Studies on mechanisms of resistance to rust Uromyces phaseoli Reben Wint and pyramiding the resistant genes to develop durable resistant pole type French bean Phaseolus vulgaris L

Abstract

Author : G. INDRAJA newlineTitleofthesis : Studies on mechanisms of resistance to rust newline(Uromyces phaseoli (Reben) Wint) and pyramiding the resistant genes to develop durable resistant pole type French bean (Phaseolus vulgaris L.) newlineDegree for which it is submitted newline: DOCTOR OF PHILOSOPHY newlineFaculty : HORTICULTURE newlineMajor Field : VEGETABLE SCIENCE newlineChairman of Advisory Committee newline: Dr. SYED SADARUNNISA newlineUniversity : Dr.Y.S.R. HORTICULTURAL UNIVERSITY newlineYear of submission : 2023 newlineABSTRACT newlineThe present study, titled, Studies on mechanisms of resistance to rust (Uromyces phaseoli (Reben) Wint) and pyramiding the resistant genes to develop durable resistant pole type French bean (Phaseolus vulgaris L.) was conducted from 2019 to 2022 at ICAR-Indian Institute of Horticultural Research, Bengaluru, Karnataka. A total of ten French bean varieties/lines were assessed for rust resistance at both the field and molecular levels. Different components of partial resistance were evaluated under conditions of natural epiphytotic and artificial inoculation. In terms of disease appearance, the varieties Arka Suvidha (25.33 days) and US 2 (22.66 days) took less number of days for disease appearance, while US 2 demonstrated the highest per cent disease index (PDI) for rust, with US2 recording 81.52% and 65.13%, followed by NZ with 73.71% and 64.21% in the years 2019-2020 and 2020-2021, respectively, in open field conditions. After challenge inoculation, US 2 took less number of days for disease appearance (12.00 days, 10.00 days) under controlled environmental conditions in both years. newlineCorrelation analysis revealed significant negative correlations between yield per plant and per cent disease index (PDI) at the end of the season (-0.63*) as well as the rate of infection during the pod formation to pod development stage (-0.67*). Under artificially inoculated conditions, PDI at different stages after inoculation showed significant positive correlations with the area under the disease progress curve (AUDPC), the number of pustules per 5 cm2, and the rate