Transplanting Research Articles

Direct seeding rice: A solution to improve establishment of rice under unpredictable climate condition

Swampy is identified as a potential areas to boost national rice production, however, Fe exposure and lack of labour are some of main obstacles to get high yield of rice. Specific land preparation, puddling and levelling without exposing active Fe is required to maintain high yield. A field experiment aims to examine the effectiveness of perfect land levelling to increase yield under direct seeding method. The trial was arranged in large areas, each treatment was set in 0.5 ha, with 5 replications in 2021 dry-season in Central Kalimantan. The treatments were combination of land preparation and establishment system with direct seeding rice (DSR) or transplanting (TRP). The results showed that land levelling used the farming bulldozer improved the number of productive tillers lead to higher grain yield compare to that of hand tractor. Highest grain yield was produced in FB-TRP (land preparation done by Farming Bulldozer in combination with transplanting) at average 3326 kg/ha, followed by HT-TRP (Hand Tractor-Transplanting) at 3064 kg/ha. Whereas FB-DSR yielded at 2146 and FB-TRP at 1778 kg/ha. Good land levelling had greater effect on the seed germination and increase the number of tiller by 17.6% under direct seeding with farming bulldozer compare to hand tractor.

Enhancing climate resilience in northern Ghana: A stochastic dominance analysis of risk-efficient climate-smart technologies for smallholder farmers

Northern Ghana is a semi-arid region characterised by a unimodal rainfall pattern, and hot and dry weather conditions. Heavy reliance on rain-fed agriculture and the lack of resources for irrigation, makes smallholder farmers in the region increasingly vulnerable to climate-related crop failures. In recent years, climate-smart technologies (CSTs) such as changing planting dates (PD), compartmental bunding (CB), mulching (M), and transplanting (TP) have been recommended to minimise yield losses. However, there is limited information on the most risk-efficient CSTs for crops cultivated in the region. This study used a stochastic dominance approach to identify the most risk-efficient CSTs for maize, rice, and sorghum. The stochastic modelling process employed the Aqua-crop model to simulate climate-related yield variability using Ghana climate data, and gross margin variability with crop budgets from literature sources. From the study's findings, changing planting date from April to May was the most risk-efficient choice for maize and sorghum under farmers' and recommended practices. In contrast, transplanting was the most risk-efficient technology for rice farming in the study area. The study also highlights the importance of considering the risk-averse nature of smallholder farmers when selecting CSTs. By identifying the most risk-efficient CSTs, the study can help improve the resilience of smallholder farmers. These findings have important implications for the development and adoption of CSTs in northern Ghana.

Influence of Liquid Nano Urea Fertilizer on Growth and Yield of Summer Rice (Oryza sativa L.) under South Gujarat Conditions

A field experiment was conducted during summer season for two consecutive years (2022-2023) at Navsari, Gujarat to study the effect of liquid Nano urea fertilizer on summer rice (Oryza sativa L.) under South Gujarat conditions. The experiment was laid out in randomized block design with three replications and twelve treatments comprising T1: 100 % RDN (Recommended dose of nitrogen) through urea (120 kg N ha-1), T2: 75 % RDN + Seedling root dip in Nano urea at transplanting (TP) (4 ml L-1), T3: 50 % RDN + Seedling root dip in Nano urea at TP (4 ml L-1), T4: 25 % RDN + Seedling root dip in Nano urea at TP (4 ml L-1), T5: 75 % RDN + Spray of Nano urea at tillering stage (4 ml L-1), T6: 50 % RDN + Spray of Nano urea at tillering stag (4 ml L-1), T7: 25 % RDN + Spray of Nano urea at tillering stage (4 ml L-1), T8: 75 % RDN + Spray of Nano urea at tillering and panicle initiation stage (4 ml L-1), T9: 50 % RDN + Spray of Nano urea at tillering and panicle initiation stage (4 ml L-1), T10: 25 % RDN + Spray of Nano urea at tillering and panicle initiation stage (4 ml L-1), T11: Spray of Nano urea at tillering and panicle initiation stage (4 ml L-1) and T12: Seedling root dip in Nano urea at TP + Spray of Nano urea at tillering and panicle initiation stage (4 ml L-1). Application of 75 % RDN + Spray of Nano urea at tillering and panicle initiation stage (4 ml L-1) obtain significantly higher growth attributes viz., periodical plant height, number of tillers plant-1, dry matter accumulation plant-1, chlorophyll content and growth indices including leaf area index (LAI) at 60 and 90 DAS, crop growth rate (CGR), relative growth rate (RGR) and net assimilation rate (NAR) during 30-60 DAS, 60-90 DAS, and 90 DAS-Harvest. Similarly, significantly higher grain yield was produced under treatment T8 (4435 kg ha-1) which was 3.24% higher than 100% RDN through conventional urea.

