Mehmet Emin Caliskan

Genotype × environment interaction and stability analysis of sweetpotato (Ipomoea batatas) genotypes

Abstract Nine introductions of sweetpotato (Ipomoea batatas) of diverse origin and two local genotypes were evaluated for storage root yield and average storage root weight in four locations of Turkey (Diyarbakir and Sanliurfa representing semi‐arid environment and Adana and Hatay representing Mediterranean environment) in 2000 and 2001. The genotype × environment (GE) interaction was evaluated for two yield components (mean storage root weight and storage root yield) using the joint regression analysis and the Additive Main Effects and Multiplicative Interaction (AMMI) analysis. Stability of the genotypes over environments was estimated by using different stability parameters. GE interaction was found to be significant for both yield components, and genotype main effect contributed more than environment and GE interaction to total variability. Total storage root yield varied from 6.72 to 112.60 t ha−1, depending on genotypes and environments. The introduced genotypes produced a higher yield than local genotypes. Our study revealed that sweetpotato has a great adaptability and yield potential in irrigated Mediterranean‐type and semi‐arid environments, whereas non‐traditional production areas such as Adana, Diyarbakir, and Sanliurfa may be more suitable for sweetpotato production than Hatay, the traditional production area, because of the potential for higher yield. The AMMI model appeared to be a better option for evaluating both GE interaction and the stability of sweetpotato genotypes in multilocational trials. The stability parameters tested in this study could not identify high yielding and stable genotypes.

Growth and development of Virginia type groundnut cultivars under Mediterranean conditions

Abstract The growth and development of groundnut (Arachis hypogaea L.) are under the influence of complex environmental factors. Understanding of the growth responses of the groundnut to environmental factors may improve the application of better management practices and develop better cultivars to overcome the problems causing reductions in yield. A two-year field experiment was conducted to determine the growth and development response of groundnut genotypes to environmental factors in the eastern Mediterranean region of Turkey in 2001 and 2002. Time from sowing to physiological maturity (R8) ranged from 2513°Cd to 2588°Cd in 2001 and from 2514°Cd to 2573°Cd in 2002 while total calendar days varied between 147 and 153 and between 156 and 161 depending on genotypes in 2001 and 2002, respectively. Dry matter accumulation in each part of the plants continued until maturity although accumulation rate differed depending on plant age. Combination of suitable temperature and photoperiod during the reproductive stages resulted in continuous and abundant reproductive plant parts, which led to delayed harvest and increased unmarketable pods. The slower growth rate due to the cooler conditions during early stages caused slower biomass accumulation in successive stages indicating the importance of initial crop growth for final yield. Therefore, the genotypes having high initial growth rate, less reproductive organs, and shorter growing period should be developed for the Mediterranean conditions by breeders. The management studies should also deal with increased initial growth rate and reduced number of flowers, pegs or pods per plant. Based on our results, groundnut has a great yield potential under the Mediterranean conditions. However, further breeding and management studies are needed to improve the yield and profitability and reduce the complications arisen from the Mediterranean climate.

Preface to Special Issue

Potato (Solanum tuberosum L.) is grown from sea level up to 4,000-m altitudes and between the latitudes of 70 °N and 50 °S. In terms of total fresh matter production, potato ranks fourth after maize, rice, and wheat. The crop is very versatile, as it can be used fresh or processed into a variety of products, such as French fries, crisps, mashed potatoes, flour, alcohol, starch, and its derivatives. Potato tubers and leaves are also used as animal feed. Tubers are rich in carbohydrates, proteins, vitamins, and minerals. Its high yield potential and high nutritional quality have made potato one of the most important plant food sources in the world: Jacques Diouf, Director-General of the Food and Agriculture Organization of the United Nations (FAO) stated that “The potato is on the frontline in the fight against world hunger and poverty”. To make maximum use of the potential of potato production and potato utilization, research, development, and innovation (R&D&I) play a crucial role. The European Association for Potato Research (EAPR) is an organization aiming to create platforms for scientific exchange: the EAPR offers an excellent forum for discussion and distribution of the results of studies conducted on potato all over the world by organizing conferences and section meetings. This special issue contains the proceedings of the International Symposium on Agronomy and Physiology held as the first meeting of the merged EAPR sections Agronomy and Physiology. The meeting was organized by staff of the Mustafa Kemal University and the General Directorate of Agricultural Research and held in Nevsehīr, Turkey, from 20 to 24 September, 2010. A total of 70 researchers from 18 countries in Asia, Australia, Europe, Africa, and North America participated in the Potato Research (2010) 53:253–254 DOI 10.1007/s11540-010-9171-0