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Title: Inter-relationship between powdery mildew resistance to other economic trails in pea (Pisum sativum L.)
Authors: R, Krishna Manohara
Guide/Chairperson: O P, Dutta
Keywords: Inter-relationship
powdery mildew
Issue Date: 1983
Year of Submission: 1983
Abstract: An investigation was carried out to study the influence of the disease powdery mildew on growth and yield characters in pea (Pisum sativum L.). Eight parents with different reactions to the disease as resistant, tolerant and susceptible and six segregating populations (F2) resulting from the crosses between different categories of the above parents were used. To have a better picture of the effect of the disease to different degrees of infestation the study was conducted under two sets of conditions. The first set of the crop (3 replications) was sprayed with fungicides to control the disease and the second set crop (3 replications) was not sprayed to enable disease infestation. The influence of disease on growth in terms of plant height was observed only during the later stage i.e., after infestation occurred which was further substantiated by negative correlation. The resistant and tolerant lines maintained superiority over susceptible varieties with regard to green pod yield. The general reduction in green pod yield of unsprayed plants as a result of disease infection was to the tune of 57% in the most susceptible variety. The difference in yield between resistance and susceptible was 34% during the fourth picking which was the peak period of production. The effect of the disease on green seed yield was similar to that observed in case of green pod yield, which was also shown by a negative correlation. There was increase in both pod size as well as seed number per pod up to the middle of harvesting period and then a gradual decrease which was also observed by negative correlation. Under both conditions resistant varieties were stable and under unprotected conditions the tolerant varieties suffered to some extent because of the disease with regard to number of pods per plant. In one particular F2 significant and positive correlation was observed which could be due to a higher frequency of tolerant segregants. The seed number per plant was found to be always superior in case of resistant and tolerant varieties compared to susceptible ones. The growth of stems as measured by thickness (diameter) was found to be unrelated to disease incidence, but the variance seen in this character could be attributed to genetic or varietal characters.
URI: http://www.erepo.iihr.ernet.in/handle/123456789/359
University in which they received their degree: University of Agricultural Sciences, Bangalore
Degree Level: M.Sc

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