Morphology, Carbohydrate Composition and Vernalization Response in a Genetically Diverse Collection of Asian and European Turnips (Brassica rapa subsp. rapa)

Abstract

Brassica rapa displays enormous morphological diversity, with leafy vegetables, turnips and oil crops. Turnips (Brassica rapa subsp. rapa) represent one of the morphotypes, which form tubers and can be used to study the genetics underlying storage organ formation. In the present study we investigated several characteristics of an extensive turnip collection comprising 56 accessions from both Asia (mainly Japanese origin) and Europe. Population structure was calculated using data from 280 evenly distributed SNP markers over 56 turnip accessions. We studied the anatomy of turnip tubers and measured carbohydrate composition of the mature turnip tubers of a subset of the collection. The variation in 16 leaf traits, 12 tuber traits and flowering time was evaluated in five independent experiments for the entire collection. The effect of vernalization on flowering and tuber formation was also investigated. SNP marker profiling basically divided the turnip accessions into two subpopulations, with admixture, generally corresponding with geographical origin (Europe or Asia). The enlarged turnip tuber consists of both hypocotyl and root tissue, but the proportion of the two tissues differs between accessions. The ratio of sucrose to fructose and glucose differed among accessions, while generally starch content was low. The evaluated traits segregated in both subpopulations, with leaf shape, tuber colour and number of shoots per tuber explaining most variation between the two subpopulations. Vernalization resulted in reduced flowering time and smaller tubers for the Asian turnips whereas the European turnips were less affected by vernalization.

SNP diversity within and amongBrassica rapaaccessions reveals no geographic differentiation

“…Thereafter, genomes from two other morphotypes, turnip and oiltype, have been sequenced (Lin et al 2014). Nowadays, several studies have been published which describe the use of Infinium SNP array (Liu et al 2013;Raman et al 2014), or the development and use of novel SNP markersmainly for linkage mappingin Brassica A genome (Li et al 2009;Park et al 2010;Delourme et al 2013;Paritosh et al 2013;Devisetty et al 2014;Chung et al 2014;Zhang et al 2014;Song et al 2015). However, genetic diversity in oilseed B.rapa has not been studied with SNPs.…”

“…Genetic diversity in B.rapa has been studied with different marker types such as allozymes, isozymes, Restriction Fragment Length Polymorphisms (RFLPs), Amplified Fragment Length Polymorphisms (AFLPs), and SSRs (McGrath and Quiros 1992;Zhao et al 2005;Takuno et al 2007;Zhao et al 2009;Pino Del Carpio et al 2011;Annisa et al 2013;Guo et al 2014). SNP markers have only been used to study genetic variation in turnips (Zhang et al 2014) but not in other morphotypes.…”

Single-Molecule Real-Time Transcript Sequencing of Turnips Unveiling the Complexity of the Turnip Transcriptome

“…rapa) represent an important morphological type of B. rapa species, cultivated in Europe since 2,500-2,000 B.C. and spread to other parts of the world afterward ( Gray 1883 ; Zhang et al 2014 ; Qi et al 2017 ). Turnips are cultivated as fodder crop or vegetables, and its leaves and tubers are consumed depending on the region.…”

“…Turnips are cultivated as fodder crop or vegetables, and its leaves and tubers are consumed depending on the region. The shoots and leaves are consumed in southern European countries, while fleshy root in northern and eastern Europe and China ( Zhang et al 2014 ).…”

Morphological and genetic characterization of the leafy head of Chinese cabbage (Brassica rapa)

“…Tubers are also used as fodder crop (Reiner et al, 1995;Vogl-Lukasser et al, 2007). There are in fact two different groups of turnips, suggesting that they were domesticated twice: the Japanese turnips are annual, while European turnips are biannual (Gómez-Campo, 1999;Zhang et al, 2014). Chinese cabbages (ssp.…”