In Situ as Opposed to Ex Situ Maintenance of PGR
The ex situ maintenance in genebanks lost its predominance (Brush 2000). For wild wheats, the in situ approach has definite advantages. But also for landraces, on-farm maintenance is increasingly being proposed, particularly in their areas of high diversity (Vavilovian gene centres). Since such areas sometimes are suffering from political instability, a loss of genetic resources of wheat is possible. A complementary consideration of the different levels of diversity (infraspecific, species, and ecosystem diversity) is necessary. Wild wheats can be most effectively maintained and protected in the wild, whereas landraces do well on farm, but only if farmers are interested and have the possibilities to take care of them. Here, the methods are still developing but did not lead to the expected progress.
Another shift took place from emphasis on collecting and rescuing landraces and crop wild relatives (CWR), to emphasis on their preservation, evaluation and utilization. Some genebanks still continue collecting, because of the threats of genetic erosion and the expected loss of valuable material for future breeding and utilization. Genetic erosion was an important argument for the Plant Genetic Resources Movement.
Inclusion of Neglected and Underutilized Cultivated Plants
Their importance has been highlighted by Padulosi et al. (2012). Apart from Triticum aestivum L., T. compactum Host, T. durum Desf., and T. turgidum L., all other domesticated wheat species can be considered rare, perhaps with the exception of T. turanicum Jakubz. (“Kamut”) and T. polonicum L. with a slightly increasing area of cultivation because of their larger grains for improved and new bakery products. Some wheat species are probably extinct in their traditional cultivation areas, such as T. ispahanicum Heslot first described by Heslot (1958), also reported by Kihara's expedition (Kihara et al. 1965) and Kuckuck's FAO missions in 1952–54 (Kuckuck and Schiemann 1957), but later not found again in Iran despite intensive searches (Damania et al. 1993; Khoshbakht and Hammer 2010);
T. jakubzineri (Udachin et Shakhm.) Udachin et Shakhm., T. karamyschevii Nevski,
T. macha Dekapr. et Menabde, T. parvicoccum Kislev, T. timopheevii (Zhuk.) Zhuk., and T. zhukovskyi Menabde et Ericzjan. Most of them are, however, maintained in genebanks (Table 3.1). Landraces were recently found (re-discovered) for
T. sphaerococcum Percival in India (Mori et al. 2013), T. aethiopicum Jakubz. in Yemen, Oman, and Egypt, T. dicoccon Schrank, and T. monococcum L.
We want to provide two examples. In Italy from 1980 on, PGR have been collected every year in a collaborative programme between the genebanks of Gatersleben and Bari. In Basilicata province, P. Perrino and K. Hammer found relics
Table 3.1 Total number of accessions of some rare cultivated Triticum species in genebanks, and the number of genebanks preserving them
of emmer and einkorn cultivation (Perrino et al. 1981), which had been considered extinct in Italy. This encouraged other Italian researchers to successfully look for these species, as well as T. spelta L., in other parts of Italy (e.g. Laghetti et al. 2009). Discoveries of relic cultivation of hulled wheat species in other European countries and beyond led to a workshop on “Hulled Wheats” in Italy (Padulosi et al. 1996). Since that time, the scientific interest in traditional hulled wheats is unbroken. Their cultivation is gradually increasing.
In the 1930s, T. aethiopicum was described as a new species from Ethiopia and Yemen by Vavilov and co-workers. This wheat is recognized as a good species in Flora Ethiopica (Phillips 1995), contrary to other treatments proposing infraspecific recognition at the best. Triticum aethiopicum is not yet fully understood, being related with T. durum and T. turgidum. A large proportion of the wheats grown in Ethiopia still belong to this species (Teklu and Hammer 2006). It was also found in cultivation in Oman (Hammer et al. 2009) and in Egypt, concluding from herbarium sheets in the Vavilov Institute (St. Petersburg) that were re-classified as T. aethiopicum (Gowayed 2009). The variable landraces still present in Oman (often mixtures of T. aethiopicum, T. compactum, T. aestivum, T. durum, and T. turgidum) and in Ethiopia deserve our special consideration.
Crop wild relatives, i.e. T. urartu Thumanjan ex Gandilyan, T. boeoticum Boiss.,
T. dicoccoides (Körn. ex Asch. et Graebn.) Körn. ex Schweinf., and T. araraticum Jakubz., have gained importance. This is in agreement with increasing priority attributed to CWR (cf. Maxted et al. 2008). – Aegilops (Kilian et al. 2011), Secale, Hordeum and many other genera of the Hordeeae (formerly Triticeae) are increasingly being used for improving yield, adaptation and quality characters in wheat. The diagram (Fig. 3.1) by Bothmer et al. (1992) today needs revision and amplification. ×Triticosecale Wittm. (triticale) has already reached world importance (Hammer et al. 2011). ×Tritordeum Asch. et Graebn. (Martín et al. 1999) will follow soon. Other grass genera have been included in crossing experiments.