Medium Slender Grain Research Articles

Biochemical foundation of the aroma and antioxidant activity of Indian traditional rice landrace Maharaji and the effect of radiation-induced mutagenesis on its metabolome

Maharaji rice, an aromatic variety with medium slender grains, is traditionally cultivated in the central regions of India. This study aimed to identify the biochemical compounds responsible for Maharaji rice's distinctive fragrance and enhance its agro-morphological traits through mutation breeding. Using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) analysis, forty major metabolites were identified which may be responsible for its characteristic aroma. The bioactive compounds included terpenes, flavonoids, and amino acids. Maharaji brown rice extract exhibited potent radical scavenging activity. Radiation-induced mutation breeding improved the agro-morphological traits and also triggered biochemical diversification in different mutants. Maharaji Mutant-2 exhibited improved aroma due to higher abundance of aromatic compounds, improved yield and morphological characters as compared to the parent. This study, for the first time identifies the compounds associated with the characteristic aroma of Maharaji rice. Global metabolomics may, therefore, expedite the selection of mutants with suitable aroma and desirable biological properties.

Marker Assisted Characterization of TGMS Gene in Rice Cultigen Ts 29 (Oryza Sativa L.) to Develop Two Line Hybrids

The application of the thermsensitive genic male sterility (TGMS) system has great potential for revolutionizing hybrid rice production through simple and effective seed production technology. For the successful utilization of this novel male sterility system, knowledge of the fertility behaviour and genetic control of a TGMS line is essential. In this study, an investigation was carried out to characterize the TGMS gene present in the mapping population of TS 29 x CO(R)49. Through Bulk Segregant Analysis RM 3476 alone produced a polymorphic relationship between the parents and corresponding bulks and was used for surveying the individual plants of F3/F4 population. The marker RM 3476 produced contrasting fragments between sterile and fertile plants. The result was associated with the phenotypic observations on pollen fertility under the field conditions, confirming co-segregation of the marker with the gene of interest. Hence, the tight linkage of marker with TGMS gene was identified by RM 3476 which was already identified as a marker located near tms 6 gene in chromosome 5. From this study four TGMS lines were also identified with desirable floral traits for high out crossing and medium slender grain type. Bangladesh J. Bot. 53(2): 345-351, 2024 (June)

Genetic enhancement of reproductive stage drought tolerance in RPHR-1005R and derivative rice hybrids through marker-assisted backcross breeding in rice (Oryza sativa L.).

Drought stress is considered as one of the major production constraints in rice. RPHR-1005R is a restorer line (R-Line) with a popular, medium-slender grain type, and is the male parent of the popular Indian rice hybrid, DRR-H3. However, both the hybrid and its restorer are highly vulnerable to the drought stress, which limits the adoption of the hybrid. Therefore, the selection of the restorer line RPHR-1005R has been made with the objective of enhancing drought tolerance. In this study, we have introgressed a major QTL for grain yield under drought (qDTY 1.1) from Nagina22 through a marker-assisted backcross breeding (MABB) strategy. PCR based SSR markers linked to grain yield under drought (qDTY1.1 - RM431, RM11943), fertility restorer genes (Rf3-DRRM-Rf3-10, Rf4-RM6100) and wide compatibility (S5n allele) were deployed for foreground selection. At BC2F1, a single plant (RPHR6339-4-16-14) with target QTL in heterozygous condition and with the highest recurrent parent genome recovery (85.41%) and phenotypically like RPHR-1005R was identified and selfed to generate BC2F2. Fifty-eight homozygous lines were advanced to BC2F4 and six promising restorer lines and a hybrid combination (APMS6A/RPHR6339-4-16-14-3) were identified. In summary, the six improved restorer lines could be employed for developing heterotic hybrids possessing reproductive stage drought tolerance. The hybrid combination (APMS6A/RPHR6339-4-16-14-3) was estimated to ensure stable yields in drought-prone irrigated lowlands as well as in directly seeded aerobic and upland areas of India.

Panicle Architecture in Enhancing Grain Yield in Rice (Oryza sativa L.)

