Local Rice Research Articles

Perception and Attitude of Consumer Patronage of Ghana-Grown Rice: Evidence from Kumasi, Ghana

Increasing human population, urbanization, and changing consumer trends have contributed to the emergence of rice as the leading staple food in Ghana. Despite its importance in the Ghanaian diet, patronage and consumption of locally grown rice are not yet widespread. This study investigates consumer patronage of locally grown rice in the Kumasi Metropolis, Ghana, and fills a critical gap in understanding the specific factors that influence consumer preferences in urban settings. Data were collected through a cross-sectional survey of 120 respondents across different income categories using a multistage sampling technique and analyzed using descriptive statistics, a Probit model, and Kendall's coefficient of concordance. The study found that cooking quality, palatability, colour, and fragrance were the primary attributes that influenced consumer preferences. Probit analysis revealed that income and the frequency of rice consumption significantly influenced the likelihood of purchasing locally grown rice. Specifically, a higher income decreases, while frequent rice consumption increases the likelihood of choosing local rice. Key constraints identified include perceived high cost, limited availability, and concerns about the quality of rice. This study recommends that local rice producers, agricultural organizations, and government bodies should make efforts to improve the sensory and culinary qualities of locally grown rice through improved processing techniques, increased promotion, and campaigns to ensure the commodity is readily available to consumers. These strategies aim to boost local rice consumption and support agricultural sustainability and food security in Ghana.

Enhancing salt tolerance in rice genotypes through exogenous melatonin application by modulating growth patterns and antistress agents

Melatonin is a bioactive molecule with an important role in plants responding to various abiotic and biotic stresses. This study aims to determine the role of melatonin in rice under salt stress. This study used a factorial completely randomized design. The first factor was local rice varieties (IR64 and Silaun), and the second factor was plant treatments (control, 1 µM melatonin, 150 mM NaCl, 150 mM NaCl + 1µM melatonin). This study shows that exogenous melatonin can increase plant growth, such as plant height, root length, stem length, leaf length, leaf area, and plant biomass under salt stress compared to treatment without melatonin. Exogenous melatonin can increase the total chlorophyll content, relative water content, and proline content, reduce the total sodium content, and increase potassium absorption under conditions of salinity stress. Melatonin is also able to scavenge ROS in plants, resulted the decrease in ROS and MDA content. In terms of gene expression, OsAPX1 and cytosolic APX exhibited the highest expression in IR64 under combined salt and melatonin treatment, while GPOD, Mn-SOD, and Cu/Zn-SOD were upregulated under various conditions in both varieties. Additionally, OsLEA showed high expression in both varieties under control conditions, and CAT was significantly upregulated under salt stress. Our findings indicate that exogenous melatonin has the potential to enhance various factors under salt stress and helping in the recovery of rice plants from sodium (Na+) damage.

Grain quality attributes of an on-farm Thailand's highland rice germplasm directly beneficial to the farming households

Rice (Oryza sativa) from the highlands of Northern Thailand where the crop is predominantly planted with local varieties was examined for grain quality features having direct benefits for the local population. Un-husked rice seed provided by farmers of 10 minority groups had large grains, in contrast to the slender grain type found in the lowlands. The highland-grown rice directly benefits the local population by providing a higher dietary intake of Fe but not of Zn. The highlands have been identified as a rich source of pigmented rice with a high anthocyanin content and an environment favouring the production of premium quality rice. On-farm experiments confirmed the effects of genotype (G) and environment (E) and the G × E interaction on grain quality. The local rice with high grain Zn exhibited higher concentrations under the upland conditions, while the high anthocyanin variety produced greater levels under wetland conditions. The pigmented rice had a higher anthocyanin content at high altitudes than at lower altitudes. The information concerning the value of local rice germplasm benefits the local population and should facilitate more sustainable on-farm conservation efforts than rewards offered to the farmers from external funding sources.

