Thumbnail Image

Thesis

Browse

2014 - 201912020 - 20211
Reset filters
Subject: Plant Pathology × Author: Ashish ×
Reset filters

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    ThesisItemRestricted
    Molecular mapping of resistance gene(s) for cereal cyst nematode in bread wheat (Triticum aestivum L.)
    (Punjab Agricultural University, Ludhiana, 2021) Ashish; Koulagi, Ramanna
    Wheat is one of the most important human food grains and it’s a staple food of the maximum population of the world. Heterodera avenae causing Molya disease in northern and northwestern plain zones is responsible for an annual loss of 8967.52 million rupees per year in India. To overcome this resistant breeding is the most economical and eco-friendly approach. The introgression lines were derived in background of PBW343 by crossing AUS15895. Phenotypic data was recorded for two consecutive cropping seasons (2019-20 and 2020-21). The phenotypic results revealed from both cropping seasons (2019-20 and 2020-21) that among 116 introgression lines 68 were found resistant and 10 were moderately resistant, 14 were moderately susceptible and 24 were susceptible. Upon calculation of chi square test, the BC1F6 population followed resistant 1:1 susceptible segregation ratio. Six SSR (Xwmc382, Cre5, Cre8, Cre1, CreX and Cre3) markers were employed in this study to survey the polymorphism in parents. Among the six, four markers (Xwmc382, Cre5, Cre8 and Cre1) showed the polymorphism on parents as well as on introgression lines. The marker Xwmc382 is tightly linked to resistance with highest correlation coefficient (0.1). Markers efficacy was calculated to know the efficacy rate of the markers, these results followed the same trend of marker correlation coefficient Xwmc382 is more efficient to determine the resistance against Ludhiana population of cereal cyst nematode, Heterodera avenae with 66% efficacy.
  • Thumbnail Image
    ThesisItemOpen Access
    Epidemiology and management of bacterial blight of pomegranate
    (Punjab Agricultural University, 2014) Ashish; Arora, anita
    Bacterial blight of pomegranate caused by Xanthomonas axonopodis pv. punicae has been observed as a serious impediment in the cultivation of pomegranate in Punjab. The disease initiated in June. Symptoms appeared as small, circular to irregular, water-soaked spots on leaves, flowers and fruits. On fruits, the spots developed into typical cankers with cracks on the necrotic areas. The bacterium produced pale yellow, circular, convex, slightly raised, opaque and mucoid colonies on nutrient agar medium. The bacterial cells were straight rods, Gram-negative and motile. The pathogen successfully established on all the inoculated plant part viz. leaves, flowers, twigs and fruits. Per cent disease index and infection rate were high, when inoculations were carried out in the month of July than in the months of June and August. Weather parameters like mean maximum and minimum atmospheric temperature, relative humidity and rainfall influenced disease progression significantly. None of the strains screened against this disease was found resistant. The strains expressed moderate to highly susceptible reactions. Four sprays of blitox + streptocycline on the pruned plants starting from mid June to end July at 15 days interval proved effective against bacterial blight of pomegranate. Kocide + Streptocycline was the next best treatment in reducing the per cent disease index.