Environmental Efficiency of Monsoon Rice (Oryza sativa) Production between Transplanting and Broadcasting Sowing Methods in Myanmar

Introduction Myanmar relies on rice for its food security and economic significance, ranking seventh in the world for rice exports as of 2021. The most significant concern in rice production is exceeding the recommended nitrogen (N) fertilizer usage rate. Nitrogen is a crucial fertilizer for rice production, but it poses negative environmental consequences, such as nitrous oxide emissions. Therefore, this study intended to assess the technical (TE) and environmental efficiency (EE) of monsoon rice production in Myanmar and compare the efficiencies of broadcasting (BC) and transplanting (TP) sowing methods. Methods A translog stochastic frontier production function approach estimated the output-oriented technical efficiency and environmental efficiency of monsoon rice production. The study conducted face-to-face interviews with 317 farmers in Nay Pyi Taw Union Territory, Myanmar. Results The overall mean TE and EE were 81% and 23%, respectively. The average TE and EE for N fertilizer were 84% and 35% using the TP method and 80% and 20% using the BC method, respectively. Conclusion Our findings confirmed that the TP method was technically and environmentally superior to the BC method. The adoption of the TP method should be promoted by highlighting its positive impacts on achieving sustainable monsoon rice production in Myanmar.

Quantifying and Comparing Greenhouse Gas Emissions in Monsoon Rice Production: A Comprehensive Analysis of Transplanting and Broadcasting Sowing Methods in Myanmar

Introduction Rice is a staple food, an economic crop, and the second-highest source of greenhouse gas (GHG) emissions in the agricultural sector in Myanmar. To develop the rice sector in a sustainable way, this study aimed to determine the comparative GHG emissions between the two major sowing methods used in monsoon rice production. Methods Next, comparative GHG emissions analysis was done by using the Student t-test. This study first quantified GHG emissions from land preparation to straw burning by using emission factors for agricultural inputs and the formulation, default values, and scaling factors of a carbon footprint calculator customized for rice products (CF-Rice). Results Soil and water management was the largest contributor among the management practices in monsoon rice production and accounted for 64.8% of the total GHG emissions. At 4,479.5 kg CO2 eq. ha-1, GHG emissions from the broadcasting (BC) method were significantly higher than those from the transplanting (TP) method. Conclusion Therefore, the TP method is a better sowing technique than the BC method for reducing GHG emissions without reducing grain yield.

Effect of Bt traits on transgenic rice’s growth and weed competitiveness

Transgene escape could lead to genetically modified rice establishing wild populations in the natural environment and competing for survival space with weeds. However, whether the expression of the Bacillus thuringiensis (Bt) gene in rice will alter the relationship between transgene plants and weeds and induce undesirable environmental consequences are poorly understood. Thus, field experiments were conducted to investigate the weed competitiveness and assess the ecological risk of transgenic Bt rice under herbicide-free and lepidopterous pest-controlled environments. Results showed that weed–rice competition in the direct-sowing (DS) field was earlier and more severe than that in the transplanting (TP) field, which resulted in a significant decrease in biomass and yield in DS. However, conventional Bt and non-Bt rice yield was not significantly different. The weed number, weed coverage ratio, and weed diversity of conventional Bt rice were significantly higher than those of non-Bt rice at the early growth and mature stages, especially in DS plots, suggesting that Bt traits did not increase the weed competitiveness of transgenic rice and had no negative effect on weed diversity. Grain yield and weed number varied between different hybrid rice lines, but those differences were insignificant between Bt and non-Bt rice. The number of insects increased with the increase of weeds in hybrid rice plots, whereas the insect number and diversity did not display a significant difference between Bt and non-Bt rice. Therefore, the ecological risk of transgenic Bt rice is comparable to non-Bt rice.

