پژوهشهای حبوبات ایران (Dec 2021)
Evaluating the damage of onion thrips (Thrips tabaci) on five cultivars and one genotype of chiti bean in field conditions
Abstract
IntroductionAccording to statistics released by the Ministry of Agricultural Jahad, the area under cultivation of beans in Iran is 105,000 hectares, with an average yield of 2200 kg/ha. Thrips is one of the pests that reduce bean yield. The different developmental stages of Thrips tabaci, by settling under the bean leaves and feeding on the plant sap, cause colored silver spots, that the black feces of pest are visible inside these spots. These signs of damage indicate the presence of pests. Thrips is evident from the beginning to the end of its growing population of active beans in the fields and its damage. Onion thrips is the most well-known thrips in the world and causes significant damage to onion, cotton, lettuce, tomato. It also carries some viral diseases. Materials and MethodsPhaseolus vulgaris is one of the most important legumes cultivated in most countries of the world. This crop is attacked by various pests including onion thrips. This study was conducted in two years in field condition by planting cultivars Ghaffar, Sadri, Koosha, talash, local chiti of Khomein (control) and KS-21492 genotype in a randomized complete block design with four replications in two experiments with spraying and non-spraying treatments, at the National Bean Research of Khomein Station. Sampling was also conducted weekly to evaluate changes in pest populations (separately from larvae, nymph and adult) from the beginning of infestation to the end of infestation was performed. For sampling, five plants were randomly selected from each plot and scored based on the amount of damage and contaminated leaf area. Yield and yield components were also calculated. The results of this study were analyzed using SAS 9.1 statistical software and the means were compared by Tukey test in 1% and 5%. Results and DiscussionThe two-year results of this study showed that Ghaffar and Koosha cultivars had the highest average yield of 3749.88 and 3602.25 kg/ha, respectively. Chiti of Khomein and sadri had the highest of population. On the other hand, KS-21492 genotype had less damage scale than Sadri and control, but its yield (2212.50) was lower than other cultivars. Given that this genotype had the lowest yield loss and population among cultivars. Sedaratian et al, (2010) also studied the population density of thrips onion on seven cultivars and one soybean genotype and reported the highest density of thrips on Dpx and genotype KS-3494 and the lowest population density on two cultivars L17 and Tellar. This is not consistent with the results of the present study due to differences in the product studied. Cultivars resistance based on population count of onion thrips and evaluation of crop yield characteristics were also used by Kalafchi et al, (2002). These researchers evaluated nine onion varieties for damage. Red Azarshahr cultivar with the highest number of thrips and the highest damage to other cultivars was sensitive, and Sefid-Qom cultivar with the lowest number of thrips, it is less contaminated than this pest. The results of this study are different from the results of recent research due to differences in product and cultivars tested. The results of the research (Mohiseni & Kushki, 2016) showed that the plant growth type had a significant effect on the resistance of cultivars to two spotted mites, which requires further investigation on the impact of the plant growth type on the onion population. Research has shown that different varieties of common beans contain anti-nutritional compounds such as phytic acid, lectin and trypsin inhibitors that can influence the biology of herbivorous pests such as onion thrips. This is similar to the results of the present study due to differences in populations studied as well as differences in yield and damage scale. Studies have shown that the levels of these anti-growth factors in different bean genotypes are different. ConclusionBased on the results of this study Koosha and Ghaffar cultivars due to higher yield Priority for cultivation in the area.
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