High-yielding Rice Lines Research Articles

A low-methane rice with high-yield potential realized via optimized carbon partitioning

Global rice cultivation significantly contributes to anthropogenic methane emissions. The methane emissions are caused by methane-producing microorganisms (methanogenic archaea) that are favoured by the anoxic conditions of paddy soils and small carbon molecules released from rice roots. However, different rice cultivars are associated with differences in methane emission rates suggesting that there is a considerable natural variation in this trait. Starting from the hypothesis that sugar allocation within a plant is an important factor influencing both yields and methane emissions, the aim of this study was to produce high-yielding rice lines associated with low methane emissions. In this study, the offspring (here termed progeny lines) of crosses between a newly characterized low-methane rice variety, Heijing 5, and three high-yielding elite varieties, Xiushui, Huayu and Jiahua, were selected for combined low-methane and high-yield properties. Analyses of total organic carbon and carbohydrates showed that the progeny lines stored more carbon in above-ground tissues than the maternal elite varieties. Also, metabolomic analysis of rhizospheric soil surrounding the progeny lines showed reduced levels of glucose and other carbohydrates. The carbon allocation, from roots to shoots, was further supported by a transcriptome analysis using massively parallel sequencing of mRNAs that demonstrated elevated expression of the sugar transporters SUT-C and SWEET in the progeny lines as compared to the parental varieties. Furthermore, measurement of methane emissions from plants, grown in greenhouse as well as outdoor rice paddies, showed a reduction in methane emissions by approximately 70 % in the progeny lines compared to the maternal elite varieties. Taken together, we report here on three independent low-methane-emission rice lines with high yield potential. We also provide a first molecular characterisation of the progeny lines that can serve as a foundation for further studies of candidate genes involved in sugar allocation and reduced methane emissions from rice cultivation.

G×E analysis to Identify the Stable High-yielding Rice Lines among a Set of Selected Germplasm Panel

Rice lines need to be grown and evaluated for yield under different agro-ecological locations to identify stable and high-yielding lines for deployment in breeding programs. With this aim, a set of rice germplasm was evaluated for G×E in four different environments (E1-Dadesuguru-Wet 2020, E2-ICAR–IIRR-Dry 2019, E3-ICAR–IIRR-Wet 2020, E4-ICAR–IIRR-Dry 2020). The experimental trial was laid out in a randomized complete block (RCB) design with three replications at each location for 118 rice lines. Data on yield per plant was analyzed using the Additive Main Effect and Multiplicative Interaction (AMMI) and Genotype, and Genotype × Environment Interaction (GGE) models. The combined analysis of variance (ANOVA) manifested significant variations for tested genotypes, locations, years, genotype × year, and genotype × location interactions revealing the influence of environmental factors on yield traits. All four environments showed discrimination power, whereas E2 and E3 were found as the representative environment as they fall near the Average-Environment axis (AEA). The AMMI biplot PC1 contributed 79.20% variability and PC2 contributed 15.18% variability. From the GGE biplot analysis, the rice lines Phouren, JBB-631-1, and JBB-1325 were found to be the best and most stable. The rice lines Phouren, PUP-229, and TI-112 were stable in the first sub-group Dhadesugur-Wet 2020 (E1). The rice lines Langphou, and NPK-45 were stable in the second sub-group ICAR-IIRR-Wet 2020 (E3). Environment ICAR-IIRR-Dry 2019 (E2) was the third subgroup and the rice lines Moirangphou-Yenthik and TI-3 topped for the same. The ICAR IIRR-Dry 2020 (E4) environment formed the fourth subgroup where Phouren-Amubi, TI-128 and JBB-1325 topped the season. In conclusion, this study revealed that G × E interactions are significant for yield variation, and its AMMI and biplots analysis are efficient tools for visualizing the response of genotypes to different locations.

Rice hybrid mimics have stable yields equivalent to those of the F1 hybrid and suggest a basis for hybrid vigour.