Determinants of net value added to produced and processed paddy rice in South East, Nigeria

The study principally examined the determinants of net value added to produced and processed paddy rice in South east Nigeria It specifically, identified the socio-economic characteristics of the respondents, analyzed the determinants of net value added to produced and processed paddy rice as well as ascertained the constraints to processed and produced paddy rice. Multi-stage sampling technique involving purposive and random sampling methods was used to select 240 respondents. Primary data were collected on rain-fed production season using structured questionnaires administered to the respondents by personal interview. Descriptive statistics,, multiple regression and principal component analysis were used to analyze the data. Results obtained showed that gender distribution of the respondents was 63%males and 38% females. More respondents are between the ages of 41-50 and31-40 respectively and house hold size of 4-6 .Farming experience showed that 136 respondents representing 57% had engaged in the business between 11-20yrs.The results also showed that 67% of the respondents accessed farm credit while 25% did not.66% of the respondents belonged to farmers association while 75% were not visited by extension agents. Variables (age, gender, years in school, household size, years of experience, training/extension visits, costs incurred, value addition technique and market price) significantly influenced the net value added while marital status, membership of cooperative, and access to credit did not. Constraints to paddy producers and processors were accessibility to farm machine, poor infrastructure and scarcity/high cost of labor, low access to credit/grant; low proactive measures to flood and drought control; insufficient knowledge of agro-chemicals, and late provision of essential training and services; and processors: use of outdated rice milling machines, high cost of modern rice processing machines, low access to modern rice processing machineries and low acceptability of local rice. Recommendations include; establishment of farm machinery hiring centers for producers and supply of modern rice milling machines to rice processing clusters, development of dams and irrigable lands, training and re-training on access to fund, utilization of biodegradable wastes from paddy rice, proactive measures of flood and drainage control, adequate use of agro-chemicals, use of modem techniques, and involvement of National Agency for Food and Drug Administration and Control in quality control. Keywords: Agriculture, Paddy Rice, Value Addition, Nigeria.

Beyond yield: Unveiling farmer perceptions and needs regarding weed management in Bangladesh.

More than 3.5 billion people depend on rice for more than 20% of their daily calories. Globally, Bangladesh is the third largest rice producer. With 171 million people, Bangladesh is also among the top consumers. Local rice production not only affects the country's food security but also influences the global rice trade. A large yield gap has been reported due to weeds. Traditional hand weeding is very costly because of labor shortages resulting from industrialization. Limited data showed a higher yield and profits when using herbicides. However, quantitative data on various aspects of weed management and associated issues representing the country's variable rice ecosystem, which is characterized by 30 agroecological zones, are lacking. We collected data on weed management practices from 865 farmers and 69 agrochemical shops covering all 30 agro-ecological zones (AEZs) through a structured survey. We observed a significant regional variation among various parameters. Approximately 82% of farmers use herbicides, and few rely solely on either manual weeding or herbicides. Pre-emergence herbicides are the predominant. Application procedures are almost the same across the country. Although 40% of farmers had secondary and higher-level education, most depend upon local sellers' suggestions rather than reading the product label regarding the dose. Few farmers consider herbicides hazardous, and respondents rarely perceive any environmental impact. Pyrazosulfuron ethyl (35%) and acetochlor-containing bensulfuron methyl (27%) are the most-used chemical species. Approximately 45% of farmers observed that herbicides suppress early seedling growth. Additional fertilizer is required to compensate for this. Multiple weed species that are difficult to control through presently used herbicides were noted in all AEZs. Around 64% of farmers observed that herbicide application contributes to higher yields as a function of timely weeding. Cost comparisons showed that high labor prices will make rice cropping unprofitable in most parts of the country if herbicides are eliminated. Clear adverse effects of pre-emergence herbicides on early crop growth implied the potential benefits of broad-spectrum herbicide-tolerant genetically engineered (GE) rice to sustain the country's food security. Additionally, such GE rice could incentivize the adoption of alternate wet and dry irrigation methods, leading to water and cost savings.

