Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, 500 046, Telangana, India.
Institute of Biotechnology, Prof. Jayashankar Telangana State Agricultural University, Hyderabad, 500 030, Telangana, India.
Photosynth Res. 2021 Mar;147(3):253-267. doi: 10.1007/s11120-021-00822-6. Epub 2021 Feb 8.
Heterosis is a phenomenon wherein F hybrid often displays phenotypic superiority and surpasses its parents in terms of growth and agronomic traits. Investigations on the physiological and biochemical properties of the heterotic F hybrid are important to uncover the mechanisms underlying heterosis in plants. In the present study, the photosynthetic capacity of a heterotic F hybrid of Zea mays L. (DHM 117) that exhibited a higher growth rate and increased biomass was compared with its parental inbreds at vegetative and reproductive stages in the field during 2017 and 2018. The net photosynthetic rate (P), stomatal conductance (g), transpiration rate (E) as well as foliar carbohydrates were higher in F hybrid than parental inbreds at vegetative and reproductive stages. An increase in total chlorophyll content along with better chlorophyll a fluorescence characteristics including effective quantum yield of photosystem II (ΔF/F'), maximum quantum yield of PSII (F/F), photochemical quenching (q) and decreased non-photochemical quenching (NPQ) was observed in F hybrid than the parental inbreds. Further, the expression of potential genes related to C photosynthesis was considerably upregulated in F hybrid than the parental inbreds during vegetative and reproductive stages. Moreover, the F hybrid exhibited distinct heterosis in yield with 63% and 62% increase relative to parental inbreds during 2017 and 2018. We conclude that improved photosynthetic efficiency associated with increased foliar carbohydrates could have contributed to higher growth rate, biomass and yield in the F hybrid.
杂种优势是一种现象，杂种 F1 通常表现出表型优势，在生长和农艺性状方面超过其双亲。研究杂种 F1 的生理和生化特性对于揭示植物杂种优势的机制非常重要。本研究比较了 2017 年和 2018 年田间生长和生殖阶段杂种玉米 DHM 117 的光合能力，该杂种表现出较高的生长速度和增加的生物量。在营养生长和生殖生长阶段，杂种的净光合速率（P）、气孔导度（g）、蒸腾速率（E）以及叶片碳水化合物均高于亲本自交系。杂种的总叶绿素含量增加，叶绿素 a 荧光特性更好，包括光系统 II 的有效量子产量（ΔF/F'）、PSII 的最大量子产量（F/F）、光化学猝灭（q）和非光化学猝灭（NPQ）降低。此外，在营养生长和生殖生长阶段，与亲本自交系相比，杂种中与 C 光合作用相关的潜在基因的表达显著上调。此外，杂种在产量上表现出明显的杂种优势，与亲本自交系相比，2017 年和 2018 年分别增加了 63%和 62%。我们得出结论，与增加的叶片碳水化合物相关的提高的光合效率可能导致杂种 F1 具有更高的生长速度、生物量和产量。
