Germination of Chloris barbata, Cynodon dactylon, and Cyperus rotundus from Angola at Constant and Alternate Temperatures

Donato Loddo,Adérito Tomás Pais Da Cunha,Stefano Carlesi

doi:10.3390/agronomy9100615

Abstract

The study of weed germination can improve knowledge on their seasonal dynamics in fields and facilitate the design of ecologically sustainable management. An experiment was conducted to evaluate the effect of a range of constant and alternate temperatures on the germination of Chloris barbata, Cynodon dactylon, and Cyperus rotundus collected in Angola. Interesting differences were observed between the germination responses of the three species. No germination was observed for any species at 10 or 15–5 °C. Chloris barbata quickly germinated at most constant and alternate incubation temperatures, showing low primary dormancy and high germinability. Fast and high germination was observed for Cynodon dactylon at most alternate temperatures, while lower germination percentages were achieved at constant temperatures, especially the highest ones. Cyperus rotundus achieved good germination percentage at alternate temperatures, even if with slower and more extended germination dynamics than the other species, while almost no seeds germinated at constant temperatures. This study improves our knowledge of germination ecology for these species and allows some control tools to be identified, such as soil tillage, cover crops, and living or dead mulches, which can contribute to their ecologically sustainable management.

Highlights

Weeds are a major constraint for crop production and, among crop pests, are responsible for the highest potential yield losses [1]
No germination was observed for any species at 10 or 15–5 ◦ C (Figure 1), and, the values corresponding to those treatments were removed from the post hoc analysis because it was not possible to calculate any variance due to the absence of variability in the data collected
The first germinated seeds were observed at 2–7 days after sowing (DAS) at all temperatures, and germination lasted until 15–46 DAS (Figure 2)

Summary

Introduction

Weeds are a major constraint for crop production and, among crop pests, are responsible for the highest potential yield losses [1]. In the absence of adequate control measures, weeds are estimated to cause an average of 50% yield loss for maize and soybean in North America [2,3]. Similar results were reported in various studies from European countries [4,5], and even higher losses were observed for maize, sorghum, and rice in Africa [6,7,8]. Due to the lack of available machinery, pesticides, and trained operators, weed management in Africa is largely based on hand weeding [9], requiring an impressive amount of labour, estimated at more than 300 h/ha in sorghum [7] to achieve satisfactory weed control. The presence of competitive weed species is a common constraint for small farmers, causing important yield losses [9] and limiting the size of their farms [10]

Methods

Results

Conclusion