Enhancing maize grain yield under salt-affected field conditions using salt-resistant maize hybrids and higher planting density

Abstract

Background: In arid and semiarid countries, grain yield of maize is increasingly impaired by soil salinity. Beside soil amelioration, the development of salt-resistant cultivars is a possibility to enhance crop yield on salt-affected soils. Aims: This study aimed at testing yield performance in the field of salt-resistant maize hybrids on a salt-affected soil. In addition, planting density was optimized under the saline conditions. Methods: Four salt-resistant maize hybrids (Zea mays L. SR-05, SR-12, SR-15, and SR-16) were grown under control (EC = 2.0–2.5 dSm−1) and saline (EC = 10.0–12.0 dSm−1) field conditions and compared to the salt-sensitive maize cv. Pioneer-3906. Planting density (5, 8, or 11 plantsm−2) was optimized for saline soil conditions for SR-12 and the local hybrid EV-78. Results: Yield of Pioneer-3906 was significantly reduced under salinity because of inhibited kernel setting, whereas the SR hybrids showed no decrease in grain yield. Based on grain yield, the optimum planting density was 8 plants m−2 with no further increase with 11 plants m−2. In contrast to SR-12, for cv. EV-78 no increase of harvest index with 8 relative to 5 plantsm−2 was observed. Conclusions: Vegetative growth of Pioneer-3906 and the SR hybrids was decreased due to Phase-I effects but neither due to water deficiency nor ion toxicity. The experiment corroborated the salt resistance of the SR hybrids under field conditions. Under saline conditions, optimum planting density of salt-resistant cultivarsmay be higher than under nonsaline conditions when sufficient water supply by artificial irrigation is guaranteed.