Estimation of seed yield in oilseed rape to identify the potential of semi-resynthesized parents for the development of new hybrid cultivars

RESEARCH ARTICLE Estimation of seed yield in oilseed rape to identify the potential of semi-resynthesized parents for the development of new hybrid cultivars Laurencja Szała ID1*, Zygmunt Kaczmarek2, Wiesława Popławska1, Alina Liersch1, Marek Wójtowicz1, Marcin Matuszczak1, Zdzisław R. Biliński3, Katarzyna Sosnowska1, Michał Stefanowicz4, Teresa Cegielska-Taras1 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 1 Plant Breeding and Acclimatization Institute—National Research Institute, Department of Genetics and Breeding of Oilseed Crops, Poznań, Poland, 2 Institute of Plant Genetics, Polish Academy of Sciences, Department of Biometry and Bioinformatics, Poznań, Poland, 3 Plant Breeding Company Smolice Ltd., Group IHAR, Division Bąków, Poland, 4 Plant Breeding Company Strzelce Ltd., Group IHAR, Division Małyszyn, Poland * OPEN ACCESS Citation: Szała L, Kaczmarek Z, Popławska W, Liersch A, Wójtowicz M, Matuszczak M, et al. (2019) Estimation of seed yield in oilseed rape to identify the potential of semi-resynthesized parents for the development of new hybrid cultivars. PLoS ONE 14(4): e0215661. https://doi.org/10.1371/ journal.pone.0215661 Editor: Maoteng Li, Huazhong University of Science and Technology, CHINA Received: October 12, 2018 Accepted: April 4, 2019 Published: April 18, 2019 Copyright: © 2019 Szała et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All data files are available from the protocols.io database (http://dx. doi.org/10.17504/protocols.io.x9wfr7e). Funding: Plant Breeding Company Smolice Ltd., Division Bąków, Poland provided funding in the form of salary for author ZB. Additionally, Plant Breeding Company Strzelce Ltd., Division Małyszyn, Poland provided funding in the form of salary for author MS. These funders provided support in the form of salaries for authors ZB and Abstract Resynthesized (RS) Brassica napus can be used to increase the genetic diversity of this important crop plant and to develop the heterotic gene pool required for successful hybrid breeding programmes. The level of heterosis in F1 hybrids depends on the individual performance of the parents and on the degree of genetic difference between them. However, RS forms obtained from crosses of B. rapa ssp. with B. oleracea ssp. possess many undesirable agronomic traits, such as low quality of seeds, low yield and seed oil content, high erucic acid level in the oil and high glucosinolate content in seed meal. Therefore, RS oilseed rape needs to be improved by crossing with natural double-low oilseed rape, leading to selected double-low quality semi-RS lines that can be used for breeding. In this study, we evaluated the seed yield potential of F1 hybrids derived from crosses between Ogura cytoplasmic male-sterility (CMS) lines and doubled haploid (DH) semi-RS lines with restorer gene in three locations in Poland. The genotype by environment interaction (GE interaction) and general combining ability (GCA) of the restorer and CMS line effects, as well as the effects of heterosis, were also assessed. The results of the study provide the first insights into the use of semi-RS lines as components for the development of new hybrid cultivars. Even the introduction of 50% of the RS oilseed rape genotype to natural restorer lines resulted in a marked heterosis effect, with seed yield ranging from 4.56% to 90.17% more than that of the better parent. The yield of the best hybrid amounted to 108.6% of the seed yield of the open-pollinated cultivar Monolit and 94.4% of that of the hybrid cultivar Arsenal. The best DH semi-RS line S1, which had a significantly positive GCA for seed yield, can be recommended as a possible parent for inclusion in breeding programmes aimed at developing new hybrid cultivars. PLOS ONE | https://doi.org/10.1371/journal.pone.0215661 April 18, 2019 1 / 14 The seed yield in oilseed rape to identify the potential of semi-resynthesized parents MS, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section. Competing interests: Plant Breeding Company Smolice Ltd., Division Bąków, Poland provided funding in the form of salary for author ZB. Additionally, Plant Breeding Company Strzelce Ltd., Division Małyszyn, Poland provided funding in the form of salary for author MS. These funders provided support in the form of salaries for authors ZB and MS, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section. This does not alter the authors’ adherence to PLOS ONE policies on sharing data and materials. Introduction Oilseed rape (Brassica napus L.) is considered a relatively young species. Although its origin is not yet fully explained, it is thought that B. napus was formed as a result of multiple spontaneous and independent hybridizations of B. rapa and B. oleracea on the coast of northern Europe, where both diploid parental species grow wild. Other researchers believe that oilseed rape originated in the Mediterranean region or in western or northern Europe [1]. It is also possible that B. napus could have formed elsewhere from crosses between different forms of B. oleracea and B. rapa [2]. Based on the sequencing of its polyploid genome, Chalhoub et al. have suggested that the hybridization that gave rise to B. napus occurred about 7500 years ago [3]. Oilseed rape began to be used in Europe as a cultivated plant 500 years ago, but it was not until the nineteenth century that it was grown widely. However, since the 1960s, strong selection pressure has been applied to breed zero erucic acid and low glucosinolate content in seeds (double-low quality), which, together with globalization in recent years, has led to a narrowing of the gene pool in this species. This relatively limited genetic diversity of modern oilseed rape breeding materials restricts the potential for further improvement in yield [4]. In contrast, B. rapa and B. oleracea are both highly polymorphic and offer a much broader genetic variability, and this can be exploited for oilseed rape improvement via experimental hybridization–resynthesis–from diploid progenitors. Resythesized (RS) B. napus can be used to increase genetic diversity and to develop a heterotic gene pool, which is one requirement for successful hybrid breeding programmes [5]. The number and diversity of available Brassica gene bank accessions is enormous. Boukema and van Hintum report that there are 20,106 accessions of B. oleracea and 18,224 accessions of B. rapa (...truncated)