The QTL Mapping On Maternal And Endosperm Genome For Cooking And Nutrition Quality Traits In Rice (Oryza Sativa L.)

As a staple cereal crop in the world, rice feeds more than 50% of the world population. The improvement of rice quality is an important work to meet the demands of a growing population. Cooking quality including amylose content (AC), gel consistency (GC), gelatinization temperature (GT), and nutrition quality such as protein content (PC) are considered to be the most concerned traits. The genetic analysis on rice had indicated that the inheritance of cooking and nutrition quality traits are complex, which involved the genetic effects from endosperm genes and the maternal plant genes, being further partitioned into additive and dominance effects, and their genotype×environment (GE) interaction effects. Therefore, it is significant to study the magnitude of genetic main effects and GE interaction effects between the QTL (Quantitative trait loci) of the triploid endosperm or diploid maternal genomes and environments for rice quality traits.Investigations to identify the quantitative trait loci (QTLs) governing cooking quality traits including amylose content, gel consistency, gelatinization temperature (expressed by the alkali spread value) and nutrition quality such as protein content (PC), 241 RIL populations derived from an elite hybrid cross of ' Zhenshan 97'×' Minghui 63' and their reciprocal backcrosses BC₁F₁ and BC₂F₁ populations were used in present experiment across environments. QTL genetic main effects and their QTL×environment interaction effects were analyzed by using the new developed genetic model with endosperm effects, maternal effects and environmental interaction effects on quantitative traits of seed in cereal crops. The results are as follows:QTL analysis identified a total of seven QTLs associated with the cooking quality traits which were subsequently mapped to chromosomes 1, 4 and 6, namely qAC-1-1, qAC-1-2, qAC-4-3 and qAC-6-4 for AC, qGC-1-1 and qGC-6-2 for GC and qASV-6-1 for ASV, respectively. Significant additive effects (Am and Ae) of QTLs from diploid maternal plant and triploid endosperm were detected for all of seven QTLs, and QTL×environment interaction effects for six of these. A total of nine QTLs associated with the protein content was identified and subsequently mapped to chromosomes 2, 3, 5, 6, 7, 10, 11 and 12, namely qPC-2-1, qPC-3-2, qPC-5-3, qPC-6-4, qPC-6-5, qPC-7-6, qPC-10-7, qPC-11-8, qPC-12-9, respectively. Significant additive effects (Am and Ae) of QTLs from diploid maternal plant and triploid endosperm were detected for these QTLs. QTL×environment interaction effects and endosperm dominance effect were detected for two and one of these, respectively.These results revealed that the control for rice cooking and nutrition quality was distributed over several chromosomes and the environmental interaction effects were important for the performance of these quality traits.