نوع مقاله : مقاله پژوهشی
نویسندگان
1 استاد، پژوهشکده میوه های معتدله و سردسیری، موسسه تحقیقات علوم باغبانی، سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج، ایران.
2 دانشیار، پژوهشکده میوه های معتدله و سردسیری، موسسه تحقیقات علوم باغبانی، سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج، ایران.
3 استادیار، بخش تحقیقات نماتد شناسی، موسسه تحقیقات گیاهپزشکی کشور، سازمان تحقیقات، آموزش و ترویج کشاورزی، تهران، ایران.
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
Pear psylla [(Cacopsylla pyricola (Foerster)] is one of the most important pests affecting pear production. The main purpose of this research was to investigate the resistance of pear cultivars to pear psylla for recommendation in integrated pest management and national pear breeding programs. This research was carried out using randomized complete block design with foure replications in Kamalshahr research station in Karaj, Iran, in four growing seasons from 2019 to 2023. Nine pear cultivars; Boheme, Shah Mieveh, Natanzi, Sebri, Dargazi, Louis Bonne, Harvest Queen, Potomac and Coscia. Data about psyllids population at different stages; eggs, nymphs, and dult, was collected and recorded at the peak of its activity, i.e., from early February to November, every seven days. Antixenosis resistance indices included; attraction index, mean crowding intensity, relative abundance establishment rate, non-preference index and prevalence index of eggs, nymphs and adults were calculated. Tree characteristics; form, one year old branches growth, leaves, flowers and fruits were examined. The results showed that the most resistant cultivars to pear psylla were; Cosia, Boheme, Sabri, Natanzi and Potomac. Atteraction index was 0.99, 0.99 and 0.95, crowding intensity index was 58.30, 149.14 and 16.13, relative establishment rate was 3.68, 3.65 and 3.40 for egg, nymph and adult stages, respectively. Non-perference index was 98.04, 98.06 and 19.98 and the prevalence index was 49.66, 49.47 and 47.50 for egg, nymph and adult stages, respectively.
Keywords: Pear, Psylla, Host finding, Host acceptance, Cultivar sensitivity.
Introduction
Current management practices are sufficient to effectively control pear psylla (Murray et al., 2021). In many countries, collections of pear cultivars have been established in some important pear-growing areas with a wide range of cultivars of national, local and foreign origin to evaluate resistance to diseases and pests (Braniste and Militaru, 2007). Antixenosis resistance of pear cultivars to pear psylla has been described with non-preferential egg laying. It has also been found that this type of resistance mechanism affects the size of the initial nymph population (Bell and Puterka, 2003). The main goal of this research was to investigate the details of the host preference and resistance mechanism of nine pear cultivars to pear psylla for recommendation in integrated pest management and national pear breeding programs.
Materials and Methods
This research was carried out using randomized complete block design with foure replications in Kamalshahr research station in Karaj, Iran, in four growing seasons from 2019 to 2023. Nine pear cultivars; Boheme, Shah Mieveh, Natanzi, Sebri, Dargazi, Beiruti (Louis Bonne), Harvest Queen, Potomac and Coscia. Data about psyllids population at different stages; eggs, nymphs, and dult, was collected and recorded at the peak of its activity, i.e., from early February to November, every 7 days. Antixenosis resistance indices included; attraction index, mean crowding intensity, relative abundance establishment rate, non-preference index and prevalence index of eggs, nymphs and adults were calculated. Tree characteristics; form, one year old branches growth, leaves, flowers and fruits were examined. After testing normality of the data Kolmogorov-Smirnov test, analysis of variance was performed based on priciples of random complete block design using IBM SPSS Statistics 27.0.1.0 software. For grouping pear cultivars based on the level of sensitivity to pear psylla, cluster analysis was employed. The relationship between characteristics of pear cultivars and antixenosis resistance indices was studied using correlation analysis. Factor analysis was performed to identify unobservable effective combined factors on resistance mechanism based on sets of observable indices. The accuracy of cluster analysis method was examined using linear discriminant analysis (LDA), normal discriminant analysis (NDA), or discriminant function analysis and Fisher's linear discriminant analysis.
Results and Discussion
Shah Miveh pear cultivar was the most sensitive cultivar to pear psylla. The most resistant cultivars to pear psylla were; Coscia, Boheme, Sebri, Natanzi and Potomac. Increase in host antixenosis properties based on reduction of attraction index led to increase in the time spent in egg-laying activities, decrease in the egg-laying rate, and as its consequences, decrease in attractiveness of the host for egg-laying in resistant pear cultivars. In host-finding stage, adult psylla must randomly search in a habitat until it finds one of the important stimuli for selection of pear cultivars.
Morphological stimuli of pear cultivars for host-finding include different growth characteristics of the tree, flower, leaves and availability of host. Pear cultivars resistant to pear psylla can be good alternatives to chemical control and manage the pest. It has been reported that the genetic control of resistance to pear psylla is polygenic trait (Dondini et al., 2015). This genetic mechanism reduces the possibility of the emergence of resistant biotypes of the pest, and rewards investing in development and use of resistant pear cultivars to psylla in integrated pest management and control. This approach is very important and eco-friendly.
References
Bell, R.L. and Puterka, G.L. 2003. Modes of host plant resistance to pear psylla: a review. Proceedings of the XI Eucarpia Symposium on Fruit Breeding and Genetics 663 (pp. 183-188). DOI: 10.17660/ActaHortic.2004.663.26
Branişte, N. and Militaru, M. 2007. Germplasm fund of Pyrus sp. presently in ex situ Romanian collections. In X International Pear Symposium 800 (pp. 497-502). DOI: 10.17660/ActaHortic.2008.800.63
Dondini, L., De Franceschi, P., Ancarani, V., Civolani, S., Fano, E.A. and Musacchi, S. 2015. Identification of a QTL for psylla resistance in pear via genome scanning approach. Scientia Horticulturae, 197, pp.568-572. DOI: 10.1016/j.scienta.2015.10.018
Murray, K., Jepson, P.C. and Hedstrom, C. 2021. Integrated pest management strategic plan for Oregon and Washington pears: Summary of a Workshop Held on March 5, 2020 in Hood River, Oregon. Oregon State University Extension Service. 80 pp.
کلیدواژه‌ها [English]
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