Path Coefficient Analysis of Growth and Yield Traits of Rice (Oryza sativa L.) at Bokolori, Talata Mafara, Sudan Savanna Ecological Zone, Nigeria

In order to determine the direct and indirect effects of yield and yield components of rice, a field experiment was conducted in each of the wet seasons of 2016 and 2017 at Irrigation Research Stations of the Institute for Agricultural Research, Bokolori, Talata Mafara, in the Sudan Savanna ecological zone of Nigeria (12° 34’ N; 06° 04’E). The treatment consisted of four (4) weed management practice (Oxadiazon at 1.0 kg a.i ha-1 [pre-emergence], Orizo-plus [proponil 360 g/l + 2,4-D 200 g/l] at 2.8 kg a.i ha-1[post emergence at 3 WAS], manual weeding [at 3 and 6 WAS] and weedy check [control]); three (3) each of seeding method (Drilling, Dibbling and Broadcast) and seed rate (40 kg ha-1; 70 kg ha-1; 100 kg ha-1). The experiment was laid in a split plot design replicated three times. Weed management practice was assigned to the main plots while the combination of seeding method and seed rate to the subplots. Data were collected on plant height, leaf area, crop dry matter, tillering ability, crop growth rate, harvest index (HI), panicle length, number of grains per panicle, 1000-grain weight and paddy yield. The result indicated that, the highest individual contribution of 25.04% to paddy yield was made by dry matter followed by 1000-grain weight (8.74%), tillering ability (8.46%), leaf area (3.13%), number of grains per panicle (1.03%) and the least was from panicle length (0.83%). The contribution of these growth and yield attributes to yield suggests that, priority be given to these traits when making selection for improvement.

Review of rice transplanter and direct seeder to be applied in Indonesia paddy field

The challenge to plant one seed or plant per hill by rice ordinary rice transplanter (RT) is still difficult to be achieved due to random in sowing seed by on rice nursery tray. But due to the vigority of seed after sowing in the field and also the unfavorable condition, the more number of seed are still needed and the yield lower compare transplanter method. Recently, the use of rice direct seeding has been increasing rapidly owing to rural labor shortages and continuous increases in agricultural production costs. This article reviews the research and application progress of mechanized rice direct seeding including direct seeding technologies, precision rice seeding, precision rice seed-metering devices. The other important component on succession direct seeding method is also discussed i.e. calcium gypsum coating and iron powder coating. Operating direct seeding machine also need consider about land and water management. Paddy field need to be managed since the seed drooped in order give favor condition of seed and facility the seed with optimum growing condition. In this approach, pre-germinated seeds are uniformly hill-dropped in the expected positions in puddled soil. The both technology PNRT and RDS have prospect and great potential for promoting the development of precession on rice cultivation in Asia.

Preparation of polyethylene oxide single crystals via liquid gating technology and morphology design strategy

A novel type of liquid gating technology has been developed to prepare a polyethylene oxide (PEO) single-crystal film, and the crystal growth was observed via atomic force microscopy. The self-seeding method has been widely used in the preparation of polymer single crystals, but the mechanism through which single polymer crystals are formed via the combination of liquid gating technology and the self-seeding method remains unclear. To elucidate the mechanism of this process, a series of experiments were conducted in which a dilute polymer solution was sprayed onto a mica substrate to form a single-crystal film through liquid gating technology to study the effect of the crystallization time on the morphology of a thiol PEO (mPEO-SH) crystal. Based on this research, it was found that liquid gating helps to prevent twinning during crystal growth. The combination of liquid gating and self-seeding technology thus provides a new strategy for polymer single-crystal growth.

Speed-Breeding System in Soybean: Integrating Off-Site Generation Advancement, Fresh Seeding, and Marker-Assisted Selection

Speed breeding by artificial control of photothermal conditions facilitates generation advancement but was limited in scale and cost. In this study, we demonstrated a cost-saving off-site summer nursery pattern, taking full advantage of shorter daylength and higher temperature with lower latitude compared to the origin of the soybean cultivars used in the study. This substantially reduced the generation cycles under totally natural conditions. Using this approach, two generations of soybean cultivars from Northeastern Spring Planting Region (NE) and Yellow-Huai-Hai Valleys Summer Planting Region (YHH) were successfully obtained in Beijing and Hainan, respectively, compared to one generation in origin. Fresh-seeding method was also used to further shorten the generation duration by 7–10 days, thereby allowing at least four generations per year. Using DNA markers to define haplotypes of maturity genes E1–E4, we proposed a model to predict the optimum adaptation region of the advanced generation lines. Taken together, we present a speed-breeding methodology combining off-site nursery, fresh-seeding method, and marker-assisted selection, aimed at accelerating soybean improvement.

