Fertile Grains Research Articles

Diversities of soil weed seed bank and rice yield performance in response to tillage method and weeding regime

Rice field was infested with eight weed species. Among the species found in conventionally tilled plots, the five dominant species ranked in order of importance value were Cynodon dactylon (L.), Paspalum distichum (L.), Cyperus rotundus (L.), Azolla pinnata (L.) and Cyanotis axillaris (L.) while in stale seedbed the rank was Paspalum distichum (L.), Cynodon dactylon (L.), Cyanotis axillaris (L.), Leersia hexandra (L.) and Cyperus rotundus (L.). There were 15 weed species found in the soil weed seed bank studied at the net house. Among them five species were common of rice field. Ten new species were found in the seed bank. Azolla pinnata (L.), Cyperus difformis (L.) and Paspalum commersonii (L.) of field rice were not found in net house seed bank. In the field, Cynodon dactylon (L.) was the dominant over Paspalum distichum (L.) but at the net house Paspalum distichum (L.) was dominant over Cynodon dactylon (L.). In seed bank under conventional tillage, 11 species were found consisting of 3559 heads count and in stale seedbed 12 species consisting 3826 heads were counted. Among the identified species, nine were common in both tillage practice. Parapholis strigose (Dumort.) and Phyllanthus niruri (L.) were present in the soil of conventional tillage but not in stale bed while Echinochloa colonum (L.), Fimbristylis miliaceae (L.) and Eragrotis gangetica (Roxb.) were found in stale bed but not in conventional tillage. At the rice field grass weeds were dominant over sedges and broad leaf under the both types of tillage. At the seed bank of net house, grass weeds were dominant over sedges and broadleaf under conventional tillage while under stale seedbed, sedges were dominant over broad leaf and grass. Around 7% higher grain was recorded from stale seedbed compared to conventional tillage which attributed from higher number of effective tillers hill-1, higher number of fertile grains panicle-1, and lower number of sterile grains panicle-1. Weed free condition yield the highest grains followed by the combination of pre and post-emergence herbicides and unweeded control yielded the lowest. Stale seedbed kept weed free yielded the highest followed by stale seedbed sprayed the two herbicides. Conventional tillage remained unweeded yielded the lowest grain.Progressive Agriculture 27 (1): 39-47, 2016

Evaluation of elite fine grain aromatic rice lines for agro-morphological traits under mid hill condition of Uttarakhand

The present investigation was carried out to find out the yield performance and extent of genetic variability present in the fine grain aromatic rice advanced lines under mid hill conditions of Uttarakhand. Sixteen fine grain aromatic rice genotypes were evaluated for fifteen quantitative traits in a completely randomized block design with three replications during Kharif season. Highly significant differences were found for most of the traits, indicating the existence of genetic variability varying from lower to higher coefficients. The results found that the highest estimates of genotypic and phenotypic coefficient of variability for grain yield per plot (20.74% and 22.21%) whereas moderate level was observed for plant height (12.19% and 12.27%), panicles per plant (9.78% and15.19%), grains per panicle (11.40% and12.05%) and fertile grains per panicle (11.74% and 12.29%) respectively, indicating considerable amount of variability expressed for these traits. High heritability as well as high genetic advance was exhibited by traits viz., plant height (97.71% and 29.05%), number of grains per panicle (89.49% and 27.81%) and fertile grains per panicle (91.23% and 22.98%) signifying that for the improvement of these traits selection may be rewarding. Grain yield was observed to be significantly and positively correlated with plant height (0.467), flag leaf length (0.389), thousand grain weights (0.523) and kernel length (0.322) suggesting the scope of these traits for improving yield of fine grain aromatic rice through indirect selection. The path coefficient analysis showed that kernel length (1.675) had the highest positive direct effect on grain yield followed by days to maturity (1.053), grains per panicle (0.585), thousand grain weight (0.501), panicles per plant (0.305) and plant height (0.285). Therefore, these traits should be considered as significant while formulating the selection criteria in fine grain aromatic rice breeding for yield under the mid hill conditions of Uttarakhand.

