Effect of Row Spacing and Seed Rate on Ascochyta Blight Severity and Yield of Chickpea (Cicer arietinum L.) in Tunisia

Abstract

Background: In Tunisia, chickpea (Cicer arietinum L.) is the second major food legume. The development of chickpea production is facing several biotic constraints. Ascochyta blight (ABL) caused by Ascochyta rabiei (Pass.) Labr. is the most devastating disease and can cause complete yield losses under favorable conditions. In absence of chickpea variety totally resistance to ABL, some methods should be used to control and reduce this disease effects and help for its management. Therefore, this work was undertaken to evaluate the effect of row spacing and seed rate on ABL severity, growth and yield of chickpea. Methods: A split-plot design with three replicates was adopted to carry out this study during 2018 and 2019 cropping seasons. ‘Beja1’ chickpea variety was sown at 40 and 60 cm row spacing and at three seed rates (80, 110 and 140 kg ha-1). ABL severity was assessed visually on a 0-9 scale and agro morphological traits were measured. Analysis of variance was used to analyze the data. Correlations between agronomic traits, row spacing, seed rate and ABL severity were investigated. Result: Results showed that most of the variation in disease severity was associated with seed rate (r=0.61). The highest ABL score severity was noted at 140 kg ha-1 rate. Over both years, wide row spacing and low seed rate reduced ABL severity. Chickpea sown under narrow row spacing (40 cm) produced higher grain yield (1014 and 1099.7 kg ha-1 for 2018 and 2019 cropping seasons, respectively). Grain yield was tending to decrease with increasing sowing rates but at a density higher than optimal, grain yields decrease. In this study, ABL disease severity reached a score of 3.7 and 4.3 in 2018 and 2019, respectively. These disease severities levels had little effect on yield.