Effects of High Temperature on Quality of Japonica Rice at Early and Middle Heading Stage under Different Planting Modes

With the intensified greenhouse effect, high temperature has gradually become an adverse factor in growth of rice. Transplanting (TP) and direct seeding (DS) are two common rice planting modes. At present, the response of rice quality to high temperature under different planting modes and at different growth stages have not yet to be identified. Therefore, in our study, high-quality japonica rice Nanjing 9108 (NJ9108) and Nanjing 46 (NJ46) were cultivated through TP and DS under the setting of normal temperature (NT), moderate heating (2 °C higher than NT, MT) and extreme high temperature (5 °C higher than NT, HT) at early heading stage (EH, 0–14 d after heading) and middle heading stage (MH, 15–28 d after heading) respectively. The results showed that better resistance to high temperature was achieved with TP. The head rice rate, gel consistency and amylose content of rice decreased with the increase of temperature, while chalkiness degree, setback viscosity, average particle size, crystallinity and gelatinization temperature were opposite. Compared with high temperature at MH, the effect of EH on rice quality was more significant. In terms of varieties, the resistance to high temperature was stronger for NJ46 relative to NJ9108, mainly because NJ46 has a longer growth period and can avoid the stress of high temperature at heading stage. Above all, our results suggest that NJ46 could have better resistance with a longer growth period through TP under background of climate warming.

Transplanting and Seed Hydropriming Affects Yield, Water Use Efficiency, and Grain Quality of Maize Cultivars under Delayed Planting

To evaluate the effect of planting method (PM), planting date (PD), and cultivar (CV) on the yield, irrigation water use efficiency (IWUE), and grain quality of maize, a two-year field study was conducted during the 2017 and 2018 growing seasons. The experiment was arranged as split-plot factorial with three PD, including PD1 (July 1st), PD2 (July 11th), and PD3 (July 23rd) as main plots. Three PM including direct seeding (DS), seed hydropriming (HP), and transplanting (TP) were factorially combined with two maize cultivars (SC704 and SC260), as sub-plots. The highest herbage and grain yield (76685 and 7369 kg ha-1, respectively), and the maximum IWUE for herbage and grain production (13.1 and 1.21 kg.m-3, respectively) were found in the TP. The CV SC704 obtained higher grain yield (GY) on PD1 compared with SC260, but as planting was delayed the GY of SC704 affected more negatively in both years. Delay planting enhanced IWUEH, however, IWUEG decreased when planting was delayed. The highest IWUEG was obtained from TP on each PD. The CV SC260 in delay planting resulted in better IWUEG in both years. The highest and lowest contents of crude protein, starch, ash, crude fiber, and fat were obtained from hydro-primed and transplanted maize, respectively. In conclusion, the yield in the transplanting method had superiority over DS and HP. Also, HP was found to be the optimal PM in terms of enhancing qualitative parameters of grain maize in delayed planting. Furthermore, selecting SC260 as a high-yielding hybrid on delayed planting is suggested.

