Molecular genetic characteristics of broccoli (Brassica oleracea L. var. italica Plenck) from the VIR collection

Abstract

Background. Broccoli is an early-ripening vegetable crop that contains many biologically active compounds and mineral elements. According to the Genesys database, the global genebank collections contain no more than 465 different broccoli accessions. Fourteen cultivars and hybrids developed in Russia are registered in the State Register of the Russian Federation. The need to improve the assortment in a number of important breeding target areas (small habitus, non-spawning, bud size, disease resistance, etc.) requires the use of new effective techniques, including marker-assisted selection methods and association mapping. In this regard, it seems relevant to evaluate the VIR collection of broccoli using molecular genetic markers, which will provide new source material for breeding.Materials and methods. A molecular genetic study involved 39 broccoli cultivars and hybrid populations of different geographical origin, with various biological characteristics, and for various uses. For the analysis, 35 markers of microsatellite sequences specific to the Brassica L. genome were selected. PCR products were separated by electrophoresis on a 3% agarose gel.Results and conclusions. As a result, 110 polymorphic fragments were identified. In the studied loci, 3 to 7 alleles were pinpointed. The discriminating power of markers ranged from 0.75 to 0.96, and averaged 0.91; the average number of fragments per marker was 4.4. Ten unique alleles and 12 rare alleles (found in less than 8% of the samples) were observed in the studied accessions. On the other hand, the 201 bp allele of the locus BC65 was found in 95% of accessions, that is, it was almost common. All used markers have a sufficiently high diagnostic value and can be recommended for DNA identification in broccoli cultivars. An analysis of the genetic similarity of the collection accessions, carried out in the DarWin program using the Unweighted Neighbor-Joining method, made it possible to establish four closely related clusters.

Opening the Treasure Chest: The Current Status of Research on Brassica oleracea and B. rapa Vegetables From ex situ Germplasm Collections

“…Sequence-specific amplification polymorphism has been shown to be useful for phylogenetic analysis of the B. rapa core collection of VIR, encompassing 96 accessions ( Budahn et al, 2013 ). Others have used single-sequence repeat markers to investigate genebank germplasms, such as 25 accessions of different B. oleracea subspecies ( El-Esawi et al, 2016 ) and 239 accessions of B. rapa divided into the main morphotypes ( Zhao et al, 2010 ), as well as several core collections from the VIR B. oleracea and B. rapa accessions: 18 Russian local white cabbage accessions by SSRs were divided into Northern and Central Russian, Dutch and Central European, Southern European cultivars, when the level of single-sequence repeat DNA polymorphism within the Russian gene pool was higher than within the European gene pool ( Artemyeva et al, 2006 ), 96 accessions of B. rapa ( Artemyeva et al, 2008 ), 50 accessions from different B. oleracea varieties – cabbages, cauliflower, kales ( Artemyeva et al, 2009 ) and 40 broccoli accessions were divided into four clusters according to vegetation period length, curd size and sprout development ( Fateev and Artemyeva, 2020 ).…”