Intraspecific diversity of durum wheat (Triticum durum Desf.): a unif ied classif ication

The Department of Wheat Genetic Resources of the All-Russian Research Institute of Plant Genetic Resources (VIR) had developed and published in 1979 a classification of the genus Triticum L., which is based on the genomic composition of species and the presence or absence of a number of main genes that govern the “classification” traits. The grounds have been laid by F. Körnicke and J. Percival, and supplemented by N.I. Vavilov and K.A. Flaksberger. The classification, which is most often referred to as the “Classification of Triticum by Dorofeev et al.”, belongs to a number of the main modern classifications of the genus. This is the world’s first standardized system that contains all known intraspecific (infraspecific) taxa of wild and cultivated wheat species. A detailed classification makes it possible to identify a wide variety of forms in the genus Triticum L. and its individual species, which is especially important for collections preserved in genetic seed banks. The use of the intraspecific classification of the genus Triticum L. greatly simplifies the identification of the VIR collection accessions introduced from various sources or checking accession identity after regeneration in the field. However, the direct use of such a voluminous classification meets several difficulties. Therefore, we propose a unified intraspecific classification of durum wheat, based on the description of only 16 main botanical varieties out of 131 described so far, which have complexes of morphological traits of the spike and kernel that occur most frequently in durum wheat collections. The remaining 115 botanical varieties, which have additional traits, get their name by the addition of the abbreviated Latin name of one or another additional trait to the main name. Having mastered this way of describing the morphological traits of accessions, any user can easily navigate oneself in the systematized intraspecific diversity of collections. The purpose of this work is to acquaint the reader with the intraspecific classification of durum wheat (Triticum durum Desf.) developed at VIR and to offer its simplified version, which is based on the identification of the main and additional morphological traits of the spike and kernel.

The role of Prunus cerasifera Ehrh. in the origin, evolution and improvement of stone fruit cultivars

At Krymsk Experiment Breeding Station of VIR, as a result of collecting, studying, and selective use of myrobalan plum genetic diversity, the intraspecific taxonomy of the species Prunus cerasifera Ehrh. was clarified. Donors of traits significant for breeding were identified and, with their use, adaptable cultivars of myrobalan plum, Russian plum and clonal rootstocks of stone fruit plants were developed.Intraspecific classification of P. cerasifera is proposed, with the identified subspecies:subsp. cerasifera (typical myrobalan plum);subsp. orientalis (M. Pop.) Erem. et Garcov. (Oriental myrobalan plum);and subsp. macrocarpa Erem. et Garcov. (large-fruited myrobalan plum).Within subsp. P. cerasifera subsp. macrocarpa, varieties were identified:var. macrocarpa (typical, or Krymsk);var. georgica Erem. et Garcov. (Georgian);var. iranica (Koval.) Erem. et Garcov. (Iranian);var. nairica (Koval.) Erem. et Garcov. (Armenian);var. pissardii Carr. (Pissard);and var. taurica (Kost.) Erem. et Garcov. (Taurida).The participation of myrobalan plum in the origin of spp. P. brigantiaca Vill., P. cocomilia Tem., and P. spinosa L. was traced. Involvement of large-fruited myrobalan plum in hybridization with blackthorn contributed to the manifestation of an exceptional polymorphism among the varieties of the hybridogenic species P. domestica L. (P. cerasifera × P. spinosa). As a result of hybridization between myrobalan plum and Chinese plum varieties, a new cultigen species emerged – Russian plum (× P. rossica Erem.). By now, 127 cultivars of this species and 7 clonal rootstocks for stone fruit crops have been developed. These cultivars and clonal rootstocks are zoned for Russia and a number of other countries.

Systematic implications of achene characteristics in genera Centaurea L., Cyanus Mill., Psephellus Cass. and Rhaponticoides Vaill. (Asteraceae)

This study examines the exomorphic achene characteristics of 23 taxa belonging to Centaurea, Cyanus, Psephellus and Rhaponticoides in Asteraceae using light microscope and scanning electron microscope (SEM). The exomorphic characteristics studied are shape, size, colour and surface pattern of achene, and hair, length and colour of pappus. The results of the present investigation showed that achene size of the studied taxa is 3–7 × 1–4 mm. Pappus length is 1–14 mm, deciduous for three taxa and inner row is differentiated from the outer, 1–3 mm long, for 10 taxa. SEM studies showed eight different types of achene surface patterns for the studied taxa: Glebulate, glebulate-ruminate, reticulate, ribbed, ruminate, smooth, smooth-glebulate and undulate. Achene characteristics are useful for both intrageneric and intraspecific classification of the studied taxa.Bangladesh J. Plant Taxon. 22(2): 125-136, 2015 (December)