Increased Number of Spikelets per Panicle Is the Main Factor in Higher Yield of Transplanted vs. Direct-Seeded Rice

With increasing water shortages and labor costs, rice planting is gradually undergoing a transformation from traditional transplanting to direct seeding. However, the yield of direct-seeded rice is unstable and the reasons for this instability are disputed. Therefore, we established a field experiment conducted over 3 years to investigate the reasons for the difference in rice yield under different planting methods. The planting methods compared were transplanting (TR), broadcast sowing (BS), and sowing in line (SL). The yield of rice under TR was higher (10,390 kg ha−1) than that of BS (7790.7 kg ha−1) and SL (9105.2 kg ha−1). Given that the harvest index showed little variation among the three planting methods, the yield differences reflected that shoot dry matter production under TR was higher. Two reasons for the latter observation are suggested: (1) the planting density under TR was lower than that under BS and SL, thus competition for nutrient resources would have been reduced; (2) the growth period of TR was longer. The higher shoot dry matter accumulation under TR contributed to enhanced panicle number per m2 and number of spikelets per panicle than under BS. A significant correlation between number of spikelets per panicle and yield was observed. Although yield was highest under TR, the costs under TR were the highest among the three planting methods. In contrast, the benefit-to-cost ratio under SL was higher than that of TR and BS. The higher yield under TR reflected the production of larger spikelets per panicle than those produced under direct-seeding methods. However, the benefits of SL are conducive to enhanced profitability of rice production.

Effect of Dates and Methods of Sowing with and without Hydropriming on Growth, Phenology and Yield of Sorghum under Semi Arid Conditions of Eritrea

A study was carried out at the research farm of Hamelmalo Agricultural College during summer 2015 to study the effect of dates and methods of sowing with and without hydro-priming on growth, development and yield of sorghum. The experiment consisted of 2 factors- three dates of sowing viz. D0 (Sowing before the onset of first summer rain, June 30), D1 (Sowing with the onset of first summer rains, July 7) and D2 (Sowing after the onset of summer rains, July 14) and three methods of sowing viz. SP (Direct sowing with hydro seed priming), TR (Transplanting) and DS (Direct sowing without hydro seed priming). The experiment was conducted in split plot design with 4 replications by keeping dates of sowing in the main plots and methods of sowing in the sub plots. The data on growth parameters, crop phenology, yield components and yield were recorded. The data were analysed using GENSTAT software and inferences were drawn by using LSD at 5% level of significance. Sowing methods significantly affected leaf area and leaf area index but sowing dates and their interaction with sowing methods did not show significant difference. Stand count, plant height, phenological parameters, thousand grain weight, grain and biomass yield were significantly affected by the sowing dates and methods but no significant difference in their interaction on all the parameters except in stand count and phenological parameters. Sowing before the onset of first summer rains (D0) resulted in significantly highest grain yield. Among the sowing methods, transplanting resulted in significantly higher grain yield seconded by direct sowing with hydro seed priming. Transplanting is less profitable and practicable as it is more laborious and difficult to apply in larger areas.

Luffa Gourd Production Practices from Transplanting and Direct Seeding Methods for Composite Productions

World is facing an increase of environmental concerns recently regarding on natural and synthetic fibers problems. Producing synthetic fibers may cost highly and create a few financial issues on the production matter. Moreover, synthetic fiber products have several disadvantages such as they are non-biodegradable. Some of them may cause health related problems and expose a significant risk. Researchers aimed to find the replacement for synthetic fibers with less cost production and renewable sources which lead to development of biomaterials-based composites production. Luffa is an eco-friendly crop, has been added as the new fibrous fruit with short harvest period. This study have applied a few practices using direct seeding and transplanting methods for low cost luffa production that aim for composites production. On the other hand, this study showed that transplanting (TP) method is better than direct seeding (DS) method based on the growth performance. TP method showed highest average of plant height (cm) and average total dry weight (g) of luffa fruits with 74.42±0.68 and 91.08±2.26 respectively whereas lower growth yield performance showed by DS method. Other parameters observed are the number of leaves and number of fruits which is a competent sources to the current composites sources, synthetic fibers. Hence, the results showed that luffa has the potential as a low cost and short harvest duration production plant.