The Impact of the Implementation of the Rice Provision Policy for Civil Servants (ASN): A Case Study in Sumenep Regency Government

The local government’s policy on providing rice for Civil Servants (ASN) in Sumenep Regency expresses a commitment to supporting local farmers by purchasing agricultural products as a gesture of appreciation. This study aims to assess the impact of the rice provision policy for ASN in the Sumenep Regency Government. Employing a qualitative research methodology, data collection focuses on social phenomena. Grounded in constructivist philosophy, the qualitative approach explores natural settings, with the researcher as the primary instrument. Data sources are purposively sampled using a snowball technique, employing triangulation in data collection. Inductive and qualitative data analysis, emphasizing the generalizability of meaning, reveals that the policy can boost local rice demand, providing opportunities for farmers to increase sales and income. The program’s implementation has potential social and political implications. A successful and positively received program can enhance the regional government’s image and garner political support. However, disparities exist in benefits received by government departments (OPD) and Civil Servants (ASN) under the rice provision policy. Keywords: Civil Servants (ASN), policy implementation, local government

Stakeholders Analysis in the Development of Local Paddy Varieties in Padang City

The development of local paddy varieties involves many stakeholders. Each stakeholder has a different role ranging from the socialization and farming to the marketing of local rice varieties. This research aims to identify stakeholders and analyze their role in developing local paddy varieties using a descriptive qualitative method. The respondents in this research are stakeholders involved in the development of local paddy varieties in Padang City. The results show that the stakeholders involved are the Padang City Agriculture Office, Agricultural Extension Center, farmers, farmer groups, landowners, seed breeders, production facilities providers, agricultural labor, rice milling units, collecting traders, colleges, sub-district administration, urban village administration, financial institutions, the Regional People’s Representative Council, retailers, and consumers. Classifications of stakeholders show that the Padang City Agriculture Office, the Agricultural Extension Center, farmers, and farmer groups have high influence and interest. These stakeholders are classified as key players. Meanwhile, sub-district administration, urban village administration, financial institutions, and Regional People’s Representative Council have low influence and interest. They are classified as the crowd. All of the stakeholders mentioned that roles play their position as policymakers, coordinators, facilitators, implementers, and accelerators. Keywords: paddy, stakeholders, interest, power, role

Tolerance of local gogo rice sprouts under salinity stress conditions

The expansion of rice planting areas in the future needs to be carried out outside Java, as fertile land in Java is shrinking due to land conversion. Most of the land outside Java consists of marginal land, such as areas with high salinity. High salinity levels in the soil cause a decrease in plant germination, growth, and production. The research aimed to examine the tolerance of each cultivar at each level of NaCl concentration, to obtain cultivars that were tolerant to salinity stress, and to determine the NaCl concentration that suppresses the germination of local upland rice. The research was structured using a completely randomized design with a two-factor factorial pattern. The first was the six upland rice cultivars, namely, dongan, jahara, Pulu Konta, pomegranate, kalendeng, and pulu tau leru, while the second factor was the NaCl concentration consisting of 0%, 0.2%, 0.4%, 0.6%, 0.8% and 1%. Thus, there were 36 experimental units, which were repeated three times so that there were 108 experimental units. The results of the research showed that there was no interaction with all germination variables; cultivar and concentration had a significant effect on maximum growth potential, germination capacity, germination time, plumule length, radicle length and dry weight of sprouts, while cultivar affected the wet weight of sprouts. Kalendeng has a high salinity tolerance. The use of NaCl concentrations of up to 0.6% has been able to reduce the germination capacity of local upland rice. The conclusion of the research showe that there was no interaction between all germination variables.

Sistem Pemasaran Beras Bujang Marantau Di Kecamatan Sungai Tarab, Kabupaten Tanah Datar, Provinsi Sumatera Barat

The “Bujang Marantau” rice variety is local rice from Tanah Datar Regency which was registered as a national superior rice variety by BPTP West Sumatra in 2015 and grows well in Tanah Datar Regency. This increase in “Bujang Marantau” rice production must be balanced with a good marketing system so that farmers and institutions marketing can receive more favorable prices. The study is aimed to analyze the channels, functions and operational efficiency of rice marketing (marketing margin, farmer’s share, and profit to cost ratio) in Sungai Tarab District. This research involved 45 farmers as samples obtained through a simple random sampling method. Marketing institution respondents were obtained using the snowball method based on the flow of information from farmers and 15 marketing institution respondents were obtained. Qualitative data is used to analyze marketing channels and institutions. Quantitative data is used to analyze marketing margin, farmer’s share, profit to cost ratio and marketing efficiency index. The results showed that there are 3 marketing channels and 3 types of marketing institutions involved. The results of the marketing operational efficiency analysis show that the relatively efficient marketing channel is channel III because it has the lowest marketing margin value, the highest farmer’s share, and the shortest marketing channel compared to other channels. Marketing institutions should further optimize the marketing functions of each institution, such as the transportation function, so that transportation costs can be lower and minimize marketing costs more efficiently.