We have developed long term stable high yielding rice lines, Hybrid Mimics, from commercial hybrids. The vigour of the Mimic and the hybrid are developmental changes. These Mimics could substitute for hybrid seed for planting. We have used two pre-existing high-yielding hybrid systems (FLY1 and DY527) to develop Hybrid Mimics. In the FLY1 hybrid system we selected, under field conditions, F6 lines which have high grain yields and biomass equivalent to the F1 hybrids, stable over subsequent F7, F8 and later generations. We have termed these lines Hybrid Mimics. The mimics are mostly homozygous as a consequence of selfing in each generation. We have repeated this selection procedure in the second independent hybrid system DY527, producing Mimics with similar characteristics to the F1 hybrid. In both hybrid systems the selection criterion, based on the phenotype of the F1 hybrid, results in the Mimics having grain yield and biomass similar to that of the F1 hybrid. In each generation of the breeding program the plant population has increased phenotypic homogeneity. The genomes of the Mimic plants do not contain any common heterozygous segments negating claims that the vigour of hybrids depends upon heterozygosity of particular loci. Both hybrids and Mimics have early germination and commence photosynthesis before the parents, providing enhanced growth which is maintained throughout the life cycle. The biochemical parameters of photosynthesis in the hybrids and Mimics do not differ from those of the parents. Grain quality and resistance to the two major diseases, bacterial blight and rice blast are similar in the Mimics and hybrids. The Mimics overcome the major disadvantage of hybrids where F2 phenotypic segregation prevents their use as a crop beyond the F1 generation.

Incorporating Drought and Submergence Tolerance QTL in Rice (Oryza sativa L.)-The Effects under Reproductive Stage Drought and Vegetative Stage Submergence Stresses.

Drought and submergence have been the major constraint in rice production. The present study was conducted to develop high-yielding rice lines with tolerance to drought and submergence by introgressing Sub1 into a rice line with drought yield QTL (qDTY; QTL = quantitative trait loci) viz. qDTY3.1 and qDTY12.1 using marker-assisted breeding. We report here the effect of different combinations of Sub1 and qDTY on morpho-physiological, agronomical traits and yield under reproductive stage drought stress (RS) and non-stress (NS) conditions. Lines with outstanding performance in RS and NS trials were also evaluated in vegetative stage submergence stress (VS) trial to assess the tolerance level. The QTL class analysis revealed Sub1 + qDTY3.1 as the best QTL combination affecting the measured traits in RS trial followed by Sub1 + qDTY12.1. The effects of single Sub1, qDTY3.1 and qDTY12.1 were not as superior as when the QTLs are combined, suggesting the positive interaction of Sub1 and qDTY. Best performing lines selected from the RS and NS trials recorded yield advantage up to 4453.69 kg ha−1 and 6954 kg ha−1 over the parents, respectively. The lines were also found having great tolerance to submergence ranging from 80% to 100%, contributed by a lower percentage of shoot elongation and reduction of chlorophyll content after 14 days of VS. These lines could provide yield sustainability to farmers in regions impacted with drought and submergence while serving as important genetic materials for future breeding programs.

Identification and analysis of low light tolerant rice genotypes in field conditions and their SSR-based diversity in various abiotic stress tolerant lines

The yield potentiality of kharif rice is not completely used even under well-irrigated agro-ecosystem, mainly due to low irradiance by overcast cloud throughout the growing season in eastern India. We observed more than 50% yield reduction compared to the performance of 100 high-yield genotypes for consecutive three years both under open and 30-35% reduced light intensity, mainly by 34%, 25% and 12% reduction of panicle number, grains per panicle and test weight. As per the analysis of variance, genotypic variance explained 39% of the total yield-variation under shade with 58% heritability. Overall, the maintenance of equal panicle per plant in both open and shade has the highest association with shade tolerance. Purnendu, Sashi and Pantdhan19 showed less than 28% yield-reduction by maintenance or even by increasing grain numbers under shade and test weight. On the other hand, maintenance of an equal number of panicle under both situations was the key to the tolerance of Bhasamanik, Sasarang, Rudra and Swarnaprabha. As compared to open, we noticed the improvement of chlorophyll a and b under shade but saw a poor correlation with the shade tolerance index. Comparing the net photosynthesis rate (Pn) in eight genotypes, we found the best tolerant line ranked last with least Pn at low light intensity (400 μmol m-2 s-1). We also identified diverse parental combinations between newly identified shade tolerant and abiotic stress tolerant high-yielding rice lines following diversity analysis using 54 simple-sequence repeats. Thus, the selected tolerant lines from a large set of genotypes with different adjustment ability to keep up high yield under low light intensity can be used for physiological, molecular analysis as well as pyramiding of traits.

