Evaluation of chickpea (Cicer arietinum L.) cultivars tolerance to some herbicides

Chickpea (Cicer arietinum L.) is an important food legume, is presently grown in more than 50 countries and imported by more than 150 countries. It is the second largest grown and produced food legume after dry beans. During 2011, chickpea was grown on 13.2 million ha and about 80% of this area was in south and southeast Asia (India 68%, Pakistan 8.9% and Myanmar 2.3%). The other major chickpea growing countries include Turkey, Australia, Ethiopia, Iran, Mexico, Canada and USA. Weeds are a serious constraint to increased production. Chickpea, however, is a poor competitor with weeds because of slow growth rate and limited leaf area development at early life stages. Weeds compete with chickpea plants for water, nutrients, sunlight and also harbor insect-pests and diseases. If the weeds are not controlled, they can significantly reduce chickpea yield. Significant yield losses (up to 84%) due to weeds have been reported in chickpea, and even more severely (up to 98%) in autumn-sown chickpea. Thus, weed management is crucial in chickpea to realize maximum yields and also to maintain high its quality. Because of the sensitivity of chickpea to herbicides, most effective are the pre-emergence herbicides, and choices for post-emergence herbicides are limited. The pre-emergence herbicides are effective in controlling weeds at early stage of seedling growth, but weeds germinating after crop emergence become dominant in the field and cause substantial yield loses. Therefore, chickpea cultivars with improved herbicide tolerance, which can offer greater flexibility for use of post-emergence herbicides, are required by the farmers. There are few reports on identification of herbicide tolerance in chickpea. However, these reports indicate presence of genotypic variations for herbicide tolerance in chickpea. This study was aimed to identify chickpea cultivars tolerance to pyridate, imazethapyr, foramsulforun and rimsolforun herbicides by screening. In order to study chickpea cultivars toleration against some post-emergence herbicides, a pot experiment was carried out in a completely randomized design in four replications at research greenhouse Ferdowsi University of Mashhad. Factors included herbicides application in 4 levels (foramsulfuron, rimsulfuron, imazethapyr and Pyridate), herbicide dose in 3 levels (100 and 75% of the herbicides recommended dose for weed control with control treatment without of herbicide use) and chickpea cultivars in 5 levels, (Hashem, ILC 482, Kaka, Azad and Arman). Chickpea seeds were prepared from chickpea seed bank of Research Center for Plant Sciences, Ferdowsi University of Mashhad. Plants were in pots with 14 cm diameter and sprayed at 2nd true leaf of chickpea cultivars. To evaluate the effects of experimental results, survival and dry matter of chickpea cultivars were indicated, 2 and 4 weeks after herbicides spraying. Analysis of variance of data was carried out after their conversion to plant with MSTATC software and for means comparisons LSD (p≤0.05) test was used. Based on the results, chickpea cultivars were not significantly different in terms of dry matter, but they had a different reaction to the herbicides application. It is indicated that foramsulfuron and rimsulfuron had the highest phytotoxicity and negative effects on chickpea; and the lowest negative impact was related to pyridate herbicide application. Also reduced dose of imazethapyr herbicide had no effect on chickpea cultivars. According to the results ILC 482 and Azad chickpea cultivars were the most tolerant and Arman cultivar was the most susceptible cultivars toward mentioned herbicides application, especially pyridate and imazethapyr. According to this study, the effects of pyridate, imazethapyr, rimsulfuron and foramsulfuron herbicides in chickpea cultivars were different. The intensity of phytotoxicity effects of investigated herbicides were ranked as rimsulfuron > foramsulfuron> Imazethapyr> pyridate. So, use of rimsulfuron and foramsulfuron herbicides chickpea not recommended in chickpea weed control. The research findings will increase our awareness regarding chickpea tolerance to the above herbicides and provide guidelines for adjustment for minimizing crop injury.