Authors:M Khalequzzaman, N Haq Pages: 1 - 16 Abstract: Drought is one of the major challenging abiotic stresses for rice production in Bangladesh. This study investigated 48 rice landraces obtained from different Eco-zones of Bangladesh for their drought tolerance characteristics. Significant variation was observed in morpho-physiological traits such as length of root and shoot, dry weight of root and shoot, leaf stomatal resistance and stomata number. Stomatal conductance, root length, root dry weight showed significant correlation with visual drought score. A cluster analysis based on morpho-physiological characteristics identified six cluster groups and most of the promising drought tolerance landraces were found in cluster VI. Five landraces - Dhapa, Dud Kalam, Dular, Hogla Pata and Keora showed key desired characteristics for dry weight, stomatal conductance, evapotranspiration, water use efficiency and root parameters for drought tolerance. These landraces could be potential sources in breeding program for the development of drought tolerant rice varieties. Bangladesh Rice J. 26 (1): 1-16, 2022 PubDate: 2023-09-05 DOI: 10.3329/brj.v26i1.65871 Issue No:Vol. 26, No. 1 (2023)
Authors:A Ara, S A I Nihad, M M Rashid, A Akter, A B M A Uddin, T H Ansari, M A Latif Pages: 17 - 31 Abstract: Bacterial blight disease (causal organism: Xanthomonas oryzae pv. oryzae) is an economically significant menace to rice cultivation in Bangladesh as well as in the world, which reduces significant yield loss in rice and hampers food security. The most sustainable strategy to fight this disease is the adoption of disease-resistant cultivars. The morphological trait and nature of diversity of 92 bacterial blight-resistant INGER (International Network for Genetic Evaluation of Rice) genotypes collected from the International Rice Research Institute (IRRI, Philippines) were analyzed to explore for sources of resistance. Artificial inoculation by BXO9, a virulent race of Xoo was used to evaluate and screen those genotypes in the field. Twelve genotypes, out of 92 had resistance, and another twelve had moderately resistance. Eleven morphological traits including disease data of each genotype were recorded and found noticeable diversity among the genotypes. Pearson’s correlation analysis among genotypes revealed that yield per hill is positively correlated with number of tiller per hill, number of effective tiller per hill, number of spikelets per panicle, number of filled spikelets per panicle and thousand grain weight. In cluster analysis, 15 major groups were obtained in ninety-two rice genotypes by using Euclidean distance and the UPGMA method. Cluster-1 comprises single genotypes SVIN310 which showed resistant reaction to bacterial blight disease had the highest tiller number, effective tiller number, number of spikelets per panicle, filled spikelets per panicle and thousand-grain weight. In PCA analysis, the first four principal components narrated around 77.32% variation. Among ninety-two genotypes, G1 (SVIN310), G23 (SVIN018), G70 (SVIN012), G75 (SVIN054), G33 (SVIN007), G48 (SVIN006), G80 (SVIN049), G90 (BRRI dhan84), G30 (SVIN290) near to the vector line of yield per hill are highly and positively responsive to the yield per hill. Considering all of these, cluster-1 having genotype SVIN310 with resistant phenomena would be the potential genotype for further use in a breeding program. Bangladesh Rice J. 26 (1): 17-31, 2022 PubDate: 2023-09-05 DOI: 10.3329/brj.v26i1.65876 Issue No:Vol. 26, No. 1 (2023)
Authors:M M E Ahmed, P S Biswas, W Afrin, M Y Khan, M R A Sarker, K M Iftekharuddaula Pages: 33 - 46 Abstract: Development of new high yielding varieties needs highly accelerated breeding approaches to meet the demand of increased rice production now a days. To address this issue, Rapid Generation Advance (RGA) of segregating rice population and Line Stage Testing (LST) of fixed breeding lines has been adopted as a routine work in Bangladesh Rice Research Institute. In the present study, we described the evidence of advancing a large number of segregating population and high selection pressure at LST to isolate fixed lines in the Irrigated Boro rice breeding program. This program was implemented under development of Favourable Boro Rice and Cold Tolerant Rice. In both programs, wide variation was observed among the number of population and segregating generation at RGA nursery. A total of 62,269 individual progenies from 64 crosses were advanced through RGA in 2019 whereas 12,122 individual progenies from 45 crosses were advanced in 2020 under the FBR program. In contrast, 68,531 segregating progenies from 82 crosses and 15,004 progenies from 52 crosses were advanced through RGA under CTR program during 2019 and 2020, respectively. During LST, selection pressure was imposed for the first time to isolate homozygous lines from a pool of large number of breeding lines. The selection intensity ranged between 0.21-20.1% and 0.6-14.9% for FBR and CTR, respectively. A total of 794 fixed breeding lines having different combinations of favourable alleles of BLB, Blast and different grain quality traits were isolated from 17,633 RGA derived lines. The results obtained from this study suggested that the RGA system has become an effective tool for population improvement in a breeding program. Bangladesh Rice J.26 (1): 33-46, 2022 PubDate: 2023-09-05 DOI: 10.3329/brj.v26i1.66591 Issue No:Vol. 26, No. 1 (2023)