Promising rice breeding lines adapted to acidic upland area

Abstract. Hermanasari R, Yullianida, Lestari AP, Hairmansis A. 2020. Promising rice breeding lines adapted to acidic upland area. Pros Sem Nas Masy Biodiv Indon 6: 576-585. Acid dry soil has the potential for the development of rice production to support national food security. Assembling of superior varieties of rice that are adaptive to acid dry soil is one of the keys to success in increasing rice production in these fields. The Indonesian Center for Rice Research has assembled upland rice lines that well adapted to acid dry soil, but these promising lines need advanced yield trials. This study aims to obtain well-adapted high-yielding rice lines and high-quality rice. The study was conducted in the first season of 2018 at the Tamanbogo Experimental station in Lampung. This experiment used Randomized Complete Block Design. Plant materials were 21 lines and three check varieties i.e Limboto, Situ Patenggang, and Inpago 8. The result showed that plant height ranged from 84-127 cm, the number of productive tillers ranges from 10-15 stems, the number of grains per panicle ranged from 91 to 237 grains, and the weight of 1000 grains ranged from 19.86 to 22.24 grams. Lines B15053F-PWR-3 (6.72 t ha-1), B15340-1B-TB-45 (6.04 t ha-1) and B14956-MR-2-2-2-0 (6.04 t ha-1) have higher yields than the best check Inpago 8 (5.67 t ha-1). These lines have the quality of rice with medium rice texture with amylose content ranging from 20.99-23.84%. The other tested lines were dominated by medium-length rice with a little chalkiness (LMS) and low to high amylose content ranging from 5.46-27.12% with the texture of rice varying from hard to soft. The results of testing in the greenhouse to blast disease obtained six lines resistance to blast races, two lines have tolerant to drought stress, and ten lines tolerant to Al stress.

Variation in Expression of <i>Sub</i>1 Gene and Association with Submergence Stress Related Traits in Advance Rice (<i>Oryza sativa</i> L.) Genotypes as a Tool of Climate Change Adaptation

Floods have now become most detrimental natural catastrophe worldwide due to radical climatic fluxes. Therefore, there is a dire necessity to develop a high yielding rice lines to deal with this scenario. For this purpose, a large scale experiment was conducted including one hundred and fifteen (115) rice genotypes having SUB1 gene imported from International Rice Research Institute (IRRI) Philippines, six local cultivars/approved varieties and three high yielding rice varieties i.e. Sabitri, IR6 and NSICRC222 being used as potential varieties in different countries of Asia as susceptible check and IR64-SUB1 as tolerant check. The genotypic screening was performed using two PCR-based DNA markers i.e. ART5 and SC3. Phenotypic screening was conducted in a natural pond to assess the interaction of SUB1 gene in natural stagnant flood water as well as the suitability of introgression of SUB1 gene into approved varieties and elite rice lines. The genotypes were assessed in terms of plant survival percentage, submergence tolerance index, physical condition, stem elongation, number of grains per panicle, thousand grain weight, grain yields and deviations in these traits after submergence stress. The PCR results suggested that both the primers ART5 and SC3 may be used as potential PCR-based markers for molecular screening of rice genotypes for SUB1 QTL. Furthermore, it confirmed the presence of SUB1 gene in all the lines imported from IRRI, while it was absent in all the local cultivars studied. All the genotypes with submergence tolerant gene (SUB1) showed significantly greater tolerance level in submergence stress of 14 days, as compared to other local cultivars/varieties, authenticating the effectiveness of SUB1QTL in conferring submergence tolerance. Significantly different performances of all the SUB1 genotypes in terms of all the studied traits indicate high Genotypic and Genotypic Environment Interaction (GEI) of SUB1QTL. Employment of SUB1 lines such as R105479:149-18, IR64-SUB1 and Rl05469:81-22-3 in breeding programs for developing flood tolerant rice varieties might further upsurge rice yields in flash flood areas. Correlation analysis revealed that plant survival percentage after submergence, reduced stem elongation during submergence and submergence tolerance index are very important traits for developing submergence tolerant lines.