Delayed Transplanting of Aged Rice Seedlings Causes the Yield Reduction in Farmer's Field

Four year experiments were conducted to find out the causes of yield reduction of farmer’s field of Nepal from 2011 to 2014. Randomised complete block design with three replications were used to compare twelve rice genotypes with Khumal-4 as a standard check. One set of genotypes were transplanted in the last week of June and the other set was transplanted two weeks delayed as summer season rice. Results showed that rice different parameters like grain yield, plant height, panicle length, days to heading and days to maturity were found significant (p<0.05). Plant height, panicle length and fertile grain per plant were also found significant in early transplanted rice than delayed transplanted rice. Delayed transplanted aged rice seedlings took shorter days to flower and mature than early transplanted rice. On an average, 38.44% decrease in yield was found from early to delayed transplanted rice from 2011 to 2014. Similarly, grain yield of early transplanted rice was found higher than delayed transplanted rice in all the year. The reason could be that too early and too late transplanting could not fulfill the required temperature and photoperiod for rice crop. Late transplant of aged rice seedlings are severe to cold and effect plant growth and yield. Thus the yield reduction of farmer’s field can be minimised by transplanting rice in appropriate time with recommended package of practices.

Growth, Yield and Quality of Wheat Varities as Affected by Different Levels of Nitrogen

A field experiment was conducted at the experimental field of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh during November 2012 to March 2013 to evaluate the response of three (3) wheat varieties viz., BARI Gom23, BARI Gom24 and BARI Gom25 under four levels of nitrogen fertilizer i.e, 75, 100, 125 and 150 kg N ha-1. The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. Results showed that plant height, number of leaves plant-1, leaf length and dry matter content were significantly affected due to varieties and/or nitrogen levels. Grains ear-1, number of fertile grains plant-1, 1000-grain weight, grain yield and harvest index were also significantly influenced by varieties and/or nitrogen levels. The value of all parameters studied in this experiment increased with increasing nitrogen levels up to 125 kg N ha-1 and thereafter decreased with fertilizer increasing level. Combination results showed that BARI Gom-24 with application of 125 kg N ha-1 gave the maximum grain yield (4.71 t ha-1), harvest index (49.37 %) and protein content (10.88%).Bangladesh Agron. J. 2015, 18(1): 89-98

Sex expression, population structure, and floral dimorphism in a gynodioecious herb, Agastache rugosa (Lamiaceae) in Korea

We investigated phenotypic expression and floral dimorphism in Agastache rugosa, a gynodioecious perennial herb, in five Korean populations. Three phenotypes, based on their reproductive characteristics, were found: plants with hermaphrodite flowers (male fertile); plants with female flowers (male sterile); and an intermediate phenotype, which had both hermaphrodite and female flowers within the same inflorescence. Most populations consisted of hermaphrodite and female individuals, together with the intermediate phenotype. Floral dimorphisms were found in nearly all the organs studied, including the corolla, calyx, and stamen, but not between the gynoecium of hermaphrodite and female flowers. Hermaphrodite flowers always had larger floral parts than those of the female and intermediate phenotype. Although there were no significant nutlet size differences between sexual types, nutlet weight was consistently greater in females than in hermaphrodites. Hermaphrodite flowers possessed a high proportion of fertile pollen grains, whereas in the intermediate phenotype, there was either the same amount of sterile and fertile grains or there were more sterile than fertile grains. The differences in the quality and quantity of pollen grains between the hermaphrodite and intermediate phenotype may reflect a trade-off between male and female function. These results indicate that intermediate flowers may be a transitional sexual morph toward female flowers.