The architecture of the rice panicle is a crucial focus in breeding for both high yield and quality. It stands as a significant agronomic trait that influences the number of grains per panicle, playing a direct role in contributing to the overall yield of rice grains. Unravelling the genetic basis of panicle architecture is crucial for improving the grain yield in rice. In this study, the panicle architecture traits were meticulously dissected into five distinct components viz., number of primary rachis, number of secondary rachis, grain number on primary rachis, grain number on secondary rachis and total grain number. These components were systematically phenotyped in F2 and F3 population derived from a cross between DRR Dhan 48 and Maudamani. ‘DRR Dhan 48’ is a biofortified elite fine grain medium slender grain type cultivar with high zinc (22 ppm in polished rice) and low glycemic index (51.1). It has resistance to bacterial blight with the incorporation of xa5, xa13 and Xa21 in the background of Improved Samba Mahsuri. ‘Maudamani’ is a high yielding cultivar with high grain number and short bold grain type. Analysis of variance, histograms and boxplots revealed highly significant variation for the studied traits. Grain number in F2 population ranged from 29 to 333 grain with a mean of 162.72 whereas in F3, its varied from 49 to 368 with a mean of 184.17. Correlation analysis revealed significant correlation among the studied traits. The continuous variation observed in the population for panicle traits indicates that genetic control is governed by multiple minor loci. The presence of superior transgressive segregants highlights a complementary gene action influencing panicle architecture traits. The present investigation on panicle architecture offers scope for improving rice varieties and creating new germplasm resources and provides valuable information for further unravelling the genetic basis determining rice panicle architecture.

Evaluation of Rice Recombinant Inbred Lines Developed from the Cross Rasi × Improved Samba Mahsuri for Drought Tolerance

Drought has been one of the most important limiting factors for rice productivity, particularly in the rainfed ecosystem. It is important to understand the genetic basis of drought tolerance in donor lines and develop drought tolerant rice cultivars, based on this information. We earlier identified the rice line, Rasi as tolerant to drought and developed a recombinant inbred line (RIL) mapping population consisting of 209 lines. These lines along with their parents were grown under well-watered and drought stress conditions in a two-year experiment (wet season 2020 and 2021) with drought stress imposed during reproductive stage. The study revealed high genetic variability for 12 key agro morphological traits associated with drought tolerance among the RILs. Of the 209 RILs, 59 showed superior performance over the checks and even the tolerant parent, Rasi under severe drought condition. Two RILs, RIL-33 and RIL-58 showed exceptional drought tolerance along with greater plot yield and grain weight under drought condition and they possessed medium slender grain type. These two lines can be a new novel genetic resource for drought tolerance in breeding programmes.

Market Potential and Promotional Strategies for VSPL Hybrid Paddy Seeds in Koraput District of Odisha

Indian seed industry has contributed signifi cantly to ensure continued access to quality seed for the Indian farmers. VSPL is pioneer in the Indian seed industry which is working continuously for providing quality seed to farmers. VSPL wanted to increase their market share in Koraput district of Odisha. Therefore, a study was conducted in 2021 to assess the market potential of VSPL and to formulate promotional strategy for VSPL in the study area. Primary data was collected from 100 farmers and 20 dealers/distributers/retailers. Convenience sampling technique was used to select farmers and purposive sampling technique to interview retailers and distributors. The data collected was tabulated and analysed to get meaningful results. Hybrid paddy seed dominates the paddy seed market in the study area. The US Agriseeds, Mahyco, Dhaanya, Bayer, Syngenta, VNR seed and Rasi seed were the leading brands for hybrid paddy seeds in Koraput district. Majority of the farmers were small and medium farmers and they cultivated paddy primarily for self-consumption. Thus, the farmers preferred medium slender grain with duration of 120-125 days. Unawareness of the farmers about VSPL hybrid paddy seeds was the main reason behind poor market share of VSPL products. VSPL should give importance to promotional activities to improve its market share. Therefore, based on the key fi ndings of the study, 4P’s of marketing mix was suggested for VSPL hybrid paddy seeds. A promotional strategy and a promotional game were designed to promote the hybrid paddy seeds of VSPL in the study area.

