Abstract
Biomass yield of rice (Oryza sativa L.) is an important breeding target, yet it is not easy to improve because the trait is complex and phenotyping is laborious. Using progeny derived from a cross between two high-yielding Japanese cultivars, we evaluated whether quantitative trait locus (QTL)-based selection can improve biomass yield. As a measure of biomass yield, we used plant weight (aboveground parts only), which included grain weight and stem and leaf weight. We measured these and related traits in recombinant inbred lines. Phenotypic values for these traits showed a continuous distribution with transgressive segregation, suggesting that selection can affect plant weight in the progeny. Four significant QTLs were mapped for plant weight, three for grain weight, and five for stem and leaf weight (at α = 0.05); some of them overlapped. Multiple regression analysis showed that about 43% of the phenotypic variance of plant weight was significantly explained (P < 0.0001) by six of the QTLs. From F2 plants derived from the same parental cross as the recombinant inbred lines, we divergently selected lines that carried alleles with positive or negative additive effects at these QTLs, and performed successive selfing. In the resulting F6 lines and parents, plant weight significantly differed among the genotypes (at α = 0.05). These results demonstrate that QTL-based selection is effective in improving rice biomass yield.
Highlights
By 2050, we will need to feed two billion more people than at present [1, 2]
For PW, GW, and SLW, there were no significant differences between the means of the parents
Transgressive segregation was evident in recombinant inbred lines (RILs) for all evaluated traits, supporting the hypothesis that different alleles at the quantitative trait locus (QTL) contribute to the traits in the two parents
Summary
By 2050, we will need to feed two billion more people than at present [1, 2]. How can we accomplish that task? Rice (Oryza sativa L.) is the staple food for more than half of the world’s population, in Asia (Ricepedia, http://ricepedia.org/rice-as-food/the-global-staplerice-consumers). QTL-Based Selection for Rice Biomass conservation of paddy fields. For these reasons, further improvement of rice yield potential, including biomass, is a major challenge for breeders and geneticists. Little is known about the genetic architecture of rice biomass yield, except for the semidwarfing 1 gene [3, 4]. Similar to animal quantitative traits [5], rice biomass yield (including grain yield) is governed by quantitative trait loci (QTLs) with small additive effects and greatly varies among individuals in variable and nonuniform environments. For yield and other traits under this type of genetic control (many QTLs with small effects), phenotypic values are continuously distributed in segregating populations and do not show simple Mendelian inheritance [6, 7]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
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