Improved photosynthetic characteristics correlated with enhanced biomass in a heterotic F.sub.1 hybrid of maize

• Published in: Photosynthesis research Vol. 147; no. 3; pp. 253 - 267
• Main Authors: Meena, Rajesh Kumar, Reddy, Kanubothula Sitarami, Gautam, Ranjana, Maddela, Surender, Reddy, Attipalli Ramachandra, Gudipalli, Padmaja
• Format: Journal Article
• Language: English
• Published: Springer 01.03.2021
• Subjects: Chlorophyll; Corn; Photosynthesis; Physiological aspects
• ISSN: 0166-8595; 1573-5079
• DOI: 10.1007/s11120-021-00822-6

Heterosis is a phenomenon wherein F.sub.1 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.sub.1 hybrid are important to uncover the mechanisms underlying heterosis in plants. In the present study, the photosynthetic capacity of a heterotic F.sub.1 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.sub.n), stomatal conductance (g.sub.s), transpiration rate (E) as well as foliar carbohydrates were higher in F.sub.1 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 ([DELTA]F/F.sub.m'), maximum quantum yield of PSII (F.sub.v/F.sub.m), photochemical quenching (q.sub.p) and decreased non-photochemical quenching (NPQ) was observed in F.sub.1 hybrid than the parental inbreds. Further, the expression of potential genes related to C.sub.4 photosynthesis was considerably upregulated in F.sub.1 hybrid than the parental inbreds during vegetative and reproductive stages. Moreover, the F.sub.1 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.sub.1 hybrid.