragment length polymorphism (AFLP) approach. Total number of AFLP products generated by 12 selective primer combinations was 882. The number of polymorphic fragments by each primer combination greatly varied from 4 to 51 with a mean of 20.3, bands visible on the polyacrylamide gel. A genetic similarity coefficient was used for cluster analysis following UPGMA (unweighted pair grouping method of averages) method. The resulting clusters were represented in the form of a dendrogram. The clustering was not tight in the dendrogram. There was generally no clear grouping of the adlay according to the geographic regions in which germplasms were collected. The present AFLP analysis imply that although Korean adlay displayed a larger amount of AFLP variation within germplasms, the variation was shown independently without reflecting a clinal variation. This study demonstrated that AFLP method can be used to examine the genetic relationships among different germplasms of adlay.
ent-Kaurane- and ent-pimarane-type diterpenoids were isolated from the methanol extract of Siegesbeckia pubescens by column chromatography. Their structures were elucidated as ent-16α H,17-hydroxy-kauran-19-oic acid (1), ent-4,17-dihydroxy-16α -methyl-kauran-19-oic acid (2), ent-16β ,17-dihydroxy-kauran-19-oic acid (3), kirenol (4) and ent-16β ,17,18-trihydroxy-kauran19-oic acid (5) by spectral analysis. The cytotoxicity of these compounds in Caki cells was assayed by a cell counting kit. Only one group treated with kirenol (4), an entpimarane-type diterpenoid, showed the inhibition of the cell growth in Caki cells.