Alternate phenotype–genotype selection for developing superior high-yielding irrigated rice lines

Increase grain yield potential is one of the most important objectives of any cereal crop breeding program. To efficiently develop superior rice lines by the introgression of favorable alleles for yield and yield component traits, a strategy of alternate phenotype–genotype selection was used. The present study aimed to (i) investigate the allelic diversity of loci associated with major yield-component traits and (ii) phenotype and genotype advanced populations derived from crosses between NERICA-L-20 and Giza178 for yield component traits using agro-morphological descriptors and GRiSP polymorphic markers to select superior high-yielding rice lines. A total of 100 F2:3 progeny were selected from 1000 F2 plants and genotyped with 16 polymorphic markers linked to four major yield-component traits. Four promising F2:3 lines (ARS 563–14, ARS 563–62, ARS 563–286, and ARS 563–41) bearing combinations of desirable alleles were selected. A selected set of 20 F2:4 lines showed moderate to high heritability for all target traits. Fourteen F2:5 lines derived from ARS 563–14 and 17 F2:5 from ARS 563–286 families were evaluated in preliminary trials to estimate yield gain. The three top lines, ARS 563–286–16-1-1, ARS 563–286–5-1-1, and ARS 563–14–10-1-1, showed an increase of more than 10% grain yield over the best check, Sahel 108, which is widely cultivated in the Senegal River valley. The 16 markers linked to the target yield component traits can be used to fast-track breeding programs targeting rice productivity.

Phenotypic analysis, correlation studies and linkage mapping of QTL for traits promoting cultivation under dry direct seeded aerobic conditions for the development of water-efficient high yielding rice lines

Aerobic adaptation could be an important modification in the traditional rice to cope up with the increasing water scarcity problem. Identification of stable QTL for traits promoting adaptation to aerobic conditions can facilitate the development of water-efficient aerobic rice varieties with better yields. Filial and backcross populations derived from the crosses between high-yielding low-land (HKR47) and aerobic (MAS26) indica rice varieties, were evaluated for various physio-morphological traits including root traits (in case of net house evaluation). Under aerobic field conditions, grain yield per plant showed significant positive correlation with plant height, effective number of tillers/plant and panicle length in all the populations. Grain yield per plant also showed positive correlation with root length in both filial populations and with fresh and dry root weight in F2 population. Two parental rice varieties displayed polymorphism at 125 of the 803 SSR loci, which were used to map the QTL associa...

Association of Increased Grain Iron and Zinc Concentrations with Agro-morphological Traits of Biofortified Rice.

Biofortification of rice (Oryza sativa L.) with micronutrients is widely recognized as a sustainable strategy to alleviate human iron (Fe) and zinc (Zn) deficiencies in developing countries where rice is the staple food. Constitutive overexpression of the rice nicotianamine synthase (OsNAS) genes has been successfully implemented to increase Fe and Zn concentrations in unpolished and polished rice grain. Intensive research is now needed to couple this high-micronutrient trait with high grain yields. We investigated associations of increased grain Fe and Zn concentrations with agro-morphological traits of backcross twice second filial (BC2F2) transgenic progeny carrying OsNAS1 or OsNAS2 overexpression constructs under indica/japonica and japonica/japonica genetic backgrounds. Thirteen agro-morphological traits were evaluated in BC2F2 transgenic progeny grown under hydroponic conditions. Concentrations of eight mineral nutrients (Fe, Zn, copper, manganese, calcium, magnesium, potassium, and phosphorus) in roots, stems/sheaths, non-flag leaves, flag leaves, panicles, and grain were also determined. A distance-based linear model (DistLM) was utilized to extract plant tissue nutrient predictors accounting for the largest variation in agro-morphological traits differing between transgenic and non-transgenic progeny. Overall, the BC2F2 transgenic progeny contained up to 148% higher Fe and 336% higher Zn concentrations in unpolished grain compared to non-transgenic progeny. However, unpolished grain concentrations surpassing 23 μg Fe g-1 and 40 μg Zn g-1 in BC2F2 indica/japonica progeny, and 36 μg Fe g-1 and 56 μg Zn g1 in BC2F2 japonica/japonica progeny, were associated with significant reductions in grain yield. DistLM analyses identified grain-Zn and panicle-magnesium as the primary nutrient predictors associated with grain yield reductions in the indica/japonica and japonica/japonica background, respectively. We subsequently produced polished grain from high-yield BC2F2 transgenic progeny carrying either the OsNAS1 or OsNAS2 overexpression constructs. The OsNAS2 overexpressing progeny had higher percentages of Fe and Zn in polished rice grain compared to the OsNAS1 overexpressing progeny. Results from this study demonstrate that genetic background has a major effect on the development of Fe and Zn biofortified rice. Moreover, our study shows that high-yielding rice lines with Fe and Zn biofortified polished grain can be developed by OsNAS2 overexpression and monitoring for Zn overaccumulation in the grain.