Estimating the potential cooling effect of cirrus thinning achieved via the seeding approach

Cirrus thinning is a newly emerging geoengineering approach to mitigate global warming. To sufficiently exploit the potential cooling effect of cirrus thinning with the seeding approach, a flexible seeding method is used to calculate the optimal seeding number concentration, which is just enough to prevent homogeneous ice nucleation from occurring. A simulation using the Community Atmosphere Model version 5 (CAM5) with the flexible seeding method shows a global cooling effect of -1.36±0.18 W m−2, which is approximately two-thirds of that from artificially turning off homogeneous nucleation (-1.98±0.26 W m−2). However, simulations with fixed seeding ice nuclei particle number concentrations of 20 and 200 L−1 show a weak cooling effect of -0.27±0.26 W m−2 and warming effect of 0.35±0.28 W m−2, respectively. Further analysis shows that cirrus seeding leads to a significant warming effect of liquid and mixed-phase clouds, which counteracts the cooling effect of cirrus clouds. This counteraction is more prominent at low latitudes and leads to a pronounced net warming effect over some low-latitude regions. The sensitivity experiment shows that cirrus seeding carried out at latitudes with solar noon zenith angles greater than 12∘ could yield a stronger global cooling effect of −2.00 ± 0.25 W m−2. Overall, the potential cooling effect of cirrus thinning is considerable, and the flexible seeding method is essential.

Mapping of Qtl for Anaerobic Germination Using the Donor Ac39416a in the Genetic Background of Swarna Sub-1 (Oryza Sativa L.)

Background: Anaerobic germination is an important trait in particular for cultivation under direct seeding method in kharif season, as well as during nursery rising for transplant rice, as sometimes unexpected rains immediately after sowing will drastically reduce the plant population.Methods and Results: In the present investigation phenotypic screening for Anaerobic germination (AG) was carried out using 188 F2:3 population of Swarna Sub1/AC39416A at RARS (APRRI), Maruteru. The mean anaerobic germination per cent recorded after the two weeks of submergence ranged from 0% to 95% with overall mean of 47.51% whereas, for three weeks of submergence, the mean anaerobic germination per cent recorded between 0 and 95%, with overall mean of 37.66%. 134 (19.42%) out of 687 Simple Sequence Repeats (SSR) markers surveyed were polymorphic between the parents. Linkage analysis was done with 83 SSR markers showing polymorphism clearly using the integrated software called QTL IciMapping software version 4.1.0. The length of linkage map constructed across whole genome was 3600.8 cM and identified seven QTLs viz., qAG2, qAG3, qAG7-1, qAG7-2, qAG9, qAG10 and qAG12. All these seven QTLs explained phenotypic variance of about 37.47% collectively for AG trait, with their individual contributions ranging from 3.5% to 8.67% of phenotypic variation and LOD scores of 2.6 to 5.86. The LOD score and phenotypic variance is 5.86 and 8.67% respectively for qAG10 a novel QTL identified in the present study using ICIM method. Conclusion: QTL “qAG12-1” identified in this study may be considered for introgression into popular elite rice varieties otherwise susceptible for anaerobic germination after fine mapping studies.

Experimental Study on Mechanical Properties of Hydrate-Bearing Sand: The Influence of Sand-Water Mixing Methods

Laboratory-synthesized specimens are employed for an experimental study on the mechanical properties of hydrate-bearing sediments (HBS) due to the difficulty of field coring. A representative synthesized sample for the analysis of the mechanical properties of HBS in the experimental study requires evenly distributed hydrates in the pores of the sample. However, a specimen made with an improper sand–water mixing method might have an uneven water distribution, resulting in an uneven hydrate distribution when applying the ice-seeding method for hydrate formation. This study adopted three kinds of methods to mix sand and water before forming hydrates and applied the low-field nuclear magnetic resonance (NMR) technique to investigate how these methods affect the hydrate distribution, further affecting the mechanical properties. To analyze the mechanical properties of HBS, we conducted drained triaxial tests. As shown in low-field NMR, when we compacted a sample of the sand–water mixture and froze it upside-down before hydrate formation, a sample with an even water distribution was obtained. Subsequently, the hydrate in HBS distributed also evenly. The stress-strain curves present different strain softening and hardening patterns due to the different hydrate distributions. Moreover, the samples with the evenly distributed hydrates have higher initial elastic modulus and strength than the ones made with other methods.