Current Strategies and Future of Mutation Breeding in Soybean Improvement

Abstract

Soybean, which has many foods, feed, and industrial raw material products, has relatively limited genetic diversity due to the domestication practices which mainly focused on higher yield for many centuries. Besides, cleistogamy in soybean plant reduces genetic variations even further. Improving genetic variation in soybean is crucial for breeding applications to improve traits such as higher yield, early maturity, herbicide, and pest resistance, lodging and shattering resistance, seed quality and composition, abiotic stress tolerance and more. In the 21st century, there are numerous alternatives from conventional breeding to biotechnological approaches. Among these, mutation breeding is still a major method to produce new alleles and desired traits within the crop genomes. Physical and chemical mutagen protocols are still improving and mutation breeding proves its value to be fast, flexible, and viable in crop sciences. In the verge of revolutionary genome editing era, induced mutagenesis passed important cross-roads successfully with the help of emerging supportive NGS based-methods and non-destructive screening approaches that reduce the time-consuming labor-intensive selection practices of mutation breeding. Induced mutagenesis will retain its place in crop science in the next decades, especially for plants such as soybean for which cross breeding is limited or not applicable.

Induced Mutation to Enhance Plant Biodiversity and Genetic Resources for Intensification of Crop Production to Mitigate Climatic Changes

“…Crop breeding's objectives in earlier decades included enhanced potential yield, increased and altered oil and protein content, and tolerance to biotic and abiotic stresses [77]. In traditional breeding, we selected plants with desirable traits and culled those with fewer desirable traits.…”

“…Molecular markers, such TILLING (targeted induced local lesions in the genome), which allows for the direct determination of mutations in a specific gene, assisted breeders in accelerating the process of combining the desirable traits into an employed variety [19]. At the same time, there are some restrictions on the application mutation breeding such as most of the mutations are lethal, rate is very low, screening is a quite laborious, mostly reversible, mutations mostly are recessive, and the mutations must be induced in gametes to appear [77]. In the coming decades, though, mutations will continue to occupy a place in crop research, particularly for the intensification of crop production to mitigate climate change [77].…”

“…At the same time, there are some restrictions on the application mutation breeding such as most of the mutations are lethal, rate is very low, screening is a quite laborious, mostly reversible, mutations mostly are recessive, and the mutations must be induced in gametes to appear [77]. In the coming decades, though, mutations will continue to occupy a place in crop research, particularly for the intensification of crop production to mitigate climate change [77].…”

Transgenic Plants in Heat Stress Adaptation: Present Achievements and Prospects

“…In past decade, substantial knowledge has been accumulated on mechanism of HSPs and chaperones as they are regulatory molecules that participation in stress sensing, signal transduction, and transcription activation of stress responsive genes in heat stress management. Therefore, transgenic plant approach is widespread among the studies which aim to improve crop productivity during consistently increasing heat stress worldwide [20]. Table 1 summarizes the recent progress of transgenic approach regarding HSPs to improve heat stress tolerance in crop and model plants.…”

Stress Memory and Priming Applications in Plants: Potential for Breeders

“…In mutation breeding, various physical, chemical, or biological mutagens are used to increase genetic variability. High mutation frequency is obtained compared to naturally occurring spontaneous mutations [1][2][3][4]. The selection process requirement in each generation is a major disadvantage of mutation breeding.…”