Rice Breeding and Varietal Improvements in Turkey from 1990 to 2020

Currently, approximately 900,000 tons of rice is produced annually in Turkey from a rice cultivation area of around 120,000 ha, which is equivalent to 28% of the rice growing area in the European Union. Since 1990, 63 rice varieties have been bred in Turkey and national rice production has increased 3.5-fold. Therefore, we reviewed the shifts in agronomic traits and the genetic resources used in rice varietal improvements in Turkey from 1990 to the present. We also compared the agronomic traits of Turkish-bred and Italian rice varieties. The shifts in agronomic traits in this period showed that the number of days to flowering decreased by about one day from S1 (1990-2003) and S2 (2004-2015) to S3 (2016-present). Additionally, culm length decreased by 6 cm from S1 to S2 and S3, and 1000 grain weight decreased continuously from S1 to S3 to the current average value of 24.1 g. In contrast, the head rice ratio increased continuously from 59.8% in S1 to 64.9% in S3. The rice sector in Turkey must overcome new challenges of market competition with Italian rice varieties; we found that three Italian rice varieties (Cameo, Ronaldo, and Luna CL) shared 25% of the 2016 rice market in Turkey. In addition, Turkish rice had longer maturation periods, shorter caryopsis, and lower head rice recovery relative to Italian varieties. Pedigree analysis of Turkish varieties also revealed that 62% had at least one Italian variety as a hybridization parent. We suggest that extensive use of Italian varieties in Turkish rice breeding programs may result in reduced genetic diversity; hence, low genetic diversity could be a critical constraint in future rice breeding in Turkey.