The effect of cycocel spraying on yield and yield components of spring chickpea (Cicer arietinum L.) under rainfed conditions

IntroductionChickpea (Cicer arietinum L.) is one of the herbaceous plants. Most of the producing countries of this crop are in arid and semi-arid regions, and about 90% of the world's chickpea is produced in rainfed conditions. Chlormequat chloride or cycocel (2- Chloroethyl 3 methyl ammonium chloride) is a choline esters derivative. Chlormequat chloride interacts with the gibberellic acid biosynthesis pathway, inhibits the activity of ent-kaurene synthesis and reduces plant height. Reports have shown that the use of cycocel reduced the stem height, increased the number of tillers per plant, the number of seeds per spike, cold resistance, salinity, fungi, and insects. Studies show that cycocel solubilization increases cytokinin from root to stem, which increases the growth period, photosynthesis, and increased yield. The aim of this study was to investigate the response of yield and grain yield components of two chickpea cultivars to three concentrations of cycocel foliar application under rainfed conditions. Materials and MethodsIn order to study the yield and yield components of chickpea in response to different levels of cycocel in rain fed conditions, a factorial experiment was conducted in a randomized complete block design with three replications at the research farm of Sararood Research Center of Kermanshah. The treatments consisted of two factors of cycocel concentration in three levels: zero (water as control), 200 and 400 mg L-1 as the main factor and two cultivars of Chickpea bionij (local cultivar Mahidasht) and Samin as a minor. Cycocel treatments were sprayed manually until the water was checked from leaves and air organs. In order to maintain the effects of cycocel, the treatments were applied in two steps, including 45 days after planting (one week before flowering) and 60 days after planting (50% flowering) for the planned plots. At the same time the experiment coincided with the onset of drought stress in the study area. In each experimental unit, two rows of five rows and a half meter from the beginning and the end of the rows were considered as the range. To determine the yield components after harvest, 10 plants were selected randomly from each plot. Plant height, number of branches, the number of shells per plant, shell weight per plant, seed weight per plant, 1000-grain weight, biological yield, grain yield and harvest index were measured. Data were analyzed by SAS Ver. 9.1 and the minimum significant difference test (LSD) at the probability level of (p≤0.05) was applied for comparisons between treatment means. Results and DiscussionThe results of analysis of variance showed that the simple effects of cultivar and cycocel on all studied traits were significant at level of (p≤0.01), and their interactions on harvest index and 1000-seed weight was significant at level of (p≤0.01), and finally the number of lateral branches, pod weight per plant, the number of seeds per pod, biomass yield, grain yield was significant at level of (p≤0.05). High cycocel (400 mg L-1) treatments increased yield and yield components compared to other treatments. According to the studied traits, Bionij cultivar had more yield than Samson cultivar. Generally, the growth mobility through the change in the photocells and the direction it directs to the target increases the yield. Cycocel also increased the grain weight and yield in plants due to the changes in the allocation of the material to seed filling. ConclusionThe results of this study showed that Samson had the highest plant height among the other cultivars, while the highest number of secondary branches, weight of pod per plant, the number of seeds per plant, 1000 seed weight, seed number per pod, grain yield, biomass yield and harvest index was observed in Bionaj. All studied traits were positively affected by cycocel. In most cases, soluble cycocel with a concentration of 400 mg L-1 had the greatest effect on growth and yield of chickpea cultivars. It seems that spraying chickpea plants, especially Bionij cultivar with a concentration of 400 mg L-1 of cycocel is recommended for similar climatic conditions.