Development of High-yielding Rice Lines and Analysis of Panicle and Yield-related Traits Using Doubled Haploid Lines Derived from the Cross between Deuraechan and Boramchan, High-yielding japonica Rice Cultivars in Korea

Hyun-Su Park1*, Ki-Yong Ha1, Ki-Young Kim1, Woo-Jae Kim1, Jeong-Kwon Nam1, Man-Kee Baek1, Jeong-Ju Kim1, Jong-Min Jeong1, Young-Chan Cho1, Jeom-Ho Lee2, Bo-Kyeong Kim1, and Sang-Nag Ahn3. Korean J. Breed. Sci. 2015;47:384-402. https://doi.org/10.9787/KJBS.2015.47.4.384

Mapping Consistent Rice (Oryza sativa L.) Yield QTLs under Drought Stress in Target Rainfed Environments.

BackgroundDrought stress is a major limitation to rainfed rice production and yield stability. Identifying yield-associated quantitative trait loci (QTLs) that are consistent under drought stress predominant in target production environments, as well as across different genetic backgrounds, will help to develop high-yielding rice cultivars suitable for water-limited environments through marker-assisted breeding (MAB). Considerable progress has been made in mapping QTLs for drought resistance traits in rice; however, few have been successfully used in MAB.ResultsRecombinant inbred lines of IR20 × Nootripathu, two indica cultivars adapted to rainfed target populations of environments (TPEs), were evaluated in one and two seasons under managed stress and in a rainfed target drought stress environment, respectively. In the managed stress environment, the severity of the stress meant that measurements could be made only on secondary traits and biomass. In the target environment, the lines experienced varying timings, durations, and intensities of drought stress. The rice recombinant inbred lines exhibited significant genotypic variation for physio-morphological, phenological, and plant production traits under drought. Nine and 24 QTLs for physio-morphological and plant production traits were identified in managed and natural drought stress conditions in the TPEs, respectively. Yield QTLs that were consistent in the target environment over seasons were identified on chromosomes 1, 4, and 6, which could stabilize the productivity in high-yielding rice lines in a water-limited rainfed ecosystem. These yield QTLs also govern highly heritable key secondary traits, such as leaf drying, canopy temperature, panicle harvest index and harvest index.ConclusionThree QTL regions on chromosome 1 (RM8085), chromosome 4 (I12S), and chromosome 6 (RM6836) harbor significant additive QTLs for various physiological and yield traits under drought stress. The similar chromosomal region on 4 and 6 were found to harbor QTLs for canopy temperature and leaf drying under drought stress conditions. Thus, the identified large effect yield QTLs could be introgressed to develop rice lines with stable yields under varying natural drought stress predominant in TPEs.Electronic supplementary materialThe online version of this article (doi:10.1186/s12284-015-0053-6) contains supplementary material, which is available to authorized users.

Drought yield index to select high yielding rice lines under different drought stress severities.

BackgroundDrought is the most severe abiotic stress reducing rice yield in rainfed drought prone ecosystems. Variation in intensity and severity of drought from season to season and place to place requires cultivation of rice varieties with different level of drought tolerance in different areas. Multi environment evaluation of breeding lines helps breeder to identify appropriate genotypes for areas prone to similar level of drought stress. From a set of 129 advanced rice (Oryza sativa L.) breeding lines evaluated under rainfed drought-prone situations at three locations in eastern India from 2005 to 2007, a subset of 39 genotypes that were tested for two or more years was selected to develop a drought yield index (DYI) and mean yield index (MYI) based on yield under irrigated, moderate and severe reproductive-stage drought stress to help breeders select appropriate genotypes for different environments.ResultsARB 8 and IR55419-04 recorded the highest drought yield index (DYI) and are identified as the best drought-tolerant lines. The proposed DYI provides a more effective assessment as it is calculated after accounting for a significant genotype x stress-level interaction across environments. For rainfed areas with variable frequency of drought occurrence, Mean yield index (MYI) along with deviation in performance of genotypes from currently cultivated popular varieties in all situations helps to select genotypes with a superior performance across irrigated, moderate and severe reproductive-stage drought situations. IR74371-70-1-1 and DGI 75 are the two genotypes identified to have shown a superior performance over IR64 and MTU1010 under all situations.ConclusionFor highly drought-prone areas, a combination of DYI with deviation in performance of genotypes under irrigated situations can enable breeders to select genotypes with no reduction in yield under favorable environments compared with currently cultivated varieties. For rainfed areas with variable frequency of drought stress, use of MYI together with deviation in performance of genotypes under different situations as compared to presently cultivated varieties will help breeders to select genotypes with superior performance under all situations.