Introgression of tsv1 improves tungro disease resistance of a rice variety BRRI dhan71

Rice Tungro disease poses a threat to rice production in Asia. Marker assisted backcross breeding is the most feasible approach to address the tungro disease. We targeted to introgress tungro resistance locus tsv1 from Matatag 1 into a popular but tungro susceptible rice variety of Bangladesh, BRRI dhan71. The tsv1 locus was traced using two tightly linked markers RM336 and RM21801, and background genotyping was carried out using 7 K SNPs. A series of three back crosses followed by selfing resulted in identification of plants similar to BRRI dhan71. The background recovery varied at 91–95% with most of the lines having 95%. The disease screening of the lines showed moderate to high level of tungro resistance with a disease index score of ≤ 5. Introgression Lines (ILs) had medium slender grain type, and head rice recovery (59.2%), amylose content (20.1%), gel consistency (40.1 mm) and gelatinization temperature were within the acceptable range. AMMI and Kang’s stability analysis based on multi-location data revealed that multiple selected ILs outperformed BRRI dhan71 across the locations. IR144480-2-2-5, IR144483-1-2-4, IR144484-1-2-2 and IR144484-1-2-5 are the most promising lines. These lines will be further evaluated and nominated for varietal testing in Bangladesh.

CO 54 (IET 24313) : An early maturing high yielding rice variety with marketable grain quality suitable for Tamil Nadu

The rice culture, CB 12588 evolved by crossing CB 04110 x CB 05501 was released as CO 54 during the year 2021 as an alternate variety to CO 51 and ADT 43 with 105-110 days duration. CO 54 is a medium tall variety with a profuse tillering habit, long erect leaves and droopy compact panicles possessing more number of filled grains per panicle. CB 12588  recorded an overall mean grain yield of 6354 kg/ha in various yield trials which was 10.83 per cent improvement over CO 51 and 10.35 per cent over ADT 53.  CO 54 has got high yielding potential due to its high agronomic and physiological efficiency and the maximum yield of 9259 was recorded in Bhavanisagar, Erode district under multi location trial. A High yield of more than 7000 kg/ha was realized in 16 locations in an adaptive research trial.  Besides yield, the culture CB 12588 has got marketable grain type i.e. medium slender grains with high milling outturn and head rice recovery percentage. Desirable cooking quality parameters like good linear elongation ratio, high volume expansion, intermediate amylose, soft gel consistency and moderate gelatinization temperature along with highly productive plant traits make CO 54 a suitable alternate variety to CO 51 and ADT 53. The culture CB 12588 is moderately resistant to blast, sheath rot, sheath blight and BPH under artificial conditions. The rice culture CB 12588 was released as CO 54 with a higher yield, better pest and disease resistance and good cooking quality in comparison to the checks CO 51 and ADT 53. It is suitable for cultivation during Kar/ Kuruvai/Sornavari/Navarai and the seasons/tracts wherever early maturing rice varieties are cultivated throughout Tamil Nadu.  Keywords: CO 54, Short duration, high yield, medium slender, cooking quality

KNM 1638 - A High Yielding Gall Midge Resistant Early Duration PJTSAU Rice (Oryza sativa L.) Variety Suitable for Telangana State

The promising high yielding rice genotype, KNM 1638 is a medium slender, early duration (120 –125 days) and photo insensitive culture with high yield potential (7356 kg ha-1) having resistance to gall midge and leaf blast, and moderately resistant to neck blast with better adaptability. This rice culture KNM 1638, a derivative of the cross JGL 11727×JGL 17004 was released through State Varietal Release Committee on the name of Kunaram Vari 2 for Telangana state during the year 2021 as an alternate variety to BPT 5204. It has semi-dwarf plant type with moderate tillering, semi-erect flag leaf, all plant parts green, semi-compact well exerted semi-erect attitude of branching panicle, straw-colored awn less grains and its grain classified as a translucent medium slender grain. In the overall performance, KNM 1638 recorded mean productivity of 7356 kg ha-1 in the eight years of trials with 12.8% increase over the check varieties. It has good grain, cooking and eating quality, and good marketing facility as quality-wise it recorded 63% head rice recovery and 21.47% amylose content with soft gel consistency and moderate gelatinization temperature. The rice variety, KNM 1638 is suitable for cultivation during kharif, late kharif and rabi seasons throughout Telangana State with higher yield, better pest and disease resistance and good cooking quality in comparison to the check varieties.