Effect of Biogas Volume Flow Rate and Burner Temperature on Moisture Content of Organic Fertilizer in a Rotary Drying Process

Different factors can influence the moisture content of product in an organic fertilizer drying process. In this study, biogas volume flow rate and burner temperature were systematically studied in an effort to ascertain their effect on the moisture content of organic fertilizer grain that had been subjected to rotary drum indirect heating procedures. It was found that these two factors did major effect on the moisture content of organic fertilizer in a rotary drum drying process. Additionally, it was also discovered that acceptable organic fertilizer moisture content occurred when the rotary drum drier utilized both the biogas volume flow rate of 0.058 m3/min. in combination with the drying temperature of 500°C while the percentage of biogas blower and burner operation were reduced by 22.67 % and 9.1%, respectively.

Genomic composition and yield heterosis of the partial inter-specific hybrid rice between Oryza sativa L. and Oryza glaberrima Steud.

SUMMARYDevelopment of partial inter-specific hybrid (PIH) rice is a promising approach for exploiting inter-specific heterosis between Oryza glaberrima and Oryza sativa. In the present study, the relationship between genetic distance (GD) of parental lines and yield performance of the PIHs was assessed using partial diallel crosses between three indica male sterile lines and 14 introgression lines (ILs) with different fragments of O. glaberrima genes. Twenty two out of the 42 PIHs expressed positive heterobeltiosis (i.e., the Fl hybrid showed superiority over the better parent in the target trait) for panicle number, spikelet number, thousand grain weight and grain yield/plant. The proportion of O. glaberrima genome in the ILs ranged from 0·03 to 0·41, as revealed by 16 informative simple sequence repeat markers. Significant positive correlations were found between the proportion of O. glaberrima genome of the ILs and the GD between the ILs and the three different female parents. Heterosis of spikelet number per panicle in the hybrids was positively proportional with the O. glaberrima genome content of the parental ILs, while that of fertile grain percentage was negatively proportional to the O. glaberrima genome proportion. On average, the PIHs with higher grain yield and highest heterobeltiosis were obtained from the ILs carrying between 0·15 and 0·30 of O. glaberrima genome. The results indicated that a small proportion (&lt;0·15) of the O. glaberrima genome in the ILs might limit heterosis expression of spikelet number per panicle, while a very large proportion (&gt;0·30) of the O. glaberrima genome decreased the grain filling percentage in the PIHs, thus an intermediate range of O. glaberrima genome proportion should be more suitable for breeding heterotic PIHs. The exploitation of inter-specific heterosis between O. glaberrima and O. sativa has potential value for heterotic breeding in rice.

Rice Ratoon Crop: A Sustainable Rice Production System for Tropical Hill Agriculture

Increasing and sustainable production of rice in tropical hill area is facing various problems where rice ratooning can overcome the limitations. In this study; 22 rice entries were transplanted into experimental tank placed in the hill slope following Completely Randomized Design with five replications to asses’ agronomic performance of main crop and ratoon crop where Entry 13 demonstrated highest grain yield per plant (42.06 ± 1.2 gm) as main crop, as well as ratoon crop (3.37 ± 0.28 gm); Entry 19 produced lowest grain yield per plant (5.01 ± 0.31 gm) as main crop and Entry 31 as ratoon crop (0.47 ± 0.03 gm). The grain yield per plant of both the main and ratoon crop demonstrated significant (** at 5% level and *** at 1% level) positive correlation with number of tiller per plant (0.64 ** and 0.52); number of fertile tiller per plant (0.66 ** and 0.63 **); grain per panicle (0.72 ** and 0.53); fertile grain per panicle (0.80 *** and 0.63) and thousand-grain weight (0.66 ** and 0.54). The Duncan Multiple Range test and Analysis of Variance also confirmed the different grouping and significant differences of productivity and agronomic performances of the entries. The information of this investigation will helps the rice breeder as well as marginal rice farmers to consider rice ratooning as an important practice for sustainable rice production in tropical agriculture system for maximum gains.