How Does Cultural and Colonial Heritage Affect Optimal Branding Strategies? Evidence From the Rice Sector in Senegal

ABSTRACTAfrica's cultural and colonial heritage has profoundly segmented rice markets. Whereas in ancient centers of rice domestication, consumers maintained preferences for local rice consistent with their cultural heritage, preferences have shifted toward imported Asian rice in coastal areas around seaports, due to prior exposure to colonial import substitution policies. To enhance the competitiveness of locally produced rice relative to imported versions, it is necessary to tailor new local rice products to both market segments. A study was conducted in Senegal to test branding strategies for local rice in a country where both market segments coexist. Brands that mimic local and international labels were developed for local rice, and urban consumers bid to upgrade non‐preferred to preferred brands through the Becker–DeGroot–Marschak (BDM) mechanism. Contrary to expectations, results from an endogenous switching regression show that descendants from ancient Senegalese rice domesticators placed premiums on local rice with foreign‐looking brands, indicating that foreignness is perceived as a quality cue even in market segments rooted in cultural heritage. Thus, branding local rice using a combination of local and foreign cues could be an effective strategy in promoting domestic rice to both segments shaped by cultural and colonial heritage.

Differential physiological responses to salt stress in rice landraces in Thailand

Soil salinity is a limitation factor for rice cultivation in the north-eastern Thailand. Understanding the mechanisms of salt stress tolerance is critical for maintaining or improving crop yield under salt stress. Over the past ten years, many landrace rice varieties have been examined for genetic diversity. To utilize the richness of natural resources and to explore novel genetic resources for developing a new variety, evaluating local rice varieties for salinity is still needed. This study investigated the physiological and biochemical responses of 8 landrace rice varieties in comparison to ‘Pokkali’, the standard salt-tolerant rice genotype, to clarify the major salt tolerance mechanisms in the landraces found in Thailand. After being exposed to 120 mM NaCl for 7 days, ‘Pokkali’ expressed physiological parameters in response to salt stress which are indicative of salt tolerance ability including low growth reduction, low Na+/K+ ratio, low chlorophyll degradation and low membrane integrity. In contrast, the landrace varieties displayed varying patterns of response. No landrace variety showed an outstanding ion exclusion mechanism as ‘Pokkali’, as evidenced by the fact that all landrace varieties showed approximately two times higher Na+/K+ ratios than ‘Pokkali’. However, it was found that ‘Surin’ had a similar salt stress response to ‘Pokkali’ (low growth reduction, low chlorophyll degradation, low membrane integrity), except for the markedly increased proline and sugar accumulation, suggesting an osmotic adjustment mechanism. Therefore, this variety could be a potential genetic resource to be developed as a donor for the osmotic adjustment trait to improve salt-tolerant rice in the future.

Boosting domestic rice production in Ghana: Analysis of consumer opinions, purchasing behavior and determinants among different income strata