Improving N, P, K content, other properties of soil and system productivity through integrated nutrient management practices in SRI hybrid rice -mustard cropping sequence in Eastern India

A field experiment was conducted at Regional Research and Technology Transfer Station of Orissa University of Agriculture and Technology, Bhawanipatna, Kalahandi during the year 2013-14 and 2014-15 to study the effect of integrated nutrient management (INM) practices on yield of hybrid rice grown under system of rice intensification (SRI) during kharif season followed by mustard during rabi season and it's residual effect on different soil properties. Eight treatment combinations comprising of K1: RDF i.e.,120:60:60 kg N:P2O5:K2O ha-1 (1/3rd N each at transplanting (TP), active tillering (AT) and panicle initiation (PI), K2:50 % RDF (1/3rd N each at TP, AT and PI) + FYM 5 t ha-1, K3:75 %RDF (1/3rd N each at TP, AT and PI) + FYM 5 t ha-1 , K4:100 % RDF (1/3rd N each at TP, AT and PI) + FYM 5 t ha-1, K5:100% RDF (½ N at TP, ¼th N at AT, ¼ th N at PI) + FYM 5 t ha-1 , K6:100 % RDF (¼th N at TP, ½ N at AT, ¼ th N at PI) + FYM 5 t ha-1, K7:50% RDF (1/3rd N each at TP, AT and PI) + FYM 10 t ha-1 and K8: FYM 5 t ha-1 + Vermicompost (VC) 2.5 ha-1 + Azospirillum 5 kg ha-1 + PSB 5 kg ha-1 were applied to hybrid rice var. Ajay grown under SRI method during kharif season and during rabi season mustard was grown taking the eight kharif season plots as main plot and three nutrient management practices viz., R1:100% RDF (40:20:20 kg N:P2O5:K2O ha-1), R2: 50% RDF + Azotobacter and R3-control (no fertilizer) in sub-plot and replicated thrice. The results revealed that application of 100% RDF + FYM 5 t ha-1 to rice registered significantly higher grain (7545 kg ha-1) and straw yield (7241 kg ha-1) of rice and higher seed yield (806 kg ha-1), stover yield(1423 kg ha-1), harvest index (36.3%) of subsequent mustard crop and system rice equivalent yield (9629 kg ha-1). Application of 50% RDF with BF to mustard recorded higher soil organic carbon and pH than RDF and control. The decrease in bulk density was more in the plots applied with 50% RDF+10t FYM to kharif rice (1.38 Mg m-3) and 50% RDF + BF to rabi mustard (1.41 Mg m-3). The available N, P and K content of soil increased to 237.6, 17.1 and 374.9 kg ha-1 from its initial value 148.2, 12.7 and 352.4 kg ha-1, respectively, at the end of second year with application of 50% RDF + BF to mustard.

Early sowing increases grain yield of machine-transplanted late-season rice under single-seed sowing

The shift from hand transplanting to machine transplanting has increased seed sowing rates and hence shortened seedling age and delayed sowing for late-season rice. The development of a single-seed sowing system for machine-transplanted rice can reduce seed sowing rates and provides a possible way to determine the performance of machine-transplanted late-season rice with early sowing. In this study, field experiments were conducted in two years with two rice cultivars to compare seedling shoot biomass at transplanting (TP), crop growth characteristics, and yield attributes in machine-transplanted late-season rice under single-seed sowing between two sowing dates, i.e., 30 June (SD30) and 15 June (SD15). Averaged across two cultivars and two years, seedling shoot biomass at TP under SD15 was 352% higher than those under SD30. Specific leaf weight (SLW) at heading (HD), crop growth rate (CGR) and biomass production during TP to HD, harvest index, and translocation of biomass accumulated before HD to the grain were higher under SD15 than under SD30 by 4–21%. SD15 had a 5–6% higher spikelet-filling percentage and grain yield than SD30. These results suggest that early sowing can improve the CGR during TP to HD by enhancing seedling growth and increasing SLW, and consequently, increase the biomass production during TP to HD, biomass translocation, and grain yield in machine-transplanted late-season rice under single-seed sowing.