Introgression the Salinity Tolerance QTLs <i>Saltol</i> into AS996, the Elite Rice Variety of Vietnam

This study focus on developing new salinity tolerance and high yielding rice lines, using markers assisted backrossing (MABC). Total of 500 SSR markers on 12 rice chromosomes were screened for parental polymorphic markers. Of which, 52 primers in the Saltol region were checked with the two parents varieties to identify polymorphic primers for screening the Saltol region of the breeding populations. For each backcross generation of ASS996/FL478, approx. 500 plants were screened with 63 polymorphic markers distributed on 12 chromosomes. The two BC1F1 plants P284 and P307 which had the highest recipient alleles up to 89.06% and 86.36%, were chosen for the next backcrossing. Three BC2F1 plants with the recipient alleles up to 94.03% and 93.18% were used to develop BC3F1 generation. The best BC3F1 plant was P284-112-209 with all the recipient alleles and Saltol region. The four plants P307-305-21, P284-112-195, P284-112-198, P284-112-213 were the second ranking with only one loci heterozygous (applied 63 markers covered on 12 chromosomes). These five plants were chosen as the breeding lines for result of Saltol-AS996 introgression. The breeding line BC4F1 having 100% genetic background of donor variety is ready for develop new salinity tolerant variety ASS996-Saltol to cope with climate change.

Development of some high yielding rice lines tolerant to drought stress conditions

In Egypt, water requirement for the rice crop is a problem because of the limited irrigation water available from the River Nile. To solve that problem, a breeding program for drought tolerance, starting from hybridization until yield trials experiments, was designed. Ten promising lines were derived from IET 1444/ Sakha 102, Sakha 101 / IR 65600 and Sakha 101 / Gaori populations. Attentions were paid to the traits more associated with drought tolerance among segregants. The progenies from each cross were advanced from F2 until F6generation. F7 seeds were collected and bulked to provide the seed source for yield trial experiments. The best selected lines from Fn generation were evaluated under normal and drought conditions (flush irrigation every 12 days) during 2007 and 2008 rice growing seasons. The amount of irrigation water applied was determined by using flow meter. In 2009 season, the lines were evaluated under different irrigation intervals (irrigation every 4, 8 and 12 days). Each experiment was designed in a randomized complete block design, with three replications. These lines were found to be tolerant to drought conditions at different growth stages, that is, seedling stage, early and late vegetative stage, panicle initiation stage and ripening stage. Water saving ranged from 50 to 55% as compared to continuous submergence, with a rice yield of 7-9 t/ha. So, by using such lines the total water requirements might be significantly reduced without significant reduction in the yield. Also, these lines could be used as donor parents at reproductive stage to solve the problem of a lack of the donor parents in breeding rice for drought tolerance. Key words: Drought stress, rice, high yielding lines, saving irrigation water.

Agronomic and Quality Characteristics of High-Yielding Rice Lines

This study is a part of rice cultivar development program in north of Iran with the aim of yield potential increase and attention to eating quality. Thirteen lines developed from the crosses between high yielding cultivars with aromatic low yield ones based on pedigree breeding method. These lines along with two controls (Neda and Sang-e-Tarom) were evaluated for agronomic and quality traits in a randomized complete block design during 2005. Farm and laboratory tests showed that lines 33-DN-1, 33-DN-18 and 32-DN-6 were superior in yield (more than 5.5 t ha(-1)) and had suitable eating quality in comparison with Sang-e-tarom as a local control.

Promising Cold-Tolerant and High-Yielding Rice Lines for Ndop Plain, Northwest Cameroon

Promising Cold-Tolerant and High-Yielding Rice Lines for Ndop Plain, Northwest Cameroon