Interference of Brassicaceae weeds (Brassica tournefortii, Rapistrum rugosum, and Sisymbrium thellungii) in Chickpeas

Abstract

African mustard (Brassica tournefortii Gouan), turnipweed [Rapistrum rugosum (L.) All.], and African turnipweed (Sisymbrium thellungii O.E. Schulz) are common broadleaf weeds in chickpea (Cicer arietinum L.) crops, particularly under dryland regions of eastern Australia. Information on crop yield losses and the seed production potential for these weeds are limited in chickpea. Field studies were conducted in the winter seasons of 2020 and 2021 in eastern Australia with different densities of the three weeds (B. tournefortii, R. rugosum, and S. thellungii) in chickpea. Based on the sigmoid model, chickpea yield was reduced by 50% at 11 plants m-2 of B. tournefortii. Based on hyperbola models, a 50% yield reduction of chickpea occurred at 5, and 25 plants m−2 of R. rugosum, and S. thellungii, respectively. Based on the linear model, B. tournefortii, R. rugosum, and S. thellungii produced a maximum of 448,000, 206,700, and 869,400, seeds m−2, respectively. At chickpea harvest, the low seed retention (<55%) of B. tournefortii and S. thellungii suggests limited opportunities for harvest weed seed control, and the seed rain of these weeds may enrich the weed seedbank in the soil. At crop harvest, the seed retention of R. rugosum was found to be greater than 90%, suggesting that it is a suitable candidate for harvest weed seed control. This study demonstrated that R. rugosum could cause a greater reduction in chickpea yield compared with B. tournefortii and S. thellungii. Furthermore, it is recommended to restrict seed rain of B. tournefortii and S. thellungii by not allowing the plants to produce seeds in order to reduce their weed seedbank in the soil. The information generated from this study could aid in strengthening integrated weed management in chickpea.