Impact of shade-net intensities on root yield and quality of Asparagus racemosus: A viable option as an intercrop

The impact of shade net intensity on plant growth and on the yield components root yield, time of root harvest and shatavarin IV content in roots of shatavari were observed. The plants were grown under different green shade net intensity (SNI) (0, 25, 50, 75 and 90%) and harvested at three different times (06, 12 and 18 months of transplanting). The maximum number of stems/plants, stem weight, root length, root diameter, fresh root weight and dry root weight were observed under 0% SNI followed by 25% SNI. Shatavarin IV content in roots was higher all plants raised under all SNIs as compare to 0% SNI (open field conditions) however, it was maximum (8.53 μg g−1) in plants under 25% SNI. Total chlorophyll and carotenoids content were increased with increase in SNIs. Maximum root yield gain was observed at twelve months after transplanting (TP) as compared to six and eighteen months of harvesting. This study indicates that shatavari could be cultivated as an intercrop (25% SNI) for fetching higher shatavarin IV content without causing significant root yield loss.

Growth and yield of lowland rice as influenced by potassium application and cultivation method under alternate wetting and drying water regime

Besides being an essential macronutrient for plant growth, potassium (K) also acts as a stress-relieving agent against various biotic and abiotic stresses, especially water stress. An experiment consisting of three lowland Thai rice varieties (Pathumthani 1, RD57, RD41), two cultivation methods [dry direct seeding (DDS), transplanting (TP)] and four K doses (0, 80, 120,160 kg ha−1) under alternate wetting and drying (AWD) water regime was conducted to investigate the impact of K and cultivation method on lowland rice varieties subjected to AWD. Pathumthani 1 had significantly higher grain yield at the 120 kg K ha−1 compared with all other K doses. RD57 and RD41 had maximum grain yield at the 80 and 120 kg K ha−1, respectively, which was significantly higher than the control; however, grain yield among different K doses was mostly similar for RD57 and RD41. K application at the rate of 120 kg ha−1 for Pathumthani 1 and 80 kg ha−1 for RD57 and RD41 could be a feasible option. The performance of DDS and TP was better at the 80 and 120 kg K ha−1, respectively. Application of K at the optimum dose with proper selection of variety and cultivation method could help in sustainable rice production.

Performance of SRI Rice-Mustard cropping system under system based integrated nutrient management practices

System based integrated nutrient management practices for SRI rice-mustard cropping system was studied in a field experiment during 2013–14 and 2014–15 at RRTTS, Bhawanipatna, Kalahandi, Odisha. Application of 100% recommended dose of fertilizer (RDF-120: 60: 60 kg N: P 2O5: K2O ha−1) + 5t FYM ha−1 with split application of nitrogen as ¼ at transplanting(TP) ½ at active tillering (AT) and ¼ at panicle initiation (PI) recorded maximum effective tillers m−2 (183), filled grains panicle−1 (213), test weight (26.4 g) and grain yield (7.54 t ha −1) of rice under SRI. The increase in yield in this best INM treatment was 59.07% higher over existing practice of application of 100% RDF with split application of nitrogen as 1/3 at TP, 1/3 at AT and 1/3at PI. The highest residual effect on mustard seed yield (0.81 t ha−1), system productivity (9.63 t ha−1), net return (Rs. 82, 488/-ha−1) and return rupee−1 invested (2.55) was noticed with this treatment. As regards to the nutrient management in mustard, higher seed yield of mustard (0.80 t ha −1), system productivity (7.98 t ha−1), net return (Rs 59, 163/-ha−1) and return rupee−1 invested (2.11) was recorded with application of 50% RDF (RDF-40: 20: 20 kg N: P 2O5: K2O ha−1) + bio-fertilizer to mustard which was at par with 100%RDF treatment. The yield of mustard in this best treatment was 90.47% higher over control.