Grain yield performance of hybrid rice in relation to inbred cultivars in long‐term multi‐environment tests in India

AbstractWe analyzed the yield data of 2,070 rice hybrid F1 genotypes with inbred local cultivars (ILCv) evaluated over 32 yr (from 1988 to 2019) in 2,376 multi‐environment experiments executed at 102 locations in the irrigated ecosystem across India. The genetic gain or loss in yield of hybrid F1 genotypes estimated over the test duration was nonsignificant. The differences were highly significant between the means of group of F1 hybrid genotypes with yields higher than ILCvs in 985 experiments and the group of F1 hybrid genotypes with yields lower than ILCvs in 962 experiments. Hybrids produced 10% more yield (728–2,588 kg ha–1) than ILCvs in 672 experiments at several locations. Our analyses have established that grain yields of 7.0–7.9 Mg ha–1, were harvested in hybrid F1 genotypes with early‐ (110–120 d), mid‐early‐ (121–130 d), and medium‐ (131–140 d) maturity duration, and in those with medium slender grains (130±5 d) at many locations in 374 out of the 985 experiments. A higher level of rice (Oryza sativa L.) productivity per day (62–63 kg ha–1) was recorded with the early‐maturing and mid‐early‐maturing hybrid genotypes. Both the hybrid F1 genotypes and ILCvs produced grain yields (≥10 Mg ha–1) similar to values that were recorded previously with commercial inbred cultivars since 1968 at many locations. The attainable grain yield records of ILCvs were not broken by the yields of hybrid F1 genotypes. Hence the doubt arises whether there was any overestimation of hybrid genotypes or an underestimation of inbred yields. Therefore, any genetic gain or loss for grain yields in new genotypes developed in experiments can be estimated only when ILCvs produce their attainable yield recorded previously. There is scope for breeders to limit test locations to represent specific target areas to avoid data loss.

Assessment of Genetic Stability of Medium Slender Rice Genotypes for Yield Traits using AMMI Model and GGE biplot Methodology over Different Locations of Karnataka

Medium slender grain varieties of rice are one of the most preferred among the south Indian rice consumers and has a high demand in both national as well as international markets. In the study, 18 medium slender rice genotypes were examined along with four individual checks in Karnataka across four different locations to assess genetic stability using additive main effects and multiplicative interaction (AMMI) model and GGE bi-plot methodology. The genotype environment interaction (G×E interaction) were partitioned into two principal components and were found highly significant. Together, IPCA1 and IPCA2 explained more than 75 percent of G×E interactions for yield trait, with IPCA I explaining maximum G×E interaction. Gangavati and Malnoor were found to be favorable environments. AMMI analysis indicated that the BPT mutant 1801, BPT mutant 1804 and BPT mutant 1811 were found to be most stable genotypes for grain yield across locations over check GGV-05-01. Among rice genotypes, the best elite genotype, BPT mutant 1801 recorded highest grain yield and was also the most stable in grain yield across four locations.

Rajendranagar Vari-1 [IET 27077 (RNR 11718)] – Multiple stress resistant, high yielding rice variety

Rajendranagar vari-1 was derived through pedigree method of breeding from a cross MTU 1010 x NLR 34449 with an aim to develop high yielding multiple stress resistant variety. It is a medium duration variety having medium slender grain. It has recorded 6.81% and 9.7% increase in yield over check variety in station trials and minikits, respectively. Rajendranagar vari-1 (IET 27077) was evaluated during 2017 to 2020 in AICRIP trials and recorded 23.29, 18.61, 39.69, 40.12 and 12.46 percent increase in yield over alkaline, inland saline, saline tolerant, sensitive and local check, respectively in in zone VI and VII states (Puducherry, Telangana and Gujarat). It is identified as fertilizer responsive with potential to yield about 8.0 t/ha. It has multiple resistance to different insect pests and diseases (BPH, Blast, Brown Spot, Sheath Rot, grain discoloration) besides having salinity tolerance. Rajendranagar vari-1 was released through Telangana State Variety Release Committee and notified vide gazette number S.O. 8 (E) Dated 24.12.2021.th

