Direct and Joint Effects of Genotype, Defoliation and Crop Density on the Yield of Three Inbred Maize Lines

Dejan Ranković,Marijenka Tabaković,Jan Boćanski,Goran Todorović,Nenad Delić,Slaven Prodanović

doi:10.3390/agriculture11060509

Dejan Ranković, Marijenka Tabaković + Show 4 more

Open Access

https://doi.org/10.3390/agriculture11060509

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Abstract

The aim of this study was to observe direct and joint effects of three factors (genotypes, ecological environmental conditions and the applied crop density) on the level of defoliation intensity and yield. Three inbred lines (G) of maize (G1–L217RfC, G2–L335/99 and G3–L76B004) were used in the study. The trials were performed in two years (Y) (Y1 = 2016 and Y2 = 2017) and in two locations (L) (L1 and L2) under four ecological conditions of the year–location interaction (E1–E4) and in two densities (D1 and D2) (50,000 and 65,000 plants ha−1). Prior to tasselling, the following five treatments of detasseling and defoliation (T) were applied: T1—control, no leaf removal only detasseling, T2–T5—removal of tassels and top leaves (from one to four top leaves). The defoliation treatments had the most pronounced effect on the yield reduction in G1 (T1–Tn+1… T5), p < 0.05. The ecological conditions on yield variability were expressed under poor weather conditions (E3 and E4), while lower densities were less favorable for the application of defoliation treatments. The result of joint effects of factors was the lowest grain yield (896 kg/ha) in G3 in the variant E3D1 for T2 and the highest grain yield (11,389 kg/ha) in G3 in the variant E2D2 for T1. The smallest effect of the defoliation treatment was on the kernel row number (KRN).

Highlights

The seed production of inbred lines and F1 hybrids requires the removal of tassels from the female parent
analysis of variance (ANOVA) showed that there were statistically significant differences among variants G, E and D, as well as among treatments of defoliation (T) (Table 3). This points out that the grain yield, morphological traits or yield components (KRN, kernel number per row (KNR), ear length (EL), kernel weight (KW)) significantly depended on the intensity of defoliation, as well as on effects of defoliation that were observed in this study [20]
Environmental conditions, especially those related to rainfall, were more unfavorable for the maize production in 2017 than in 2016, which resulted in significantly lower yields obtained in E3 and E4 than in E1 and E2

Summary

Introduction

The seed production of inbred lines and F1 hybrids requires the removal of tassels from the female parent. This removal prevents uncontrolled pollination, and the appropriate genetic background in the seed is provided by self-pollination or by effects of anemophily [1,2] or by any other appropriate crossing. Regardless of manual or mechanical detasseling, more intensive defoliation reduces the cost of control of the presence of tassel residues on plants in the seed crop. The loss in the grain yield results in the lower income from the seed production, which can nullify the savings achieved by the decreased defoliation intensity

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