Seasonal differences in the rice grain yield and nitrogen use efficiency response to seedling establishment methods in the Middle and Lower reaches of the Yangtze River in China

The seedling establishment phase is important for the productivity and profitability of rice (Oryza sativa L.) production. To evaluate the role of climatic and physiological factors in different growth seasons in determining the rice grain yield, field experiments were conducted with four seedling establishment methods: manual transplanting (TP), seedling throwing (ST), machine transplanting (MT), and direct seeding (DS). Three nitrogen application rates were also tested (zero, medium, and high N rate) under single, early, and late seasons in the Middle and Lower reaches of the Yangtze River in 2013 and 2014. The results showed that the average grain yields of MT, ST and TP did not differ significantly under the N rate of 127.5–142.5kgN/ha. Under the high N rate (187.5–202.5kg/ha), the average grain yields in TP were 6.5%, 10.6%, and 36.7% greater than those in MT, ST, and DS, respectively, suggesting that TP rice had greater yield potential than the others, irrespective of rice seasons. In the single season condition, the grain yield advantage of TP over MT and SC might be attributable to the higher panicle-bearing tiller rate and greater sink size in TP with high N rates. It is less clear why the yield was not significantly higher in the double season. On the other hand, the average grain yields were −3.5%–8.8%, 6.4%–15.0%, and 29.4%–37.1% lower under DS than under the other treatments in the single, early, and late seasons, respectively, suggesting that DS might be a promising choice with less input and stable yield output in the single season. The dramatic yield loss in DS in the late season might be attributed to the reduced grain setting rate (a 20.3%–33.3% decrease under DS compared with the other treatments in the late season), indicating that the current varieties used for TP in the late season were not suitable for DS cultivation. The correlation between the grain yield and climate factors suggests that the light and temperature accumulation in the double season might be a barrier to narrowing the yield gaps between DS and TP rice in early and late rice, but was not the yield-limiting factor in the single season.

Responses of super rice (Oryza sativa L.) to different planting methods for grain yield and nitrogen-use efficiency in the single cropping season.

To break the yield ceiling of rice production, a super rice project was developed in 1996 to breed rice varieties with super high yield. A two-year experiment was conducted to evaluate yield and nitrogen (N)-use response of super rice to different planting methods in the single cropping season. A total of 17 rice varieties, including 13 super rice and four non-super checks (CK), were grown under three N levels [0 (N0), 150 (N150), and 225 (N225) kg ha−1] and two planting methods [transplanting (TP) and direct-seeding in wet conditions (WDS)]. Grain yield under WDS (7.69 t ha−1) was generally lower than TP (8.58 t ha−1). However, grain yield under different planting methods was affected by N rates as well as variety groups. In both years, there was no difference in grain yield between super and CK varieties at N150, irrespective of planting methods. However, grain yield difference was dramatic in japonica groups at N225, that is, there was an 11.3% and 14.1% average increase in super rice than in CK varieties in WDS and TP, respectively. This suggests that high N input contributes to narrowing the yield gap in super rice varieties, which also indicates that super rice was bred for high fertility conditions. In the japonica group, more N was accumulated in super rice than in CK at N225, but no difference was found between super and CK varieties at N0 and N150. Similar results were also found for N agronomic efficiency. The results suggest that super rice varieties have an advantage for N-use efficiency when high N is applied. The response of super rice was greater under TP than under WDS. The results suggest that the need to further improve agronomic and other management practices to achieve high yield and N-use efficiency for super rice varieties in WDS.

Effect of Enhanced Panicle Fertilization on Nitrogen Use Efficiency Traits of Rice (Oryza Sativa) with Different Planting Patterns

