Evaluation of durum wheat (Triticum durum Desf.) lines response to terminal drought stress

Wheat, bread and durum, is most important crop of Iran and durum wheat has a historical cultivation background in country. Pasta and macaronis industries of country need 400000 ton of durum annually. To cover this tonnage, releasing and introducing new and high yielding durum cultivar to wheat growers is crucial. On other hand, drought stress, especially terminal drought stress, TDS, is one of the most important factors affecting cultivation of wheat in various environments (Kilic and Yagbasanlar, 2010) and usually happened during filling period in Mediterranean countries (Golabadi et al., 2006). Totally, drought resistance is an erratic and complex trait and its effects depend on growth stage of crop. Lack of drought tolerance cultivars plus drought periods during wheat growing season are main reasons of Iran wheat production fluctuation. Drought resistance indices widely used by scientist to screening and selection drought tolerate wheat genotypes (Bennani et. al., 2017). So to combating these hazard and mitigate effects of water shortage and drought stress on durum wheat production, identifying and releasing new terminal drought tolerate durum wheat cultivars, present study was conducted. The154 durum wheat lines originated from International Maize and Wheat Improvement Center (CIMMYT) plus Syrian4 (Saji) cultivar as durum check were investigated under normal irrigation and TDS conditions at Islamabad Agricultural Research Station over 2013-14 and 2014-15 cropping period. Each plot consisted of 2 rows, 2 m length with 0.3m inter row spaces. Cropping density was 450 seed per m2. Sowing was done by hand. Irrigation cut at boating stage (Z = 4.5) of crop. The grain yield, GY, (Kg/ha) of two years was used to calculating 21 drought tolerance indices namely MP, TOL, SSI, STI, GMP, YI, DI, ATI, SSPI, SNPI, MRP, REI, MSTIk1, MSTIk2, HARM, Red, RDI, GM, DTE. The SPSS software was used for cluster analysis and drawing of bipolot. High variation was observed among the studied lines for GY and drought resistance indices. The cluster analysis by using UPGMA method and square of Euclidean distance, sorted evaluated lines in 6 groups. According to most drought resistance indices and the performance in both environments, the 12 genotypes namely g29, g38, g41, g46, g50, g93, g105, g116, g123, g157, g159 and g199 located at first group and showed remarkable advantages over other groups. The results of the analysis of the main components indicated that g116, g199, g41 and g123 lines were the best genotypes for TDS, which showed good performance under irrigated conditions also. On the other hand, the g50, g46 and g38 lines were the best ones for optimal conditions that showed TDS resistance also. The g29 and g157 lines were among superior lines with less resistance to TDS suitable for optimal conditions, whereas g105, g93 and g159 lines were relatively resistance to TDS with low yield under normal irrigation. Totally four genotypes, g41 (STORLOM/3/RASCON_37/TARRO_2//RASCON_37/4/ D00003A…), g116 (SIMETO/4/DUKEM_1//PATKA_7/YAZI_1/3/PATKA_7/YAZI_1…) g123 (ADAMAR _15/PLATA_18/3/SORA/2*PLATA_12//SOMAT_3/6/LIRO…) and g199 (PLATA_10/6/MQUE/4/ USDA573//QFN/AA_7/3/ALBA-D…), with emphasis on g116 lines, showed potential to mention as candidates to releasing as new cultivars, recommending and presenting to wheat growers of TDS conditions of area of study and similar condition.