Research on lncRNA Related to Drought Resistance of Shanlan Upland Rice

Background Drought has become the major abiotic stress that causes losses in rice yields and consequently is one of the main environmental factors threatening food security. Long non-coding RNA (lncRNA) is known to play an important role in plant response to drought stress, while the mechanisms of competing endogenous RNA (ceRNA) in drought resistance in upland rice have been rarely reported. Results In our study, a total of 191 lncRNAs, 2115 mRNAs and 32 miRNAs (microRNAs) were found by strand-specific sequencing and small RNA sequencing to be differentially expressed in drought-stressed rice. Functional analysis of results indicate that they play important roles in hormone signal transduction, chlorophyll synthesis, protein synthesis and other pathways. Construction of a ceRNA network revealed that MSTRG.28732.3 may interact with miR171 in the chlorophyll biosynthesis pathway and affect the ability of plants to withstand drought stress by regulating Os02g0662700, Os02g0663100 and Os06g0105350. The accuracy of the regulatory network was verified by qRT-PCR. Conclusion Our results provide a theoretical basis for future studies on the potential function of lncRNA in plant drought resistance, and they provide new genetic resources for drought-resistant rice breeding.

Application of local microbes increases growth and yield of several local upland rice cultivars of Southeast Sulawesi, Indonesia

Rice is the major food commodity in Indonesia and many other countries, as the main source of carbohydrate. Rice production must be increased continuously to meet food needs, one of which is by utilizing largely available dry land areas. Two important factors required to increase rice production on marginal soils are the use of high-production adaptive varieties and biological agents. It is necessary to conduct research on the application of local microbes to the cultivation of upland rice cultivars, with the aim to determine the best genotypes and/or suitable microbes. This research was carried out at the Research Field and laboratories of Faculty of Agriculture, University of Halu Oleo, from April 2020 to April 2021. The first tested factor was biological agents (local microbes), consisting of three levels, namely: without microbes (M0), the fungus Trichoderma sp. (M1), and the bacteria Pseudomonas sp. (M2). The second factor was the upland rice cultivar, which consisted of five levels, namely: V1 (Tinangge cultivar), V2 (Enggalaru cultivar), V3 (Bakala cultivar), V4 (Momea cultivar), and 1 nasional variety, namely V5 (Inpago-12 variety), as check variety. The research results showed that the interaction between local microbes Trichoderma sp. (M1) and Pseudomonas sp. (M2) on Tinangge (V1) and Momea (V4) cultivars gave a better effect on crop production. The best cultivar based on the growth and yield variables was generally obtained from the Momea cultivar (V4), although in many variables it was not significantly different from the Tinangge cultivar (V1). These cultivars could be further studied and possibly developed for promising cultivars in Kendari areas.

Seaweed extract effect on arbuscular mycorrhizae spore in soil engineered by earthworm, and the soil effect on upland rice growth

Seaweed extract is known to contain nutrients and growth-regulating substances that affect soil biota, and a source of protection against pests and diseases. Earthworm, which is an example of a soil biota and playing the role of ecosystem engineer, has the ability to produce suitable land biostructures, for the inhabitation of arbuscular mycorrhizal fungi (AMF), which has an impact on upland rice growth. Therefore, this study aims to determine, (i) the effect of seaweed extract on the population of earthworms and spores of arbuscular mycorrhizal fungi, and (ii) the impact of the engineered soil on the growth of local upland rice varieties. Furthermore, the extract of seaweed, such as Kappapychus alvarezii, was divided into five concentration levels, namely 0%, 20%, 40%, 60%, and 80%. Each treatment was drenched into the soil from the cogongrass vegetated area, mixed with 20 Pheretima sp., and maintained for 49 days in the greenhouse. The result showed that the total difference in the earthworms’ concentration treatments was not significant. It also showed that the total AMF spores in the engineered soil products of 20% concentration was the highest. Based on treatment with the earthworm engineered soil products, the highest and lowest vegetative growth and yield components of upland rice were observed at the concentrations of 80% and 0%, respectively. In conclusion, the application of seaweed extract to the soil did not significantly reduce the earthworm population. The extract concentration of 20% also increased the total AMF spore in the engineered soil. Moreover, highly treated engineered soil products increased the growth and yield components of upland Kambowa rice on cogongrass soils.