Agro-morphological variation in “Jhinuwa” rice landraces (Oryza sativa L.) of Nepal

Jhinuwa is an aromatic rice (Oryza sativa L.) landrace from the Pokhara Valley of Nepal. A total of 210 accessions comprising seven types of Jhinuwa rice landraces were randomly collected from the rice fields to evaluate inter- and intra-population variability based on agro-morphological traits. The experiment was conducted in factorial randomized complete block design with three replicates in 2005. The first six principal components (PCs) accounted for 76.6 % variation for agro-morphological traits. Major traits that accounted for the variation by six PCs includes days to heading, days to maturity, total grain panicle−1, fertile grain panicle−1, culm length, panicle length, milling recovery, head rice recovery, aroma, 1,000 grain weight, sterile grain panicle−1, grain sterility %, and leaf characteristics. Both principal coordinate analysis and cluster analyses revealed four phenotypic groups, two of which represent Bayarni, Jhinuwa, and Biramphul while the other two account for Tunde and Pakho Tunde. Tunde, Pakho Tunde, Kalo Bayarni, and Seto Bayarni showed higher intra- as well as inter-population variation compared to other populations. The phenotypic and genotypic coefficients of variation, broad sense heritability (h 2B) and genetic advance (GA) as a percent of the mean assessed for 210 accessions revealed high h 2B and GA estimates for leaf width, leaf length breadth ratio, ligule length, sterile grain panicle−1, grain sterility % and 1,000 grain weight. The current study demonstrates that improvement in Jhinuwa rice landrace is possible by selecting superior accessions from existing natural populations while selection should be focussed to market traits with higher h 2B and GA estimates.

Diversity analysis of indica rice (oryza sativa l.) genotypes against low and high temperature stress

Morphological characterization of 470 rice (Oryza sativa L.) accessions including five checks collected from different regions country were assessed using 19 quantitative characters traits. Accessions were evaluated in a field experiment in an augmented experimental design. The aim of the research was to study variations and to select lines that could be used as potential parents in future breeding programs. A principal components plot and distance between genotypes in different cluster groups were used to group the accessions. The rice genotypesgrouped into divergent cluster 12 and 18 are expected to give promising and desirable recombinants in the segregating generations. Also, traits contributing maximum to genetic divergence viz. Seed vigor followed by Fertile Grains/ Panicle, Fertile Grains/ Panicle and panicle length may be utilized in selecting genetically diverse parents.

Genotype-environment interaction and stability analysis of four fine rice varieties

Genotype-environment interactions through different stability parameters and performance traits of four fine rice genotypes were studied. The traits were; days to 50% flowering, days to maturity, plant height (cm), number of effective tillers per hill, panicle length (cm), number of fertile grains per panicle, number of sterile grains per panicle and yield (t/ha) in four fine rice genotypes across nine environments along with experimental farm of Genetics and Plant Breeding department, Bangladesh Agricultural University (BAU) Mymensingh. Significant differences were observed for genotypes, environments and genotypes–environment interaction. Stability analysis after Eberhat and Russell’s model suggested that the genotypes used in study were more or less responsive to environmental changes. Most of the genotypes performed better in Comilla. BAU125 was found stable for effective tillers per hill and comparatively less sensitive to other genotypes in panicle length and number of sterile grains per panicle. BR5 was stable for days to maturity and plant height whereas Kalizira performed better than other genotypes for fertile grains per panicle. In general, only the genotype BAU125 was found stable for effective tillers per hill, panicle length and lowest number of sterile grains per panicle. DOI: http://dx.doi.org/10.3329/jbau.v10i1.12011 J. Bangladesh Agril. Univ. 10(1): 1–7, 2012

PENGARUH CARA PENYEMAIAN DAN PEMUPUKAN NPK TERHADAP PERTUMBUHAN BIBIT MAHONI DAUN LEBAR DI PESEMAIAN

Swietenia macrophylla King is one of popular tree species for timber product in Java. In order to increase the productivity of planting stock production at nursery, this research was conducted. The objectives of this research was to study the influences of sowing method and NPK fertilizer application on the growth of mahogany seedlings at nursery. The treatments were sowing methods (with and without pricking out), types of NPK fertilizer (grain and solution) and the dosages of NPK fertilizer (0, 0.2, 0.4 and 0.6 gram/seedlings). The result showed that sowing methods and type of NPK fertilizer did not give significant effect on the growth of mahogany seedlings. The dosages of NPK fertilizer caused significant different on the variation of height, diameter, total dry weight and seedling quality index. The application of NPK fertilizer at 0.6 g/seedlings/month showed the best result i.e: the seedling heigth (42 cm), stem diameter (5.15 mm), total dry weight (5.28 g) and seedling quality index (0.38).