Uttar Sona: A medium-slender grain rice variety suitable for cultivation during Boro-season

Uttar Sona has been developed from the cross between MTU 7029 × Gontra Bidhan-1. It was tested under All India Coordinated Rice Improvement Project (AICRIP) in IVT-Boro during 2013-14 and 2014-15. It out yielded national, regional, local and hybrid checks with a yield advantage of 18.57, 29.03, 16.36 and 6.63 per cent, respectively. Overall rank of Uttar Sona during the first year of testing was third in IVT Boro 2013-14 and it ranked sixth during the second year of testing in IVT-Boro 2014-15. The entry has also tested under IVT-E-TP during 2013. It ranked first in IVT-E-TP 2013.Uttar Sona already has been adopted by the farmers of Unishbisha G.P. (Mathabhanga-II block), Patlakhawa G.P. (Cooch Behar-II block), Bamunhat G.P. (Dinhata-II block) and Chotosalbari G.P. (Sitalkuchi block) of Cooch Behar district. It showed field resistance to major pest and diseases. Key wordsUttar Sona, rice variety, medium slender, Boro-season, West Bengal

BRRI Dhan100: A Zinc Enriched Rice Variety Suitable for Irrigated Ecosystem in Bangladesh

Recently released zinc enriched, high yielding, medium slender grain containing rice variety BRRI dhan100, appropriate for irrigated ecosystem of Bangladesh is an improvement over existing zinc enriched rice varieties for Bangladesh. The variety has satisfactorily passed the Proposed Variety Trial (PVT) conducted in the farmers’ field in Boro 2019-20 season. As a result National Seed Board (NSB) approved this variety for commercial cultivation in the Boro season (dry season) in 2021. It has modern plant type with 101 cm plant height and matures by 148 days. The proposed variety showed 1.20 t/ha higher yield than check variety BRRI dhan84. Identifying characters of this variety are green leaf, intermediate plant height, erect flag leaf, medium slender grain, intermediate leaf senescence grain. It can produce 7.7 - 8.8 t/ha grain yield. Thousand grain weight of the variety is 16.7 gm and head rice yield is 64%. The rice has zinc content 25.7 mg/kg, 26.8% amylose content with 7.8% protein content. The zinc enriched BRRI dhan100 is a superb variety for cultivating in the Boro season (dry) and farmers can be economically benefited and the country will be nutritionally benefited by the cultivation of BRRI dhan100.

Efficiency of electron beam over gamma rays to induce desirable grain-type mutation in rice (Oryza sativa L.)

Purpose Rice is the predominant crop of Tamil Nadu state, India that occupies about 30% of the total cropped area. However, grain type and quality are the critical traits that determine the market value and domestic consumption rice variety. Most of the households of Tamil Nadu, India prefer to consume medium slender to fine grain type of rice. Hence, the present study was conducted to induce medium slender grain type in popular rice variety ADT 37 (Aduthurai 37), a short bold rice variety using gamma rays (GR) and electron beam (EB) mutagens. Materials and methods Healthy, dried seeds (12.0% moisture content) of ADT 37 rice variety were exposed to various doses of GR (100–500 Gy) and EB (200–600 Gy). The irradiated population were maintained up to M4 generation by plant to progeny row basis to identify stable mutants for grain-type variation. The selected grain-type mutants (medium slender- and slender-type mutants) in M4 generation were characterized for phenotypic and grain quality traits. Results A high frequency of desirable grain-type variation was observed in EB-irradiated population than gamma-irradiated population. A total of 25 grain-type mutants (long slender and medium slender) were obtained in M4 generation of ADT 37 variety. The morphological characterization and cooking quality assessment of the ‘grain-type’ mutants revealed that six out of 25 mutants viz., M-3 (Mutant-3), M-5, M-9, M-10, M-13 and M-15 recorded single plant yield of more than 30 g. There was non-significant variation in yield per plant (g) among the mutants and control (parent) due to key changes in grain type and thousand grain weight. Conclusion EB showed higher mutation frequency, mutagenic effectiveness and efficiency than the GR in inducing both chlorophyll and viable mutants. This study revealed that the percentage contribution of the EB was 2.57 times higher than that of GR in obtaining desirable slender and medium slender grain-type mutants. The grain-type mutants obtained in the present study can be either directly released as variety or used as parents in hybridization program of rice crop improvement.

