Effect of Plant Geometry on Different Rapeseed Varieties under Rainfed Upland Condition in Nepal

The field experiment was carried out during winter of 2018/19 with two varieties (Unnati and Surkhet-Local) and three plant geometry (15cm × 10 cm, 30cm × 10 cm, 45cm × 10cm) in Randomized complete block design (RCBD) with four replications. Statistically there was no difference between two varieties while differences were found on different spacing and interaction between variety and spacing on final seed yield. High significant differences on seed yield was due to spacing and yield of rapeseed were higher at the 30 cm inter row spacing as compared to the 15 cm and 45 cm inter row spacing. Statistically significant effect was found on mean values of seed yield for interaction which showed that Unnati cultivar in 30 cm x 10 cm plant geometry had the highest seed yield (969.86 kg/ha) followed by Surkhet-local with spacing of 15 cm × 10 cm (843.75 kg/ha) and 30 cm × 10 cm (823.76 kg/ha). Yield of these varieties decreased as spacing is increased, thus sowing of Unnati should be done at cropping geometry of 30 cm × 10 cm and for Surkhet-local it should not be done beyond 30 cm inter row spacing to get the maximum potential yield. Int. J. Appl. Sci. Biotechnol. Vol 9(2): 113-121.

GENETIC DIVERSITY OF SABAH RICE CULTIVARS USING RANDOM AMPLIFIED POLYMORPHIC DNA (RAPD) MARKERS

Rice is the most important staple crop in Malaysia and is cultivated all over the country, including the state of Sabah. The uniqueness of rice cultivation in Sabah lies in the type of rice itself, deriving mainly from local or non-commercial cultivars but with distinctive characteristics including long grains, aromatic properties, and drought tolerance. However, despite having these important agricultural traits, information on the genetic diversity of Sabah rice remains limited. Hence, the purpose of this study was to determine the genetic polymorphisms of Sabah rice using random amplification of polymorphic DNA (RAPD) markers. A total of 101 alleles were profiled, from which 94% were identified as polymorphic. Phylogenetic analysis grouped the rice samples into three clusters, with two clusters classifying the ability of rice to grow under different planting conditions, suitable for growth irrigate and upland condition. The first cluster was dominated by cultivars that could survive in wet (irrigated) areas, while the other featured those that were found in dry (upland) areas. Furthermore, two alleles, OPA-05-B2 and OPA-01-B11, were found to be unique to cultivars within the upland cluster and were thus proposed to be involved in dry environmental adaptation. The results of the present study provide an insight into the genetic relationships and diversity of Sabah rice.

Identification of Fungal Isolates from Soils of Rice and Napier Grass

Microbial diversity of cultivated soil is the key resource for maintaining the functional capacity of agricultural and natural ecosystem. The research aimed to study the prevalence of soil fungi from the soils of rice and napier grass fields. Soil samples were collected from the fields of rice in flooded condition and napier grass in the upland condition at the University farm. Soil fungi were cultured on RB media through the serial dilution method. A total of 13 isolates were cultured, in which 11 from the soil collected from rice cultivated field and 2 from napier grass field. Seven out of 11 isolates collected from rice and 2 from napier grass were selected and identified through the morphological characters such as colony color, mycelium diameter, color and segmentaiton, spore size and color. Mycelium growths were examined on the PDA and RB media. Fungal isolates collected in this study were morphologically identified/ characterized as Aspergillus niger, A. flavus, A. terreus, A. carbonarius, A. nidulans, Alternaria sp., Penicillium and Talaromyces. Fungal species differed among the soils were discussed.

Biochar production under low pyrolysis temperature leads to lesser overall global warming potential and greenhouse gas intensity under lowland and upland short-term condition

<p>Biochar is a carbon-rich black stable solid substance that when utilized as soil amendment can effectively mitigate greenhouse gas (GHG) emission. However, during the pyrolysis process of organic feedstock (i.e. manure) greenhouse gases are released as the feedstock undergo thermochemical degradation. Many studies were reported with regards to the effectiveness of biochar to mitigate greenhouse gas emission and to maintain soil quality via carbon sequestration. However, no clear investigation was done regarding biochar utilization on reducing GHG emission in an integrated perspective that starts from pyrolysis (production) to field application (utilization). To evaluate the integrated influence of biochar utilization on the overall Global Warming Potential (GWP) and (Greenhouse Gas Intensity) GHGI at different temperature, the fluxes of GHGs during feedstock pyrolysis to soil application were calculated. The key components include GHGs released during production processes and biogenic GHG emissions taking place in the soil via short-term incubation experiment in lowland and upland condition treated with biochar pyrolyzed at different temperature. Highest pyrolysis temperature of 700<sup>o</sup>C emitted 6.92 Mg CO<sub>2</sub>-eq ton<sup>-1</sup> biochar, wherein 8.7% and 91.2% was contributed by Carbon dioxide (CO<sub>2</sub>) and Methane (CH<sub>4</sub>) effluxes, respectively, during pyrolysis. This GHG emission during pyrolysis at 700<sup>o</sup>C was 5.6, 2.2, and 1.5 times higher than at 400<sup>o</sup>C, 500<sup>o</sup>C and 600<sup>o</sup>C, respectively. Meanwhile, biochar produced at lowest temperature (Biochar400) when utilized as soil amendment emitted 43.4 and 38.2 Mg CO<sub>2</sub>-eq ha<sup>-1</sup> in lowland and upland condition, respectively. In addition, this emission value under lowland (and upland) condition was 1.38 (1.36), 1.51 (1.56) and 1.86 (1.91) times higher than Biochar500, Biochar600 and Biochar700, respectively. Combining the GWP during the production and the utilization processes in lowland and upland condition reveal that at 400<sup>o</sup>C emanates the lowest overall GWP of 93.3 and 88.1 Mg CO<sub>2</sub>-eq ha<sup>-1</sup>, respectively.  Moreover, under lowland (and upland) condition, overall GWP at 400<sup>o</sup>C was noted to be 65.7% (71.7%), 131.6% (140.4%) and 221.9% (237.1%), lower than at 500<sup>o</sup>C, 600<sup>o</sup>C and 700<sup>o</sup>C, respectively. In conclusion, the use of lower temperature during biomass pyrolysis and utilization of its derived biochar could be a practical approach to mitigate GHG emissions.</p><p> </p><p>Keywords: Biochar, Pyrolysis, Greenhouse gas, Methane, Global warming potential, Greenhouse gas intensity</p>

CoBln 04174: A promising high yielding variety for north east under rainfed upland condition

A promising midlate maturing sugarcane variety, CoBln 04174 was developed at Sugarcane Research Station, Buralikson, Assam from the general collection of C 79180 through clonal selection. The variety was tested in the AICRP trial under different discipline and on farm trials of different agro climatic zones of Assam. The variety CoBln 04174 recorded an average cane yield of 65.54t/ha and sugar yield of 7.63 t/ha with an improvement of 4.58% for cane yield and 3.52% CCS yield over the best standard CoSe 92423 across the centres in two plant crop and one ratoon crop. Besides this, the variety CoBln 04174 recorded average cane yield of 70.4 t/ha which is 22.26% higher over the best standard CoP 9301 (57.58t/ha) in the trials conducted at Sugarcane Research Station, Buralikson. The variety was moderately susceptible to red rot but moderately resistant to borer insect of sugarcane. The variety CoBln 04174 has been identified for release in North Eastern Zone.