Continuous Maize Cropping Accelerates Loss of Soil Organic Matter in Northern Thailand as Revealed by Natural 13C Abundance

AimsThe loss of soil organic matter (SOM) has widely been reported in the tropics after changing land use from shifting cultivation to continuous cropping. We tested whether continuous maize cultivation accelerates SOM loss compared to upland rice and forest fallow. Methods: Because litter sources include C4 plants (maize in maize fields and Imperata grass in upland rice fields) in Thailand, C3-derived and C4-derived SOM can be traced using the differences in natural 13C abundance (δ13C) between C3 and C4 plants. We analyzed the effects of land use history (cultivation or forest fallow period) on C stocks in the surface soil. Soil C stocks decreased with the cultivation period in both upland rice and maize fields. ResultsThe rate of soil organic carbon loss was higher in maize fields than in upland rice fields. The decomposition rate constant (first order kinetics) of C3-plant-derived SOM was higher in the maize fields than in the upland rice fields and the C4-plant-derived SOM in the forest fallow. Soil surface exposure and low input of root-derived C in the maize fields are considered to accelerate SOM loss. Soil C stocks increased with the forest fallow period, consistent with the slow decomposition of C4-plant-derived SOM in the forest fallows. ConclusionsContinuous maize cultivation accelerates SOM loss, while forest fallow and upland rice cultivation could mitigate the SOM loss caused by continuous maize cultivation.

Upland rice intercropped with green manures and its impact on the succession with common bean

The aim of this work was to verify the possibility of intercropping rice with green manures, as well as the impact of the dry biomass yield of these intercropping systems on common bean in succession, evaluating the agronomic and qualitative performance of grains from both crops. The experiment was conducted in Southeastern Brazil in the years 2018 and 2019, with succession of rice (spring/summer) and common bean (autumn/winter). The treatments were composed of cropping systems with rice as a sole crop and intercropped with forage peanut, calopo, Crotalaria breviflora, Crotalaria spectabilis, stylo, jack bean and dwarf pigeon pea. No intercropping increased the system's yield compared to sole-crop rice, but intercropping of rice with forage peanut and stylo promoted grain yield and quality similar to those of sole-crop rice. Intercropping with C. breviflora affected the agronomic and qualitative performance of rice. Common bean yield after rice intercropped with dwarf pigeon pea, C. spectabilis and C. breviflora was similar in yield after sole-crop rice, while the other intercrops reduced common bean yield. Common bean grain quality was not affected by the cultivation of rice as sole crop and intercropped with green manures. Although none of the intercropping systems increased yield compared to sole-crop rice (control), it can be concluded that the intercropping of upland rice is viable depending on the green manure species, allowing greater biomass production per area that can help long-term soil conservation and increase the system's yield.

Technical Efficiency and Technological Gaps of Rice Production in Anambra State, Nigeria

The traditional approach to modeling productive efficiency assumes that technology is constant across the sample. However, farms in different regions may face different production opportunities, and the technologies they employ may differ due to environmental factors. Therefore, rather than using a traditional stochastic frontier model in such cases, a stochastic meta-frontier (SMF) analysis is recommended to account for environmental factors between regions. It follows that differences in environmental factors between the upland and lowland regions in Anambra State, Nigeria, may result in farmers producing rice under different production and environmental conditions. Using the SMF model, this study, for the first time, determines technical efficiency (TE) and technological gap ratios (TGRs) of rice production from the upland and lowland regions in the Awka North Local Government Area of Anambra State, Nigeria. Our data are from a cross-section sample of randomly selected rice farmers. Results reveal that lowland regional rice producers are on average, significantly more technically efficient (91.7%) than their upland counterparts (84.2%). Additionally, mean TGRs associated with lowland rice farmers are higher (92.1%) than their corresponding upland producers (84.7%). While the upland rice producers are less technically efficient and further away from their full potential, results indicate that both sets of farmers do not use advanced technologies to match the industry’s potential. We suggest that agricultural policy should focus on providing regionally specific technologies, such as improved rice varieties that fit the working environment of the lagging area, to help rice farmers improve their resource efficiency and minimize technological gaps.

Agronomic Response of Local Upland Rice Cultivars on Growing under Two Cultivation Systems

Background: This study aimed to observe the agronomic response of 18 Southeast Sulawesi local upland rice cultivars that were grown under two cultivation systems (dry land and wet rice field) and optimize local potential to support self-sufficiency and food security. Methods: The research used a split-plot design with the following main plot: cultivation system (L) including upland (L1) and rice field cultivation system (L2). The subplots were 18 local upland rice cultivars such as Wangkomina (K1), Wuna Lapodidi (K2), Waburi-buri (K3), Wapantoga (K4), Nggalaru (K5), Wuna Parigi (K6), Bakala (K7), Biu (K8), Ikulaku (K9), Bou (K1), Momea (K11), Daindomoronene (K12), Konkep (K13), Tinangge (K14), Ndoamoito (K15), Uwa (K16), Ndowatu (K17) and Indalibana (K18). Result: The local upland rice responded better to the wetland cultivation system than the upland cultivation system. The local upland rice cultivar Ndowatu showed the highest production potential, which was statistically similar to the Biu, Ikulaku, Momea, Konkep and Uwa cultivars. Ndowatu cultivar showed high production potential (842.80 g.m-2). Thus, this cultivar can be considered suitable for development in the rainfed lowlands to increase the planting index and to support the self-sufficiency and food security of the region.