Physico-chemical, nutritional and Anti-oxidative properties of different colored grain genotypes of rice (Oryza sativa L.)

The commonly consumed white rice is a highly refined staple cereal, which is lack of almost all minerals and nutrients. The pigmented rice, enriched with anthocyanin is known for it’s taste and health benefits. Colored rice (Oryza sativa L) genotypes are evaluated under this study. Twenty six genotypes were studied for 8 yield components and 12 physico-chemical, nutritional and Anti-oxidative properties. Among the non-pigmented varieties, BPT 5204, BPT 2270, BPT 2595, BPT 2782 and BPT 2776 recorded the desirable quality traits with excellent cooking quality. The pigmented rice genotypes recorded high amount of total phenols, antioxidant activity and flavonoid contents than non-pigmented varieties. When compared with light brown pericarp colored rice genotypes, red and black rice genotypes possess more protein content, high Zn and Fe content also. Variability studies showing that, high GCV and PCV coupled with high heritability and high genetic advance as percent of mean were recorded for test weight and total number of grains per panicle among yield components, while among quality traits solid loss, alkali spreading value, total phenol content, total antioxidant activity, flavonoid content, zinc and iron content. It indicates that these characters are controlled by additive type of gene action, which can be improved by direct selection. The results of correlation studies revealed that total phenol content, flavonoid content, total antioxidant activity are positively associated with each other and also with protein content, Zn and Fe content, hence simultaneous improvement of all these traits is anticipated. The colored rice varieties reported in the present study recorded medium duration, high yield potential coupled with medium slender grain type and good cooking quality and may be exploited commercially. Black and red rice genotypes viz., BPT 2848, BPT 3140, BPT 3141, BPT 2858, BPT 3111 which recorded desirable physical quality traits, high antioxidant activity, high protein, Fe & Zn content can be included in daily diet for their potential bioactive compounds and neutraceutical benefits to human health.

Effect of on-farm trials in popularization of rice variety NDLR-7 (Nandyal Sona) in Chittoor district of Andhra Pradesh

Rice crop is grown in 43934 ha in Chittoor district of Andhra Pradesh during Kharif and Rabi. The traditional medium slender grain cultivar BPT-5204 is most popularly grown variety during Kharif and occupies 30-40 per cent of area in the district, which is susceptible to BPH and blast resulting in low yields and low net returns. Hence, on farm trials were conducted during 2012-13, 2013- 14 and 2014-15 with objective to assess the performance of new rice variety NDLR-7 which is medium slender short duration (130-135d) variety with tolerance to BPH and blast. During all the three years maximum number of BPH/sample was very low in NDLR-7 than BPT 5204 and maximum collections were recorded in November followed by October month. During all the years the variety recorded 6.1t/ha with average net returns of Rs.76,808/- per ha whereas BPT-5204 recorded 5.83t/ha with average net returns of Rs.68,542/ha. Because of its high yield, pest tolerance and good cooking quality it is widely accepted by farmers through horizontal spread of technology. Due to extension activities of KVK, Kalikiri area under NDLR-7 has been increased from 80ha in 2013-14 to 2000 ha in 2016-17 owing to its tolerance to BPH, fine grain and high market price and first choice of farmers, millers and traders.