Development of Near Isogenic Lines of Wheat Carrying Different Spike Branching Genes and Their Agronomic and Spike Characters

The branched spike introduced from T. turgidum in common wheat was controlled by two recessive genes (sb1 and sb2). The effect of specific sb on the development and spike characters can be accurately determined by using isogenic lines (NILs), which, however, were not usually available. In this study, four genotypes having different combinations of the two sb genes with a common genetic background cv. Taishan were produced by continuous backcrossing and determined by crossing and test-crossing. The four NILs included one line with branched spike, DR (sb1sb1 sb2sb2), and three lines with normal spike, SR1 (sb1sb1 Sb2Sb2), SR2 (Sb1Sb1 sb2sb2), and DD (Sb1Sb1 Sb2Sb2). These NILs were grown during two growing seasons (2008–2009 and 2009–2010) to investigate the effects of sb genes on agronomic and spike characters. The results showed that SR1 postponed significantly the days to heading and the days to anthesis, and SR2 decreased significantly grain number by reducing the fertile floret in a spike. DR not only displayed the branched spike but also had great effects on agronomic and spike characters. In DR, the days to maturate was significantly postponed, and the number of fertile floret and grain number increased in a spike, but the grain set reduced significantly. This indicated the sb combinations have different effects on the agronomic and spike characters. This research made foundation for analyses of mechanisms of branched spike formation and associated properties in hexaploid wheat in future.

Water-deficit tolerant classification in mutant lines of indica rice

Water shortage is a major abiotic stress for crop production worldwide, limiting the productivity of crop species, especially in dry-land agricultural areas. This investigation aimed to classify the water-deficit tolerance in mutant rice (Oryza sativa L. spp. indica) genotypes during the reproductive stage. Proline content in the flag leaf of mutant lines increased when plants were subjected to water deficit. Relative water content (RWC) in the flag leaf of different mutant lines dropped in relation to water deficit stress. A decrease RWC was positively related to chlorophyll a degradation. Chlorophyll a , chlorophyll b , total chlorophyll , total carotenoids , maximum quantum yield of PSII , stomatal conductance , transpiration rate and water use efficiency in mutant lines grown under water deficit conditions declined in comparison to the well-watered, leading to a reduction in net-photosynthetic rate. In addition, when exposed to water deficit, panicle traits, including panicle length and fertile grains were dropped. The biochemical and physiological data were subjected to classify the water deficit tolerance. NSG19 (positive control) and DD14 were identified as water deficit tolerant, and AA11, AA12, AA16, BB13, BB16, CC12, CC15, EE12, FF15, FF17, G11 and IR20 (negative control) as water deficit sensitive, using Ward's method.

Effects of Plant Density on Grain Number and Grain Weight at Different Spikelets and Grain Positions in Winter Wheat Cultivars

