Winter and spring rapeseed (Brassica napus) is genetic base expansion and prediction of vernalization quality

ABSTRACT WINTER AND SPRING RAPESEED (Brassica napus) IS GENETIC BASE EXPANSION AND PREDICTION OF VERNALIZATION QUALITY Emrullah GÜLDEMİR Master Thesis, Department of Agricultural Biotechnology Supervisor: Prof. Dr. Nedim MUTLU April 2019; 48 pages Rapeseed can be winter-type or spring-type, with and without vernalization requirement. Hybrid cultivar breeding has narrowed the genetic variation within both groups. The aim of the study was to broaden the genetic base of both winter and spring rapeseed lines and determine the heritability of vernalization requirement. For this purpose, the lines / varieties need to be improved higher yield and quality (oil quality, disease resistance and stress tolerance etc.). The most effective way to achieve this is to expand the genetic base. In order to achieve these objectives, five winter F1 commercial and one winter standard varieties and six spring F1 commercial and four spring standard varieties were reciprocally crossed. The plants of segregating populations were planted in greenhouse in September / October in the following year and flowering dates were recorded. The winter / spring ratios in the populations were used to calculate the inheritance of the genes that control the vernalization requirement. As a result of these crosses, a large genetic variation was created within both groups. The plants of parents F1, F2, and BC1 were grown and flowering dates were noted individually. Winter:Spring-type ratio showed that vernalization is controlled by a single dominant gene. Of the 15000 plants grown over the course of 3,5 years, 5008 plants belonged to Maintainer group, 4796 plants to CMS and 2265 plants to Restorer while the rest were the selfing generations of these lines and the control groups. The advanced line that will be developed from these populations are expected to yield higher heterosis, hence higher yielding hybrids.