CRISPR (clustered regularly interspaced short palindromic repeats) gene-edited (GEd) crops have demonstrated significant potential to enhance global food security in the face of escalating climate challenges and rapid population growth. Since 2019, for regulatory purposes, the United States (U.S.) and several other countries have recognized transgene-free, genome-edited lines as equivalent to conventionally bred varieties. Notably, the first genome-edited food product, Calyno™ soybean oil, was commercialized in the U.S. and marketed as a non-genetically modified organism (GMO) item. Recently, regulatory frameworks, such as the enactment of the Precision Breeding Law in the United Kingdom, the European Union’s New Genomic Techniques (NGT) legislation, and the repeal of the SECURE Rule in the United States, have further established guidelines permitting the use of genome-edited lines in agriculture similar to with conventionally bred crops, provided that these lines are free of transgenic elements. In Korea, researchers and policymakers are actively engaging in discussions to establish a preliminary review committee for GEd crops to align regulatory practices with international trade standards. Thus, this study aimed to evaluate two gene-edited rice lines for generational stability in terms of molecular characteristics, focusing on edited nucleotide sequences, gene expression, target phenotypes, the presence of transgene elements, and potential off-target effects across multiple generations. Additionally, several technical challenges in nucleotide editing tracing emerged during the evaluation process that warrant further attention. The findings presented in this study are expected to offer valuable insights for shaping the regulatory framework in Korea for CRISPR-based gene-edited crops.
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In salinity affected areas, variation in salinity level is the major cause of yield fluctuations in rice during the dry season (
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Seed starch content (SSC) is a decisive factor influencing soy food quality. Variation in SSC affects the composition of major components, oil, and protein in soybean seeds. Therefore, understanding G × E interaction of SSC is important to produce soybeans with stable SSC. In the present study, G × E interactions of 17 soybean genotypes having different SSC (0.24–1.48%) and correlation of SSC with crude protein (CP) and crude fat (CF) were investigated. The genotypes were evaluated for SSC and other traits at two planting dates across three locations over two years (2015 and 2016). The genotype × year, genotype × location, and genotype × year × location interactions were found to be significant (
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Eight advanced breeding lines of cowpea [
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Poor seed yield remains a great challenge for cowpea production in sub-Sahara Africa and continuous evaluation of available genetic resource to develop high and stable yielding varieties is the panacea to this regional food security conundrum. In this study, 21 cowpea breeding lines were evaluated for phenotypic analysis of seed yield components for two years in a randomized complete block design of 3 replications. All the yield components exhibited significant genotypic variation, while flowering, pod maturity and seed yield traits recorded significant variation for years and its interactions. These cowpeas, which are predominantly early-medium maturing biotypes, exhibited relative phenotypic stability for the yield components across years (seasons) except seed yield, being a final product of complex physiological process. Relationships between flowering/pod maturity and seed size were positive and significant. By contrast, pods/plant, seeds/plant and total seed yield recorded negative correlations with pod maturity. However, seeds/plant and pods/plant are the most contributory components to seed-yield with correlation coefficients of
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The genetic variability and yield stability are complex traits with large environmental components that are utilized for breeding of improved plant performance under drought conditions. In order to better understand the relationship among genotype, trait components, and environment, marker-trait associations in 20 wheat varieties using phenotypic and ISSR (Inter-Simple Sequence Repeat) markers under drought conditions were examined. The combined analysis of variance results showed that the tested traits were significantly influenced by years, irrigation treatments, and the varieties. The drought stress conditions resulted in a substantial reduction in grain yield by 33.70%. The varieties
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Perennial poor fruit-set and variability in tree yield are among major problems of cashew nut production. Thus, development of improved stable genotypes would be a sustainable strategy to address this perpetual problem in order to boost income and livelihood of many smallholder farmers of this important commodity crop. Here, we have applied additive main effect and multiplicative interaction (AMMI) and genotype, genotype by environment (GGE) biplot analysis to a 3-year multi-locational trial data on nine yield component characters of cashew to evaluate phenotypic stability across diverse environments. Variance analysis showed significant variability in the cashew genotypes and strong influence of genotype by environment (GxE) on tree yield as none of the genotypes was stable for any of the yield components across locations. GxE data showed that a substantial portion of the variation was explained by the genotype (highly heritable), accounting for between 10% and 87% of the variation, while the environment accounted for between 0.7% and 37%. Data showed significant higher values of interaction (GxE) than the respective values for environment, and were mostly captured and could be explained by the first principal component axis (IPCA 1) for all the yield component characters. There was an inverse relationship between stability and yield as the best three yielding genotypes (KT_26, IW_222 and IW_31) were found to be the most unstable. Among the yield component tested, hermaphrodite flowers per panicle, nuts per panicle, nuts per tree, nut weight, and tree fruiting efficiency were identified to be critical components for nut yield. Although there was wide variation between the three environments evaluated, the data effectively identified two mega-environments (ME), and two superior genotypes (IW_222 and KT_26) suitable for these two mega-environments. The GxE complex exposes the short-comings of broad recommendations of common agronomic-husbandry technologies across diverse cashew ecologies as each mega-environment would require specific adaptable technologies for optimal plant output. Above all, the data presented here underscore the importance of multi-locational evaluation of genotypes for varietal development in cashew.
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Confirmation of T-DNA inheritance and stability requires testing of several parameters such as phenotypic performance of transgenic lines, transgene integrity structure and expression stability for at least three consecutive generations, and Mendelian inheritance analysis, which are very important to transgenic breeding and commercialization of genetically modified crops (GMOs). In the present study, we measured nine agronomic and yield-related traits of Iksan526 and confirmed stable phenotypic performance comparing to the donor variety Dongjin over three years. Transgene integrity structure, flanking sequence, functional element copy numbers, absence of backbone sequence and transgene expression were all verified in Iksan526 over three consecutive generations, indicating a stable inheritance of the transgene. In addition, phenotypic and genotypic segregation were analyzed on F2 and F3 populations derived from a cross of Dongjin/Iksan526, and results complied with Mendel’s law of segregation based on single transgene locus. This study demonstrated detailed analyses and confirmation of transgene event Iksan526 which is crucial for commercialization of GMO.
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