Seed-setting traits and grain weight are influenced by either genetic factor or cultivation environment in wheat (Triticum aestivum L.), such as plant density. Due to the unbalanced development of a spike, grain number and grain weight at different spikelets and grain positions are largely different. Although their distributions have been described in earlier reports, the effect of plant density is not clear. This study focused on the effect of plant density on the grain number and grain weight of two wheat cultivars (Lankao Aizao 8 of large-spike type and Zhoumai 18 of medium-spike type) at different spikelets and grain positions. The grain number, spikelet weight, and grain weight with the spikelets positions from the bottom to the top increased first and then decreased. The differences of seed-setting traits between two cultivars were significant. Meanwhile, seed-setting traits of main sipke were superior than that of tillering spike. Under low sowing density, the seed setting characteristics and grain weight in Lankao Aizao 8 were more superior than those in Zhoumai 18, and those of main stem spike were more superior than those of tillering spike. The effects of spikelet and grain positions on the weight of individual grain varied with the grain number of spikelet. For the basal and middle spikelets, the grain weight was higher at second grain position than at the first one, whereas it was inverse for the upper and top spikelets. The grain weight was lower in the third grain position than in the first and second grain position, and the least in the fourth grain position. In conclusion, appropriate plant density is important for high yield of different spike-type cultivars, and in wheat production we should properly increase the proportion of tillering spike on the basis of ensuring main stem spike number; increase grain weight on the basis of ensuring fertile grain number especially for basal spikelet; and develop the potential of grain weight in the third and fourth grain positions on the basis of ensuring that in the first and second grain positions of spikelet.

A Comparison of Side-dressed Liquid Hog Manure to Urea Ammonium Nitrate in Corn

Liquid hog manure is frequently spring-applied prior to corn planting, but concern regarding compaction, planting delays, and nitrogen losses have increased corn producer interest in side dressing. The objective of this study was to compare available nitrogen in side-dressed liquid hog manure versus 28% urea ammonium nitrate (UAN) in terms of fertilizer nitrogen equivalent, yield response, grain protein, soil compaction, and end of season soil nitrates. Field experiments were conducted at three sites in southwestern Ontario from 2003 to 2005. Three rates of liquid hog manure (zero, low, and high) and five rates of UAN (0, 53, 106, 159, 220 lb of N per acre) were applied at side-dress timing in corn. Available nitrogen in side-dress applications of liquid hog manure was equally effective as UAN in supplying corn nitrogen requirements based on comparisons of yield and grain protein concentration. Drier conditions at side-dress timing reduced soil compaction risks and yield reductions arising from possible root pruning were not observed. Side-dressed liquid hog manure should be applied at rates of available nitrogen that correspond to crop nitrogen demand, since like UAN, excess applied nitrogen will be susceptible to late season losses.

Dry-Matter Partitioning and Accumulation of Carbon and Nitrogen during Ripening in a Female-Sterile Line of Rice

To evaluate the effect of sink restriction on dry-matter partitioning to rice plant organs during ripening, we observed the dry-weight partitioning and accumulation of carbon and nitrogen in a female-sterile line, FS1, which has intact panicles with only a few fertile grains, in comparison with those in a normal counterpart, Fujisaka 5. In spite of the loss of sink function in the panicles, FS1 produced a larger amount of dry-matter than Fujisaka 5. Without a change of panicle dry weight throughout the ripening period, FS1 increased dry weights of culms and leaf sheaths at the early stage and of late tillers at the late stage. The amounts of dry-matter partitioned to panicles, culms plus leaf sheaths and late tillers in FS1 were comparable to those amounts in Fujisaka 5 at maturity, indicating that the latter two organs function as a sink of dry matter to substitute for panicles. Carbon partitioning to plant organs was basically similar to the dry-matter partitioning. Since the amount of nitrogen in a plant hardly increased during the ripening period in FS1 and Fujisaka 5, nitrogen partitioning to plant organs was different from the partitioning of dry matter and that of carbon. Culms, leaf sheaths and late tillers function as a sink of nitrogen partly to substitute for panicles, but the sum of nitrogen partitioned to these organs and panicles in FS1 was markedly smaller than in Fujisaka 5 at maturity, suggesting that other organs do not substitute for panicles in the sink function for nitrogen partitioning. FS1 developed late tillers rapidly at the late stage and had a carbon-nitrogen ratio in the stems different from that in Fujisaka 5.

