Identification and Genetic Diversity Analysis of Ascochyta Species Associated with Blight Complex of Pea in a Northwestern Hill State of India

Abstract

Forty isolates of Ascochyta spp. infecting pea collected from different commercial pea growing areas of Himachal Pradesh were characterized into three species-Ascochyta pinodes, A. pisi and A. pinodella-based on symptoms, morphological and cultural traits. The identity of the isolates was confirmed by studying the rDNA sequence patterns. Based on various cultural and morphological trait combinations, 36 isolates were identified as A. pinodes, one isolate as A. pisi and one isolate as A. pinodella. Whereas two isolates, As3 and As14, could not be placed in any of the species as equal number of characters matched with A. pisi and A. pinodes. However, sequencing of ITS region of these isolates resolved the ambiguity and placed them in A. pinodes. This necessitates ITS sequencing as one of the criteria to establish the taxonomic status of Ascochyta species infecting pea. RAPD, RAMS, and Rep-PCR analysis with 10, 4 and universal ERIC, and BOX-AIR primers categorized different isolates according to their geographical locations. This study established the predominance of A. pinodes in Himachal Pradesh where edible pea is one of the remunerative offseason vegetable crops. This also constitutes first report of genetic variability of Ascochyta species infecting pea in India.

Temporal and Spatial Changes in the Pea Black Spot Disease Complex in Western Australia

“…A recent pea black spot epidemic in 2005-06 in Spain was primarily attributed to A. pisi (24), despite it being widely considered the least damaging among the pathogens in the pea black spot complex (53). In India, A. pisi was recovered in 1 of 40 isolates in pea-growing areas of Himachal Pradesh (41 A. pisi as an important pathogen in the pea black spot complex, A. pisi is likely no longer present in Western Australia. If the reports of its presence in Western Australia in 1912, 1927, and 1968 were a case of mistaken identity, then perhaps it was never established in Western Australia on field pea.…”

Challenges With Managing Disease Complexes During Application of Different Measures Against Foliar Diseases of Field Pea

“…In Spain, a pea Ascochyta blight epidemic in 2005-2006 was primarily attributed to A. pisi (Kaiser et al 2008), despite it being widely considered the least damaging among the pathogens in the pea Ascochyta blight complex (Wallen 1965). In contrast, in India, only 1 out of 40 Ascochyta blight isolates recovered across pea growing areas of Himachal Pradesh was A. pisi (Padder et al 2012).…”

Causal agent of anthracnose in the pea crop (Pisum sativumL.) in northern of Perú: Symptomatology, isolation and identification, pathogenicity and control

“…Las placas sembradas fueron cubiertas con parafilm e incubadas a 19 ± 1 °C (Rubiales et al, 2018) hasta obtener el crecimiento del hongo y luego, se realizaron siembras sucesivas hasta obtener el cultivo puro. Los aislamientos purificados fueron entubados e incubados en refrigeración a 5 °C con la finalidad de mantener la viabilidad y patogenicidad (French & Hebert, 1980;Padder et al, 2012). La identificación se realizó a través de la clave propuesta por Sutton (1980).…”

“…Para las evaluaciones, en la base de las placas se marcó dos líneas perpendiculares entre sí, en cada extremo de las líneas se escribió letras a-b y c-d y se realizaron mediciones diarias del diámetro (cm) del crecimiento micelial de los hongos. Las evaluaciones culminaron cuando el testigo cubrió toda la superficie del medio (Padder et al, 2012). La eficacia de los fungicidas se determinó por cálculo del porcentaje de inhibición en el crecimiento micelial de la colonia usando la siguiente fórmula: Inhibición (%) = (C-T/C)*100 (donde T: crecimiento micelial (cm) del diámetro en cada tratamiento; y C: crecimiento micelial del diámetro en el testigo).…”