Two Novel QTLs for the Harvest Index that Contribute to High-Yield Production in Rice (Oryza sativa L.)

Abstract

Background The harvest index (HI) is a measure of the biological success of forming harvestable products. However, our understanding of the genetic basis of HI in rice (Oryza sativa L.) is limited, because it is a complex trait consisting of various yield-related traits and physiological attributes. YTH183 is a high-yielding line with large panicles and high HI derived from a cross between the Indica Group variety IR 64 and the NPT line IR 69093-41-2-3-2 (YP5). Results Here, we detected two novel QTLs for HI, designated qHI5.1 on chromosome 5 and qHI8.1 on chromosome 8, by using 155 recombinant inbred lines (RILs) derived from the cross between IR 64 and YTH183. The YTH183 allele at qHI5.1 contributed to a wide grain, resulting in heavy grain weight and panicle weight, and was consistently effective under the different environmental conditions of subtropical (Ishigaki) and temperate (Tsukuba) regions. Genetic polymorphism revealed that qHI5.1 was identical to GSE5/GW5, which is known to control the grain weight. On the other hand, although qHI8.1 functioned additively with qHI5.1 for higher HI, it did not show any significant effect on grain or panicle weight. In addition, its effects on HI were shown only in the first seasons at Ishigaki but not at Tsukuba or in the second season at Ishigaki. Conclusion Our results indicate that qHI5.1 controls the grain size, regardless of whether environmental conditions are of subtropical or temperate regions, while qHI8.1 might be involved in controlling the physiological processes of source ability or the translocation of photosynthesis products from vegetative organs to grains depending on environmental conditions during the maturing stage. These QTLs will be useful genetic resources for future breeding programs to break through the ceiling of maximum yield in Indica Group varieties.

Synergistic effects of silicon and phosphorus co-application on rice (Oryza sativa L.) growth, yield and nutrient use efficiency in saline soil

“…[27] recorded that Si did not influence the 1000-grain weight, which is aligned to this experiment. GHI is a complex characteristic comprised of several yield-related traits and physiological properties [56], could be the reason for the insignificant result on GHI in this study. Moreover, there are some other factors which can contribute to this phenomenon; nutrient availability, water availability, temperature and grain quality may have a greater impact on GY, which is considered as a crucial factor for determining GHI.…”

The Impact of Water-Saving Irrigation on Rice Growth and Comprehensive Evaluation of Irrigation Strategies

“…Similarly, several studies found that mild water stress has little impact on rice plant height, while severe water stress significantly reduces rice plant height [21][22][23]. Other research revealed that when the soil moisture content reached 90% of the field capacity, rice yield was the highest [24,25]. This demonstrates that appropriate irrigation plays a key role in rice growth and development.…”

Agronomic characteristics and genetic relationship of putative transgenic rice lines of cv. Fatmawati with the Glu-1Dx5 transgene

“…Harvest index, number of productive tillers, number of maximum tillers, grain dry weight per panicle, number of filled grains and number of empty grains in rice are affected by genetic, environment and genetic-environment interactions. Saito et al (2021) found two novel QTLs (quantitative trait loci) controlling harvest index in rice. Harvest index is also affected by Phosphorous and Zinc concentration (Amanullah and Imanullah, 2016).…”