RESUMO
BACKGROUND: Plant breeding requires numerous generations to be cycled and evaluated before an improved cultivar is released. This lengthy process is required to introduce and test multiple traits of interest. However, a technology for rapid generation advance named 'speed breeding' was successfully deployed in bread wheat (Triticum aestivum L.) to achieve six generations per year while imposing phenotypic selection for foliar disease resistance and grain dormancy. Here, for the first time the deployment of this methodology is presented in durum wheat (Triticum durum Desf.) by integrating selection for key traits, including above and below ground traits on the same set of plants. This involved phenotyping for seminal root angle (RA), seminal root number (RN), tolerance to crown rot (CR), resistance to leaf rust (LR) and plant height (PH). In durum wheat, these traits are desirable in environments where yield is limited by in-season rainfall with the occurrence of CR and epidemics of LR. To evaluate this multi-trait screening approach, we applied selection to a large segregating F2 population (n = 1000) derived from a bi-parental cross (Outrob4/Caparoi). A weighted selection index (SI) was developed and applied. The gain for each trait was determined by evaluating F3 progeny derived from 100 'selected' and 100 'unselected' F2 individuals. RESULTS: Transgressive segregation was observed for all assayed traits in the Outrob4/Caparoi F2 population. Application of the SI successfully shifted the population mean for four traits, as determined by a significant mean difference between 'selected' and 'unselected' F3 families for CR tolerance, LR resistance, RA and RN. No significant shift for PH was observed. CONCLUSIONS: The novel multi-trait phenotyping method presents a useful tool for rapid selection of early filial generations or for the characterization of fixed lines out-of-season. Further, it offers efficient use of resources by assaying multiple traits on the same set of plants. Results suggest that when performed in parallel with speed breeding in early generations, selection will enrich recombinant inbred lines with desirable alleles and will reduce the length and number of years required to combine these traits in elite breeding populations and therefore cultivars.
RESUMO
Since the first studies in Algeria in 1999, 2002 and 2005, triticale has been used in arid and semi-arid areas mainly for livestock production. Efforts have been done for the utilization of triticale as hay, silage and hole grain to feed dairy cattle and small ruminants (sheep). Studies have shown that triticale could be easily integrated in the existing crop-livestock system of northern Algeria. In spite of the good results in the yield performance and adaptation to diverse environments, decision makers are not giving the necessary attention to triticale. Dairy cattle holders that tested the crop have adopted it quickly and developed it in an informal way. Now, more than 90% of the triticale seed business is in the hands of private farmers without any help or subsidies nor a good price policy to develop strongly this crop. The utilization of triticale in Algeria is roughly as follow: human consumption 5%, forage crop (hay or silage) 60% and 30% as feed grain, the remaining 5% are kept for sowing seed. In our studies we have compared different feed sources (barley, triticale, concentrate diet and mixtures) to dairy cattle and sheep. Triticale showed highly significantly better results for meat production and gave also an amazing response for dairy and sheep milk production in Algeria. Milk production of animals fed with triticale over exceeded the other feed sources by 26% to 53%; mean weight gain exhibited the same rates.
