Abstract
Difficulties in breeding new rice cultivars that have a high yield, are acceptable quality, and are tolerant to environmental stresses have been the major constraint of rice production in many developing countries, as these traits are determined by multiple genes associated with complicated and uncontrollable gene segregations.Furthermore, the gene/QTL (quantitative trait locus) introduced to the cultivar is unstable due to the interaction among the active genes, which determine the phenotypic performance, not yet been well understood or controllable. In this study, the N-methyl-N-nitrosourea (MNU)-induced mutation was applied to the heterozygote of the F1 generation from the cross between TBR1 (female) and KD18 (male parent). The phenotype and genotype of the M2 and M3 generations were evaluated and showed that the mutant population phenotypes, including the plant height, semi-dwarfism, amylose content, protein content, gel consistency, grain yield, and spikelet fertility, varied. Interestingly, no segregation among the genotypes in the M2 and M3 generations was observed, while the genotypes of the control population were either paternally inherited or indeterminable when using 28 polymorphism simple sequence repeat (SSR) markers that were identified on parental lines from 200 markers. The MNU-induced mutation caused maternal inheritance in the segregating populations, as primarily important agronomic traits were maternally succeeded from the female line TBR1. The findings of this study indicated that, through the use of MNU, the breeding of rice cultivars with close genetic backgrounds (similarity coefficient = 0.52) could be shortened by the maternal control of important qualities, such as pest and disease resistance and high yield, thus contributing to sustainable rice production for rice farmers. Further examination of rice cultivars with a greater difference in the genetic background should be subsequently conducted.
Highlights
Food security and sustainability have focused on rice (Oryza sativa L.), as it is a staple crop for more than half of the world’s population
This study demonstrated the role of MNU-induced mutation and supports the fact that conventional mutation by MNU can reduce the breeding time in rice cultivars with a close genetic background
This study revealed that, the phenotypic performances of both the mutant and control populations were variable, few important agronomic traits were maternally inherited in the two rice cultivar, TBR1 and Khang dan 18 (KD18)
Summary
Food security and sustainability have focused on rice (Oryza sativa L.), as it is a staple crop for more than half of the world’s population. The development of new rice cultivars with a high yield, strong resistance, acceptable quality, and wide adaptation is urgently needed [2], but this commonly takes 8–10 years or more because of the great recombination in phenotypes and genotypes required, with laborious work and a huge expenditure involved. It has been reported that a few traits inherited from the recurrent parent (female cultivar) exhibited cytoplasmic effects in rice, such as a low temperature [3], a low yield and width of the flag leaf [4], a low grain weight [5], a low protein content [6,7], chalkiness [8], a low cooking quality [9], and low nutrient levels [7]. A genetic investigation of the inherited effects indicated that the genetic variation in the cytoplasmic effects was low (2.41%–20.80%), whereas the maternal influence on the lysine content was greater than on the protein content and index [7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