Despite the fact that domestic rice production contributes significantly to the livelihood of millions of people in Ghana, it has been observed that consumers show a strong preference for expensive and imported rice over locally produced rice. The purpose of this study was to investigate the perception, purchasing behaviour and determinants of local rice consumption across three income households in the Kumasi Metropolis, Ghana. A total of 414 rice consumers were selected through a multi-stage sampling technique. Descriptive and inferential techniques, including perception analysis and ordered probit model, were used to analyse the data. The overall perception index of 3.61 denotes that consumers generally have a positive perception of local rice regarding health benefits (index = 4.44), affordability (index = 3.86), and cooking attributes (index = 3.48), despite its poor appearance (index = 2.80). The ordered probit model depicted heterogeneity of covariates as determinants of local rice consumption-based income strata of the household. For instance, various factors, including gender, age, occupation, and attributes of local rice such as affordability, nutrition, cooking attributes, and appearance, have a notable impact on the consumption of local rice among low-income households. In contrast, education, household decision-making, the place of purchasing local rice, and three perception attributes, namely affordability, nutrition, and cooking attributes, were found to be significant determinants of local rice consumption among middle-income households. According to the data, local rice consumption among high-income families was significantly predicted by gender, occupation, household size, and two perception attributes—affordability and nutrition. The study has practical implications for improving the competitiveness of local rice to increase its acceptance and consumption among consumers in the country.

Effects of different phosphorus and potassium supply on the root architecture, phosphorus and potassium uptake, and utilization efficiency of hydroponic rice

Phosphorus (P) and potassium (K) affect seedling growth, root configuration, and nutrient uptake in hydroponic rice, but there are few studies on all growth stages of rice. The purpose of this experiment was to determine the response characteristics of root morphology, plant physiology, and P and K uptake and utilization efficiency to different supplies of P and K. Two local conventional rice varieties (Shennong 265 and Liaojing 294) were used as experimental materials across four treatments, including HPHK (sufficient P and K supply), HPLK (sufficient P supply under low K levels), LPHK (sufficient K supply under low P levels) and LPLK (low P and K levels) in a hydroponic setting. The results showed that HPHK and HPLK significantly decreased the acid phosphatase activity of leaves and roots from full heading to filling stages when compared to LPHK and LPLK. Sufficient supply of P or K significantly increased the accumulation of P and K (aboveground, leaves, stem sheath, and whole plant) and root morphological parameters (root length, root surface area, total root volume, and tips) during major growth stages when compared to LP or LK levels. HPHK was significantly higher than other treatments in terms of dry weight and the root activity at the main growth stage, P and K uptake rates in nutrient solutions at various stages, related P and K efficiency at the maturity stage, yield, effective panicle number, and grain number per panicle. In addition, the effect of HPHK on the above indexes were significantly greater than those of single sufficient supply of P or K. In conclusion, HPHK can improve plant configuration, increase plant P and K absorption and root activity, and increase rice yield and related P and K utilization efficiency.

Assessment of the utilization of modern agricultural machinery in rice production and its problems: A case from San Leonardo, Philippines

This study examines the relationship between the utilization of modern agricultural machinery and the business technical aspect of rice production of paddy field farmers in San Leonardo, Nueva Ecija, Philippines. The objective of this study is to assess the effectiveness of modern machinery on the business technical aspect of the farmers and the paddy field owners. The study utilized descriptive analysis to assess the use of modern agricultural machinery in rice production and its problems. The design was quantitative, using percentage, frequencies, and weighted mean. The results revealed that the majority of respondents have been operating for 11 to 20 years, owned 1 hectare of land that cultivate 2 times a year and harvest 86 rice sacks per hectare. Rice cultivation is happened during wet and dry season. To maximizing the land, farmers can try other crops while waiting for the season of rice cultivation. In agricultural mechanization, it concluded that plowing machines helps remove clods from the soil, transplanting rice seedlings and applying chemicals using machine can saves time. Harvester machine is suitable in small and large farmland for harvesting and may help farmers to save time, effort and total cost requirements. Local Government Unit to support through grants and funding the local rice farmers in maximizing utilization of machines that shows positive effect.

First Report of Burkholderia glumae Causing Bacterial Panicle Blight in Rice in Bangladesh.

