Heterosis is a phenomenon wherein F₁ 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 F₁ hybrid are important to uncover the mechanisms underlying heterosis in plants. In the present study, the photosynthetic capacity of a heterotic F₁ 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_n), stomatal conductance (g_s), transpiration rate (E) as well as foliar carbohydrates were higher in F₁ 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_m’), maximum quantum yield of PSII (F_v/F_m), photochemical quenching (q_p) and decreased non-photochemical quenching (NPQ) was observed in F₁ hybrid than the parental inbreds. Further, the expression of potential genes related to C₄ photosynthesis was considerably upregulated in F₁ hybrid than the parental inbreds during vegetative and reproductive stages. Moreover, the F₁ 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 F₁ hybrid.

杂种优势是F ₁杂种经常表现出表型优势并在生长和农艺性状方面超过其亲本的现象。研究杂种优势 F ₁杂种的生理和生化特性对于揭示植物杂种优势的潜在机制很重要。在本研究中，在 2017 年和 2018 年期间，在田间营养和繁殖阶段，与亲本近交种相比，玉米杂种 F ₁杂种（DHM 117）的光合能力表现出更高的生长速度和增加的生物量. 净光合速率（P _n）、气孔导度（g _s）、蒸腾速率（E ) 以及在营养和繁殖阶段，F ₁杂种中的叶面碳水化合物高于亲本自交系。叶绿素总含量增加，叶绿素a荧光特性更好，包括光系统 II 的有效量子产率 ( ΔF/F _m ')、PSII 的最大量子产率 ( F _v /F _m )、光化学淬灭 ( q _p ) 和非与亲本近交系相比，在 F ₁杂种中观察到光化学猝灭 ( NPQ ) 。此外，与 C ₄光合作用相关的潜在基因的表达在 F 中显着上调₁杂种比在营养和繁殖阶段的亲本近交系。此外，在 2017 年和 2018 年期间，F ₁杂种在产量方面表现出明显的杂种优势，相对于亲本自交系增加了 63% 和 62%。 F ₁混合动力车。