This brief historical review focuses on durum wheat domestication and breeding in the Mediterranean region. Important milestones in durum wheat breeding programs across the countries of the Mediterranean basin before and after the Green Revolution are discussed. Additionally, the main achievements of the classical breeding methodology are presented using a comparison of old and new cultivars. Furthermore, current breeding goals and challenges are analyzed. An overview of classical breeding methods in combination with current molecular techniques and tools for cultivar development is presented. Important issues of seed quality are outlined, focusing on protein and characteristics that affect human health and are connected with the consumption of wheat end-products.
Tomato is one of the most consumed fruit vegetables globally and is a high dietary source of minerals, fiber, carotenoids, and vitamin C. The tomato is also well known for its nutraceutical chemical content which strengthens human immune systems and is protective against infectious and degenerative diseases. For this reason, there has been recent emphasis on breeding new tomato cultivars with nutraceutical value. Most of the modern tomato cultivars are F1 hybrids, and many of the characteristics associated with fruit quality have additive gene action; so, in theory, inbred vigor could reach hybrid vigor. A sum of 20 recombinant lines was released from the commercial single-cross hybrids Iron, Sahara, Formula, and Elpida, through a breeding process. Those recombinant lines were evaluated during spring–summer 2015 under organic farming conditions in a randomized complete block design (RCBD) experimental design with three replications. A sum of eleven qualitative characteristics of the fruit was recorded on an individual plant basis. Results from this study indicated that the simultaneous selection of individual tomato plants, both in terms of their high yield and desired fruit quality characteristics, can lead to highly productive recombinant lines with integrated quality characteristics. So, inbred vigor can reach and even surpass hybrid vigor. The response to selection for all characteristics evaluated shows additive gene action of all characteristics measured. These recombinant lines can fulfill this role as alternatives to hybrid cultivars and those that possess high nutritional values to function as functional-protective food.
Bread wheat landraces were an important source of biodiversity used in agriculture before the widespread adoption of high-yielding commercial cultivars adapted to high inputs. Could future agriculture exploit these landraces in different cropping systems in organic or lower-input environments? A two-year field trial was conducted to evaluate grain yield, agronomic performance, and grain quality of bread wheat landraces under different cropping systems, including low-input/organic/conventional environments. Significant variability was found for almost all characteristics among landraces, which makes landraces valuable sources of genetic variation for breeding programs aimed at achieving high and consistent production as well as high-quality products in low-input/organic environments. Additionally, landraces play a crucial role in expanding the genetic diversity of cultivated bread wheat and mitigating biodiversity erosion, thereby enabling crops to better withstand the challenges of low-input/organic agriculture. The landrace “Xilokastro Lamias” had the highest yield among the landraces evaluated in the first growing season (2.65 t·ha−1) and one of the highest yields (2.52 t·ha−1) of all genotypes in the second growing season, which shows promising potential as a starting material in breeding programs targeting high and stable yields. GGE biplot analysis identified the landrace ”Xilokastro Lamias”, along with commercial cultivars “Yecora E” and “Panifor”, as suitable candidates for direct use in low-input/organic wheat farming systems to achieve enhanced productivity. In the conventional environment (C2-IPGRB), commercial cultivars showed the highest values (3.09 to 3.41 ton·ha−1). Of the landraces, only the X4 showed a high GY (3.10 ton·ha−1) while the other landraces had ~33–85% lower yield. In the organic environment (O2-IPGRB), the highest productivity was found in the commercial cultivar X5 and the landrace X4. Commercial cultivars X8 and X7 showed ~68% reduction in GY in the organic environment compared to the conventional, while this reduction was half for the landraces. Finally, the reduction in grain yield between conventional and organic environments was observed to be 45% for commercial cultivars, while it was only half for landraces. This finding confirms the adaptability of landraces to organic agriculture.
Randomized complete block design was used, with three replications. Heterosis for yield and fruit quality characteristics was studied, and expressed as Relative heterosis, heterobeltiosis and Standard heterosis. It would be expected, according to the dominance model, that the heterosis recorded after crossing the recombinant lines, having only a small portion of recessive deleterious alleles, would be minimal. The results showed that the elite recombinant inbred lines became the parents of elite restructured hybrids, with increased levels of re-heterosis for all characters measured. This may prove that dominance is not the only case in explaining heterosis in tomato for yield components and fruit quality characteristics. Several recombinant lines, and most of the new reconstructed F1 hybrids, showed excellent productivity under a low input farming system. The evaluation and selection of the different types of cultivars (recombinant pure lines or reconstructed hybrids) under low input conditions could point towards the most suitable/ideal genotype for organic cultivation.
It is estimated that more than 95% of organic agriculture is based on crop cultivars that were bred for the conventional high-input sector. Most selections were made through conventional breeding programs and lack important traits required under organic and low-input conditions. Hybrids are the most common type of cultivars used in tomato because of heterosis. In tomato, continuous selfing enabled homozygosity to exploit favorable additive genes, resulting in the so-called inbred vigor. This paper presented the possibility to express inbred vigor at a level equal to or greater than hybrid vigor in tomato when cultivated under organic low input conditions. The evaluation of the recombinant lines produced through classical reverse breeding from four F1 single cross hybrids was done at low- and high-input farming systems. The results show that, following the appropriate breeding process in early generation selection and under low-input conditions, it is possible to produce recombinant lines, demonstrating inbred vigor in yield potential and fruit quality. These genetic materials can stand as new dynamic cultivars intended for cultivation in organic, low-input, or high-input conditions, depending on their performance in different farming systems at the later stages of evaluation.
1 June 2016 in Acta Biologica Cracoviensia s. Botanica
The present study was conducted to determine the effect of the D genome on embryoid induction and green plant regeneration in wheat anther culture and how it is influenced by low temperature and mannitol treatment. For this reason, the anther culture response of two Canadian bread wheat cultivars and their extracted tetraploids (AABB) was studied. As controls two cultivars well responding to anther-culture (i.e. cvs. Kavkaz/Cgn and Acheron) and a no-responding cultivar (cv. Vergina) were used. Approximately 3000 anthers of these cultivars were cultured and three pre-treatments were applied: cold pre-treatment for 7 and 18 days at 4°C, and 0.3M mannitol for seven days at 4°C. W14 and 190-2 were used as induction and regeneration media, respectively, and the basic MS medium as the rooting medium. No green plants were produced from the tetraploids, which supports the view that the D-genome chromosomes are necessary for androgenic response in wheat. Furthermore, the Canadian cultivars performed better after 18-day pre-treatment at 4°C. The extracted tetraploids produced fewer embryoids and performed better after seven days of cold pre-treatment. The controls well responding to anther culture performed better than the Canadian cultivars, although their best response was recorded after seven-day cold pre-treatment. Cultivar Vergina produced no green plants. The presence of mannitol influenced negatively both embryoid and green plant production. It was concluded that the D genome plays a crucial role in anther culture response of wheat and that this response is influenced by both the genotype and the duration of cold pre-treatment.