Bacterial panicle blight (BPB) is one of the emerging diseases occurring in different Agro-Ecological Zones (AEZ) of Bangladesh and can cause up to 75% yield loss. In Bangladesh, the typical symptoms of BPB include sheath rot, panicle blight, grain spotting, and grain rot in both inbred and hybrid rice varieties, which resemble those reported by Zhou (2019). To confirm, 300 field samples of 20 panicles each with typical BPB symptoms from 20 districts (3 locations each district and 5 fields per location) were collected during mid-November 2022 for the causal pathogen(s) isolation. Nearly 70% of the panicles showed a dark brown chaffy appearance in the fields. For identification of the causal pathogen(s), 1 g of rice grains with typical BPB symptoms was surface sterilized by immersing for 15 seconds in 70% ethanol, 1 min in 3% sodium hypochlorite solution followed by rinsing the grains three times, and soaked in 1 mL sterile distilled water for 10 min (Mirghasempour et al. 2018). During grinding using mortar and pestle, 5 mL water was added (Islam et al. 2023) after which the suspension (20 μL) was then streaked onto the selective medium (S-PG) (Tsushima et al. 1986). Purple color colonies on the S-PG medium were selected and purified as candidate pathogens. For further confirmation, the genomic DNA of the bacterial isolates was extracted and amplified by PCR using 16SF (5'-AGAGTTTGATCCTGGCTCAG-3') and 16SR (5'-GGCTACCTTGTTACGACTT-3') (Nandakumar et al. 2009), and glu-FW (5'-GAAGTGTCGCCGATGGAG-3') and glu-RV (5'-CCTTCACCGACAGCACGCAT-3') primers (Maeda et al. 2006). The PCR products were visualized on 1% agarose gel resulting amplicons of 1494bp for 16S-rDNA and 529bp for gyrB. The PCR results revealed 529bp amplification for gyrB gene in one sample that was collected from a field in Natore (24°21'0.00" N 89°04'59.88" E) district cultivating Swarna (a local rice variety), primarily indicating the causal pathogen is Burkholderia glumae. The PCR products were sequenced using both primers and sequence data was analyzed by the BLAST nucleotide program. The obtained partial sequences of 16S rDNA and gyrB were deposited in Genbank (OR573691 and PP332812 respectively). The homology of 16S rDNA resulted over 98% with B. glumae (OK559611 and ON870618.1) and 100% with B. glumae (PP332812 and KX213523) for gyrB gene. To confirm B. glumae by pathogenicity test, 10 mL (108 UFC/ml) suspension of the representative strains, 0.5 mL was then injected into the panicles and sheaths of Horidhan (a susceptible local variety) in greenhouse condition and a control was inoculated with distilled water (Nandakumar et al. 2009). Typical BPB like symptoms were observed after 3 weeks post inoculation. The pathogen was again confirmed by reisolating from the infected spots as B. glumae to fulfill Koch's postulates. This report confirms the presence of B. glumae causing BPB of rice in Bangladesh. Future research for the investigation of BPB and the evolutionary origins of its causal bacteria is necessary to reduce the emergence of the disease and its management in Bangladesh.

Genetic Diversity and Divergence between Southern Japonica and Northern Japonica Rice Varieties in China.

Given the notable ecological and breeding disparities between southern and northern rice regions, delving into the genetic diversity and divergence between southern and northern japonica rice contributes to enhancing the genetic pool for japonica rice breeding. In this study, we analyzed 90 southern and 51 northern japonica rice varieties, focusing on nucleotide diversity (Pi), agronomic trait variations, population structure, genetic divergence, and a neutral test. For genetic diversity, the results demonstrated higher Pi in northern japonica rice varieties (NJRVs) on Chr2, Chr5, Chr6, Chr8, and Chr10, whereas in southern japonica rice varieties (SJRVs) on Chr7 and Chr9. In addition, SJRVs exhibited higher grain width and thickness, whereas NJRVs featured a higher grain aspect ratio, filled grain number, and grain number per panicle. Regarding genetic divergence, geographic differentiation existed between NJRVs and SJRVs, with Chr5 exhibiting numerous higher genetic differentiation windows, including cloned grain shape-controlling genes RGA1 and SFD5, stemming from intensified selection pressure on SJRVs. In summary, SJRVs and NJRVs exhibited diversity differences and genetic differentiation. Hence, it was suggested to conduct genetic introgression between NJRVs and SJRVs to broaden the genetic basis of the local japonica rice germplasm. By exploiting their heterotic advantage, new japonica rice cultivars with superior comprehensive traits could be developed.

