Effects of foliar spraying of γ-aminobutyric acid on yield formation and photosynthetic characteristics of waxy corn

【Objective】The effects of γ-aminobutyric acid(GABA) on waxy corn yield formation and its photosynthetic physiology were investigated in order to provide guidance for the application of chemical control technology to improve the yield of waxy corn varieties.【Method】The waxy corn varieties Yuecainuo 2, Jingkenuo 928, and Yuebaitiannuo 7 were used as materials. The foliar spraying of water was taken as control(CK) and the foliar spraying of GABA5 mmol/L treatmentat booting stageas the treatment(FS). Observed and recorded the growth period and plant agronomic characteristics of waxy corn in the field, detected and analyzed waxy corn yield, photosynthetic parameters and chlorophyll content at filling stage and maturity stage, studied the response of yield and physiological characteristics of waxy corn to GABA foliar spraying at booting stage.【Result】Compared with CK, FS treatment increased the net ear yield, fresh bract yield andratio of fresh bracts to ears and leaves to a certain extent, net ear yield, fresh bract yield increased by 5.45%-11.08% and 5.66%-14.23%, respectively compared with CK. The number of grains per spike, net photosynthetic rate, stomatal conductance, transpiration rate and plant height at maturity stageall increased by 6.28%-8.76%, 14.01%-70.67%, 14.60%-29.92%, 8.94%-23.19% and 3.35%-5.21%, respectively. FS treatment did not significantly affect the ear height, bald length, ear diameter, SPAD value at filling stage and maturity stage, and leaf aging index at maturity stage(P>0.05). The FS treatment promoted the heading stage, powder period and spinning stage of waxy maize varieties by 1 d. There was extremely significant positive correlation between net ear yield and fresh bract yield, ear diameter, number of rows per ear, transpiration rate of leaf at maturity stage(P<0.01, the same below), and extremely significant positive correlation between fresh bract yieldand net ear yield, ear diameter, leaf stomatal conductance and transpiration rateat maturity stage.【Conclusion】The increase of yield of waxy maize varieties under foliar spraying GABA treatment is related to the increase of number of grains per ear, net photosynthetic rate, plant height, and the regulation of growth period.