Authors:S Paul, M A Rahman, H Paul , M M Rahman, B C Nath, M D Huda, M G K Bhuiyan Pages: 47 - 57 Abstract: A study was aimed at modifying and manufacturing a power weeder at the local workshop using locally available material and evaluating its performance in the condition of Bangladesh. The Bangladesh Rice Research Institute's Farm Machinery and Post-harvest Technology (FMPHT) division (BRRI) took the initiative to fabricate a power weeder using locally available materials. In the wetland of the BRRI research field and farmer's field at Jogitola of Gazipur district, the developed power weeder was tested during the boro season of 2017-2018. The average weeding efficiency of the power weeder was 80.38% and 81.43% at the research and farmers' field respectively. The percent of tiller damage was observed 2.78% and 2.81% respectively. 910 m2 h-1 (0.091 ha h-1) was the average effective field capacity of the power weeder. After 5 days, the percentage of weeds revived for power weeder was observed at 32.26% and 34.90% at the BRRI research and farmers' fields, respectively. Weed biomass was found 35.43 gm m-2 in a farmer’s field and 30.88 gm m-2 in the BRRI research field, Gazipur. This machine can be run by one man/woman easily. The weight of the complete weeder is 18.3 kg. The benefit-cost ratio of the weeder is 1.85. Farmers can use this weeder in wetland conditions. In the line transplanted wetland field conditions, the power weeder was found suitable for controlling weeds with minimum standing water. Bangladesh Rice J.26 (1): 47-57, 2022 PubDate: 2023-09-05 DOI: 10.3329/brj.v26i1.65883 Issue No:Vol. 26, No. 1 (2023)
Authors:M A Badshah, M R Hasan, T K Roy, M A Rahman Pages: 59 - 68 Abstract: Boro rice cultivation is often limit due to lack of a farmer's friendly technique for raising quality seedling in irrigated ecosystem. Experiment was conducted in Boro 2019-20 at R/S Rangpur to compare different polythene covering treatment on raising quality seedling of BRRI dhan88 and BRRI dhan89 and to measure it’s carryover effect on growth duration and grain yield of rice. The treatments were as T1: Day polythene cover (from10:00 am to Sunset), T2: Night polythene cover (Sunset to Sunrise), T3: Day-night polythene cover but round shape opening (30 cm diameter) at both sides and T4: No polythene cover (control). Seedbed was covered by transparent polythene from seeding to 30 days after seeding (DAS). Seedling strength was higher on 01 December seeding than 15 December in both the tested varieties. Day cover always had the lowest seedling strength in both varieties. Day-night polythene cover treatment (T3) produced significantly tallest seedling than other polythene covering treatments for both the plantings dates. Seedling mortality was higher in 30 January planting than 15 January planting for both the tested varieties due to prevailing low temperature (below 10°C for eight days). In 15 January planting, BRRI dhan88 and BRRI dhan89 produced higher number of tillers with day cover and night cover treatment, respectively. In 30 January planting, BRRI dhan88 produced higher tiller with day-night and control treatment but day cover had the lowest. Tiller production rate was sharply increased from 35 – 45 DAT and then decreased. Up to 45 DAT, it was statistically similar in both the varietiers with all treatments. Although, tiller number was higher in T1, T2 and T4 than T3 but productive tiller (%) was satistically similar among the treatments for both the varieties and planting dates. There was no significant difference in grain yield among the treatments for planting dates and varieties. Day-night polythene cover treatment (T3) reduces growth duration by 2-3 days over other treatments. This treatment (T3) is farmer's friendly for raising quality seedling in cold prone areas of Bangladesh. Bangladesh Rice J.26 (1): 59-68, 2022 PubDate: 2023-09-05 DOI: 10.3329/brj.v26i1.66595 Issue No:Vol. 26, No. 1 (2023)
Authors:M R Quddus , M A Qayum, L F Lipi, A Akter, M U Kulsum, M S Islam, M J Hasan Pages: 69 - 78 Abstract: Assessment of genetic variability in the nursery of the breeding population is essential for crop improvement successfully. Thirteen (13) maintainer lines of hybrid rice were evaluated to estimate the level of their genetic diversity and heritability of grain yield influencing parameters in the transplanted Aman, 2020 season. The studied traits were days to 50% flowering, total effective tillers plant-1, plant tallness (cm), length of flag leaf (cm), breadth of flag leaf (cm), panicle size (cm), filled grains panicle-1, unfilled grains panicle-1, growth duration (days) and grain yield (tha-1). Coefficient of variation (genotypic and phenotypic) was noticed high for most traits that revealed high variability among the studied genotypes. Broad-sense heritability ( ) was high in all traits except flag leaf breadth. Analysis of the cluster and its mean comparison showed that cluster 2 (i.e. BRRI 11B, BRRI 99B, IR 79125B and IR 79156B) represented the best agronomic traits and yield potentials. Therefore, selection of genotypes with valuable attributes from cluster 2 will be considered for maintainer line improvement programs. The use and estimation of predicted genetic gain will provide a visionary insight of the future genotypes produced after the crossing of the genotypes under study. Bangladesh Rice J. 26 (1): 69-78, 2022 PubDate: 2023-09-05 DOI: 10.3329/brj.v26i1.66593 Issue No:Vol. 26, No. 1 (2023)
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