Determinants of consumer preference for imported and local rice among households in Sokoto metropolis

Determinants of consumer preference for imported and local rice among households in Sokoto metropolis

Growth and Production Character Response of Kuantan Singingi Local Rice Mutants Resulting from Gamma Irradiation

Rice (Oryza sativa L.) is a crucial crop with significant importance in various regions. In Riau, specifically in Kuantan Singingi Regency, it ranks as the fourth largest area for rice production, showcasing numerous local rice varieties with substantial development potential. This study aimed to generate mutants exhibiting early maturity and reduced plant height through gamma-ray induced mutations. A non-factorial Randomized Block Design (RAK) was employed, with the primary factor being the irradiation dose: R0 served as the control group without radiation, while the experimental group received an irradiation dose of 300 Gy, determined to be effective in prior research. Each treatment was replicated five times, utilizing a total of 600 plants per treatment. The findings indicated that rice plants subjected to 300 Gy irradiation exhibited shorter heights compared to those in the control group. Additionally, the stem circumference of plants irradiated with 300 Gy was significantly greater than that of the non-irradiated plants. Furthermore, the number of productive tillers was higher in the 300 Gy group compared to the control. However, the harvest age for rice plants exposed to 300 Gy was extended relative to those without radiation. Conversely, the length of the flag leaf in rice plants irradiated at 300 Gy was shorter than that of the control group. There remains a considerable need for data on the desired characteristics of rice mutants to facilitate advanced breeding efforts.

Linkage Mapping and Discovery of Candidate Genes for Drought Tolerance in Rice During the Vegetative Growth Period

Drought is a major abiotic stress affecting crop yields. Mapping quantitative trait loci (QTLs) and mining genes for drought tolerance in rice are important for identifying gene functions and targets for molecular breeding. Here, we performed linkage analysis of drought tolerance using a recombinant inbred line population derived from Jileng 1 (drought sensitive) and Milyang 23 (drought tolerant). An ultra-high-density genetic map, previously constructed by our research team using genotype data from whole-genome sequencing, was used in combination with phenotypic data for rice grown under drought stress conditions in the field in 2017–2019. Thirty-nine QTLs related to leaf rolling index and leaf withering degree were identified, and QTLs were found on all chromosomes except chromosomes 6, 10, and 11. qLWD4-1 was detected after 32 days and 46 days of drought stress in 2017 and explained 7.07–8.19% of the phenotypic variation. Two loci, qLRI2-2 and qLWD4-2, were identified after 29, 42, and 57 days of drought stress in 2018. These loci explained 10.59–17.04% and 5.14–5.71% of the phenotypic variation, respectively. There were 281 genes within the QTL interval. Through gene functional annotation and expression analysis, two candidate genes, Os04g0574600 and OsCHR731, were found. Quantitative reverse transcription PCR analysis showed that the expression levels of these genes were significantly higher under drought stress than under normal conditions, indicating positive regulation. Notably, Os04g0574600 was a newly discovered drought tolerance gene. Haplotype analysis showed that the RIL population carried two haplotypes (Hap1 and Hap2) of both genes. Lines carrying Hap2 exhibited significantly or extremely stronger drought tolerance than those carrying Hap1, indicating that Hap2 is an excellent haplotype. Among rice germplasm resources, there were two and three haplotypes of Os04g0574600 and OsCHR731, respectively. A high proportion of local rice resources in Sichuan, Yunnan, Anhui, Guangdong and Fujian provinces had Hap of both genes. In wild rice, 50% of accessions contained Hap1 of Os04g0574600 and 50% carried Hap4; 13.51%, 59.46% and 27.03% of wild rice accessions contained Hap1, Hap2, and Hap3, respectively. Hap2 of Os04g0574600 was found in more indica rice resources than in japonica rice. Therefore, Hap2 has more potential for utilization in future drought tolerance breeding of japonica rice.

Physicochemical and Biochemical Characteristics of Local Rice Variety (Sahel 108) Samples Grown in the Senegal River Valley

Physicochemical and Biochemical Characteristics of Local Rice Variety (Sahel 108) Samples Grown in the Senegal River Valley