Screening of Advanced Aromatic Rice Lines Using Morphological and Physico-Chemical Characteristics

Short-statured and lodging resistant rice plants with long to medium slender grain are the expected criteria for aromatic rice. However, most of the aromatic rice varieties in Bangladesh do not meet the expected criteria. Therefore, this study was undertaken to detect short-statured rice plants with aromatic and long to medium slender grain where twelve advanced rice lines (derived from the local rice germplasm) with a local check Kataribhog were evaluated. All the genotypes demonstrated significant variation for different parameters such as plant height at harvest, yield per hectare, grain length, grain size, grain shape, and aroma. At harvest, the shortest plant height was obtained from SAU ADL11 (107.09cm), and it was statistically similar to SAU ADL4 (111.68cm) and SAU ADL5 (111.89cm). However, the plant height of check variety Kataribhog was 167.17cm. The highest grain yield per hectare was found in SAU ADL5 (4.79 tha-1), where it was 2.71 tha-1 in Kataribhog. Besides, the grain yield of shorter genotypes SAU ADL4 and SAU ADL11 was 3.47 t ha-1 and 3.84 t ha-1 , respectively. The SAU ADL1 provided the highest kernel length (7.31mm), and the lowest kernel length (4.87 mm) was recorded in the check. Kernel length of short-statured genotypes ranged from 7.01 mm to 6.57 mm. Kernel size of all evaluated genotypes was long to medium; whereas, it was short for Kataribhog. Kernel shape of these short-statured genotypes was slender to medium. In case of aroma, SAU ADL3, SAU ADL5, SAU ADL7, SAU ADL9, SAU ADL10, and SAU ADL11 were moderately aromatic, and other genotypes were non-aromatic. However, Kataribhog was strongly aromatic. Finally, SAU ADL5 and SAU ADL11 were evaluated as important germplasms in respect of different characters such as shortstatured plant, long to medium slender grain, and aroma. These two lines could be potential inbreed aromatic rice genotypes for Bangladesh.
 Bangladesh Agron. J. 2019, 22(2): 91-102

ADT 53- Short duration high yielding fine grain rice variety for kuruvai /Kodai seasons of Tamil Nadu

The rice variety ADT 53 (AD07073) is a short duration culture (110-115 days) which was released during 2019 by TNAU for Kuruvai/ Kodai/ Navarai season of Tamil Nadu. This variety was evolved through pedigree breeding from the cross ADT 43 / JGL 384. It has non-lodging compact plant type with well exerted compact panicle. The variety recorded an average grain yield of 6334 kg/ha in 242 trials which are 9.4 per cent higher than ADT 43 (5788 kg/ha in 112days) and 14.0 per cent over CO 51 (5562 kg/ha in 112 days). The culture had shown a resistance reaction to leaf folder and moderately resistant to brown spot, blast diseases and rot under field condition. The variety ADT 53 possesses a medium slender grain with a 1000 grain weight of 14.8 grams. It has 65 per cent milling outturn and good cooking quality parameters like a soft gel consistency, moderate amylose and gelatinization temperature.

Accelerating hybrid rice breeding through the adoption of doubled haploid technology for R-line development

Hybrid rice holds significant yield advantage over inbred lines, but its adoption rate is very slow in India. Development of cytoplasmic male sterile line (CMS) and fertility restorer line with superior grain quality is the prerequisite in three line hybrid rice breeding programme. Minimum of three to four years are required for development of useful R-line which severely delays the pace of hybrid breeding. Application of doubled haploid (DH) technology will be very useful to develop elite R-lines within short period of time. An elite inbred line LAXMI was crossed with the R-line RPR158 and anthers from the resulting F1 population was used for development of DH plants. Eight hormonal combinations and four different cold pre-treatment conditions were tried in tissue culture. Maximum callusing frequency was observed in N6 medium supplemented with 2.0 mg L−1 2, 4-diclorophenoxyacetic acid (2,4-D), 0.5 mg L−1 napthalene acetic acid (NAA), 0.5 mg L−1 benzyl amino purine(BAP) and 6% maltose with 3 days cold pre-treatment. Highest green plant regeneration frequency was found with Murashige and Skoog medium supplemented with 0.5 mg L−1 NAA, 0.5 mg L−1 kinetin, 2 mg L−1 BAP. A total of 280 DH plants were generated and evaluated under field conditions for agronomic characters and fertility restoration capacity in CMS system. Two distinct DH lines were identified as improved R-lines based on high restoration ability (94%), superior grain quality and medium slender grain type. This study successfully demonstrated that superior R-lines can be developed within two crop seasons through the application of DH technology.