Photosynthesis and Dry-Matter Production during Ripening Stage in a Female-Sterile Line of Rice

The relation between the source capacity of leaves and the sink capacity of panicles affects dry-matter production and determines grain yield in rice. The source-sink relation has so far been studied on rice plants from which panicles were artificially removed. We examined the source-sink relation using a female-sterile line FS1 with intact panicles each havinga few fertile grains instead of panicle removal. The leaf photosynthetic rate during the ripening stage in FS1 was measured, in comparison with a normal counterpart Fujisaka 5, and the effect of losing sink function on dry-matter production in the rice plant was characterized. The photosynthetic rate in flag leaves was maintained at a slightly higher rate in FS1 than in Fujisaka 5 in the late ripening stage, though panicles did not function as a sink organ in FS1, and dry-matter production in this line was not lower than that in Fujisaka 5. In the early ripening stage of FS1, culms and leaf sheaths fulfilled the sink function instead of panicles, and the tillers that appeared in the late ripening stage became a new sink organ. Roots also functioned as a possible sink of photosynthates. Owing to the unique character of dry-matter production after heading, FS1 may be useful as a forage crop.

Heterosis for yield and yield attributes in aromatic rice

Twenty five aromatic rice hybrids developed by line x tester mating design involving 8 scented and 2 non-scented parents were evaluated for heterosis over mid parent, better parent and standard variety, Pusa Basmati 1 for nine yield components. All the 25 hybrids exhibited significant negative heterobeltiosis for plant height and significant positive heterosis over mid parent, better parent and standard check for tiller number. IR 64/HBC 85, IR 64/Basmati 6129, PR 109/Basmati 410 and PK 1379- 9-1-1/Basmati 6129 manifested high average heterosis, heterobeltiosis and standard heterosis for grain yield per plant. From this study it is revealed that heterosis for grain yield was mainly because of simultaneous manifestation of heterosis for tillers number, panicle length, fertile grains per panicle, total spikelets per panicle and test weight.

방사선을 이용한 내염성 계통의 기내선발 및 특징

1.5% NaCl이 함유된 배지에 캘러스를 치상하여 방사선을 처리한 결과 무처리구보다 처리구 (30, 50 Gy)에서 캘러스 생존율 및 재분화율이 증가하여 내염성 캘러스를 선발하는데 방사선의 적용이 효과적임을 알 수 있었고, 내염성 캘러스에서 재분화된 M<TEX>$_3$</TEX>세대 종자에서 내염성 계통들은 모품종보다 초장, 근장 및 근수의 생육이 우수하여 이러한 계통은 내염성 연구를 위한 유용한 유전자원으로 이용할 수 있을 것으로 생각된다. 또한 RAPD 기술은 대조구와 내염성 캘러스에서 재분화된 계통을 구분하는데 유용한 기술임을 알 수 있었다. The combination of radiation technique with an in vitro culture system was initiated to develop salt tolerant rice. We established an in vitro culture system to select tolerant lines against salt stress. NaCl tolerant cell lines were selected from the callus irradiated with gamma ray on N<TEX>$_{6}$</TEX> medium with 1.5% NaCl and 2 mg/L 2,4-D. Regenerants (M<TEX>$_1$</TEX>) were obtained from the tolerant callus which was cultured for 30 days auxin-free medium. The M<TEX>$_2$</TEX>seeds were harvested from M<TEX>$_1$</TEX>plants on an individual plant basis. Thirty seedlings from each 450 M<TEX>$_2$</TEX>lines were transplanted in a field and total 5,000 M<TEX>$_3$</TEX>lines were harvested with an average 90 percent of fertile grain. M<TEX>$_3$</TEX>lines were utilized for selection of salt tolerance. Salinity-tolerant lines (225) were selected among 5,000 M<TEX>$_3$</TEX>lines. Of the 225 lines tested, the morphological traits of two lines (120-10 and -11) were far superior to control (Donagjinbyeo) in agromomic traits such as plant height, root length and no. of roots. Control and tolerant lines were analyzed by RAPD markers. Three polymorphic bands were presented in only tolerant lines, demonstrating a genetic difference between control and the tolerant lines. Such tolerant lines could be used as genetic resources to improve salt tolerance.e.