Pollen Genotype Effects on Seed Quality and Selection of Single Seeds by Near-Infrared Reflectance Spectroscopy (NIRS) in Winter Oilseed Rape

Abstract

Oilseed rape is one of the most important oilseed crops of the world. Because of the success in quality breeding, the growing area of oilseed rape is gradually increasing. Although the seed quality is a very important breeding objective, the inheritance of the seed quality is not yet completely understood. It is often assumed, that most seed quality traits like oil, protein and glucosinolate (GSL) content are only determined by the maternal plant on which the seeds is grown and not influenced by the genotype of the pollinator. Therefore, the main objective of this study is to determine the effects of the pollen genotype on the important seed quality traits oil, protein, glucosinolate, tocopherol and sinapic acid content.Two separate experiments were conducted to meet this objective. In the first experiment ten pollen parents and two male sterile females (Falcon and Express) were used. For each pollen parent blocks with seven plots were grown containing three plots of the parent between two plots of each F1. Ten single plants of the two male sterile parents were transplanted into the center of the pollinator plots by hand before winter. The experiment was performed with two replications in a randomized complete block design at three locations (Goettingen, Einbeck, and Teendorf) in the season 2002/2003. The seed quality traits oil, protein and sinapic acid ester content were analysed by near-infrared reflectance spectroscopy (NIRS), glucosinolate and tocopherol contents were analysed by high performance liquid spectroscopy (HPLC), and the fatty acids were analysed by gas liquid chromatography (GLC).In the second experiment single F2 seeds from four crosses were analysed by NIRS for protein and glucosinolate content. In each cross four bulks were selected: high and low in protein and in glucosinolate, respectively. In the season 2002/2003 the four bulks from each cross were grown in a randomized complete block design with two replications in three locations (Goettingen, Einbeck, Teendorf). Six parental lines were also included in the experiment. The seed quality traits oil, protein and glucosinolate content were analysed by near-infrared reflectance spectroscopy (NIRS).In the first experiment, the results have revealed that highly significant correlations between pollen parents and F1s were observed for indole GSL, sinapoylglucose and total sinapic acid ester. In the analysis of variance, significant effects for pollen genotype were observed for oil, indole GSL, indole/aliphatic GSL, fatty acids, sinapoylglucose, γ-tocopherol and α/γ-tocopherol. In the second experiment the response to selection of F2 single seeds from individual plants was investigated. First reliable NIRS calibration equations for the single seeds were developed with a wide-range of oil, protein, and glucosinolate content. High correlations of R2 = 0.98, R2 = 0.99 and R2 = 0.97 were found between the reference methods and the NIRS predictions for the contents of oil, protein and glucosinolate, respectively. When comparing the seed quality between selfed and open pollinated plants of the parents, higher oil content (+2.2%), lower protein content (-2%) and lower glucosinolate content (-3.9 µmol/g) was observed in the open pollinated plants. The selection of single seeds resulted in significant responses to selection for oil, protein and glucosinolate content.Based on these results, it can be concluded that not only the fatty acid contents were influenced by the pollen genotype, but also contents of oil, sinigrin, gluconapoleiferin, 4-hydroxyglucobrassicin, indole glucosinolate, indole/aliphatic glucosinolate, sinapoylglucose, total sinapic acid esters, γ-tocopherol and α/γ-tocopherol. In some cases pollen influences were also observed for aliphatic glucosinolate, total glucosinolate, protein and sinapine contents.Therefore the pollen genotype has to be considered as disturbing factor when harvesting open pollinated plants and selection of single seeds in the segregating F2 generation is possible.