To evaluate the nitrogen (N) use efficiency of rice plants applied with enhanced panicle N fertilization (PN) on different planting patterns, field experiments were carried out with 5 nitrogen managements (two PN levels combined with two total N levels, and check, CK) under transplanting (TP) and direct seeded (DS). Our result showed that nitrogen use efficiency traits of physiological efficiency (PE), nitrogen use efficiency for grain (NUEg), and recovery efficiency (RE) of DS rice were decreased compared with TP rice, and total nitrogen accumulation (TN+N) were kept consistent between TP and DS. However, PN × PT interaction effect was significant in partial factor productive of applied N (PEP), agronomic efficiency (AE), nitrogen harvest index (NHI) and nitrogen translocation rate (NTR). High PN improved the AE value in DS system, but showed little effect in TP system. Oppositely, high PN decreased the PEP in TP system, while showed little effect in DS rice. The results indicated that improved PN applied in the TP system might affect the farmer's benefits without improving plant nitrogen utilization. For DS rice, though PEP was not significantly improved, but the N utilization efficiency of fertilizer uptake was enhanced. Furthermore, PE, AE, PEP, and NUEg, which were related to the performance of yield production, were significantly correlated with each other with P value <0.01. RE was correlated with all traits but NTR and NUEg with P value <0.01. NTR was correlated with NHI and NUEg with P<0.01. Results showed that NUEg was significantly correlated with PE, AE, PEP, and NTR. Considering most of the agronomic practice was carried out without zero N control, NUEg might be a practical option for farmers to evaluate the plant N fertilizer physiological use efficiency when soil texture is similar.

ISOLATION AND CHARACTERIZATION OF RHIZOBIA AND PLANT GROWTH-PROMOTING RHIZOBACTERIA AND THEIR EFFECTS ON GROWTH OF RICE SEEDLINGS

Biofertilizer is a relatively safer, environmentall y friendly and cost-effective approach as an altern ative to reduce chemical fertilizer usage. The selection of bacterial strains with multiple beneficial characte ristics are important to maximize the effectiveness on the host plant. Due to aforementioned interest, several Plant Growth-Promoting Rhizobacterial (PGPR) and rhizobial strains were isolated from rice and legume roots, respectively, at four locations in Malaysia namely Universiti Putra Malaysia (UPM), Serdang, Selangor; Besut, Terengganu; Tunjung, Kelantan and Sik, Kedah. Bacterial isolations were undertaken to select th e best isolates which exhibit multiple beneficial eff ects to the rice plant and a total of 205 bacterial strains were isolated and categorized as follows; 94 rhizos pheric and 107 endophytic bacteria from rice roots, one rhizobial strain from soybean and three from Mimosa pudica . These isolates were screened for their abilities to fix N 2 and solubilize phosphate; 52 were positive for bot h tests. The selected isolates were then tested for IAA production and other biochemical tests such as pota ssium solubilization, hydrolyzing enzymes (cellulas e and pectinase) and iron siderophore productions. Four i solates, namely UPMB19 (rhizospheric PGPR from Tunjung, Kelantan), UPMB20 (endophytic PGPR from Besut, Terengganu), UPMR30 (rhizobia from soybean) and UPMR31 (rhizobia from Mimosa ) were selected for subsequent plant inoculation te sts with UPMB10, a PGPR isolated from oil palm root, as the reference strai n. Based on 16S rDNA gene sequencing, these bacterial strains were identified under several genera: Lysinibacillus , Alcaligenes , Bradyrhizobium , Rhizobium and Bacillus , respectively. Results of plant inoculation test ind icated that UPMB19 significantly enhanced the seedling height at the early growth stage (7 days after tran splanting, DAT) which could be attributed to the hi gher N 2 fixation rate of this strain as compared to the oth er strains, except UPMB20. UPMB10 and UPMR31 also showed significant effects with increased seedling height and Total Dry Weight (TDW) at the later stage (14 DAT) possibly due to the higher bacterial populatio n and IAA produced as observed in the residual nutr ient solution without addition of fertilizer-N. This stu dy has successfully demonstrated the effectiveness of locally isolated PGPR and rhizobial strains with multiple b eneficial characteristics on early growth and vigor of rice seedlings under controlled condition. The result pr oved to be a vital information in the development o f a liquid biofertilizer for rice; thus further studies will b e done to evaluate the effectiveness of these isola tes under glasshouse and field conditions on growth, tillerin g and yield of rice.