Bouquet ears in maize inbred lines as affected by agronomic factors

Abstract

ABSTRACT “Bouquet ears” is known to reduce grain yield in maize (Zea mays L.). The impact of agronomic factors on the bouquet occurrence rate (BOR) needs to be investigated. Two separate trials were conducted to assess the effects of nitrogen fertilizer, planting density, herbicide application, and planting date on the BOR in maize inbred lines (Mo17, K615/1, and KE72012/12) across two locations and 2 years (2018 and 2019). In Trial 1, the effects of nitrogen rate (200, 450, and 700 kg ha−1) and planting density (55,000, 70,000, and 85,000 plants ha−1) and in Trial 2, the effects of herbicide application (no-2,4-D application and 2,4-D at V5 and V7 stages) and planting date (May 25, June 4, and June 14) were evaluated. Planting density had no significant impact on the BOR in the inbred lines Mo17 and KE72012/12. In the inbred line K615/1, the BOR was inversely affected by planting density; BOR was 14% at 55,000 plants ha−1, 10% at 70,000 plants ha−1, and 8% at 85,000 plants ha−1. Delaying the planting date (PD) from May 25 till June 4 did not affect BOR; however, delaying PD to June 14 drastically increased BOR; KE72012/12 showed 3.56% BOR for June 14 PD, which was 215% higher than that for June 4 PD. Overall, the BOR could be significantly decreased in maize, provided proper genotypes are planted at suitable times (May 25 to June 4) at densities higher than 55,000 plants ha−1.